WorldWideScience

Sample records for surrounding rice fields

  1. Conservation and Utilization of a Ramsar Site“ Kabukuri-numa and the Surrounding Rice Paddies"

    OpenAIRE

    淺野, 敏久; 光武, 昌作; 林, 健児郎; 榎本, 隆明

    2012-01-01

    “Kabukuri-numa and the surrounding rice paddies" is the first case bearing the name of “rice paddy" in the Ramsar site of Japan. The residents around this site are aiming at community development and the coexistence of agriculture and geese. The purpose of this paper is to summarize the results of interviews about the efforts here before and after the Great East Japan Earthquake. And then we consider the problems related to wise use of the Ramsar site including the surrounding rice paddies in...

  2. Preliminary design of surrounding heliostat fields

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Francisco J. [Zaragoza University, Dpto. de Ingenieria Mecanica, CPS-B, Maria de Luna 3, 50018 Zaragoza (Spain)

    2009-05-15

    Recently, the author has shown elsewhere a simplified model that allows quick evaluations of the annual overall energy collected by a surrounding heliostat field. This model is the combination of an analytical flux density function produced by a heliostat, developed by the own author, and an optimized mirror density distribution developed by University of Houston for the Solar One Project. As main conclusion of this previous work, it was recognized that such pseudo-continuous simplified model should not substitute much more accurate discrete evaluations, which manage thousands of individual heliostat coordinates. Here in this work, the difficulty of generating a preliminary discrete layout of a large number of heliostats is addressed. The main novelty is the direct definition of thousands of heliostat coordinates through basically two parameters i.e. a simplified blocking factor and an additional security distance. Such procedure, which was formerly theoretically suggested by the author, is put into practice here, showing examples and commenting their problems and advantages. Getting a previous set of thousands of heliostat coordinates would be a major first step in the complex process of designing solar power tower (SPT). (author)

  3. Methane emission from wetland rice fields.

    OpenAIRE

    H.A.C. Denier van der Gon

    1996-01-01

    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic methane emission. Methane fluxes from wetland rice fields in the Philippines were monitored with a closed chamber technique in close cooperation with the International Rice Research Institute (IRRI). The field studies were complemented by laboratory and greenhouse ex...

  4. A Markov Random Field Model for Image Segmentation of Rice Planthopper in Rice Fields

    OpenAIRE

    Hongwei Yue; Ken Cai; Hanhui Lin; Hong Man; Zhaofeng Zeng

    2016-01-01

    It is meaningful to develop the automation segmentation of rice planthopper pests based on imaging technology in precision agriculture. However, rice planthopper images affected by light and complicated backgrounds in open rice fields make the segmentation difficult. This study proposed a segmentation approach of rice planthopper images based on the Markov random field to conduct effective segmentation. First, fractional order differential was introduced into the extraction proces...

  5. Benthic macroinvertebrates in Italian rice fields

    Directory of Open Access Journals (Sweden)

    Daniela Lupi

    2013-02-01

    Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

  6. Methane emission from wetland rice fields

    NARCIS (Netherlands)

    Denier van der Gon, H.A.C.

    1996-01-01


    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic

  7. Methane emission from wetland rice fields.

    NARCIS (Netherlands)

    Denier van der Gon, H.A.C.

    1996-01-01

    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic methane emission. Methane fluxes fro

  8. Nitrogen Losses from Flooded Rice Field

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A field microplot experiment was conducted during the tillering stage of paddy rice to investigate nitrogen (N) losses from flooded rice fields following fertilizer application. After application of ammonium bicarbonate,most of nitrogen in the floodwater was present as NHq-N and its concentration varied widely with time.Concentrations of both NO3-N and NO2-N in the floodwater were low due to the weakened nitrification.Under flooded anaerobic reducing conditions, soil solution concentrations of NO3-N and NH4-N were not high, ranging from 0.6 mg L- 1 to 4.8 mg L-1, and decreased with soil depth. However, the groundwater was still contaminated with NO3-N and NH4-N. Rainfall simulation tests showed that the N losses via runoff in rice fields were closely related to the time intervals between fertilizer applications and rainfall events. When a large rain fell for a short period after fertilizer application, the N losses via runoff could be large, which could have a considerable effect on surface water quality. Both irrigation and N fertilizer application must be controlled and managed with great care to minimize N losses via runoff from agricultural land.

  9. A Markov Random Field Model for Image Segmentation of Rice Planthopper in Rice Fields

    Directory of Open Access Journals (Sweden)

    Hongwei Yue

    2016-04-01

    Full Text Available It is meaningful to develop the automation segmentation of rice planthopper pests based on imaging technology in precision agriculture. However, rice planthopper images affected by light and complicated backgrounds in open rice fields make the segmentation difficult. This study proposed a segmentation approach of rice planthopper images based on the Markov random field to conduct effective segmentation. First, fractional order differential was introduced into the extraction process of image texture features to gain complete texture information of rice planthopper images. Observation data modeling was established by a combination of image color features and texture features to overcome the disadvantages of insufficient image texture information. Finally, the improved potential function models, the neighborhood relationship between the pixel labels, and the attributes of pixels were defined. The segmentation results were assessed by quantitative evaluation. The experiments showed that the proposed improved approach in the study was more robust, especially with the changes in the illumination condition. This approach can effectively improve segmentation accuracy and promote vision segmentation results of rice planthopper images.

  10. Wave rectification in plasma sheaths surrounding electric field antennas

    Science.gov (United States)

    Boehm, M. H.; Carlson, C. W.; Mcfadden, J. P.; Clemmons, J. H.; Ergun, R. E.; Mozer, F. S.

    1994-01-01

    Combined measurements of Langmuir or broadband whistler wave intensity and lower-frequency electric field waveforms, all at 10-microsecond time resolution, were made on several recent sounding rockets in the auroral ionosphere. It is found that Langmuir and whistler waves are partically rectified in the plasma sheaths surrounding the payload and the spheres used as antennas. This sheath rectification occurs whenever the high frequency (HF) potential across the sheath becomes of the same order as the electron temperature or higher, for wave frequencies near or above the ion plasma frequency. This rectification can introduce false low-frequency waves into measurements of electric field spectra when strong high-frequency waves are present. Second harmonic signals are also generated, although at much lower levels. The effect occurs in many different plasma conditions, primarily producing false waves at frequencies that are low enough for the antenna coupling to the plasma to be resistive.

  11. Abandoned Rice Fields Make Streams Go Dry in Upland Landscapes

    Science.gov (United States)

    Jayawickreme, D.

    2015-12-01

    In South Asia, new economic realities are driving many rural rice farmers out of agriculture. With increasing neglect, abandonment, and rising conversions of centuries old rice fields into other uses, ecological and environmental consequences of these transitions are becoming progressively clear. Field observations in Sri Lanka's central highlands suggest that small shifts in rice to non-rice land uses in headwater watersheds can have a domino effect on the productivity and viability of rice fields and other ecological systems downstream by inflicting groundwater recharge reductions, lowering groundwater yields, and causing other hydrological changes. Preliminary analysis shows that although rice itself is a very water intensive crop, the presence of rain-fed upland rice-fields is hugely beneficial to the watersheds they reside. In particular, water benefits of rice appear to be derived from ponded conditions (3-5 inches of standing water) in which rice is grown, and the contribution rice fields makes to enhance water retention and storage capacity of their watersheds during the monsoon season that coincide with the cropping season. In the absence of well managed rice-fields, hilly upland landscapes produce more runoff and retain little rainwater during the wet season. Furthermore, after centuries of intensive use, much of South Asia's rice fields are nutrient poor and minimally productive without fertilizer applications and other interventions. Consequently, when abandoned, soil erosion and other impacts that affect aquatic ecosystems and watershed health also emerge. Despite these multiple concerns however, little research is currently done to better understand the environmental significance of rice cultivations that are a dominant land-use in many South Asian landscapes. The aim of this presentation is to stir interest among the scientific community to engage more broadly in rice, water, and environmental change research in the face of new economic realities in

  12. Estimate of CH4 Emissions from Year-Round Flooded Rice Fields During Rice Growing Season in China

    Institute of Scientific and Technical Information of China (English)

    CAI Zu-Cong; KANG Guo-Ding; H. TSURUTA; A. MOSIER

    2005-01-01

    A special kind of rice field exists in China that is flooded year-round. These rice fields have substantially large CH4emissions during the rice-growing season and emit CH4 continuously in the non-rice growing season. CH4 emission factors were used to estimate the CH4 emissions from year-round flooded rice fields during the rice-growing season in China.The CH4 emissions for the year-round flooded rice fields in China for the rice growing season over a total area of 2.66Mha were estimated to be 2.44 Tg CH4 year-1. The uncertainties of these estimations are discussed as well. However,the emissions during the non-rice growing season could not be estimated because of limited available data. Nevertheless,methane emissions from rice fields that were flooded year-round could be several times higher than those from the rice fields drained in the non-rice-growing season. Thus, the classification of "continuously flooded rice fields" in the IPCC(International Panel on Climate Change) Guidelines for National Greenhouse Gas Inventories is suggested to be revised and divided into "continuously flooded rice fields during the rice growing season" and "year-round flooded rice fields".

  13. Avian foods, foraging and habitat conservation in world rice fields

    Science.gov (United States)

    Stafford, J.D.; Kaminski, R.M.; Reinecke, K.J.

    2010-01-01

    Worldwide, rice (Oryza sativa) agriculture typically involves seasonal flooding and soil tillage, which provides a variety of microhabitats and potential food for birds. Water management in rice fields creates conditions ranging from saturated mud flats to shallow (seed mass from North America ranging from 66672 kg/ha. Although initially abundant after harvest, waste rice availability can be temporally limited. Few abundance estimates for other foods, such as vertebrate prey or forage vegetation, exist for rice fields. Outside North America, Europe and Japan, little is known about abundance and importance of any avian food in rice fields. Currently, flooding rice fields after harvest is the best known management practice to attract and benefit birds. Studies from North America indicate specific agricultural practices (e.g. burning stubble) may increase use and improve access to food resources. Evaluating and implementing management practices that are ecologically sustainable, increase food for birds and are agronomically beneficial should be global priorities to integrate rice production and avian conservation. Finally, land area devoted to rice agriculture appears to be stable in the USA, declining in China, and largely unquantified in many regions. Monitoring trends in riceland area may provide information to guide avian conservation planning in rice-agriculture ecosystems.

  14. A Water Demand Curve for Rice Paddy Field

    OpenAIRE

    佐藤, 豊信

    1989-01-01

    Demand for water use in rice paddy fields in Japan has traditionally been measured according to a unit known as "Gensuishin" However, it does not consider farmer decisions on how much water to use in rice production, while the quantity of water measured by "Gensuishin" takes into account biologocal and physical conditions. This paper reports that analysis of water demand in rice production ought to incorporate a farmer's subjective equilibrium and water demand quantity. The water demand cu...

  15. Effects of landscape features on waterbird use of rice fields

    Science.gov (United States)

    King, S.; Elphick, C.S.; Guadagnin, D.; Taft, O.; Amano, T.

    2010-01-01

    Literature is reviewed to determine the effects of landscape features on waterbird use of fields in regions where rice (Oryza sativa) is grown. Rice-growing landscapes often consist of diverse land uses and land cover, including rice fields, irrigation ditches, other agricultural fields, grasslands, forests and natural wetlands. Numerous studies indicate that local management practices, such as water depth and timing of flooding and drawdown, can strongly influence waterbird use of a given rice field. However, the effects of size and distribution of rice fields and associated habitats at a landscape scale have received less attention. Even fewer studies have focused on local and landscape effects simultaneously. Habitat connectivity, area of rice, distance to natural wetlands, and presence and distance to unsuitable habitat can be important parameters influencing bird use of rice fields. However, responses to a given landscape vary with landscape structure, scale of analysis, among taxa and within taxa among seasons. A lack of multi-scale studies, particularly those extending beyond simple presence and abundance of a given species, and a lack of direct tests comparing the relative importance of landscape features with in-field management activities limits understanding of the importance of landscape in these systems and hampers waterbird conservation and management.

  16. Investigation of possible horizontal gene transfer from transgenic rice to soil microorganisms in paddy rice field.

    Science.gov (United States)

    Kim, Sung Eun; Moon, Jae Sun; Kim, Jung Kyu; Choi, Won Sik; Lee, Sang Han; Kim, Sung Uk

    2010-01-01

    In order to monitor the possibility of horizontal gene transfer between transgenic rice and microorganisms in paddy rice field, the gene flow from bifunctional fusion (TPSP) rice containing trehalose-6-phosphate synthase and phosphatase to microorganisms in soils was investigated. The soil samples collected every month from the paddy rice field during June, 2004 to March, 2006 were investigated by multiplex PCR, Southern hybridization, and amplified fragment length polymorphism (AFLP). The TPSP gene from soil genomics DNAs was not detected by PCR. Soil genomic DNAs were not shown its homologies on the Southern blotting data, indicating that gene-transfer did not occur during the last two years in paddy rice field. In addition, the AFLP band patterns produced by both soil genomic DNAs extracted from transgenic and non-transgenic rice field appeared similar to each other when analyzed by NTSYSpc program. Thus, these data suggest that transgenic rice does not give a significant impact on the communities of soil microorganisms although long-term observation may be needed.

  17. Mitigation of methane emissions from rice fields: Possible adverse effects of incorporated rice straw

    Science.gov (United States)

    Sass, R. L.; Fisher, F. M.; Harcombe, P. A.; Turner, F. T.

    1991-09-01

    Increased world demand for rice production may lead to an increase in methane emission to the atmosphere and future global warming. One suggested way to reduce methane emission is to discourage the practice of incorporating previous crop residue prior to planting rice, since the residue may enhance methane emission from flooded rice fields. This concept is supported by data from a 2-year study of flooded rice fields on two different soil types in Texas. In 1990, rice stubble from 1989 was incorporated into both soils. Seasonal methane emission from a Lake Charles clay field increased from 15.9 g m-2 in 1989 to 31.0 g m-2 in 1990. In the Beaumont clay field, seasonal methane emission increased from 4.5 to 11.4 g m-2. While methane emission increased between 1989 and 1990, grain yield dropped by 2100 and 840 kg ha-1 in the Lake Charles and Beaumont fields, respectively. Visual inspection at harvest indicated that the 1990 rice yield decrease resulted from grain abortion, presumably caused by the rice cultivar's sensitivity to soil anaerobiosis. The calculated amount of organic carbon not translocated to grain was comparable to the estimated amount of organic carbon required for the increased methane emission. We hypothesize that labile carbon in straighthead susceptible rice cultivars can "leak" from roots damaged by excessively anaerobic soil and be metabolized to its equivalent in methane. These data suggest that minimizing incorporation of crop residue prior to planting can decrease methane emission from flooded rice and reduce the potential for yield loss, particularly with some cultivars and in soils with low rates of seepage and percolation.

  18. Efficiency Test of IRRI Fertilizing Recommendations on Rainfed Low Land Rice Field in West Kalimantan

    Directory of Open Access Journals (Sweden)

    Muhammad Hatta

    2014-06-01

    Full Text Available Fertilizing recommendation for lowland rice field in West Kalimantan is still in national scale and tends to be excessive. It is less relevant due to various factors such as the test method competence, the carrying capacity of the land, and the diverse condition of rice field agro-ecosystem. Site-specific nutrient management (SSNM is an approach for rice fertilizing on paddy plot based on science, history of land fertilization, and nutrient sources surrounding the area which can affect soil fertility level and soil conservation.This study was aimed to examine fertilizing efficiency of N, P, and K and the increased productivity of rice by utilizing software (website of the IRRI. The study was conducted in farmers fields in two villages, i.e. Anjongan and Pak Bulu, Pontianak Regency, West Kalimantan. The results showed that the SSNM fertilization on rice increased yields by the average of 0.62 t ha-1 (13.47% per growing season. The efficiency of SSNM fertilization was on the average of 22.05% N, 48.25% P2O5, and 31.50% K2O. The additional profits obtained from the SSNM recommendation was on the average of IDR 1,886,317 per ha pergrowing season compared to the profits from the FFP (farmer fertilizer practice.

  19. Pollutants dynamics in a rice field and an upland field during storm events

    Science.gov (United States)

    Kim, Jin Soo; Park, Jong-Wha; Jang, Hoon; Kim, Young Hyeon

    2010-05-01

    We investigated the dynamics of pollutants such as total nitrogen (TN), total phosphorous (TP), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended sediment (SS) in runoff from a rice field and an upland field near the upper stream of the Han river in South Korea for multiple storm events. The upland field was cropped with red pepper, sweet potato, beans, and sesame. Runoff from the rice field started later than that from the upland field due to the water storage function of rice field. Unlike the upland field, runoff from the rice field was greatly affected by farmers' water management practices. Overall, event mean concentrations (EMCs) of pollutants in runoff water from the upland field were higher than those from the rice field. Especially, EMCs of TP and SS in runoff water from the upland field were one order of magnitude higher than those from the rice field. This may be because ponding condition and flat geographical features of the rice field greatly reduces the transport of particulate phosphorous associated with soil erosion. The results suggest that the rice field contributes to control particulate pollutants into adjacent water bodies.

  20. Chaos in Black holes Surrounded by Electromagnetic Fields

    OpenAIRE

    Santoprete, Manuele; Cicogna, Giampaolo

    2001-01-01

    In this paper we prove the occurence of chaos for charged particles moving around a Schwarzshild black hole, perturbed by uniform electric and magnetic fields. The appearance of chaos is studied resorting to the Poincare'-Melnikov method.

  1. Contrast sensivity in test field with bright surround.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1965-01-01

    A set of curves and two empirical formulas have been derived which represent the contrast sensivity of the human eye when both the test-object and the test-field luminance are considerable lower than the adaption level. Although derived to be used for the lighting of traffic tunnels, the data may be

  2. Rice Production without Insecticide in Smallholder Farmer's Field

    Directory of Open Access Journals (Sweden)

    M. P. Ali

    2017-05-01

    Full Text Available Highlights:Use of perching, sweeping, and need based insecticide (IPM technique useage produce at par yields compared to prophylactic insecticide useage in rice fields.There exists a technique that can reduce 75% of insecticide useage in rice field.The results were obtained in cooperation between smallholder rice farmers and researchers of Bangladesh.Currently rice protection from insect pests solely depends on chemical pesticides which have tremendous impact on biodiversity, environment, animal, and human health. To reduce their impact from our society we need to cut pesticide use from agricultural practices. To address this issue, we did an experiment to identify realistic solutions that could help farmers build sustainable crop protection systems and minimize useage of insecticides and thus reduce the impact of pesticides in the environment. Innovations developed jointly by farmers and researchers and evaluated for their potential to be adopted by more farmers. In this paper we tested four management practices jointly with smallholder farmer fields in order to select the best one. Four management practices were used namely, T1 = Prophylactic use of insecticide where insecticide was applied in rice field at every 15 days interval without judging the infestation level; T2 = Perching (that is, placing roosting (perching sites for insectivorous birds within the rice field and concurrent sweep net samples along with need-based insecticide application; T3 = Perching only; and T4 = Farmer's own practices. The results revealed that routine application of insecticides for crop protection is not mandatory which is commonly found at use in rice farmers. In our experiment, where prophylactic method or farmers used 3–4 times insecticides without judging the insect pests infestation level, the similar pest population was found when compared to the field where insecticide was not applied. Our management system reduced by 75% the use of insecticides even

  3. Analytical Modeling of Electric Field Distribution in Dual Material Junctionless Surrounding Gate MOSFETs

    Directory of Open Access Journals (Sweden)

    P. Suveetha Dhanaselvam

    2014-10-01

    Full Text Available In this paper, electric field distribution of the junctionless dual material surrounding gate MOSFETs (JLDMSG is developed. Junctionless is a device that has similar characteristics like junction based devices, but junctionless has a positive flatband voltage with zero electric field. In Surrounding gate MOSFETs gate material surrounds the channel in all direction , therefore it can overcome the short channel effects effectively than other devices. In this paper, surface potential and electric field distribution is modelled. The proposed surface potential model is compared with the existing central potential model. It is observed that the short channel effects (SCE is reduced and the performance is better than the existing method.

  4. Surround modulation characteristics of local field potential and spiking activity in primary visual cortex of cat.

    Directory of Open Access Journals (Sweden)

    Li Zhang

    Full Text Available In primary visual cortex, spiking activity that evoked by stimulus confined in receptive field can be modulated by surround stimulus. This center-surround interaction is hypothesized to be the basis of visual feature integration and segregation. Spiking output has been extensively reported to be surround suppressive. However, less is known about the modulation properties of the local field potential (LFP, which generally reflects synaptic inputs. We simultaneously recorded spiking activity and LFP in the area 17 of anesthetized cats to examine and compare their modulation characteristics. When the stimulus went beyond the classical receptive field, LFP exhibited decreased power along the gamma band (30-100 Hz in most of our recording sites. Further investigation revealed that suppression of the LFP gamma mean power (gLFP depended on the angle between the center and surround orientations. The strongest suppression was induced when center and surround orientations were parallel. Moreover, the surround influence of the gLFP exhibited an asymmetric spatial organization. These results demonstrate that the gLFP has similar but not identical surround modulation properties, as compared to the spiking activity. The spatiotemporal integration of LFP implies that the oscillation and synchronization of local synaptic inputs may have important functions in surround modulation.

  5. Mosquitoes and other aquatic insects in fallow field biotopes and rice paddy fields.

    Science.gov (United States)

    Ohba, S Y; Matsuo, T; Takagi, M

    2013-03-01

    Fallow field biotopes that develop from abandoned rice fields are man-made wetlands that provide new habitats for various aquatic animals. Although consideration of such biotopes generally focuses on their positive aspects, this study evaluated the negative aspects of establishing fallow field biotopes with regard to mosquito breeding sites. To determine whether fallow field biotopes become breeding habitats for vector mosquitoes, we evaluated mosquito fauna in fallow field biotopes and adjacent rice fields. We found larvae of Anopheles lesteri, Anopheles sinensis and Culex tritaeniorhynchus (all: Diptera: Culicidae) in the biotopes. Although abundances of mosquito larvae in the biotopes and rice fields were statistically similar, mosquito abundances in rice fields increased dramatically in August when the water level reduced after the rainy season. The abundance and variety of the mosquitoes' natural predators were greater in biotopes than in rice fields because the former are a permanent and stable aquatic environment. A generalized linear mixed model showed a negative effect of predator diversity on mosquito larvae abundance in both habitats. Although fallow field biotopes become breeding habitats for vector mosquitoes, establishing biotopes from fallow fields in order to protect various aquatic animals, including mosquito insect predators, may help to control mosquito breeding. © 2012 The Royal Entomological Society.

  6. Performance of Hybrids between Weedy Rice and Insect-resistant Transgenic Rice under Field Experiments: Implication for Environmental Biosafety Assessment

    Institute of Scientific and Technical Information of China (English)

    Qian-Jin Cao; Hui Xia; Xiao Yang; Bao-Rong Lu

    2009-01-01

    Transgene escape from genetically modified (GM) rice Into weedy rice via gene flow may cause undesired environmental consequences. Estimating the field performance of crop-weed hybrids will facilitate our understanding of potential introgression of crop genes (including transgenes) into weedy rice populations, allowing for effective biosafety assessment. Comparative studies of three weedy rice strains and their hybrids with two GM rice lines containing different insect-resistance transgenes (CpTl or BtlCpTI) indicated an enhanced relative performance of the crop-weed hybrids, with taller plants, more tillers, panicles, and spikelets per plant, as well as higher 1000-seed weight, compared with the weedy rice parents, although the hybrids produced less filled seeds per plant than their weedy parents. Seeds from the F1 hybrids had higher germination rates and produced more seedlings than the weedy parents, which correlated positively with 1000-seed weight. The crop-weed hybrids demonstrated a generally enhanced relative performance than their weedy rice parents in our field experiments. These findings indicate that transgenes from GM rice can persist to and introgress into weedy rice populations through recurrent crop-to-weed gene flow with the aid of slightly increased relative fitness in F1 hybrids.

  7. Planting Rice on the Surrounding Dry Land Soil Salinity and Soil Moisture Content Influence the Research%种稻对周围旱地土壤盐分和土壤水分含量的影响

    Institute of Scientific and Technical Information of China (English)

    田生昌; 陈新会; 马建军; 田慧萍; 冒海军

    2012-01-01

    为了研究种稻对周围旱地影响的程度和范围,选择稻旱田之间无沟和有沟相隔型两种类型,以不受种稻影响的老旱田作对照,在距稻田50.、80、150和200 m处各埋设定位观测井,监测种稻对地下水埋深、土壤水分含量和土壤盐分含量的影响.结果表明,耕层土壤水分含量与地下水埋深相关极显著,耕层土壤盐分含量与地下水埋深相关极显著,在上升期,旱田距稻田距离与地下水埋深相关极显著.因此,稻旱田之间无沟相隔时,种稻对周围旱地的影响表现为稻田水直接向旱田侧渗,而使距稻田附近旱田的地下水位上升,在距稻田220.7 m内地下水位会上升到危害旱作物生长的程度;稻旱田之间有沟相隔时,种稻会导致稻旱田之间排水沟水位上升,从而对周围旱田产生不利影响,这种影响即可通过沟水向旱田的侧渗发生,又表现在阻止旱田的排水上,其不利影响范围在200 m以内.%In order to study the impact of rice growing on surrounding dry land, we choose two types of rice fields, non-ditch separated, ditch separated and dry land as the control to monitor the ground-water depth, soil moisture and soil salt content at different distances (50, 80, 150 and 200 m) away from the rice fields by observation wells. The results showed that: topsoil moisture content was significantly related to groundwater depth. Topsoil soil salt content was significantly related to groundw-ater depth. In the rising period the distances away from the rice fields was significantly associated with groundwater depth. In conclusion, for the dry land and the non-ditch separated rice field, the lateral water seepage from rice field to dry land can increase the ground water level of dry land and in the distance away from the rice fields of 220. 7 m it can cause damage to the growth of dry land crops; for the dry land and ditch separated rice field, it will lead to the ditch water level rising, which

  8. THE EFFECT OF RICE CULTIVARS ON METHANE EMISSION FROM IRRIGATED RICE FIELD

    Directory of Open Access Journals (Sweden)

    P. Setyanto

    2016-10-01

    Full Text Available Rice plants have been reported to affect methane (CH4 emission from rice fields. The objectives of this study were to determine the effect of rice cultivars on CH4 emission from flooded rice and to develop crop management strategies with low emitting rice cultivars while sustaining high yield. The four rice cultivars studied were Memberamo, Cisadane, IR64, and Way Apoburu. The CH4 emissions were determined in the wet season of 2001/2002 (November-February using an automated closed chamber technique in an irrigated field condition. Farmyard manure at the rate of 5 t ha-1 was given to the plots to ensure carbon was not limited. Root weight, root length, biomass, and number of tillers were determined at 17, 36, and 57 days after transplanting (DAT. The results showed that the mean CH4 emission was highest in the plot planted with Cisadane (94.8 kg CH4 ha-1, and the lowest with IR64 (37.7 kg CH4 ha-1. The plots treated with emberamo and Way Apoburu resulted an intermediate CH4 emission at the average of 61.1 and 58.9 kg CH4 ha-1, respectively. There was no significant difference in yield between the cultivars tested. The yield of Memberamo, Cisadane, IR64, and Way Apoburu were 5.882, 5.764, 5.873 and 6.065 t ha-1, respectively. Statistical analysis showed that there were no significant differences in the root weight and root length among cultivars. However, Cisadane gave the highest dry matter weight (222 g hill-1 at 57 DAT compared to the other cultivars (175-190 g hill-1. Plant tillers did not show significant differences between the cultivars. Regression analysis showed that CH4 flux was significantly related with root weight, root length, aboveground biomass, and number of plant tillers. This finding shows that the use of selected cultivars, such as IR64, can potentially lower CH4 emission without scarifying yield.

  9. STUDY ON RESIDUES OF 14C-FENITROTHION IN MODEL RICE-FISH ECOSYSTEM AND FIELD RICE-FISH ECOSYSTEM

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Residues of 14C-fenitrothion in a model rice-fish ecosystem and field rice-fish ecosystem were studied.When equal amounts of the pesticide were applied.the extractable residues in brown rice (equivalent to 34.3±1.9ug/kg fenitrothion) and rice stems and leaves(20.9±1.5ug/kg) of the model rice-fish ecosystem were 10-15times higher than that of the field rice-fish ecosystem(4.48±0.13ug/kg and 1.27±0.34ug/kg respectively).Residues in upper part of the soil (6.50±0.1-8.10±0.2ug/kg)and lower part of the soil(1.30±0.1-1.50±0.1ug/kg)of the model rice-fish ecosystem were 10-40 times higher than that of the field rice-fish ecosystem (0.17±0.01ug/kg).The extractable residues in paddy water of the model ecosystem (0.30±0.01ug/kg)were similar to that of the field ecosystem(0.20±0.02ug/kg),When the fenitrothion was sprayed on the rice plants.residues in brown rice,fish body.soil and paddy water were lower than those when the pesticide was sprayed on the surface of the soil.

  10. Object-Based Flood Mapping and Affected Rice Field Estimation with Landsat 8 OLI and MODIS Data

    Directory of Open Access Journals (Sweden)

    Phuong D. Dao

    2015-04-01

    Full Text Available Cambodia is one of the most flood-prone countries in Southeast Asia. It is geographically situated in the downstream region of the Mekong River with a lowland floodplain in the middle, surrounded by plateaus and high mountains. It usually experiences devastating floods induced by an overwhelming concentration of rainfall water over the Tonle Sap Lake’s and Mekong River’s banks during monsoon seasons. Flood damage assessment in the rice ecosystem plays an important role in this region as local residents rely heavily on agricultural production. This study introduced an object-based approach to flood mapping and affected rice field estimation in central Cambodia. In this approach, image segmentation processing was conducted with optimal scale parameter estimation based on the variation of objects’ local variances. The inundated area was identified by using Landsat 8 images with an overall accuracy of higher than 95% compared to those derived from finer spatial resolution images. Moderate Resolution Imaging Spectroradiometer (MODIS vegetation index products were utilized to identify the paddy rice field based on seasonal inter-variation between vegetation and water index during the transplanting stage. The rice classification result was well correlated with the statistical data at a commune level (R2 = 0.675. The flood mapping and affected rice estimation results are useful to provide local governments with valuable information for flooding mitigation and post-flooding compensation and restoration.

  11. ANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELD

    Institute of Scientific and Technical Information of China (English)

    ZhiWang; Zhe-mingYuan; Da-xiangSong; Ming-shengZhu

    2004-01-01

    The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively.

  12. Rice Combine Harvester: Its Effects to the Livelihood of Rice-Field Tenants in a Second Class Municipality

    Directory of Open Access Journals (Sweden)

    Jesrael Medrano

    2016-11-01

    Full Text Available Over the past few years, the advancement of modern technology has intensely overhauled society. People use and benefit from modern technology, and the tremendous opportunities it provides play a significant role in almost all aspects of human life. However, too much usage of this has its repercussions as well. Technological and mechanical change in agricultural sector and its impact on the work force have already become one of the neglected concerns of farmers in Amulung, a second class municipality of Cagayan. The newly introduced rice combine harvesters are already dominating the rice fields in Amulung during harvesting seasons. Thus, it replaces the conventional system of harvesting using human labor and sickles. This study is conducted to determine the effects of rice combine harvesters to the livelihood of rice field tenants in Amulung, Cagayan. Using purposive sampling through site selection approach and networking, 25 rice field tenants were selected as participants of this study. In–depth conversations and guided interview had served as the main instruments used by the researchers to gather the needed data. The results showed that rice combine harvesters cause unemployment and migration among the participants and degrade their sense of solidarity and camaraderie. As a result, the participants sought alternative activities which they can be paid off. Also, they engage themselves in livestock and poultry production, and even in informal sector economy just to cope with the prevalence of rice combine harvesters.

  13. Estimation of methane and nitrous oxide emissions from rice field with rice straw management in Cambodia.

    Science.gov (United States)

    Vibol, S; Towprayoon, S

    2010-02-01

    To estimate the greenhouse gas emissions from paddy fields of Cambodia, the methodology of the Intergovernmental Panel on Climate Change (IPCC) guidelines, IPCC coefficients, and emission factors from the experiment in Thailand and another country were used. Total area under rice cultivation during the years 2005-2006 was 2,048,360 ha in the first crop season and 298,529 ha in the second crop season. The emission of methane from stubble incorporation with manure plus fertilizer application areas in the first crop season was estimated to be 192,783.74 ton higher than stubble with manure, stubble with fertilizer, and stubble without fertilizer areas. The fields with stubble burning emitted the highest emission of methane (75,771.29 ton) followed by stubble burning with manure (22,251.08 ton), stubble burning with fertilizer (13,213.27 ton), and stubble burning with fertilizer application areas (3,222.22 ton). The total emission of methane from rice field in Cambodia for the years 2005-2006 was approximately 342,649.26 ton (342.65 Gg) in the first crop season and 36,838.88 ton (36.84 Gg) in the second crop season. During the first crop season in the years 2005-2006, Battambang province emitted the highest amount of CH(4) (38,764.48 ton) and, in the second crop season during the years 2005-2006, the highest emission (8,262.34 ton) was found in Takeo province (8,262.34 ton). Nitrous oxide emission was between 2.70 and 1,047.92 ton in the first crop season and it ranged from 0 to 244.90 ton in the second crop season. Total nitrous oxide emission from paddy rice field was estimated to be 9,026.28 ton in the first crop season and 1,091.93 ton in the second crop season. Larger area under cultivation is responsible for higher emission of methane and nitrous oxide. Total emission of nitrous oxide by using IPCC default emission coefficient was approximately 2,328.85 ton. The total global warming potential of Cambodian paddy rice soil is 11,723,217.03 ton (11,723 Gg

  14. ECOLOGICAL INVESTIGATION OF APPLICATION OF PESTICIDES IN RICE FIELDS

    Directory of Open Access Journals (Sweden)

    J. Nouri

    2000-12-01

    Full Text Available Among several pests of rice as one of the main agricultural products in Iran, rice borer, Chilo suppressalis is one of the most important pests of this crop. Use of pesticides coincided with the occurrence of this pest in the northern region of Iran in 1972. At present in order to control this pest, more than 12000 tones of pesticides granules are used annually. Ecological effects of pesticides application and the use of Trichograma sp. as a natural enemy, for assessing the impacts of pesticides in environments, especially on different living organisms on the plant, in irrigation water, and in 5 cm depth of surface soil, were investigated in two regions of Amol, named Osk. Mahalleh and Capik Field of Tashbandan. Results indicated that the two treatments were not different on croploss. One the contrary, in the pesticide treatment, there was a considerable decrease in the population of living organisms, particularly, no organism was observed in 5 cm depth of surface soil. It is recommended that in order to maintain the balance of environment, the use of chemicals for controlling rice borer must be with extreme care, only in the inevitable was with the use of principles of Integrated Pest Management.

  15. Massive scalar field quasinormal modes of a Schwarzschild black hole surrounded by quintessence

    CERN Document Server

    Ma, C; Wang, F; Wang, W; Gui, Yuanxing; Ma, Chunrui; Wang, Fujun; Wang, Wei

    2006-01-01

    We present the quasinormal frequencies of the massive scalar field in the background of a Schwarzchild black hole surrounded by quintessence with the third-order WKB method. The mass of the scalar field $u$ plays an important role in studying the quasinormal frequencies, the real part of the frequencies increases linearly as mass $u$ increases, while the imaginary part in absolute value decreases linearly which leads to damping more slowly and the frequencies having a limited value. Moreover, owing to the presence of the quintessence, the massive scalar field damps more slowly.

  16. Visual Population Receptive Fields in People with Schizophrenia Have Reduced Inhibitory Surrounds.

    Science.gov (United States)

    Anderson, Elaine J; Tibber, Marc S; Schwarzkopf, D Sam; Shergill, Sukhwinder S; Fernandez-Egea, Emilio; Rees, Geraint; Dakin, Steven C

    2017-02-08

    People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However, differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reported in vivo Here, we probed the neural basis of these deficits using fMRI and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a difference-of-Gaussian model to capture the center-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex, as well as a reduction in size and depth of the inhibitory surround in V1, V2, and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ.SIGNIFICANCE STATEMENT People with schizophrenia (SZ) experience abnormal perception on a range of visual tasks, which has been linked to abnormal synaptic transmission and an imbalance between cortical excitation/inhibition. However, associated differences in the functional architecture of visual cortex neurons have yet to be reported in vivo We used fMRI and population receptive field (pRF) mapping to demonstrate that the fine-grained functional architecture of visual cortex in people with SZ differs from unaffected controls. SZ is associated with reduced pRF size in early retinotopic visual cortex largely due to reduced inhibitory surrounds. An imbalance between cortical excitation and inhibition could drive such a change in the center-surround pRF configuration and ultimately explain the range of visual deficits experienced in SZ.

  17. Performance indices for pumping stations in irrigated rice fields

    Directory of Open Access Journals (Sweden)

    Luciana Marini Köpp

    2016-08-01

    Full Text Available ABSTRACT: Performance indices can be used as indices of energy use in irrigation systems. Pumping stations (PSs are elements that require energy for irrigation of rice fields by conventional flood irrigation. Interplay of physical, hydraulic, and electrical parameters generates indices that determine the performance in the diagnosis of PSs, operation, and projects for new sets. In this study, it was proposed and classified performance indices for PSs in rice fields, focusing on the efficient use of energy. The study was carried out through an investigation of 160 PSs in operation, located at the western border of Rio Grande do Sul, Brazil, which constituted an actual field situation. Next, PSs were optimized in relation to the selection of a piping system, using the lowest total cost, the choice of pump, and motors with better performance for the necessary situation as criteria. Results provided nine indices that classified the performance as "excellent", "very good", "good", "poor", and "very poor", which allowed the assessment of projects and the diagnosis of PSs.

  18. Microbial degradation of clomazone under simulated California rice field conditions.

    Science.gov (United States)

    Tomco, Patrick L; Holstege, Dirk M; Zou, Wei; Tjeerdema, Ronald S

    2010-03-24

    Clomazone (trade names Cerano and Command) is a popular herbicide used on California rice fields to control aquatic weeds. Its physicochemical characteristics indicate that it will persist primarily in the water column, where microbial degradation may drive its environmental fate. The objectives were to determine microbial degradation rates and compare the metabolic products under aerobic and anaerobic conditions similar to those in California rice fields during the summer. Time-series samples were extracted and analyzed by LC/MS/MS. Metabolic profiling revealed the following clomazone-derived transitions: m/z 240 --> 125 (clomazone), m/z 242 --> 125 (ring-open clomazone), m/z 256 --> 125 (5-hydroxyclomazone), m/z 256 --> 141 (aromatic hydroxyclomazone), m/z 268 --> 125 (unknown metabolite), and m/z 272 --> 141 (4'5-dihydroxyclomazone). Results indicate an anaerobic half-life of 7.9 days, with ring-open clomazone reaching 67.4% of application at 38 days. Aerobically, clomazone degraded more slowly (t(1/2) = 47.3 days), forming mostly soil-bound residues. Thus, under summer conditions, clomazone is likely to dissipate rapidly from fields via anaerobic degradation.

  19. Efficiency of experimental rice (Oryza sativa L.) fields in mitigating diazinon runoff toxicity to Hyalella azteca.

    Science.gov (United States)

    Moore, Matthew T; Lizotte, Richard E; Kröger, Robert

    2009-06-01

    This study assessed the viability of using planted, mature rice fields in mitigating diazinon (an organophosphate insecticide) runoff toxicity using aqueous 48 h Hyalella azteca whole effluent toxicity bioassays. Rice fields decreased diazinon concentrations 80.1%-99.9% compared with 10.8% in the unvegetated field control. H. azteca survival responses coincided with observed diazinon concentrations. Estimated LC50 effects dilutions (%) ranged from 1.15 to 1.47 for inflow samples and 1.66 (unvegetated), 6.44 (rice field A), and >100 (rice field B) outflow samples. Decreases in inflow versus outflow aqueous toxicity were 77.1%-100% in rice fields compared with 18.7% in the unvegetated field.

  20. Automatic mapping of rice fields in the Sacramento Valley for water resources management

    Science.gov (United States)

    Zhong, L.; Yin, H.; Reyes, E.; Chung, F. I.

    2015-12-01

    Water use by rice fields is one of the most important components in hydrologic model simulation of the Sacramento Valley, California. In this study, rice fields were mapped by an automatic approach using Landsat imagery. The automatic approach is advantageous for its capacity of mapping rice fields repeatedly, consistently and timely without the need to collect training data. Seasonal dynamics of Enhanced Vegetation Index (EVI) and Normalized Difference Moisture Index (NDMI) were employed to identify rice based on its phenological characteristics. Classification could be conducted around planting date for early response to cropland use change, or for the full growing season to monitor rice growth. Two studies are illustrated as the applications of this mapping method: 1. A rice map was produced before mid-June to forecast rice acreage and water use in the 2015 drought. Due to continuous drought, rice acreage in the Sacramento Valley reached the historical minimum of the past 20 years in 2014, and further reduction is occurring in 2015. A quantitative measure of rice field extent is needed to forecast rice water use as early as possible. The automatic mapping method utilized the spectral dynamics during initial flooding to identify rice fields. Based on the map product, the forecast of rice water demand was made to facilitate the simulation of current-year hydrologic conditions. 2. Rice field extent has been mapped since 1989 and phenological metrics have been derived to study the change in growing season. The increasing use of short-season rice varieties and special weather condition (like El Nino in 2015) may alter the seasonal pattern of water demand by rice. Rice fields were identified based on the temporal profiles of NDMI and EVI derived from series of segmented images. Validation using field survey data and other land use maps showed a promising accuracy. The start and the end of the growing season and other phenological metrics were extracted from object

  1. Pathological Study of Blood Parasites in Rice Field Frogs, Hoplobatrachus rugulosus (Wiegmann, 1834

    Directory of Open Access Journals (Sweden)

    Achariya Sailasuta

    2011-01-01

    Full Text Available One hundred and forty adult rice field frogs, Hoplobatrachus rugulosus (Wiegmann, 1834, were collected in Srakaew province, Thailand. For blood parasite examination, thin blood smears were made and routinely stained with Giemsa. The results showed that 70% of the frogs (98/140 were infected with 5 species of blood parasites, including a Trypanosoma rotatorium-like organism, Trypanosoma chattoni, Hepatozoon sp. a, Hepatozoon sp. b, and Lankesterella minima. Pathological examination of the liver, lung, spleen, and kidney of the frogs that were apparently infected with one of these blood parasites were collected and processed by routine histology and subsequently stained with haematoxylin and eosin. Histopathological findings associated with the Trypanosoma rotatorium-like organism and Trypanosoma chattoni-infected frogs showed no pathological lesions. Hepatozoon sp. a and Hepatozoon sp. b-infected frogs developed inflammatory lesions predominantly in the liver, demonstrating granuloma-like lesions with Hepatozoon sp. meronts at the centre. Tissue sections of Lankesterella minima-infected frogs also showed lesions. Liver and spleen showed inflammatory lesions with an accumulation of melanomacrophage centres (MMCs surrounding the meronts and merozoites. It is suggested that Hepatozoon sp. a, Hepatozoon sp. b, and Lankesterella minima-infections are capable of producing inflammatory lesions in the visceral organs of rice field frogs, and the severity of lesions is tentatively related to levels of parasitemia.

  2. Evolution of scalar fields surrounding black holes on compactified constant mean curvature hypersurfaces

    CERN Document Server

    Morales, Manuel D

    2016-01-01

    Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented in [J.M. Bardeen, O. Sarbach, and L.T. Buchman, Phys. Rev. D 83, 104045 (2011)] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of...

  3. Efficiency of experimental rice (Oryza sativa L.) fields in mitigating diazinon runoff toxicity to Hyalella azteca

    Science.gov (United States)

    This study assessed the viability of using planted, mature rice fields in mitigating diazinon (an organophosphate insecticide) runoff toxicity using aqueous 48 h Hyalella azteca whole effluent toxicity bioassays. Rice fields decreased diazinon concentrations 80.1-99.9% compared with 10.8% in the unv...

  4. Relationship between CH4 and N2O emissions from rice field and its impacting factors

    Institute of Scientific and Technical Information of China (English)

    HOUAixin; CHENGuanxiong; WUJie; WANGZhengping

    1998-01-01

    To find out the relationship between CH4 and N2O emissions from rice field and determine the key factors affecting the emissions, and give a scientifie basis for working out mitigation options of their emissions from flooded rice field, we measured the emissions and their impacting environmental factors systematically and simultaneously from Mar to Dee in 1995-1996 in northern China.

  5. Utilizing NASA Earth Observations to Monitor Land Management Practices and the Development of Marshlands to Rice Fields in Rwanda

    Science.gov (United States)

    Dusabimana, M. R.; Blach, D.; Mwiza, F.; Muzungu, E.; Swaminathan, R.; Tate, Z.

    2014-12-01

    Rwanda, a small country with the highest population density in Sub-Saharan Africa, is one of the world's poorest countries. Although agriculture is the backbone of Rwandan economy, agricultural productivity is extremely low. Over 90 % of the population is engaged in subsistence farming and only 52 % of the total land surface area is arable. Of this land, approximately 165,000 hectares are marshlands, of which only 57 % has been cultivated. Rwandan government has invested in the advancement of agriculture with activities such as irrigation, marshland reclamation, and crop regionalization. In 2001, Ministry of Agriculture and Animal Resources (MINAGRI) released the Rural Sector Support Program (RSSP), which aimed at converting marshlands into rice fields at various development sites across the country. The focus of this project was to monitor rice fields in Rwanda utilizing NASA Earth observations such as Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager. Modified Normalized Difference Water Index (MNDWI) was used to depict the progress of marshland to rice field conversion as it highlights the presence of irrigated rice fields from the surrounding area. Additionally, Decision Support System for Agrotechnology Transfer (DSSAT) was used to estimate rice yield at RSSP sites. Various simulations were run to find perfect conditions for cultivating the highest yield for a given farm. Furthermore, soil erosion susceptibility masks were created by combining factors derived from ASTER, MERRA, and ground truth data using Revised Universal Soil Loss Equation (RUSLE). The end results, maps, and tutorials were delivered to the partners and policy makers in Rwanda to help make informed decisions. It can be clearly seen that Earth observations can be successfully used to monitor agricultural and land management practices as a cost effective method that will enable farmers to improve crop yield production and food security.

  6. Numerical analysis and field monitoring tests on shallow tunnels under weak surrounding rock

    Institute of Scientific and Technical Information of China (English)

    刘建华; 刘晓明; 张永杰; 肖庭

    2015-01-01

    The Jianpudong No. 4 tunnel is a shallow tunnel, which belongs to Shaoshan County scenic highway in Hunan province, China and whose surrounding rock is weak. According to its characteristics, the field monitoring tests and numerical analysis were done. The mechanical characteristics of shallow tunnels under weak surrounding rock and the stress−strain rule of surrounding rock and support were analyzed. The numerical analysis results show that the settlement caused by upper bench excavating accounts for 44% of the total settlement, and the settlement caused by tunnel upper bench supporting accounts for 56% of the total settlement. The maximum axial force of shotcrete lining is 177.2 kN, which locates in hance under the secondary lining. The maximum moment of shotcrete lining is 5.08 kN·m, which locates in the arch foot. The stress curve of steel arch has three obvious stages during the tunnel construction. The maximum axial force of steel arch is 297.4 kN, which locates in tunnel vault. The axial forces of steel arch are respectively 23.5 kN and−21.8 kN, which is influenced by eccentric compression of shallow tunnel and locates in hance. The results show that there is larger earth pressure in tunnel vault which is most unfavorable position of steel arch. Therefore, the advance support should be strengthened in tunnel vault during construction process.

  7. Dual-Material Surrounding-Gate Metal-Oxide-Semiconductor Field Effect Transistors with Asymmetric Halo

    Institute of Scientific and Technical Information of China (English)

    LI Zun-Chao

    2009-01-01

    Asymmetrical halo and dual-material gate structure are used in the sub-100 nm surrounding-gate metal-oxide-semiconductor field effect transistor (MOSFET) to improve the performance. Using three-region parabolic po-tential distribution and universal boundary condition, analytical surface potential and threshold voltage models of the novel MOSFET are developed based on the solution of Poisson's equation. The performance of the MOS-FET is examined by the analytical models and the 3D numerical device simulator Davinci. It is shown that the novel MOSFET can suppress short channel effect and improve carrier transport efficiency. The derived analytical models agree well with Davinci.

  8. The Dynamics Of Rice Field Conversion Into Settlement In The District Of Bandung

    Directory of Open Access Journals (Sweden)

    Ivan Chofyan

    2016-12-01

    Full Text Available Bandung District as one of the rice-producing areas in West Java has a strong interest in maintaining rice field. However, the land conversion of rice field in the Bandung District continues to occur with various factors. This study aims to identify the elements that make up the structure of the phenomenon and the linkages between these elements which lead to the conversion of rice fields and recommend some policy alternatives that are useful for efforts to control the conversion of rice field. In order to achieve the stated goals, this study uses system dynamics which is one method of thinking system that could see the various aspects of integral and structurally enable to explain the phenomenon of land conversion happens. On this study determines 4 scenarios consists of a basic scenario, rice field cropping intensity scenarios (RFCI, necessity standard of land settlement scenarios (NSLS, and food diversification scenarios (FD. The final result of this study states that the necessity standard of land settlement scenarios result in a decrease in the rate of land conversion is smaller and the rice stock inventory is more stable compared to other scenarios. Under these conditions, policies that support the above scenario should be established, namely the policy of land-saving settlement development and establishment of sustainable rice field.

  9. The archaeobotany of Asian rice expansion and the development of wet-field cultivation

    Science.gov (United States)

    Fuller, D.

    2008-12-01

    Archaeobotanical evidence provides direct data on past human diet and agriculture, including a geographical and chronological framework for studying the expansion of rice agriculture. The growth of systematic archaeobotanical sampling in recent years has allowed for the past presence of rice to be seen in relation to cultivation of other crops and associated weeds. The weed flora provides a basis for inferring the nature of cultivation systems, whether rain-fed dry rice or wetland "paddy" rice, a key distinction for considerations of past methane production. Nevertheless, current data is very unevenly distributed. This poster will summarize available evidence for the origins and spread of rice in South Asia (India and Pakistan), and mainland and Island Southeast Asia deriving from an earlier Chinese domestication. Where possible, such as in India or China, the potential of the weed flora remains for distinguishing wetland rice crops will be summarized. In broad terms, although the origins of rice use and cultivation begins by or during the Middle Holocene (6000- 3000 BC), rice cultivation spread outside the regions of the wild progenitor after this time. Two phases of rice expansion can be distinguished. Phase 1, between 3000 and 1500 BC, introduced rice to Southeast Asia, probably under wetland cultivation, and the spread of dry rice over northern India and Pakistan. Phase 2, taking place between 1000 and 0 BC, sees the spread of rice throughout the Southern Indian Peninsula, with weed evidence suggesting irrigated wetland rice. Similarly, this period sees the spread of intensive paddy agriculture through Korea and Japan, but in Southeast Asia is probably related to a spread of rice in upland, dry field systems.

  10. Automatic Rice Crop Height Measurement Using a Field Server and Digital Image Processing

    Directory of Open Access Journals (Sweden)

    Tanakorn Sritarapipat

    2014-01-01

    Full Text Available Rice crop height is an important agronomic trait linked to plant type and yield potential. This research developed an automatic image processing technique to detect rice crop height based on images taken by a digital camera attached to a field server. The camera acquires rice paddy images daily at a consistent time of day. The images include the rice plants and a marker bar used to provide a height reference. The rice crop height can be indirectly measured from the images by measuring the height of the marker bar compared to the height of the initial marker bar. Four digital image processing steps are employed to automatically measure the rice crop height: band selection, filtering, thresholding, and height measurement. Band selection is used to remove redundant features. Filtering extracts significant features of the marker bar. The thresholding method is applied to separate objects and boundaries of the marker bar versus other areas. The marker bar is detected and compared with the initial marker bar to measure the rice crop height. Our experiment used a field server with a digital camera to continuously monitor a rice field located in Suphanburi Province, Thailand. The experimental results show that the proposed method measures rice crop height effectively, with no human intervention required.

  11. Automatic rice crop height measurement using a field server and digital image processing.

    Science.gov (United States)

    Sritarapipat, Tanakorn; Rakwatin, Preesan; Kasetkasem, Teerasit

    2014-01-07

    Rice crop height is an important agronomic trait linked to plant type and yield potential. This research developed an automatic image processing technique to detect rice crop height based on images taken by a digital camera attached to a field server. The camera acquires rice paddy images daily at a consistent time of day. The images include the rice plants and a marker bar used to provide a height reference. The rice crop height can be indirectly measured from the images by measuring the height of the marker bar compared to the height of the initial marker bar. Four digital image processing steps are employed to automatically measure the rice crop height: band selection, filtering, thresholding, and height measurement. Band selection is used to remove redundant features. Filtering extracts significant features of the marker bar. The thresholding method is applied to separate objects and boundaries of the marker bar versus other areas. The marker bar is detected and compared with the initial marker bar to measure the rice crop height. Our experiment used a field server with a digital camera to continuously monitor a rice field located in Suphanburi Province, Thailand. The experimental results show that the proposed method measures rice crop height effectively, with no human intervention required.

  12. Mechanical Behavior of the Near-field Host Rock Surrounding Excavations

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, Sharad M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Robinson, Bruce Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-01-09

    This report is being prepared under the FY14 activity FT-14LA0818069, Mechanical and Hydrological Behavior of the Near-Field Host Rock Surrounding Excavations, and fulfills the Los Alamos National Laboratory deliverable M4FT-14LA08180610, which in PICS:NE is titled “Draft report, Test Plan for Mechanical and Hydrological Behavior of the Near-field Host Rock Surrounding Excavations.” Since the report is an intermediate deliverable intended as input to the eventual test plan for this test, rather than being an actual test plan, the activity title is used as the title of this document to avoid confusion as to the contents in the report. This report summarizes efforts to simulate mechanical processes occurring within a hypothetical high-level waste (HLW) repository in bedded salt. The report summarizes work completed since the last project deliverable, “Coupled model for heat and water transport in a high level waste repository in salt “, a Level 2 milestone submitted to DOE in September 2013 (Stauffer et al., 2013).

  13. BASIC CONCEPT AND APPLICATION IPM RICE FIELD AT THE FARMER

    Directory of Open Access Journals (Sweden)

    IGP. Alit Diratmaja

    2015-01-01

    Full Text Available One of the problems is the rice farming Plant Pest Organisms disorders (OPT, which can reduce the quality and quantity of even causing crop failure. In pest control, the government has been introducing technology Integrated Pest Management (IPM is a way of controlling pests that are completely environmentally sound. Some components are still difficult to apply is the use of LCC and PUTS, irrigation epektif and efficient manner, and Legowo row planting system; utilization of natural enemies; the use of botanical pesticides; observation of pest populations and determination of economic threshold. The application of pest control through IPM approach has positive benefits. For that we need the support of various stakeholders, especially government policies and increased support officer pest observers in the field

  14. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongbo, E-mail: liuyb@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu, Fang [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Chao [Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510380 (China); Quan, Zhanjun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Junsheng, E-mail: lijsh@creas.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  15. Adsorption Kinetics of Carbamate Pesticide in Rice Field Soil

    Directory of Open Access Journals (Sweden)

    Soontree Khuntong

    2010-07-01

    Full Text Available Ultrasonic extraction (75.55% with petroleum ether:acetone (1:1, v/v was employed for extraction of carbofuran in rice field soil. The amounts of carbofuran were determined by reverse phase HPLC. The analytical method provided high precision and accuracy with the relative error of 0.47%. The percentage of recoveries varied from 84% to 77% in the con¬centration ranges of 10–40 mg/L of spiked soil samples. The carbofuran residues in the rice field soil significantly decreased year by year because of pesticide properties, soil properties and degradation conditions. A high amount of residues was found in the plots that contained high organic contents. The adsorption of carbofuran in soil reached equilibrium within 23 h. The percentage of adsorption varied from almost 30% to 80% depending on concentrations of carbofuran. The adsorption of carbofuran agreed with Freundlich isotherms; q = 7.07 x 10-5Cf2.5092; with the correlation coefficient of 0.9281. Organic carbon coefficient, Koc, was 1.91 x 10-3 mg/L calculated from Kd, and half-life (8.9 d of adsorbed carbofuran. The GUS index (6.37 calculated from Koc presented a high lixiviation potential. The positive ΔG indicated the non-spontaneous reaction. Carbofuran rapidly desorbed from soil at the desorption rate of 0.0228 mg/kg soil d. Kinetic studies provided the first order reaction with the reaction rate of 0.0779 mg/d and half-life of 8.9 days.

  16. Nutritional composition of aquatic species in Laotian rice field ecosystems : possible impact of reduced biodiversity

    OpenAIRE

    Nurhasan, Mulia

    2008-01-01

    The population density of Laos PDR has increased from 15 persons per square km in 1985 to 19 persons in 1995 and to 24 persons in 2005. This has threatened food security, which in Laos PDR is generally synonymous with rice availability. Rice production in Laos rose by 70 percent from 1990 to 2004. Evidence from Vietnam, Malaysia and Central Thailand has shown that the rise of rice production steadily decreases the population of aquatic animals in rice field ecosystems, as a result of higher a...

  17. Geographical variation in inorganic arsenic in paddy field samples and commercial rice from the Iberian Peninsula.

    Science.gov (United States)

    Signes-Pastor, Antonio J; Carey, Manus; Carbonell-Barrachina, Angel A; Moreno-Jiménez, Eduardo; Green, Andy J; Meharg, Andrew A

    2016-07-01

    This study investigated total arsenic and arsenic speciation in rice using ion chromatography with mass spectrometric detection (IC-ICP-MS), covering the main rice-growing regions of the Iberian Peninsula in Europe. The main arsenic species found were inorganic and dimethylarsinic acid. Samples surveyed were soil, shoots and field-collected rice grain. From this information soil to plant arsenic transfer was investigated plus the distribution of arsenic in rice across the geographical regions of Spain and Portugal. Commercial polished rice was also obtained from each region and tested for arsenic speciation, showing a positive correlation with field-obtained rice grain. Commercial polished rice had the lowest i-As content in Andalucia, Murcia and Valencia while Extremadura had the highest concentrations. About 26% of commercial rice samples exceeded the permissible concentration for infant food production as governed by the European Commission. Some cadmium data is also presented, available with ICP-MS analyses, and show low concentration in rice samples.

  18. Transfer function control strategy of Subak rice field land and agricultural development in Denpasar city

    Science.gov (United States)

    Lanya, Indayati; Netera Subadiyasa, N.; Sardiana, Ketut; Putu Ratna Adi, Gst.

    2017-01-01

    The success of tourism development in Bali gave a negative impact on Subak rice fields, especially on land convertion over 2579 ha year-1 (2002-2013) to the area awakened. Denpasar city has lost rice fields 185 ha year-1 and six Subak, as well as potentially losing 10 Subak, as a result of the allocation of space in the region in the Spatial Planing. UNESCO, in 2012 the establishment of Subak as a cultural heritage. Most Subak rice fields designated as an Urban Green Open Space ( UGOS). Satellite image Iconos 2002, World 2015 View Coverage of Denpasar, and ArcGIS 10.3 software used for mapping the balance of rice field and violation of land use in the area of UGOS. The control strategy over the convertion of spatial land-based environment is done through zoning map. Land conversion of rice fields for 13 years (2002-2015) in Denpasar (572.76 ha), comes standard acreage of rice fields in 2015. Denpasar city has experienced of food deficits, even in the UGOS has awakened 96.04 ha (24.04 ha year-1). A period of 50 years into the future, rice fields which needs to be protected 872.83 ha, buffer area 984.77 ha, and can be converted 499.81 ha.

  19. Field investigations of high stress soft surrounding rocks and deformation control

    Directory of Open Access Journals (Sweden)

    Weijian Yu

    2015-08-01

    Full Text Available Field investigations of high stress soft rock deformations show that the high stress soft rock roadway can slide with large deformation. Severe extrusion and floor heave can also be subsequently observed. The supported roadway can be locally damaged or completely fail, where the floor has a large deformation and/or is seriously damaged. The factors inducing large deformation of surrounding rocks in deep roadway are rock strengths, structure face cutting types, stress states, stress release, support patterns, and construction methods. Based on the deformation characteristics of high stress soft rock roadway, a comprehensive support scheme is proposed. The overall support technology of “step-by-step and joint, hierarchical reinforcement” for roadway is presented, and the anchor cable and bolt parameters to check the design methods are also given. Finally, the proposed comprehensive support method “bolt + metal mesh + U-steel arch + shortcrete + grouting and cable” is used in the extension section of east main haulage roadway at −850 m level of Qujiang coal mine. The 173-day monitoring results show that the average convergence of sidewalls reaches 208 mm, and the average relative convergence of roof and floor reaches 448 mm, suggesting that this kind of support technology for controlling large deformation of high stress soft surrounding rock roadway is effective.

  20. Evolution of scalar fields surrounding black holes on compactified constant mean curvature hypersurfaces

    Science.gov (United States)

    Morales, Manuel D.; Sarbach, Olivier

    2017-02-01

    Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented by Bardeen, Sarbach, and Buchman [Phys. Rev. D 83, 104045 (2011), 10.1103/PhysRevD.83.104045] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of scalar field, part of which disperses to infinity and part of which is accreted by the black hole. As a nontrivial test, we study the tail decay of the scalar field along different curves, including one along the marginally trapped tube, one describing the world line of a timelike observer at a finite radius outside the horizon, and one corresponding to a generator of null infinity. Our results are in perfect agreement with the usual power-law decay discussed in previous work. This article also contains a detailed analysis for the asymptotic behavior and regularity of the lapse, conformal factor, extrinsic curvature and the Misner-Sharp mass function along constant mean curvature slices.

  1. Analytic modeling of a depletion-mode cylindrical surrounding-gate nanowire field-effect transistor.

    Science.gov (United States)

    Yu, Yun Seop; Park, Hyung-Kun

    2012-07-01

    A compact model for depletion-mode p-type cylindrical surrounding-gate nanowire field-effect transistors (SGNWFETs) is proposed. The SGNWFET model consists of two back-to-back Schottky diodes for the metal-semiconductor (MS) contacts and the intrinsic SGNWFET. Based on the electrostatic method, the intrinsic SGNWFET model was derived from current conduction mechanisms attributed to bulk charges through the center neutral region, in addition to accumulation charges through the surface accumulation region. The authors' previously developed Schottky diode model was used for the M-S contacts. The new model was applied to an advanced design system (ADS), whereby the intrinsic part of the SGNWFET and the Schottky diode were developed using the Verilog-A language. The results of the simulation of the newly developed SGNWFET model reproduced the experiment results considerably well.

  2. [Effects of different rice farming systems on paddy field weed community].

    Science.gov (United States)

    Zhang, Dan; Min, Qing-Wen; Cheng, Sheng-Kui; Yang, Hai-Long; He, Lu; Jiao, Wen-Jun; Liu, Shan

    2010-06-01

    Taking the paddy fields planted with glutinous rice and hybrid rice in the traditional agricultural region in Congjiang County of Guizhou Province as the case, and by using semi-experiment combined with random sampling investigation, this paper studied the characteristics of weed community in the paddy fields under rice monoculture (R), rice-fish culture (R-F), and rice-fish-duck culture (R-F-D). Under the three rice farming systems, glutinous rice had higher capability in inhibiting weeds, compared with hybrid rice. Farming system R-F-D decreased the weed density significantly, with the control effect on Monochoia vaginalis and Rotala indica being 100%. The overall weed-inhibiting effect of R-F-D was significantly higher than that of the other farming systems. Under R-F-D, the species richness and Shannon diversity index of weed community decreased markedly, while the Pielou evenness index increased, indicating that the species composition of weed community changed greatly, and the occurrence of native dominant weed species decreased. It was concluded that R-F-D was a feasible farming system for the control of paddy field weed community.

  3. μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble.

    Science.gov (United States)

    Yamaguchi, Eiichiro; Smith, Bradford J; Gaver, Donald P

    2009-08-01

    Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver (2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method.

  4. Variable stars in the open cluster NGC 6791 and its surrounding field

    CERN Document Server

    De Marchi, F; Montalto, M; Piotto, G; Desidera, S; Bedin, L R; Claudi, R; Ferro, A Arellano; Bruntt, H; Stetson, P B

    2007-01-01

    Aims: This work presents a high--precision variability survey in the field of the old, super metal-rich open cluster NGC 6791. Methods: The data sample consists of more than 75,000 high-precision CCD time series measurements in the V band obtained mainly at the Canada-France-Hawaii Telescope, with additional data from S. Pedro Martir and Loiano observatories, over a time span of ten nights. The field covers an area of 42x28 arcmin^2. Results: We have discovered 260 new variables and re-determined periods and amplitudes of 70 known variable stars. By means of a photometric evaluation of the membership in NGC 6791, and a preliminary membership based on the proper motions, we give a full description of the variable content of the cluster and surrounding field in the range 16

  5. Succession of methanogenic archaea in rice straw incorporated into a Japanese rice field: estimation by PCR-DGGE and sequence analyses

    Directory of Open Access Journals (Sweden)

    Atsuo Sugano

    2005-01-01

    Full Text Available The succession and phylogenetic profiles of methanogenic archaeal communities associated with rice straw decomposition in rice-field soil were studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE analysis followed by 16S rDNA sequencing. Nylon bags containing either leaf sheaths or blades were buried in the plowed layer of a Japanese rice field under drained conditions during the off-crop season and under flooded conditions after transplanting. In addition, rice straw samples that had been buried in the rice field under drained conditions during the off-crop season were temporarily removed during spring plowing and then re-buried in the same rice field under flooded conditions at transplanting. Populations of methanogenic archaea were examined by amplification of the 16S rRNA genes in the DNA extracted from the rice straw samples. No PCR product was produced for samples of leaf sheath or blade prior to burial or after burial under drained conditions, indicating that the methanogen population was very small during decomposition of rice straw under oxic conditions. Many common bands were observed in rice straw samples of leaf sheath and blade during decomposition of rice straw under flooded conditions. Cluster analysis based on DGGE patterns divided methanogenic archaeal communities into two groups before and after the mid-season drainage. Sequence analysis of DGGE bands that were commonly present were closely related to Methanomicrobiales and Rice cluster I. Methanomicrobiales, Rice cluster I and Methanosarcinales were major members before the mid-season drainage, whereas the DGGE bands that characterized methanogenic archaeal communities after the mid-season drainage were closely related to Methanomicrobiales. These results indicate that mid-season drainage affected the methanogenic archaeal communities irrespective of their location on rice straw (sheath and blade and the previous history of decomposition

  6. Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls

    Science.gov (United States)

    Zhang, Bowen; Tian, Hanqin; Ren, Wei; Tao, Bo; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Pan, Shufen

    2016-09-01

    Given the importance of the potential positive feedback between methane (CH4) emissions and climate change, it is critical to accurately estimate the magnitude and spatiotemporal patterns of CH4 emissions from global rice fields and better understand the underlying determinants governing the emissions. Here we used a coupled biogeochemical model in combination with satellite-derived contemporary inundation area to quantify the magnitude and spatiotemporal variation of CH4 emissions from global rice fields and attribute the environmental controls of CH4 emissions during 1901-2010. Our study estimated that CH4 emissions from global rice fields varied from 18.3 ± 0.1 Tg CH4/yr (Avg. ±1 SD) under intermittent irrigation to 38.8 ± 1.0 Tg CH4/yr under continuous flooding in the 2000s, indicating that the magnitude of CH4 emissions from global rice fields is largely dependent on different water schemes. Over the past 110 years, our simulated results showed that global CH4 emissions from rice cultivation increased by 85%. The expansion of rice fields was the dominant factor for the increasing trends of CH4 emissions, followed by elevated CO2 concentration, and nitrogen fertilizer use. On the contrary, climate variability had reduced the cumulative CH4 emissions for most of the years over the study period. Our results imply that CH4 emissions from global rice fields could be reduced through optimizing irrigation practices. Therefore, the future magnitude of CH4 emissions from rice fields will be determined by the human demand for rice production as well as the implementation of optimized water management practices.

  7. Analysis of hyperspectral field radiometric data for monitoring nitrogen concentration in rice crops

    Science.gov (United States)

    Stroppiana, D.; Boschetti, M.; Confalonieri, R.; Bocchi, S.; Brivio, P. A.

    2005-10-01

    Monitoring crop conditions and assessing nutrition requirements is fundamental for implementing sustainable agriculture. Rational nitrogen fertilization is of particular importance in rice crops in order to guarantee high production levels while minimising the impact on the environment. In fact, the typical flooded condition of rice fields can be a significant source of greenhouse gasses. Information on plant nitrogen concentration can be used, coupled with information about the phenological stage, to plan strategies for a rational and spatially differentiated fertilization schedule. A field experiment was carried out in a rice field Northern Italy, in order to evaluate the potential of field radiometric measurements for the prediction of rice nitrogen concentration. The results indicate that rice reflectance is influenced by nitrogen supply at certain wavelengths although N concentration cannot be accurately predicted based on the reflectance measured at a given wavelength. Regression analysis highlighted that the visible region of the spectrum is most sensitive to plant nitrogen concentration when reflectance measures are combined into a spectral index. An automated procedure allowed the analysis of all the possible combinations into a Normalized Difference Index (NDI) of the narrow spectral bands derived by spectral resampling of field measurements. The derived index appeared to be least influenced by plant biomass and Leaf Area Index (LAI) providing a useful approach to detect rice nutritional status. The validation of the regressive model showed that the model is able to predict rice N concentration (R2=0.55 [p<0.01] RRMSE=29.4; modelling efficiency close to the optimum value).

  8. Detection of Inorganic Arsenic in Rice Using a Field Test Kit: A Screening Method.

    Science.gov (United States)

    Bralatei, Edi; Lacan, Severine; Krupp, Eva M; Feldmann, Jörg

    2015-11-17

    Rice is a staple food eaten by more than 50% of the world's population and is a daily dietary constituent in most South East Asian countries where 70% of the rice export comes from and where there is a high level of arsenic contamination in groundwater used for irrigation. Research shows that rice can take up and store inorganic arsenic during cultivation, and rice is considered to be one of the major routes of exposure to inorganic arsenic, a class I carcinogen for humans. Here, we report the use of a screening method based on the Gutzeit methodology to detect inorganic arsenic (iAs) in rice within 1 h. After optimization, 30 rice commodities from the United Kingdom market were tested with the field method and were compared to the reference method (high-performance liquid chromatography-inductively coupled plasma-mass spectrometry, HPLC-ICP-MS). In all but three rice samples, iAs compound can be determined. The results show no bias for iAs using the field method. Results obtained show quantification limits of about 50 μg kg(-1), a good reproducibility for a field method of ±12%, and only a few false positives and negatives (<10%) could only be recorded at the 2015 European Commission (EC) guideline for baby rice of 100 μg kg(-1), while none were recorded at the maximum level suggested by the World Health Organization (WHO) and implemented by the EC for polished and white rice of 200 μg kg(-1). The method is reliable, fast, and inexpensive; hence, it is suggested to be used as a screening method in the field for preselection of rice which violates legislative guidelines.

  9. Control Effects of Two-Batch-Duck Raising with Rice Framing on Rice Diseases, Insect Pests and Weeds in Paddy Field

    Directory of Open Access Journals (Sweden)

    Kai-ming Liang

    2012-10-01

    Full Text Available Rice-duck farming system is one of the means of organic rice farming, in which the weeds, diseases and insects could be effectively controlled with minimal or no pesticide and herbicide application. Whereas in conventional rice-duck farming system the controlling effect on diseases, insect pests and weeds was slowly disappeared after the rice heading stage at which ducks were driven out of the paddy field. To fill up the blank period of pasture activities of ducks, this study put forward two new rice-duck farming systems innovated from the conventional rice-duck farming system, in these new systems, two batches of ducks were raised with rice within one rice planting season. The results revealed that the overall controlling effect of ducks on rice diseases, insect pest and weeds was significantly enhanced in the two new rice-duck farming systems without agrochemicals application. It might be suggested that these two new systems have potential application as biocontrol agent for the organic rice agriculture.

  10. Phylogenetic and functional diversity of denitrifying bacteria isolated from various rice paddy and rice-soybean rotation fields.

    Science.gov (United States)

    Tago, Kanako; Ishii, Satoshi; Nishizawa, Tomoyasu; Otsuka, Shigeto; Senoo, Keishi

    2011-01-01

    Denitrifiers can produce and consume nitrous oxide (N(2)O). While little N(2)O is emitted from rice paddy soil, the same soil produces N(2)O when the land is drained and used for upland crop cultivation. In this study, we collected soils from two types of fields each at three locations in Japan; one type of field had been used for continuous cultivation of rice and the other for rotational cultivation of rice and soybean. Active denitrifiers were isolated from these soils using a functional single-cell isolation method, and their taxonomy and denitrifying properties were examined. A total of 110 denitrifiers were obtained, including those previously detected by a culture-independent analysis. Strains belonging to the genus Pseudogulbenkiania were dominant at all locations, suggesting that Pseudogulbenkiania denitrifiers are ubiquitous in various rice paddy soils. Potential denitrifying activity was similar among the strains, regardless of the differences in taxonomic position and soil of origin. However, relative amounts of N(2) in denitrification end products varied among strains isolated from different locations. Our results also showed that crop rotation had minimal impact on the functional diversity of the denitrifying strains. These results indicate that soil and other environmental factors, excluding cropping systems, could select for N(2)-producing denitrifiers.

  11. Changing cultural landscape in post-productivism of rice field in Nyuh Kuning Village Bali

    Science.gov (United States)

    Maulidi, C.; Wulandari, L. D.

    2017-06-01

    Natural landscape in developing countries is facing a challenge due to economic growth, a cultural shift, and population dynamics. Farm land where is close to urban areas tending to be converted into more economically valuable spaces. Watershed Pakerisan listed as World Heritage of UNESCO, rich of cultural value on its landscape, especially the Subak, a traditional irrigation system, has a close relationship to the philosophy of Hindu-Bali culture. Nyuh Kuning, a village (local terms is Banjar) located adjacent to the Pakerisan Watershed, and has a spatial pattern in synergic ally connected with tradition, culture, and their religion. Rice field not only for economical but also its place to worship the Goddess (Dewi Sri). Rice Field in Nyuh Kuning declined significantly along past 10 years. The changing landscape of Nyuh Kuning traced through serial of aerial photographs from 2005 until 2015. Along with the broad decline of rice field, villager’s attachment on their cultural space is also changing. An economic motive pronounces a winner in the bargaining between the motives of economic value and cultural value in the Nyuh Kuning. Villagers revealed arguments that necessities nowadays prosecute high consumption, both for household and for education. Therefore conversion of rice fields to become more economical is understandable among communities. Villagers rent the rice fields to foreigners (migrants), and then foreigners take rice-fields as personal assets, not for the villagers (ritual activities and the cultural traditions) any longer. In theoritical term, villager’s emotional bond to the cultural landscape in post—productivism of rice field, is weakened. Wawedangan Desa and its complex cultural values are not part of their identity anymore. However, place dependence become the reason why the shifting place attachment is happening. Functional economic bond is mentioned as place dependence dominats in villager’s attachment. Certainly it’s not a

  12. Prompt Proxy Mapping of Flood Damaged Rice Fields Using MODIS-Derived Indices

    Directory of Open Access Journals (Sweden)

    Youngjoo Kwak

    2015-11-01

    Full Text Available Flood mapping, particularly hazard and risk mapping, is an imperative process and a fundamental part of emergency response and risk management. This paper aims to produce a flood risk proxy map of damaged rice fields over the whole of Bangladesh, where monsoon river floods are dominant and frequent, affecting over 80% of the total population. This proxy risk map was developed to meet the request of the government on a national level. This study represents a rapid, straightforward methodology for estimating rice-crop damage in flood areas of Bangladesh during the large flood from July to September 2007, despite the lack of primary data. We improved a water detection algorithm to achieve a better discrimination capacity to discern flood areas by using a modified land surface water index (MLSWI. Then, rice fields were estimated utilizing a hybrid rice field map from land-cover classification and MODIS-derived indices, such as the normalized difference vegetation index (NDVI and enhanced vegetation index (EVI. The results showed that the developed method is capable of providing instant, comprehensive, nationwide mapping of flood risks, such as rice field damage. The detected flood areas and damaged rice fields during the 2007 flood were verified by comparing them with the Advanced Land Observing Satellite (ALOS AVNIR-2 images (a 10 m spatial resolution and in situ field survey data with moderate agreement (K = 0.57.

  13. Carbofuran promotes biochemical changes in carp exposed to rice field and laboratory conditions.

    Science.gov (United States)

    Clasen, Bárbara; Leitemperger, Jossiele; Murussi, Camila; Pretto, Alexandra; Menezes, Charlene; Dalabona, Fabrícia; Marchezan, Enio; Adaime, Martha Bohrer; Zanella, Renato; Loro, Vania Lucia

    2014-03-01

    Effects of carbofuran commercial formulation on oxidative stress parameters were studied in carps (Cyprinus carpio) exposed to 50µg/L for 7 and 30 days under rice field and laboratory conditions. Thiobarbituric acid reactive substance (TBARS) levels were increased in the brain of fish after 7 and 30 days under rice field and laboratory conditions. In the liver and muscle, TBARS levels increased after 7 and 30 days under laboratory conditions, whereas in rice field the levels increased only after 30 days. Protein carbonyl content in the liver increased after 7 and 30 days under both experimental conditions. Acetylcholinesterase (AChE) activity was decreased in the brain and muscle after 7 and 30 days under both experimental conditions evaluated. The superoxide dismutase (SOD) activity increased in the liver after 7 and 30 days under rice field condition, whereas under laboratory condition this enzyme increased only after 30 days. The catalase (CAT) activity in the liver decreased after 30 days under rice field condition, whereas no changes were observed under laboratory conditions. In rice field, glutathione S-transferase (GST) decreased after 7 days but increased after 30 days, whereas no change was observed in fish exposed to carbofuran under laboratory conditions. These results suggest that environmental relevant carbofuran concentrations may cause oxidative stress, affecting biochemical and enzymatic parameters on carps. Some parameters could be used as biomarkers to carbofuran exposure.

  14. Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?

    Science.gov (United States)

    Maltchik, Leonardo; Rolon, Ana Silvia; Stenert, Cristina; Machado, Iberê Farina; Rocha, Odete

    2011-12-01

    Conservation of species in agroecosystems has attracted attention. Irrigation channels can improve habitats and offer conditions for freshwater species conservation. Two questions from biodiversity conservation point of view are: 1) Can the irrigated channels maintain a rich diversity of macrophytes, macroinvertebrates and amphibians over the cultivation cycle? 2) Do richness, abundance and composition of aquatic species change over the rice cultivation cycle? For this, a set of four rice field channels was randomly selected in Southern Brazilian wetlands. In each channel, six sample collection events were carried out over the rice cultivation cycle (June 2005 to June 2006). A total of 160 taxa were identified in irrigated channels, including 59 macrophyte species, 91 taxa of macroinvertebrate and 10 amphibian species. The richness and abundance of macrophytes, macroinvertebrates and amphibians did not change significantly over the rice cultivation cycle. However, the species composition of these groups in the irrigation channels varied between uncultivated and cultivated periods. Our results showed that the species diversity found in the irrigation channels, together with the permanence of water enables these man-made aquatic networks to function as important systems that can contribute to the conservation of biodiversity in regions where the wetlands were converted into rice fields. The conservation of the species in agriculture, such as rice field channels, may be an important alternative for biodiversity conservation in Southern Brazil, where more than 90% of wetland systems have already been lost and the remaining ones are still at high risk due to the expansion of rice production.

  15. Composite fish culture for mosquito control in rice fields in southern India.

    Science.gov (United States)

    Victor, T J; Chandrasekaran, B; Reuben, R

    1994-09-01

    Composite culture of edible fishes (common carp, Cryprinus carpio; silver carp, Hypopthalmithys molitrix, grass carp, Ctenopharyngodon idella; catla, Catla catla; rohu, Labeo rohita; and mrigal, Cirrhinus mrigala) in rice fields in the Cauvery delta of Tamil Nadu, southern India, resulted in 81.0% reduction in the immature mosquito population of anophelines and 83.5% of culicines. Analysis of fish feces for mosquito larval head capsules showed that common carp and silver carp are effective larvivores. The selective feeding of common carp on culicines and silver carp on anophelines is correlated to their trophic niches. Net profit in the fish-cum-rice fields was 2.5 times greater than fields in which rice alone was cultured. Hence, rice-cum-fish culture can be recommended to the farming community in this area.

  16. Identification of rice field using Multi-Temporal NDVI and PCA method on Landsat 8 (Case Study: Demak, Central Java)

    Science.gov (United States)

    Sukmono, Abdi; Ardiansyah

    2017-01-01

    Paddy is one of the most important agricultural crop in Indonesia. Indonesia’s consumption of rice per capita in 2013 amounted to 78,82 kg/capita/year. In 2017, the Indonesian government has the mission of realizing Indonesia became self-sufficient in food. Therefore, the Indonesian government should be able to seek the stability of the fulfillment of basic needs for food, such as rice field mapping. The accurate mapping for rice field can use a quick and easy method such as Remote Sensing. In this study, multi-temporal Landsat 8 are used for identification of rice field based on Rice Planting Time. It was combined with other method for extract information from the imagery. The methods which was used Normalized Difference Vegetation Index (NDVI), Principal Component Analysis (PCA) and band combination. Image classification is processed by using nine classes, those are water, settlements, mangrove, gardens, fields, rice fields 1st, rice fields 2nd, rice fields 3rd and rice fields 4th. The results showed the rice fields area obtained from the PCA method was 50,009 ha, combination bands was 51,016 ha and NDVI method was 45,893 ha. The accuracy level was obtained PCA method (84.848%), band combination (81.818%), and NDVI method (75.758%).

  17. Greenhouse gas budget from a rice paddy field in the Albufera of Valencia, Spain.

    Science.gov (United States)

    Meijide, Ana; López-Ballesteros, Ana; Calvo-Roselló, Esperanza; López-Jiménez, Ramón; Recio-Huetos, Jaime; Calatayud, Vicent; Carrara, Arnaud; Serrano-Ortiz, Penelope

    2017-04-01

    Rice paddy fields are large sources of anthropogenic methane (CH4) and therefore many studies have assessed CH4 fluxes from rice paddy fields, mainly in Asia where most of the rice cultivation takes place. However, rice is also cultivated in the Mediterranean, where climatic and management conditions greatly differ. In the Albufera of Valencia, the largest freshwater lagoon in Spain, rice paddy fields have the particularity of being flooded not only while the rice grows, but also after the harvest during the winter. These flooding conditions might result in emissions which are very specific of this ecosystem, and cannot be extrapolated from other studies. We studied CH4 fluxes in a rice paddy field in the Albufera of Valencia at different stages of rice cultivation using the eddy covariance technique and static chambers. We additionally measured carbon dioxide (CO2), water fluxes and nitrous oxide (N2O) fluxes with eddy covariance and chamber methods respectively, in order to obtain a full greenhouse gas (GHG) budget. Our study also aimed at providing a mechanistic understanding of GHG emissions at different stages of rice cultivation, and therefore we also used the Enhanced and Normalized Vegetation Indexes (EVI and NDVI, respectively), derived from remote sensing images. The general ecosystem functioning encompasses three different phases. The first one, over the autumn and the winter, a biological dormancy period causes low CO2 emissions (ca. 1-5 µmol m-2 s-1), which coincides with the EVI and NDVI. The intermittent flooding taking place during this period is expected to cause CH4 emissions. Then, during the spring months (March-May), larger CO2 respiratory emissions take place during the daytime (> 5 µmol m-2 s-1) due to an increase in air temperature, which turn to neutral at the end of spring due to the start of photosynthesis by the rice. The third phase corresponds to the vegetation growth, when the net CO2 uptake increases gradually up to maximum CO2

  18. Geostatistics applied to the study of the spatial distribution of Tibraca limbativentris in flooded rice fields

    Directory of Open Access Journals (Sweden)

    Juliano de Bastos Pazini

    2015-06-01

    Full Text Available Tibraca limbativentris (rice stem bug is an insect highly injurious to the rice crop in Brazil. The aim of this research was to define the spatial distribution of the T. limbativentris and improve the sampling process by means of geostatistical application techniques and construction of prediction maps in a flooded rice field located in the "Planalto da Campanha" Region, Rio Grande do Sul (RS, Brazil. The experiments were conducted in rice crop in the municipality of Itaqui - RS, in the crop years of 2009/10, 2010/11 and 2011/12, counting fortnightly the number of nymphs and adults in a georeferenced grid with points spaced at 50m in the first year and in 10m in the another years. It was performed a geostatistical analysis by means adjusting semivariogram and interpolation of numeric data by kriging to verify the spatial dependence and the subsequent mapping population. The results obtained indicated that the rice stem bug, T. limbativentris, has a strong spatial dependence. The prediction maps allow estimating population density of the pest and visualization of the spatial distribution in flooded rice fields, enabling the improvement of the traditional method of sampling for rice stem bug

  19. Biodiversity and Dynamics of Planthoppers and Their Natural Enemies in Rice Fields with Different Nitrogen Regimes

    Institute of Scientific and Technical Information of China (English)

    LU Zhong-xian; S.VILLAREAL; YU Xiao-ping; K.L.HEONG; HU Cui

    2006-01-01

    A field experiment was conducted to study the effect of different nitrogen fertilizer rates I.e. 200, 100 and 0 kg N/ha in paddy fields at International Rice Research Institute, Manila, Philippines. Biodiversity of arthropods sampled by Blower-Vac, and dynamics of planthoppers, egg parasitoids of Homoptera trapped by rice plants with eggs of brown planthoppers (BPH) Nilaparvata lugens (St(ā)l), and web spiders on rice canopy collected by sweeping net, were analyzed at different rice growth stages. The most abundant arthropods were sampled at the milking stage of rice, totalling 116 species identified into 14 insect orders and 15 species of spider in all samples. Meanwhile the number of arthropod species significantly increased with rice growth and the diversity indices increased with the increase of nitrogen rate at the booting stage. On the other hand, in the dominant predators, Pardosa pseudoannulata, Callitrichi formosana, Micraspis sp., Cyrtorhinus lividipennis, Veliidae sp. And Mesoveliidae sp., only C. Lividipennis and Micraspis sp. Were increased significantly in abundance following the application of nitrogen at the milking stage of rice. The egg parasitoids of plant-hoppers were predominated by Anagrus flaveolus and Oligosita sp. And their densities in the field without nitrogen fertilizer were markedly higher than those in fields with 100 and 200 kg N/ha at both booting and milking stages of rice. The number and web area of dominant residential spiders Tetragnatha sp. And Araneus sp. In rice canopy significantly reduced with the increase of nitrogen fertilizer. The population density of planthoppers, included BPH and the white-backed planthoppers (WBPH) Sogatella furcifera Horváth, peaked during the booting stage, however, the number of BPH in rice field with 200 kg N/ha was considerably higher than those in other two rice fields with 100 kg N/ha and 0 kg N/ha at the booting as well as the milking stage. These results indicated that the rapid growth in

  20. Field Evaluation of Four Spatial Repellent Devices Against Arkansas Rice-Land Mosquitoes

    Science.gov (United States)

    2014-03-01

    FIELD EVALUATION OF FOUR SPATIAL REPELLENT DEVICES AGAINST ARKANSAS RICE-LAND MOSQUITOES DAVID A. DAME,1 MAX V. MEISCH,2 CAROLYN N. LEWIS,2 DANIEL L... mosquitoes to locate a host. There are many commercially available spatial repellent products currently on the market. These products include...a large rice growing area where late-spring and summer agricultural irriga- tion generates dense mosquito populations. Spatial repellent devices

  1. Numerical modelling of salt diapirism and the surrounding temperature field during thin-skinned extension

    Science.gov (United States)

    Thieulot, Cedric; Harms, Guido

    2016-04-01

    The occurrence of salt diapirs is strongly associated with potential geothermal and hydrocarbon energy sources. Many numerical modelling studies of diapirism have been done in the past, though very few of these in fact use geologically realistic settings and materials. Besides, only analogue and structural studies have been done on full scale diapirism during thin-skinned extension. Two-dimensional numerical modelling of this problem using a Finite Element code aims at addressing the following questions: which geometrical or material parameters affect the growth rate and shape of the diapir and how? what is the effect of this diapirism on the temperature field and surface heat flux? How does the inclusion of simple surface processes influence these observations to first order ? Our results show that, in compliance with both analogue modelling and structural geological studies, a diapir formed during thin-skinned extension undergoes three phases: reactional piercement, active piercement and passive piercement. Extension rates directly influence the total time required for the diapir to reach the surface, as well as how long the system remains in a state of reactional diapirism, which both affect the shape of the resulting diapir. Erosion efficiency is found to affect the growth rate of the diapir during its active stage and the total rising time, which affects in turn its the shape. The density contrast between the salt and the sediments also influences the growth rate during active and passive piercement. Finally, the temperature surrounding a rising diapir (especially in the region above it) is found to be heightened by a few dozens of degrees.

  2. Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields

    DEFF Research Database (Denmark)

    Mutero, C M; Ng'ang'a, P N; Wekoyela, P

    2004-01-01

    Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block, and the fertili......Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block...... populations of An. arabiensis (Pmosquitoes (P... in rice fields, thereby making them visually more attractive for egg-laying by An. arabiensis and culicine mosquitoes....

  3. Preliminary studies on microbiological mechanism of the dynamics of CH4 and N2O emission from rice field

    Institute of Scientific and Technical Information of China (English)

    HOUAixin; CHENGuanxiong; WUjie; WANGZhengping

    1998-01-01

    Greenhouse gases, CH4 and N2O emitted from rice field, are the products of microbial metabolism. So the characteristics of CH4 and N2O production and emission in rice field can be understood through microbiological study. In this paper, the relationships between the dynamics of CH4 and N2O emission from rice field in northern China and the related soil bacteria groups were discussed.

  4. Measuring Radionuclides Concentration in Rice Field Soils Using Gamma Spectroscopy in Northern Iran

    Directory of Open Access Journals (Sweden)

    MZ Zareh

    2012-02-01

    Full Text Available Background: A few elements of soil are radioactive. Soil can transfer radionuclide into plants feeding human. Sometimes their levels are as high as to be concern of human healthy. Rice has an important share for Iranian foods especially in north of Iran. Therefore we decided to obtain radionuclides concentration emitting g rays in Lahijan City (Northern Iran rice fields using g spectroscopy.Methods: Twenty eight samples from rice field's soils and 12 samples from superficial soils were collected at a square of 10*10 m2 to get 2kg weight. To make dry samples were put into oven at 105oC for 24h. Then they were milled and 950 gr of each sample was transferred to Marinelli container with 1000cc volume, sealed and left for 40 days to get secular equilibrium. After measuring Ph, Electric conductivity and organic carbon, g spectroscopy was done to get sample gamma spectrum at 2000-6000 sec using HpGe detector.Results: It was found 226Ra activity in rice fields of 29.273±0.72 Bqkg-1 and city soil of 31.02±1.1 Bqkg-1 and also 232Th activity of 37.47±1.12 Bqkg-1 for rice fields' soils and 40.47±1.68 Bqkg-1 for city soil were in standard mode.Conclusion: 40K activities mean value according to UNSCEAR; 2000 was found a little greater than standard. A little value of 137Cs was found in Lahijan rice fields and city soils that could be as a result of Chernobyl accident. In except of 137Cs, for three other under studied city soil elements, activities were greater than that of rice fields.

  5. Mitigation of cadmium and arsenic in rice grain by applying different silicon fertilizers in contaminated fields.

    Science.gov (United States)

    Wang, Hong-Yan; Wen, Shi-Lin; Chen, Peng; Zhang, Lu; Cen, Kuang; Sun, Guo-Xin

    2016-02-01

    A field experiment was established to support the hypothesis that application of different silicon (Si) fertilizers can simultaneously reduce cadmium (Cd) and arsenic (As) concentration in rice grain. The "semi-finished product of Si-potash fertilizer" treatment at the high application of 9000 kg/ha (NP+S-KSi9000) significantly reduced the As concentration in rice grain by up to 20.1%, compared with the control. Si fertilization reduces the Cd concentration in rice considerably more than the As concentration. All Si fertilizers apart from sodium metasilicate (Na2SiO3) exhibited a high ability to reduce Cd concentration in rice grain. The Si-calcium (CaSi) fertilizer is the most effective in the mitigation of Cd concentration in rice grain. The CaSi fertilizer applied at 9000 kg/ha (NPK+CaSi9000) and 900 kg/ha (NPK+CaSi900) reduced the Cd concentration in rice grain about 71.5 and 48.0%, respectively, while the Si-potash fertilizer at 900 kg/ha (NP+KSi900), the semi-finished product of Si-potash fertilizer at both 900 kg/ha (NP+S-KSi900) and 9000 kg/ha (NP+S-KSi9000), and the rice straw (NPK+RS) treatments reduced the Cd concentration in rice grain about 42, 26.5, 40.7, and 23.1%, respectively. The results of this investigation demonstrated the potential effects of Si fertilizers in reducing Cd and As concentrations in rice grain.

  6. Population dinamics of Lymnaea rubiginosa in rice fields and its infection with larvae of trematodes

    Directory of Open Access Journals (Sweden)

    Suhardono

    2000-12-01

    Full Text Available Field of irrigated rice paddy was the most suitable habitat as breeding site of snail Lymnaea rubiginosa, the intermadiate host of Fasciola gigantica and other trematodes. Fluctuations in the population of fresh water snail, L. rubiginosa in irrigated rice fields and their infection with L. rubiginosa and other trematodes were studied in five villages in the subdistrict of Surade, provivine of West Java. Snail were sampled based on time collection (half man hour each site of collection. The samples of the snails were further counted and examined for the presence of larval trematodes. The result indicated that snails died during the dry season except those in persistent aquatic refuges such as streams and springs. Surviving snails recolonised rice fields near villages by passive transfer with water from refuges early in the wet season. Some recolonosation may also have resulted from haching of snail eggs deposited in habitats which had not been dried for more than a few weeks. Recolonisation with snails of further rice fields from a village occurred during the later period of the wet season. No snail infected with F. gigantica was found in the distance of more than 200 m from a village. Snail with the highest prevalence of infection occurred in rice fields which received effluent from a cattle pen were fertilised with bovine faeces. Each snail was only infected with one species of tramatodes. Infection with echinostone larvae was most common.

  7. [Chromosomal localization of the hormone-sensitive lipase gene (Hsl) in rice field eel].

    Science.gov (United States)

    Ji, Fu-Yun; Yu, Qi-Xing; Pan, Pei-Wen

    2003-03-01

    Adipose tissue triacylglycerols are the quantitatively most important source of stored energy in animals. Hormone-sensitive lipase encoded by hormone-sensitive lipase gene (Hsl) is a multifunctional enzyme that catalyzes the hydrolysis of triacylglycerol stored in adipose tissue and cholesterol esters in the adrenals, ovaries, testes and macrophages. Using pig Hsl gene inserted into pBS labeled by the radioactive isotope and the digoxigenin as the probes respectively one band, 11.5kb, has been shown to hybridized with total DNA of rice field eel digested with Pst I by Southern blotting and Hsl gene has been assigned to metaphase chromosome 5, at the position of 78.35+/-1.26 from the centromere in rice field eel by fluorescent in situ hybridization (FISH). The mapping results are corresponding to that of "specific-chromosomal DNA pool" obtained by chromosome microisolation used to map gene and the mapping result is more accurate. The results of the study further illustrate the importance of the presence of Hsl gene in rice field eel genome and provide the first FISH mapping data for rice field eel chromosome 5. The current studies would advance the addition of known genetic markers and the construction of high resolution genetic map in rice field eel genome.

  8. Occurrence and Population Dynamics of Chironomids in Early-Season Rice Fields

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-yu; YANG Hong; LAI Feng-xiang; FU Qiang; HU Yang

    2011-01-01

    The chironomid is one of the world wide distributed insects and normally occurs in a great abundance among many kinds of water bodies.Currently,our knowledge about the chironomid in rice fields is limited to the species survey,and it is considered as a group insect at the family level,termed as a kind of the neutral insects.By using the specially designed emergence traps,the species richness and the occurrence of the chironomid in rice fields were studied throughout the early season in Fuyang City,Zhejiang Province,China.There were four species,namely,Tanytarsus formosanus,Chironomus sinicus,Polypedilum nubifer and Tanypus punctipennis of chironomids collected from rice fields.All of them are widely distributed species.T.formosanus and C.sinicus were the most dominant species in rice fields.The succession of chironomids in the early season could be divided into two phases,the early and the late phases.The abundance of the chironomid was higher in the early phase than that in the late phase.It was estimated that there were around 3 million individuals of chironomids emerged from 667 m2 rice field throughout the early season.It was also found that the sex ratio of T.formosanus was female-biased during the early phase,whereas male-biased during the late phase.In contrast,the sex ratio of C.sinicus was male-biased throughout the early season.

  9. Seasonal Production and Emission of Methane from Rice Fields, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, M. Aslam K.; Rasmussen,Reinhold A.

    2002-12-03

    B 139 - Methane (CH4) is a greenhouse gas regarded second only to carbon dioxide in its ability to cause global warming. Methane is important because of its relatively fast increase, and also because it is, per molecule, some 60 times more effective than carbon dioxide in causing global warming. The largest present anthropogenic sources of methane are rice fields, cattle and biomass burning. The global emissions from these sources are still not well known. In the middle 1980s there were few available data on methane emissions from rice fields leading to estimates of a global source between 100-280 Tg/yr. Extensive worldwide research during the last decade has shown that the global emissions from rice fields are more likely to be in the range of 30-80Tg/yr. While this work has led to a substantial reduction in the estimated emissions, the uncertainty is still quite large, and seriously affects our ability to include methane in integrated assessments for future climate change and environmental management.China dominated estimates of methane emissions from rice fields because it was, and is, the largest producer of rice, and major increases in rice production had taken place in the country over the last several decades. This report summarizes the work in Sichuan Province, China, in each of the following areas: the design of the experiment; the main results on methane emissions from rice fields, delineating the factors controlling emissions; production of methane in the soil; a survey of water management practices in sample of counties in Sichuan province; and results of ambient measurements including data from the background continental site. B139

  10. [Exposure degree of important non-target arthropods to Cry2Aa in Bt rice fields].

    Science.gov (United States)

    Zhang, Qing-Ling; Li, Yun-He; Hua, Hong-Xia; Yang, Chang-Ju; Wu, Hong-Jin; Peng, Yu-Fa

    2013-06-01

    Based on the principle of "risk = hazard x exposure", the selected representative nontarget organisms in the assessment of the potential effects of insect-resistant genetically modified (GM) crops on non-target arthropods in laboratory are generally the arthropod species highly exposed to the insecticidal proteins expressed by the GM crops in farmland ecosystem. In order to understand the exposure degree of the important arthropod species to Cry proteins in Bt rice fields, and to select the appropriate non-target arthropods in the risk assessment of insect-resistant GM crops, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the Cry2Aa protein concentration in the arthropods collected from the cry2Aa rice fields at different rice growth stages. The results showed that there was a significant difference in the Cry2Aa content protein concentration in different arthropod species. Some species did not contain Cry2Aa protein, while some species contained larger amounts of Cry2Aa protein. Relative to the arthropods colleted after rice anthesis, the arthropods colleted in rice anthesis contained relative higher concentrations of Cry2Aa protein, especially for the predacious arthropods. No Cry proteins were detected in parasitic arthropods. This study provided references for the laboratory assessment of the effects of GM rice on nontarget arthropods.

  11. Estimate of Methane Emission from Rice Paddy Fields in Taihu Region,China

    Institute of Scientific and Technical Information of China (English)

    CAIZU-CONG; JINJI-SHENG; 等

    1994-01-01

    Methane fluxes from late rice and single cropping rice fields in Taihu region were measured using closed chamber method in 1992 and 1993 and CH4 emission from this region (total area of paddy soils was about 1.88 million hectares,of which 0.63 million hectares are distibuted in the south of Jiangsu province) was estimated on the basis of the meam CH4 fluxes observed.The results showed that the mean CH4 flaxes from late rice and single cropping rice field were quite similar under the prevailing cultivation practices in the region,being around 5 mg CH4/m2/h(4.31-5.31mg CH4/m2/h for various cultivars of the late rice and 3.20-6.22mg CH4/m2/h for various treatments of the single cropping rice).Total CH4 emission from paddy soils in the region was estimated to e 0.185-0.359 Tg CH4 per year.Continuously flooding the soil with a water layer till ripening caused higher mean CH4 flux;and addition of nitrification inhibitor(thiourea) stimulated CH4 emission.There was no simple repationship between CH4 flux and either soil temperature or soil Eh.

  12. Deciphering Community Structure of Methanotrophs Dwelling in Rice Rhizospheres of an Indian Rice Field Using Cultivation and Cultivation-Independent Approaches.

    Science.gov (United States)

    Pandit, Pranitha S; Rahalkar, Monali C; Dhakephalkar, Prashant K; Ranade, Dilip R; Pore, Soham; Arora, Preeti; Kapse, Neelam

    2016-04-01

    Methanotrophs play a crucial role in filtering out methane from habitats, such as flooded rice fields. India has the largest area under rice cultivation in the world; however, to the best of our knowledge, methanotrophs have not been isolated and characterized from Indian rice fields. A cultivation strategy composing of a modified medium, longer incubation time, and serial dilutions in microtiter plates was used to cultivate methanotrophs from a rice rhizosphere sample from a flooded rice field in Western India. We compared the cultured members with the uncultured community as revealed by three culture-independent methods. A novel type Ia methanotroph (Sn10-6), at the rank of a genus, and a putative novel species of a type II methanotroph (Sn-Cys) were cultivated from the terminal positive dilution (10(-6)). From lower dilution (10(-4)), a strain of Methylomonas spp. was cultivated. All the three culture-independent analyses, i.e., pmoA clone library, terminal restriction fragment length polymorphism (T-RFLP), and metagenomics approach, revealed the dominance of type I methanotrophs. Only metagenomic analysis showed significant presence of type II methanotrophs, albeit in lower proportion (37 %). All the three isolates showed relevance to the methanotrophic community as depicted by uncultured methods; however, the cultivated members might not be the most dominant ones. In conclusion, a combined cultivation and cultivation-independent strategy yielded us a broader picture of the methanotrophic community from rice rhizospheres of a flooded rice field in India.

  13. GlyRα2, not GlyRα3, modulates the receptive field surround of OFF retinal ganglion cells.

    Science.gov (United States)

    Zhang, Chi; Nobles, Regina D; McCall, Maureen A

    2015-01-01

    Receptive fields (RFs) of most retinal ganglion cells (RGCs) consist of an excitatory center and suppressive surround. The RF center arises from the summation of excitatory bipolar cell glutamatergic inputs, whereas the surround arises from lateral inhibitory inputs. In the retina, both gamma amino butyric acid (GABA) and glycine are inhibitory neurotransmitters. A clear role for GABAergic inhibition modulating the RGC RF surround has been demonstrated across species. Glycinergic inhibition is more commonly associated with RF center modulation, although there is some evidence that it may contribute to the RF surround. The synaptic glycinergic chloride channels are formed by three homomeric β and two homomeric α subunits that can be glycine receptor (GlyR) α1, α2, α3, or α4. GlyRα composition is responsible for currents with distinct decay kinetics. Their expression within the inner plexiform laminae and neuronal subtypes also differ. We studied the role of GlyR subunit selective modulation of RGC RF surrounds, using mice lacking GlyRα2 (Glra2 -/-), GlyRα3 (Glra3 -/-), or both (Glra2/3 -/-). We chose this molecular genetic approach instead of pharmacological manipulation because there are no subunit selective antagonists and strychnine blocks all GlyRs. Comparisons of annulus-evoked responses among wild type (WT) and GlyRα knockouts (Glra2 -/-, Glra3 -/- and Glra2/3 -/-) show that GlyRα2 inhibition enhances RF surround suppression and post-stimulus excitation in only WT OFF RGCs. Similarities in the responses in Glra2 -/- and Glra2/3 -/- RGCs verify these conclusions. Based on previous and current data, we propose that GlyRα2-mediated input uses a crossover inhibitory circuit. Further, we suggest that GlyRα2 modulates the OFF RGC RF center and surround independently. In summary, our results define a selective GlyR subunit-specific control of RF surround suppression in OFF RGCs.

  14. Management of Rice Fields for Birds during the Non-growing Season

    NARCIS (Netherlands)

    Elphick, Chris S.; Taft, Oriane; Lourenco, Pedro M.

    2010-01-01

    Fields planted with rice (Oryza saliva) are used by a wide variety of bird species during the non-growing season and play an important conservation role in many parts of the world. Management of fields affects the variety and number of birds that use them, and a thorough understanding of these issue

  15. Field and greenhouse inoculation methods for assessment of sheath blight resistance in rice

    Directory of Open Access Journals (Sweden)

    Leila Garcês de Araújo

    2007-01-01

    Full Text Available Field and greenhouse inoculation methods were compared to determine the genetic variation for resistance toRhizoctonia solani in 38 somaclones of rice cultivar Metica-1. Rice plants in pots were inoculated with isolate 4F1 at the ageof sixty four days, with 2.0 g of the fungal culture, multiplied on rice grain and hull medium and placed on the soil surfacearound the plant. The differences among somaclones in relation to lesion height were significant and varied from 6.5 to 15.5cm. In the field trial of artificial inoculation with fungal culture, 52 days after planting, the lesion height varied from 6.2 to 17.7cm. The correlation between disease severity in the greenhouse and the field was positive and highly significant (r=0.44;P< 0.01, indicating the greenhouse inoculation as a safe method for screening germplasm for sheath blight resistance.

  16. A possible alternative method for collecting mosquito larvae in rice fields

    Directory of Open Access Journals (Sweden)

    Goff Gilbert

    2002-04-01

    Full Text Available Abstract Background Rice fields are efficient breeding places for malaria vectors in Madagascar. In order to establish as easily as possible if a rice field is an effective larval site for anophelines, we compared classical dipping versus a net as methods of collecting larvae. Results Using similar collecting procedures, we found that the total number of anopheline larvae collected with the net was exactly double (174/87 that collected by dipping. The number of anopheline species collected was also greater with a net. Conclusions The net is an effective means of collecting anopheline larvae and can be used for qualitative ecological studies and to rapidly determine which rice fields are containing malaria vectors.

  17. Impact of fungicide and insecticide use on non-target aquatic organisms in rice paddy fields

    Directory of Open Access Journals (Sweden)

    Alana Cristina Dorneles Wandscheer

    Full Text Available ABSTRACT: The intensive use of plant protection products in rice paddy fields ( Oryza sativa L. has caused concern about the environmental impact on communities of non-target organisms that are natural inhabitants in these agroecosystems. The purpose of this review is to analyze the data currently available in the literature about some important fungicides and insecticides (such as trifloxystrobin, tebuconazole, tricyclazole, lambda-cyhalothrin, and thiamethoxam, which are currently used to control pests and diseases in rice paddy fields, as well as their effects on the community of non-target aquatic organisms.

  18. Size-resolved culturable airborne bacteria sampled in rice field, sanitary landfill, and waste incineration sites.

    Science.gov (United States)

    Heo, Yongju; Park, Jiyeon; Lim, Sung-Il; Hur, Hor-Gil; Kim, Daesung; Park, Kihong

    2010-08-01

    Size-resolved bacterial concentrations in atmospheric aerosols sampled by using a six stage viable impactor at rice field, sanitary landfill, and waste incinerator sites were determined. Culture-based and Polymerase Chain Reaction (PCR) methods were used to identify the airborne bacteria. The culturable bacteria concentration in total suspended particles (TSP) was found to be the highest (848 Colony Forming Unit (CFU)/m(3)) at the sanitary landfill sampling site, while the rice field sampling site has the lowest (125 CFU/m(3)). The closed landfill would be the main source of the observed bacteria concentration at the sanitary landfill. The rice field sampling site was fully covered by rice grain with wetted conditions before harvest and had no significant contribution to the airborne bacteria concentration. This might occur because the dry conditions favor suspension of soil particles and this area had limited personnel and vehicle flow. The respirable fraction calculated by particles less than 3.3 mum was highest (26%) at the sanitary landfill sampling site followed by waste incinerator (19%) and rice field (10%), which showed a lower level of respiratory fraction compared to previous literature values. We identified 58 species in 23 genera of culturable bacteria, and the Microbacterium, Staphylococcus, and Micrococcus were the most abundant genera at the sanitary landfill, waste incinerator, and rice field sites, respectively. An antibiotic resistant test for the above bacteria (Micrococcus sp., Microbacterium sp., and Staphylococcus sp.) showed that the Staphylococcus sp. had the strongest resistance to both antibiotics (25.0% resistance for 32 microg ml(-1) of Chloramphenicol and 62.5% resistance for 4 microg ml(-1) of Gentamicin).

  19. Soil organic carbon in riparian forests, rice fields, and pastures in Piedras, Tolima, Colombia.

    Directory of Open Access Journals (Sweden)

    Hernán Jair Andrade-Castañeda

    2016-06-01

    Full Text Available The aim of the study was to estimate the soil organic carbon (SOC storage in the interface between riparian forests and a matrix of rice fields and pastures with organic management. The study took place in Piedras, Tolima, Colombia. Two plots in production (rice and pasture were selected and SOC was estimated in these areas and in the edge and the interior of adjacent riparian forests at a depth of 0 to 20 cm. Bulk density and SOC concentration were quantified between May and July, 2013. Potential change in SOC storage due to land use change among rice fields, pastures, and riparian forests was estimated. The interfaces rice field-riparian forest and pasture-riparian forest stored an average of 65.6 and 61.3 t C/ha, respectively, with no statistical differences (p>0.05. Statistical differences were not detected (p>0.05 between agricultural matrices (rice fields and pastures in any of the variables. The sampling position (matrix and the edge and interior of forests had a significant impact (p<0.05 just in bulk density: 1.7 vs 1.1 vs 1.0 g/cm3 in interior and edge of the riparian forests and the matrix, respectively. SOC was not statistically affected (p>0.05 by the position in the riparian forest-matrix interface. Conversion from riparian forests to rice fields or pastures with organic management is not emitting greenhouse gases, on the contrary, it is increasing SOC in 3.2 t C/ha. 

  20. Distribution and identification of proteolytic Bacillus spp. in paddy field soil under rice cultivation.

    Science.gov (United States)

    Watanabe, K; Hayano, K

    1993-07-01

    Proteolytic bacteria in paddy field soils under rice cultivation were characterized and enumerated using azocoll agar plates. Bacillus spp. were the proteolytic bacteria that were most frequently present, comprising 59% of the isolates. They were always the numerically dominant proteolytic bacteria isolated from three kinds of fertilizer treatments (yearly application of rice-straw compost and chemical fertilizer, yearly application of chemical fertilizer, and no fertilizer application) and at three different stages of rice development (vegetative growth stage, maximal tillering stage, and harvest stage). Of the 411 proteolytic bacteria isolated, 124 isolates had stronger proteolytic activity than others on the basis of gelatin liquefaction tests and most of them were Bacillus spp. (100% in 1989 and 92.4% in 1991). Bacillus subtilis and Bacillus cereus were the main bacteria of this group and Bacillus mycoides, Bacillus licheniformis, and Bacillus megaterium were also present. We conclude that these Bacillus spp. are the primary source of soil protease in these paddy fields.

  1. Fertilizer nitrogen recovery of rice: /sup 15/N field studies (a short review)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.; Katyal, J.C. (Punjab Agricultural Univ., Ludhiana (India). Dept. of Soils)

    1980-12-01

    Reliable quantitative estimates of fertilizer nitrogen recovery by rice are obtained in field investigations with /sup 15/N-labelled materials. Values obtained by conventional 'difference method' of comparing fertilized and unfertilized plots are typically larger than the actual values. Estimating the recovery of fertilizer nitrogen is not a goal in itself. Although it has been an essential component of limited number of /sup 15/N-field experiments conducted with rice so far; these provide little or no information about crop growth stages when fertilizer N is most efficiently utilized by rice plant. Recently, the path coefficient analysis has been used to analyse the effect of N uptake on the development of yield components and their contribution to grain yield. Nitrogen-15 fertilizers along with path coefficient analysis can prove particularly useful in comparing the efficiency of different N fertilizers and in the development of new and more efficient nitrogen sources and management practices.

  2. Dissipation of the herbicide benzobicyclon hydrolysate in a model California rice field soil.

    Science.gov (United States)

    Williams, Katryn L; Gladfelder, Joshua J; Quigley, Lindsay L; Ball, David B; Tjeerdema, Ronald S

    2017-09-29

    The herbicide benzobicyclon (BZB; 3-(2-chloro-4-(methylsulfonyl)benzoyl)-2-phenylthiobicyclo[3.2.1]oct-2-en-4-one) has recently been approved for use on California rice fields by the United States Environmental Protection Agency (USEPA). Hydrolysis of BZB rapidly forms the active compound, benzobicyclon hydrolysate (BH), whose fate is currently not well understood. A model California rice soil was used to determine BH soil dissipation. The pKa and aqueous solubility were also determined, as experimental values are not currently available. Sorption data indicate BH does not bind tightly, or irreversibly, with this soil. Flooding resulted in decreased BH loss, indicating anaerobic microbes are less likely to transform BH compared to aerobic microorganisms. Temperature increased dissipation, while autoclaving decreased BH loss. Overall, dissipation was slow regardless of treatment. Further investigation is needed to elucidate the exact routes of loss in soil, though BH is expected to dissipate slowly in flooded rice field soil.

  3. Biodegradation of clomazone in a California rice field soil: carbon allocation and community effects.

    Science.gov (United States)

    Tomco, Patrick L; Holmes, William E; Tjeerdema, Ronald S

    2013-03-20

    Degradation pathways for the herbicide clomazone in a California rice field soil were characterized via pulse-labeling of anaerobic (flooded) and aerobic (moist) soil microcosms. Clomazone-derived (13)C in the major C pools of a rice ecosystem and soil phospholipid fatty acid (PLFA) profiles were analyzed over time to determine if (1) the compound accumulates in the microbial biomass, (2) it affects temporal microbial population dynamics, and (3) it is either preferentially metabolized or cometabolized. In anaerobic microcosms, the compound was rapidly biotransformed to ring-open clomazone, upon which it persisted in the aqueous phase, whereas aerobic microcosms degraded it slower but a greater percentage was mineralized. Anaerobic biomass decreased after clomazone was added, and aerobic actinomycete abundance differed between treatments and controls. Additionally, PLFA and (13)C PLFA were statistically similar between treatment and controls. Thus, microbial cometabolism is likely to be the dominant degrading mechanism governing clomazone fate in California rice fields.

  4. Ecosystem manipulation for increasing biological N2 fixation by blue-green algae (CYANOBACTERIA) in lowland rice fields

    OpenAIRE

    Grant, I.F.; Roger, Pierre-Armand; Watanabe, I.

    1986-01-01

    An introduction to the soil/floodwater ecosystem of lowland rice fields is given. Two primary consumers are particularly important in limiting the growth and N2-fixing activities of blue-green algae in irrigated rice ; the OSTRACODA (Class CRUSTACEA) and the PULMONATA (MULUSCA). Control of grazing by neem seeds AZADIRACHTA INDICA A. Juss and cultural practices enhanced BGA biomass and increased N2-fixation ten fold. Significant increases in rice grain protein occur if heterocystous algae bloo...

  5. Fields of rice: health hazards for women and unborn children.

    Science.gov (United States)

    Batliwala, S

    1988-01-01

    A death information study, to determine why the infant mortality rate failed to fall below 75/1000, was begun in January 1982, after 9 years of accomplishments by the rural health research project in Raigad district of coastal Maharashtra. All data were collected by 27 female rural health workers, some of whom were illiterate but received help from villagers. Death records included name, sex, age, date and time of death, and cause of death or symptoms before death. In the 0-6 age group, 64% of the deaths were girls. 80% of the dead children were infant deaths, and of these, 75% were neonatal, suggesting the influence of prenatal, obstetric and postnatal factors and maternal nutrition. The majority were related to premature and low birth weight babies. Another striking observation was that 40% of all infant deaths occurred in July-October, and 50% of these were stillbirths and premature births. July and August are the months when all women (and no men) work transplanting rice seedlings. This work is done by bending or squatting from dawn to dusk. Thus, rice culture must be considered an occupational hazard for women in late pregnancy.

  6. Paddy-field contamination with 134Cs and 137Cs due to Fukushima Dai-ichi Nuclear Power Plant accident and soil-to-rice transfer coefficients.

    Science.gov (United States)

    Endo, Satoru; Kajimoto, Tsuyoshi; Shizuma, Kiyoshi

    2013-02-01

    The transfer coefficient (TF) from soil to rice plants of (134)Cs and (137)Cs in the form of radioactive deposition from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011 was investigated in three rice paddy fields in Minami-Soma City. Rice crops were planted in the following May and harvested at the end of September. Soil cores of 30-cm depth were sampled from rice-planted paddy fields to measure (134)Cs and (137)Cs radioactivity at 5-cm intervals. (134)Cs and (137)Cs radioactivity was also measured in rice ears (rice with chaff), straws and roots. The rice ears were subdivided into chaff, brown rice, polished rice and rice bran, and the (134)Cs and (137)Cs radioactivity concentration of each plant part was measured to calculate the respective TF from the soil. The TF of roots was highest at 0.48 ± 0.10 in the field where the (40)K concentration in the soil core was relatively low, in comparison with TF values of 0.31 and 0.38 in other fields. Similar trends could be found for the TF of whole rice plants, excluding roots. The TF of rice ears was relatively low at 0.019-0.026. The TF of chaff, rice bran, brown rice and polished rice was estimated to be 0.049, 0.10-0.16, 0.013-0.017 and 0.005-0.013, respectively.

  7. Field evaluation of four spatial repellent devices against Arkansas rice-land mosquitoes

    Science.gov (United States)

    Four commercially available spatial repellent devices were tested in a rice land habitat near Stuttgart, Arkansas after semi-field level assessments had been made at the Center for Medical, Agricultural, and Veterinary Entomology, ARS, USDA in Gainesville, FL. OFF! Clip-On® (a.i. metofluthrin, S.C....

  8. Heavy metals in freshwater snails of Kuala Klawang's rice field, Negeri Sembilan, Malaysia.

    Science.gov (United States)

    Ismail, A

    1994-09-01

    A study of heavy metal contents in freshwater snails from rice fields have been made. The results indicate that the levels of heavy metals, Pb, Cu, Zn and Cd, are low and within the permissible limit of Malaysian Food Regulations. The results can serve as background data for further reference.

  9. Microbial electricity generation in rice paddy fields: recent advances and perspectives in rhizosphere microbial fuel cells.

    Science.gov (United States)

    Kouzuma, Atsushi; Kaku, Nobuo; Watanabe, Kazuya

    2014-12-01

    Microbial fuel cells (MFCs) are devices that use living microbes for the conversion of organic matter into electricity. MFC systems can be applied to the generation of electricity at water/sediment interfaces in the environment, such as bay areas, wetlands, and rice paddy fields. Using these systems, electricity generation in paddy fields as high as ∼80 mW m(-2) (based on the projected anode area) has been demonstrated, and evidence suggests that rhizosphere microbes preferentially utilize organic exudates from rice roots for generating electricity. Phylogenetic and metagenomic analyses have been conducted to identify the microbial species and catabolic pathways that are involved in the conversion of root exudates into electricity, suggesting the importance of syntrophic interactions. In parallel, pot cultures of rice and other aquatic plants have been used for rhizosphere MFC experiments under controlled laboratory conditions. The findings from these studies have demonstrated the potential of electricity generation for mitigating methane emission from the rhizosphere. Notably, however, the presence of large amounts of organics in the rhizosphere drastically reduces the effect of electricity generation on methane production. Further studies are necessary to evaluate the potential of these systems for mitigating methane emission from rice paddy fields. We suggest that paddy-field MFCs represent a promising approach for harvesting latent energy of the natural world.

  10. The phenology of malaria mosquitos in irrigated rice fields in Mali

    NARCIS (Netherlands)

    Klinkenberg, E.; Takken, W.; Huibers, F.P.; Touré, Y.T.

    2003-01-01

    A field study was carried out in the large-scale rice irrigation scheme of the Office du Niger in Mali to investigate the relation between anopheline mosquito larval development and small-scale differences in irrigation practices, such as water level, irrigation application and irrigation frequency.

  11. The rice field cyanobacteria Anabaena azotica and Anabaena sp. CH1 express vanadium-dependent nitrogenase

    NARCIS (Netherlands)

    Boison, G.; Steingen, C.; Stal, L.J.; Bothe, H.

    2006-01-01

    Anabaena azotica FACHB-118 and Anabaena sp. CH1, heterocystous cyanobacteria isolated from Chinese and Taiwanese rice fields, expressed vanadium-containing nitrogenase when under molybdenum deficiency. This is the second direct observation of an alternative nitrogenase in cyanobacteria. The vanadium

  12. ESTIMATE OF METHANE EMISSIONS FROM RICE FIELDS IN CHINA BY CLIMATE-BASED NET PRIMARY PRODUCTIVITY

    Institute of Scientific and Technical Information of China (English)

    KANG Guo-ding; CAI Zu-cong; ZHANG Zi-heng; XIAO Peng-feng

    2004-01-01

    Rice fields provide food for over half of the world population but are also an important source of atmospheric CH4. Using the climate-based GIS empirical model and the meteorological data collected from 600 meteorological stations in China, with county as the basic unit, the net primary productivity (NPP) of rice fields in China in 1990, 1995, 1998, and 2000 were estimated to be in the range from 202.19×1012g C in 1990 to 163.46×1012g C in 2000. From the measured data of the factors affecting CH4 emission and NPP, the conversion ratio of the NPP into CH4 emission for the rice fields of China was determined to be 1.8%. Using this ratio and estimated NPP, the CH4 emissions from rice fields of China in 1990, 1995, 1998, and 2000 were estimated to be 7.24×1012, 6.31×1012, 6.77×1012 and 5.85×1012g CH4, respectively.

  13. Field evidence for the potential of Rhodobacter capsulatus as Biofertilizer for flooded rice.

    Science.gov (United States)

    Gamal-Eldin, Hosny; Elbanna, Khaled

    2011-02-01

    In a previous study, we evaluated the effects of inoculating rice plants with the phototrophic purple nonsulfur bacterium Rhodobacter capsulatus (Rc) on growth and yield of rice in pots and lysimeter experiments and the results obtained have been highly encouraging. In this study, we carried out two field experiments: one in the experimental farm of the Faculty of Agriculture, Fayoum University, and the second in a farmer's field in Kafr El-sheikh, to assess the effects of Rc on growth and yield of rice in comparison and in combination with chemical nitrogen fertilizer (CNF) and farmyard manure. The results indicated that both biological and grain yields in all the Rc inoculated treatments were significantly higher than those in the uninoculated corresponding treatments in both fields. With regard to grain yield, the major factor for determining the effectiveness of any agricultural treatment, inoculation with Rc in combination with 50% of the recommended CNF rate gave a grain yield that was statistically equivalent to that obtained with 100% of the recommended CNF rate. These results provide a clear evidence for the potential of Rc as biofertilizer for flooded rice under field conditions.

  14. An influence of the petrol pump for the atmospheric electric field distribution in the surroundings of the vehicles

    Directory of Open Access Journals (Sweden)

    Milovanović Alenka

    2004-01-01

    Full Text Available In this paper the potential and electric field distribution in the surroundings of the cargo vehicles is approximately numerically determined, when they are exposed to the Atmospheric Electric Field (AEF, having uniform intensity and vertical polarization. The cases of the cargo vehicles either isolated or near by petrol pumps are observed. Several results of total induced charge and electrical moment of the vehicle including maps of equipotential and equienergetic curves are presented. The Equivalent Electrode Method (EEM is used to solve this problem.

  15. Numerical Simulation of Shear-Horizontal-Wave-Induced Electromagnetic Field in Borehole Surrounded by Porous Formation

    Institute of Scientific and Technical Information of China (English)

    CUI Zhi-Wen; WANG Ke-Xie; SUN Jian-Cuo; ZHU Zheng-Ya; YAO Gui-Jin; HU Heng-Shan

    2007-01-01

    Seismoelectric field excited by purely torsional loading applied directJy to the borehole wall is considered.A brief formulation and some computed waveforms show the advantage of using shear-horizontal (SH) transverseelectric(TE) seismoelectric waves logging to measure shear velocity in a fluid-saturated porous lormation.By assuming that the acoustic field is not influenced by its induced electromagnetic field due to seismoelectric effect,the coupling governing equations for electromagnetic field are reduced to Maxwell equations with a propagation current source.It is shown that this simplification is valid and the borehole seismoelectric conversion effcient is mainly dependent on the electrokinetic coupling coeffcient.The receivers to detect the conversion electromagnetic field and to obtain shear veloeity can be set in the borehole fluid in the SH-TE seismoelectric wave log.

  16. Photoinhibitive and Recovery Properties of Hybrid Rice Ⅱ You 129 under Field Conditions

    Institute of Scientific and Technical Information of China (English)

    XU Xiao-ming; TANG Yun-lai; WANG Ying; LU Wei; DAI Xin-bin; ZHANG Rong-xian; KUANG Ting-yun

    2003-01-01

    Photoinhibitive properties of super-high-yielding hybrid rice Ⅱ you 129 and its adaptation mechanism to strong light stress were investigated by measuring the light-response curve, diurnal variations of net photosynthetic rate and chlorophyll fluorescence parameters of Ⅱ you 129 leaves and compared with Shanyou 63. Photoinhibition of rice flag leaves under field conditions mainly resulted from the increase of thermal dissipation, especially for thermal dissipation depended on the xanthophyll circle, but no destruction of photosynthetic apparatus occurred. Potentially super-high-yielding hybrid rice Ⅱyou 129 was more tolerant to photoinhibition than Shanyou 63, because it had higher light saturation intensity and maximum net photosynthetic rate; more active xanthophyll cycle, and more rapid recovery ability after photoinhibition.

  17. Mexican rice borer (Lepidoptera: Crambidae) oviposition site selection stimuli on sugarcane, and potential field applications.

    Science.gov (United States)

    Showler, Allan T; Castro, Boris A

    2010-08-01

    The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), a key pest of sugarcane (Saccharum spp.) and rice, Oryza sativa L., in Texas, has not been controlled with chemical insecticides or biological agents, but some sugarcane varieties have shown degrees of resistance. Assessment of selected sugarcane leaf characteristics indicate that preference for oviposition sites is mostly determined by the presence of a leaf fold and secondarily by the availability of dry leaf tissue, both of which are antixenotic nonchemical stimuli. We suggest that breeding sugarcane lines bearing leaves that do not fold on drying could provide substantial antixenotic resistance against the Mexican rice borer. Previously identified antixenotic chemical stimuli, i.e., low quantities or absence of important nutrients in green leaf tissue, only become apparent when resistant and susceptible sugarcane varieties are compared. Varietal differences in oviposition preference, however, were not observed on excised dry leaf tissue, indicating that expression of resistance in terms of chemical stimuli requires detection of biochemicals in nearby living leaf tissue. Excised dry sugarcane leaves retain the two dominant nonchemical oviposition preference stimuli for Mexican rice borers, and the leaves effectively trapped eggs away from intact plants when dry leaves were used as "mulch" at the bottom of greenhouse cages. Under commercial sugarcane field conditions, bundled dry leaves also collected Mexican rice borer eggs. Possible applications of dry sugarcane leaf substrate for egg scouting and for trapping eggs are discussed.

  18. Effects of screenhouse cultivation and organic materials incorporation on global warming potential in rice fields.

    Science.gov (United States)

    Xu, Guochun; Liu, Xin; Wang, Qiangsheng; Xiong, Ruiheng; Hang, Yuhao

    2017-03-01

    Global rice production will be increasingly challenged by providing healthy food for a growing population at minimal environmental cost. In this study, a 2-year field experiment was conducted to investigate the effects of a novel rice cultivation mode (screenhouse cultivation, SHC) and organic material (OM) incorporation (wheat straw and wheat straw-based biogas residue) on methane (CH4) and nitrous oxide (N2O) emissions and rice yields. In addition, the environmental factors and soil properties were also determined. Relative to the traditional open-field cultivation (OFC), SHC decreased the CH4 and N2O emissions by 6.58-18.73 and 2.51-21.35%, respectively, and the global warming potential (GWP) was reduced by 6.49-18.65%. This trend was mainly because of lower soil temperature and higher soil redox potential in SHC. Although the rice grain yield for SHC were reduced by 2.51-4.98% compared to the OFC, the CH4 emissions and GWP per unit of grain yield (yield-scaled CH4 emissions and GWP) under SHC were declined. Compared to use of inorganic fertilizer only (IN), combining inorganic fertilizer with wheat straw (WS) or wheat straw-based biogas residue (BR) improved rice grain yield by 2.12-4.10 and 4.68-5.89%, respectively. However, OM incorporation enhanced CH4 emissions and GWP, leading to higher yield-scaled CH4 emissions and GWP in WS treatment. Due to rice yield that is relatively high, there was no obvious effect of BR treatment on them. These findings suggest that apparent environmental benefit can be realized by applying SHC and fermenting straw aerobically before its incorporation.

  19. Nitrous Oxide Emissions from Fields with Different Wheat and Rice Varieties

    Institute of Scientific and Technical Information of China (English)

    B. GOGOI; K.K. BARUAH

    2012-01-01

    Plant species of cropping systems may affect nitrous oxide (N2O) emissions.A field experiment was conducted to investigate dynamics of N2O emissions from rice-wheat fields from December 2006 to June 2007 and the relationships of soil and plant parameters with N2O emissions.The results indicated that N2O emissions from different wheat varieties ranged from 12 to 291 μg N2O-N m-2 h-1 and seasonal N2O emissions ranged from 312 to 385 mg N2O-N m-2.In the rice season,it was from 11 to 154 μg N2O-N m-2 h-1 with seasonal N2O emission of 190-216 mg N2O-N m-2.The seasonal integrated flux of N2O differed significantly among wheat and rice varieties.The wheat variety HUW 234 and rice variety Joymoti showed higher seasonal N2O emissions.In the wheat season,N2O emissions correlated with soil organic carbon (SOC),soil NO-3-N,soil temperature,shoot dry weight,and root dry weight.Among the variables assessed,soil temperature followed by SOC and soil NO-3-N were considered as the important variables influencing N2O emission.N2O emission in the rice season was significantly correlated with SOC,soil NO-3-N,soil temperature,leaf area,shoot dry weight,and root dry weight.The main driving forces influencing N2O emission in the rice season were soil NO-3-N,leaf area,and SOC.

  20. Greenhouse Gas Emissions from Northeast China Rice Fields in Fallow Season

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    CH4, N2O and CO2 emissions from northeast Chinese rice fields were measured in the fallow season (November to March) to investigate the effects of freezing-thawing on the emissions. Both CH4 emission from and atmospheric CH4oxidation by the soil occurred, but the flux was small. During the fallow season, rice fields acted as a minor source of atmospheric CH4, which accounted for about 1% of the CH4 emission during the rice growing period. The field was also a substantial source of atmospheric N2O, which ranged between 40 to 77 mg m-2 and accounted for 40%-50% of the annual N2O emission. The largest N2O flux was observed in the thawing period during the fallow season. Laboratory incubation tests showed that the largest N2O flux came from the release of N2O trapped in frozen soil. Tillage and rice straw application (either mulched on the soil surface or incorporated in the soil) stimulated the CH4 and CO2 emissions during the fallow season, but only straw application stimulated N2O emission substantially.

  1. Statistics of Stellar Populations of Star Clusters and Surrounding Fields in the Outer Disk of the Large Magellanic Cloud

    CERN Document Server

    Santos, J F C; Claria, J J; Bica, E; Geisler, D; Dottori, H

    1999-01-01

    A comparative analysis of Washington color-magnitude diagrams (CMDs) for 14 star clusters and respective surrounding fields in the Large Magellanic Cloud (LMC) outer disk is presented. Each CCD frame including field and respective cluster covers an area of 185 arcmin^2. The stellar population sampled is of intermediate age and metallicity. CMD radial analysis involving star count ratios, morphology and integrated light properties are carried out. Luminosity functions (LFs) are also presented. Two main results are: (i) Within the range 4fields are younger and; (ii) Beyond approximately 8kpc the outer fields do not show evidence of a significant intermediate-age component in their stellar populations, as inferred from red giant clump star counts.

  2. Methane emission from rice fields in relation to management of irrigation water.

    Science.gov (United States)

    Khosa, Maninder Kaur; Sidhu, B S; Benbi, D K

    2011-03-01

    A field experiment was conducted for two years to find out best water management practice to mitigate methane emission from the rice-fields. Continuously flooded conditions yielded two major flushes of methane emission and on an average resulted in relatively higher rate of methane emission (2.20 and 1.30 mg m(-2) hr(-1), respectively in 2005 and 2006) during the kharif season. The methane flux was reduced to half (1.02 and 0.47 mg m(-2) hr(-1), respectively in 2005 and 2006) when rice fields were irrigated 2-3 days after infiltration of flood water into the soil. Irrigating the field at 0.15 bar matric potential reduced seasonal methane flux by 60% (0.99 and 0.41 mg m(-2) hr(-1), respectively in 2005 and 2006) as compared to completely flooded conditions, without any decline in grain yield (60 q ha(-1)).

  3. Mosquito species succession and physicochemical factors affecting their abundance in rice fields in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Muriu, Simon; Jacob, Benjamin; Kabiru, Ephantus; Gu, Weidong; Mbogo, Charles; Githure, John; Novak, Robert

    2007-03-01

    The succession of mosquito species and abiotic factors affecting their distribution and abundance in rice (Oryza spp.) fields was investigated over a 16-wk rice growing cycle covering the period between January and May 2006. Fifteen experimental rice plots were sampled for mosquito larvae and characterized based on rice height, number of tillers, floating vegetation cover, water depth, water temperature, turbidity, salinity, pH, dissolved oxygen, total dissolved solids, and conductivity. Microscopic identification of 3,025 larvae yielded nine mosquito species predominated by Anopheles arabiensis Patton (45.0%), Culex quinquefasciatus Say (35.8%), Anopheles pharoensis Theobald (9.0%) and Ficalbia splendens Theobald (7.1%). Other species, including Anopheles rufipes Gough, Anopheles coustani Laveran, Anonopheles maculipalpis Giles, Culex annulioris Theobald, and Culex poicilipes Theobald made up 3.1% of the total collection. Anopheles gambiae s.l., Cx. quinquefasciatus, and An. pharoensis occurred throughout the cycle, but they were more abundant up to 4 wk posttransplanting with peaks after fertilizer application. As rice plants became established, three groups of mosquitoes were recognized: the first groups included An. rufipes, Fl. splendens, and Cx. annulioris, which occurred throughout much of the second half of the rice cycle, whereas the second group included Cx. poicilipes, which was found in the middle of the rice cycle. An. coustani and An. maculipalpis formed the third group occurring toward the end of the cycle. Dissolved oxygen, number of tillers, and rice height were negatively associated with the abundance ofAn. arabiensis and Cx. quinquefasciatus larvae. In addition, Cx. quinquefasciatus also was associated with water depth (-ve) and turbidity (+ve). Abundance of An. pharoensis larvae was significantly associated with water temperature (+ve), the number of tillers (-ve), and rice height (-ve), whereas Fl. splendens was significantly associated with

  4. The new integrated aeromagnetic map of the Phlegrean Fields volcano and surrounding areas

    Directory of Open Access Journals (Sweden)

    A. Rapolla

    2004-06-01

    Full Text Available In this paper we present and analyze the new detailed aeromagnetic data set resulting from a recent survey carried out in the Phlegrean Fields volcanic area. The survey was aimed at gaining new insight into the volcanological characteristics of the region north of Phlegrean Fields (Parete-Villa Literno area where remarkable thickness of volcanic/sub- volcanic rocks were found in wells. Measurement of total magnetic field was performed on two different flight levels, 70 m and 400 m above the ground surface, along flight lines spaced 400 m apart. Both aeromagnetic maps show the noisy effect of linear anomalies evidently due to the presence of railway lines. To filter out these local anomalies a method based on discrete wavelet transform was used, allowing an accurate local filtering and leaving the rest of the field practically unchanged. The filtered data set was integrated with the existing Agip aeromagnetic map of the Phlegrean Fields, leading to a new aeromagnetic map of the whole Phlegrean volcanic area. The compilation of the pole reduced map and of the maps of the Analytic Signal and of the Horizontal Derivative of the integrated data set represents a first step for the interpretation of the maps in terms of geological structures of the whole Phlegrean volcanic district.

  5. Low uptake affinity cultivars with biochar to tackle Cd-tainted rice — A field study over four rice seasons in Hunan, China

    Energy Technology Data Exchange (ETDEWEB)

    Chen, De; Guo, Hu; Li, Ruiyue [Institute of Resources, Ecosystem and Environment of Agriculture, and Center of Biochar and Green Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095 (China); Li, Lianqing, E-mail: lqli@njau.edu.cn [Institute of Resources, Ecosystem and Environment of Agriculture, and Center of Biochar and Green Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095 (China); Pan, Genxing [Institute of Resources, Ecosystem and Environment of Agriculture, and Center of Biochar and Green Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095 (China); Chang, Andrew [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Joseph, Stephen [Institute of Resources, Ecosystem and Environment of Agriculture, and Center of Biochar and Green Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing 210095 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

    2016-01-15

    Biochar is becoming an environmentally friendly material for remediation of heavy metal contaminated soils and improving food safety. A field trial over four rice seasons was conducted to investigate the use of biochar and low Cd accumulating cultivars on Cd uptake in a heavy metal contaminated soil. Wheat straw derived biochar was applied at 0, 20 and 40 t ha{sup −1}. Two rice cultivars with differing Cd accumulation abilities were selected in each season. The results showed that both biochar and low Cd affinity cultivars significantly reduced rice grain Cd accumulation. Biochar had no significant effect the first season but thereafter consistently reduced rice grain Cd by a maximum of 61, 86 and 57% over the next three seasons. Zn accumulation in the rice grains was not decreased by biochar application, although available soil Zn was sharply reduced (35–91%). Indica conventional rice cultivars had much lower Cd, but higher Zn and lower Cd/Zn ratios in the grain than indica hybrid cultivars. Biochar was more effective for mitigating grain Cd accumulation in low Cd affinity cultivars than in high affinity cultivars. Soil pH was sustainably increased (up to nearly 1 unit) while available Cd significantly decreased by a maximum of 85% after biochar addition. The translocation of Cd from rice roots to shoots was reduced from 20 to 80% by biochar. Low uptake affinity cultivars combined with biochar reduced late rice grain Cd concentration and Cd/Zn ratios by 69–80% and 72–80%, respectively. It indicated that the management of combining biochar and low Cd affinity cultivars should be an efficient way to remediate Cd contaminated rice paddies and reduce health risk associated with consuming rice from these soils. - Highlights: • Biochar sustainably reduced soil Cd availability and Cd translocation in rice plant. • Indica conventional cultivars had lower Cd but higher Zn in grains than hybrid ones. • Biochar significantly reduced grain Cd and Cd/Zn ratio

  6. Investigations of Flare Gas Emissions in Taq Taq Oil Field on the Surrounding Land

    Directory of Open Access Journals (Sweden)

    Jafar A. Ali

    2014-11-01

    Full Text Available Environmental pollution caused by oil takes many different forms; one of the most damaging sources is simply the combustion of oil products, such as a well flare burn-off. This paper presents the results of a survey of the agriculture lands around the Taq Taq Oil Production Company. The aim of the survey was to determine the potential contamination caused by the gas emissions from the well flares. Taq Taq field is located in the Kurdistan Region of Iraq, 60 km north of the giant Kirkuk oil field, 85 km south-east of Erbil and 120 km north-west of Suleimani. Samples of soil were collected from several locations around the site and analyzed to determine the content of Polycyclic Aromatic Hydrocarbons PAH present. A gas chromatography linked to a mass spectrometry (GCMS machine was used for these measurements. The PAH contamination at each location of soil was determined and the 16-PAHs, as listed in the US Environmental Protection Agency (EPA documentation were investigated. The average content of total PAH in all samples of the agricultural soil was 0.654 mg·kg-1 with the concentrations ranging from 0.310 to 0.869 mg·kg-1. It was found that the PAH concentrations decreased with increasing distance from the TTOPCO oil field, indicating that pollution was evident, the area close to the field being more affected by the gas pollution.

  7. The distance to the LMC cluster NGC 1866 and the surrounding field

    CERN Document Server

    Salaris, M; Brocato, E; Raimondo, G; Walker, A R

    2003-01-01

    We use the Main Sequence stars in the LMC cluster NGC 1866 and of Red Clump stars in the local field to obtain two independent estimates of the LMC distance. We apply an empirical Main Sequence-fitting technique based on a large sample of subdwarfs with accurate {\\sl Hipparcos} parallaxes in order to estimate the cluster distance modulus, and the multicolor Red Clump method to derive distance and reddening of the LMC field. We find that the Main Sequence-fitting and the Red Clump distance moduli are in significant disagreement; NGC 1866 distance is equal to $\\rm (m-M)_{0,NGC 1866}=18.33\\pm$0.08 (consistent with a previous estimate using the same data and theoretical Main Sequence isochrones), while the field stars provide $\\rm (m-M)_{0,field}=18.53\\pm$0.07. This difference reflects the more general dichotomy in the LMC distance estimates found in the literature. Various possible causes for this disagreement are explored, with particular attention paid to the still uncertain metallicity of the cluster and the ...

  8. BVRIJHK photometry and proper motion analysis of NGC 6253 and the surrounding field

    CERN Document Server

    Montalto, M; Desidera, S; Platais, I; Carraro, G; Momany, Y; De Marchi, F; Recio-Blanco, A

    2009-01-01

    Context. We present a photometric and astrometric catalog of 187963 stars located in the field around the old super-metal-rich Galactic open cluster NGC 6253. The total field-of-view covered by the catalog is 34' x 33'. In this field, we provide CCD BVRI photometry. For a smaller region close to the cluster's center, we also provide near-infrared JHK photometry. Aims. We analyze the properties of NGC 6253 by using our new photometric data and astrometric membership. Methods. In June 2004, we targeted the cluster during a 10 day multi-site campaign, which involved the MPG/ESO 2.2m telescope with its wide-field imager and the Anglo-Australian 3.9m telescope, equipped with the IRIS2 near-infrared imager. Archival CCD images of NGC 6253 were used to derive relative proper motions and to calculate the cluster membership probabilities. Results. We have refined the cluster's fundamental parameters, deriving (V_0-M_v)=11.15, E(B - V)=0.15, E(V - I)=0.25, E(V - J)=0.50, and E(V - H)=0.55. The color excess ratios obtai...

  9. Rice evapotranspiration at the field and canopy scales under water-saving irrigation

    Science.gov (United States)

    Liu, Xiaoyin; Xu, Junzeng; Yang, Shihong; Zhang, Jiangang

    2017-02-01

    Evapotranspiration (ET) is an important process of land surface water and thermal cycling, with large temporal and spatial variability. To reveal the effect of water-saving irrigation (WSI) on rice ET at different spatial scales and understand the cross spatial scale difference, rice ET under WSI condition at canopy (ETCML) and field scale (ETEC) were measured simultaneously by mini-lysimeter and eddy covariance (EC) in the rice season of 2014. To overcome the shortage of energy balance deficit by EC system, and evaluate the influence of energy balance closure degree on ETEC, ETEC was corrected as ET_{EC}^{*} by energy balance closure correction according to the evaporative fraction. Seasonal average daily ETEC, ET_{EC}^{*} and ETCML of rice under WSI practice were estimated as 3.12, 4.03 and 4.35 mm day-1, smaller than the values reported in flooded paddy fields. Daily ETEC, ET_{EC}^{*} and ETCML varied in a similar trends and reached the maximum in late tillering, then decreased along with the crop growth in late season. The value of ETEC was much lower than ETCML, and was frequently 1-2 h lagged behind ETCML. It indicated that the energy balance deficit resulted in underestimation of crop ET by EC system. The corrected value of ET_{EC}^{*} matched ETCML much better than ETEC, with a smaller RMSE (0.086 mm h-1) and higher R 2 (0.843) and IOA (0.961). The time lapse between ET_{EC}^{*} and ETCML was mostly shortened to less than 0.5 h. The multiple stepwise regression analysis indicated that net radiation (R n) is the dominant factor for rice ET, and soil moisture (θ) is another significant factor (p < 0.01) in WSI rice fields. The difference between ETCML and ET_{EC}^{*} (ET_{CML} - ET_{EC^{*} ) were significantly (p < 0.05) correlated with R n, air temperature (T a), and air vapor pressure deficit (D), and its partial correlation coefficients to R n and T a were slightly greater than D. Thus, R n, T a and D are important variables for understanding the spatial

  10. Unravelling trophic subsidies of agroecosystems for biodiversity conservation: food consumption and nutrient recycling by waterbirds in Mediterranean rice fields.

    Science.gov (United States)

    Navedo, Juan G; Hahn, Steffen; Parejo, Manuel; Abad-Gómez, José M; Gutiérrez, Jorge S; Villegas, Auxiliadora; Sánchez-Guzmán, Juan M; Masero, José A

    2015-04-01

    Waterbirds can reallocate a considerable amount of nutrients within agricultural fields and between agriculture sites and wetlands. However their effects on biogeochemical cycles have rarely been quantified. We estimated bird numbers, diet (from stable isotope analysis), food supply, and the food consumption on rice fields by overwintering waterbirds in one of the most important areas for rice production in southwestern Europe and a key area for various migrating and resident waterbird species. Herein, we modelled the nutrient (N and P) recycling in rice fields, and their transport to reservoirs. The energy consumption by waterbirds (96,605±18,311 individuals) on rice fields during winter averaged at 89.9±39.0 kJ·m(-2), with its majority (89.9%) belonging to foraging on rice seeds. Thus, the birds removed about 26% of rice seeds leftover after harvest (estimated in 932.5±504.7 seeds·m(-2) in early winter) wherein common cranes and dabbling ducks (four species) were the most important consumers. Waterbirds foraging and roosting in the rice fields recycled more than 24.1 (1.0 kg·ha(-1)) of N and an additional 5.0 tons (0.2 kg·ha(-1)) of P in the Extremadura's rice fields during winter. Additionally, we estimated that 2.3 tons of N and 550 kg of P were removed from rice fields and transported to reservoirs. The seasonal foraging of wildlife should result in a direct benefit for rice farmers by improving nutrient recycling through defecation by waterbirds with respect to artificial fertilisation. Additionally, rice fields located in the cranes' core wintering areas can provide sufficient food supply to induce habitat shift from their traditional wintering habitat in 'dehesas' to rice fields, which causes indirect socioeconomic benefit through reduced acorn consumption by cranes. Our modelling approach may thus be especially helpful for management decisions regarding rice agroecosystems in areas which are also important for the conservation of migratory

  11. Characteristics and land suitability of newly establish rice field in Lesung Batu Muda, Rawas Ulu, Musi Rawas, South Sumatera

    Directory of Open Access Journals (Sweden)

    R Sudaryanto

    2015-04-01

    Full Text Available Rice field has a strategic function because it is the main provider of food for the population of Indonesia. The data of the land use for the rice field in Indonesia showed that around 41% in Java Island. Agricultural technology at the level of industry experienced rapid progress, but the technology implementation at the level by farmer is relatively slow. Increased production of rice in Indonesia was reported of less than 1% per year. The research aimed to study the characteristics and land suitability of newly established rice field in Lesung Batu Muda, Rawas Ulu, Musi Rawas, South Sumatera. There were two soil land units that were tested included water availability, rooting medium, level of erosion, soil chemical properties and land preparation. The results of the study showed that newly established rice fields in Lesung Batu Muda, Rawas Ulu, Musi Rawas, South Sumatera could be used to open new rice fields by planting twice a year. In opening new rice fields, the application of organic matter and creation of terracing on sloping areas were needed.

  12. Waste rice seed in conventional and stripper-head harvested fields in California: Implications for wintering waterfowl

    Science.gov (United States)

    Fleskes, Joseph P.; Halstead, Brian J.; Casazza, Michael L.; Coates, Peter S.; Kohl, Jeffrey D.; Skalos, Daniel A.

    2012-01-01

    Waste rice seed is an important food for wintering waterfowl and current estimates of its availability are needed to determine the carrying capacity of rice fields and guide habitat conservation. We used a line-intercept method to estimate mass-density of rice seed remaining after harvest during 2010 in the Sacramento Valley (SACV) of California and compared results with estimates from previous studies in the SACV and Mississippi Alluvial Valley (MAV). Posterior mean (95% credible interval) estimates of total waste rice seed mass-density for the SACV in 2010 were 388 (336–449) kg/ha in conventionally harvested fields and 245 (198–307) kg/ha in stripper-head harvested fields; the 2010 mass-density is nearly identical to the mid-1980s estimate for conventionally harvested fields but 36% lower than the mid-1990s estimate for stripped fields. About 18% of SACV fields were stripper-head harvested in 2010 vs. 9–15% in the mid-1990s and 0% in the mid-1980s; but due to a 50% increase in planted rice area, total mass of waste rice seed in SACV remaining after harvest in 2010 was 43% greater than in the mid-1980s. However, total mass of seed-eating waterfowl also increased 82%, and the ratio of waste rice seed to seed-eating waterfowl mass was 21% smaller in 2010 than in the mid-1980s. Mass-densities of waste rice remaining after harvest in SACV fields are within the range reported for MAV fields. However, because there is a lag between harvest and waterfowl use in the MAV but not in the SACV, seed loss is greater in the MAV and estimated waste seed mass-density available to wintering waterfowl in SACV fields is about 5–30 times recent MAV estimates. Waste rice seed remains an abundant food source for waterfowl wintering in the SACV, but increased use of stripper-head harvesters would reduce this food. To provide accurate data on carrying capacities of rice fields necessary for conservation planning, trends in planted rice area, harvest method, and postharvest field

  13. Plant/microbe cooperation for electricity generation in a rice paddy field.

    Science.gov (United States)

    Kaku, Nobuo; Yonezawa, Natsuki; Kodama, Yumiko; Watanabe, Kazuya

    2008-05-01

    Soils are rich in organics, particularly those that support growth of plants. These organics are possible sources of sustainable energy, and a microbial fuel cell (MFC) system can potentially be used for this purpose. Here, we report the application of an MFC system to electricity generation in a rice paddy field. In our system, graphite felt electrodes were used; an anode was set in the rice rhizosphere, and a cathode was in the flooded water above the rhizosphere. It was observed that electricity generation (as high as 6 mW/m(2), normalized to the anode projection area) was sunlight dependent and exhibited circadian oscillation. Artificial shading of rice plants in the daytime inhibited the electricity generation. In the rhizosphere, rice roots penetrated the anode graphite felt where specific bacterial populations occurred. Supplementation to the anode region with acetate (one of the major root-exhausted organic compounds) enhanced the electricity generation in the dark. These results suggest that the paddy-field electricity-generation system was an ecological solar cell in which the plant photosynthesis was coupled to the microbial conversion of organics to electricity.

  14. Wolbachia infections in mosquitoes and their predators inhabiting rice field communities in Thailand and China.

    Science.gov (United States)

    Wiwatanaratanabutr, Itsanun; Zhang, Chongxing

    2016-07-01

    Wolbachia are inherited, endocytoplasmic bacteria that infect a wide range of arthropods. Here is the first systematic report on the study of Wolbachia infection in mosquitoes and their predators from both Thailand and China. In Thailand, 632 mosquito specimens (20 spp.) and 424 insect predators (23 spp.) were collected from the rice agroecosystem, mostly from the Central region, followed by the Northeast, the North and the South and were inhabiting rice fields, wetlands and ditches. In China, 928 mosquitoes (15 spp.) and 149 insect predators (16 spp.) were collected from rice fields along the Weishan Lake in Shandong province. Specimens were classified in the orders Diptera, Coleoptera, Odonata and Hemiptera. Using wsp, ftsZ, 16S rRNA and groE gene amplifications, Wolbachia were detected in 12 mosquito spp. and 6 predator spp. from Thailand and 11 mosquito spp. and 5 predator spp. from China. The relative Wolbachia densities of these species were determined using quantitative real-time PCR. The mosquito, Aedes albopictus, and the predator, Agriocnemis femina, had the highest bacterial densities. These results imply that Wolbachia of supergroup B are distributed throughout these insects, probably via horizontal transmission in rice agroecosystems.

  15. Effects of search efficiency on surround suppression during visual selection in frontal eye field.

    Science.gov (United States)

    Schall, Jeffrey D; Sato, Takashi R; Thompson, Kirk G; Vaughn, Amanda A; Juan, Chi-Hung

    2004-06-01

    Previous research has shown that visually responsive neurons in the frontal eye field of macaque monkeys select the target for a saccade during efficient, pop-out visual search through suppression of the representation of the nontarget distractors. For a fraction of these neurons, the magnitude of this distractor suppression varied with the proximity of the target to the receptive field, exhibiting more suppression of the distractor representation when the target was nearby than when the target was distant. The purpose of this study was to determine whether the variation of distractor suppression related to target proximity varied with target-distractor feature similarity. The effect of target proximity on distractor suppression did not vary with target-distractor similarity and therefore may be an endogenous property of the selection process.

  16. Mechanical and hydrological characterization of the near-field surrounding excavations in a geologic salt formation

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Clifford L. [Sandia National Laboratories, Albuquerque, NM (United States)

    2014-09-01

    The technical basis for salt disposal of nuclear waste resides in salt’s favorable physical, mechanical and hydrological characteristics. Undisturbed salt formations are impermeable. Upon mining, the salt formation experiences damage in the near-field rock proximal to the mined opening and salt permeability increases dramatically. The volume of rock that has been altered by such damage is called the disturbed rock zone (DRZ).

  17. Assessment of rice fields by GIS/GPS-supported classification of MODIS data

    Institute of Scientific and Technical Information of China (English)

    程乾; 黄敬峰; 王人潮

    2004-01-01

    The new Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite image offers a large choice of opportunities for operational applications. The 1-km Advanced Very High Resolution Radiometer (AVHRR) image is not suitable for retrieval of field level parameter and Landsat data are not frequent enough for monitoring changes in crop parameters during the critical crop growth periods.A methodology to map areas of paddy fields using MODIS,geographic information system (GIS) and global position system (GPS) is introduced in this paper. Training samples are selected and located with the help of GPS to provide maximal accuracy.A concept of assessing areas of potential cultivation of rice is suggested by means of GIS integration. By integration of MODIS with GIS and GPS technologies the actual areas of rice fields in 2002 have been mapped. The classification accuracy was 95.7% percent compared with the statistical data of the Agricultural Bureau of Zhejiang Province.

  18. Assessment of rice fields by GIS/GPS-supported classification of MODIS data

    Institute of Scientific and Technical Information of China (English)

    程乾; 黄敬峰; 王人潮

    2004-01-01

    The new Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite image offers a large choice of opportunities for operational applications. The 1-km Advanced Very High Resolution Radiometer (AVHRR) image is not suitable for retrieval of field level parameter and Landsat data are not frequent enough for monitoring changes in crop parameters during the critical crop growth periods. A methodology to map areas of paddy fields using MODIS, geographic information system (GIS) and global position system (GPS) is introduced in this paper. Training samples are selected and located with the help of GPS to provide maximal accuracy. A concept of assessing areas of potential cultivation of rice is suggested by means of GIS integration. By integration of MODIS with GIS and GPS technologies the actual areas of rice fields in 2002 have been mapped. The classification accuracy was 95.7% percent compared with the statistical data of the Agricultural Bureau of Zhejiang Province.

  19. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    Science.gov (United States)

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools.

  20. Dynamics, Residue and Risk Assessment of Nitenpyram in Rice and Paddy Field

    Directory of Open Access Journals (Sweden)

    YUAN Xue-xia

    2016-09-01

    Full Text Available Residues dynamics, final residual levels and dietary intake risk of nitenpyram in rice and paddy field were investigated in three dif-ferent regions of China(Shandong, Henan and Anhui. A method was illustrated to detect nitenpyram residues in paddy, plant, brown rice, paddy water and soil. The residues in paddy and rice were extracted with methanol+phosphate buffer(0.2 mol·L-1, pH=7.0(60+40, adjust pH to 2.5, then cleaned up with solid phase extraction column and 0.22 μm filter membrane, and then analyzed by HPLC with an ul-traviolet detector at 260 nm. When spiked 0.05, 0.5, 1.0 mg·kg-1, the recoveries of nitenpyram in paddy plant and brown rice were 78.4%~94.7% and 84.0%~94.2%, respectively. The residues in paddy water and soil were extracted with phosphate buffer (0.2 mol·L-1, pH=7.0, when spiked 0.01, 0.5, 1.0 mg·kg-1, the recoveries of nitenpyram in paddy water and soil were 84.6%~98.0% and 93.7%~97.1%, respective-ly, which indicated this method match the requirement of the detection. Two years results showed that nitenpyram belongs to easily degraded pesticides, because all half-lives were below 1.4 d in rice plant, as well as below 4.2 d in paddy water. Final residual levels of nitenpyram in rice were all below 0.05 mg·kg-1,which was far below the Japanese maximum residue limit(0.5 mg·kg-1. The risk quotients (RQs were low for different populations in China, which indicated its low risk in rice. Therefore, the rice with nitenpyram applied, according to the recom-mend method, 45 g·hm-2 application once, with 21 days collection interval, was safe.

  1. Impact of oil and gas field in sugar cane condition using landsat 8 in Indramayu area and its surrounding, West Java province, Republic of Indonesia

    Science.gov (United States)

    Muji Susantoro, Tri; Wikantika, Ketut; Saskia Puspitasari, Alia; Saepuloh, Asep

    2017-01-01

    This study tried to monitor sugar cane condition surrounding of oil and gas field area. The spectral approaches were conducted for mapping sugar cane stress. As an initial stage Landsat-8 was corrected radiometrically and geometrically. Radiometric correction is an important stages for spectral approaching. Then all pixel values were transformed to the surface reflectance. Several vegetation indices were calculated to monitor vegetation stress surrounding of oil and gas field. NDVI, EVI, DVI, GVI, GRVI, GDVI and GNDVI were applied for generating tentative sugar cane stress images. The results indicated that sugar cane surrounding of oil and gas field has been influenced by oil and gas field.

  2. Water management reduces greenhouse gas emissions in a Mediterranean rice paddy field

    Science.gov (United States)

    Gruening, Carsten; Meijide, Ana; Manca, Giovanni; Goded, Ignacio; Seufert, Guenther; Cescatti, Alessandro

    2016-04-01

    Rice paddy fields are one of the biggest anthropogenic sources of methane (CH4), the second most important greenhouse gas (GHG) after carbon dioxide (CO2). Therefore most studies on greenhouse gases (GHG) in these agricultural systems focus on the evaluation of CH4 production. However, there are other GHGs such as CO2 and nitrous oxide (N2O) also exchanged within the atmosphere. Since each of the GHGs has its own radiative forcing effect, the total GHG budget of rice cultivation and its global warming potential (GWP) must be assessed. For this purpose a field experiment was carried out in a Mediterranean rice paddy field in the Po Valley (Italy), the largest rice producing region in Europe. Ecosystem CO2 and CH4 fluxes were assessed using the eddy covariance technique, while soil respiration and soil CH4 and N2O fluxes were measured with closed chambers for two complete years. Combining all GHGs measured, the rice paddy field acted as a sink of -368 and -828 g CO2 eq m-2 year-1 in the first and second years respectively. Both years, it was a CO2 sink and a CH4 source, while the N2O contribution to the GWP was relatively small. Differences in the GHG budget between the two years of measurements were mainly caused by the greater CH4 emissions in the first year (37.4 g CH4 m-2 compared to 21.03 g CH4 m-2 in the second year), probably as a consequence of the drainage of the water table in the middle of the growing season during the second year, which resulted in lower CH4 emissions without significant increases of N2O and CO2 fluxes. However, midseason drainage also resulted in small decreases of yield, indicating that GHG budget studies from agricultural systems should consider carbon exports through the harvest. The balance between net GWP and carbon yield indicated a loss of carbon equivalents from the system, which was more than 30-fold higher in the first year. Our results therefore suggest that an adequate management of the water table has the potential to be an

  3. Temporal patterns of methane emissions from wetland rice fields treated by different modes of N application

    Science.gov (United States)

    Wassmann, R.; Neue, H. U.; Lantin, R. S.; Aduna, J. B.; Alberto, M. C. R.; Andales, M. J.; Tan, M. J.; van der Gon, H. A. C. Denier; Hoffmann, H.; Papen, H.; Rennenberg, H.; Seiler, W.

    1994-08-01

    Methane emission rates from wetland rice fields were determined in Los Baños (Philippines) using an automatic system that allows continuous measurements over time. Methane emission was monitored in an irrigated Aquandic Epiaqualf planted to rice cultivar IR72. Urea fertilizer was applied using four modes: (1) broadcast 10 days after transplanting, (2) broadcast at transplanting, (3) broadcast and incorporated at final harrowing, and (4) deep placement as sulfur-coated granules. The treatments were laid out in a randomized complete block design with four replicates. Measurements were done in the 1991 wet season, 1992 dry season (four treatments), and the 1992 wet season (only treatment 3). Methane emission rates from the experimental plots showed pronounced seasonal and diel variations. The diel pattern of methane emission rates followed a consistent pattern, with highest rates observed in the early afternoon and lowest rates in the early morning. Methane emission rate was generally highest at the ripening stage. The average methane emission rate during the 1992 dry season (190 mg CH4 m-2 d-1) exceeded the average flux rates of the 1992 wet season (79 mg CH4 m-2 d-1) by a factor of 2.4. The total methane emitted from these flooded rice fields amounted to 19 g CH4 m-2 in the dry season with rice yields of 5.2-6.3 t ha-1 and 7 g CH4 m-2 in the wet season with rice yields of 2.4-3.3 t ha-1 regardless of the mode of N application. Significant amounts corresponding to 20% of the methane released under waterlogged conditions were released when the soil was drained after harvest. Emission rates increased sharply when the floodwater receded and macropores started to drain. Emission of methane stopped only when the soil became fully aerated.

  4. A simplified sampling procedure for the estimation of methane emission in rice fields.

    Science.gov (United States)

    Khokhar, Nadar Hussain; Park, Jae-Woo

    2017-08-24

    Manual closed chamber methods are widely used for CH4 measurement from rice paddies. Despite diurnal and seasonal variations in CH4 emissions, fixed sampling times, usually during the day, are used. Here, we monitored CH4 emission from rice paddies for one complete rice-growing season. Daytime CH4 emission increased from 0800 h, and maximal emission was observed at 1200 h. Daily averaged CH4 flux increased during plant growth or fertilizer application and decreased upon drainage of plants. CH4 measurement results were linearly interpolated and matched with the daily averaged CH4 emission calculated from the measured results. The time when daily averaged emission and the interpolated CH4 curve coincided during the daytime was largely invariant within each of the five distinctive periods. One-hourly sampling during each of these five periods was utilized to estimate the emission during each period, and we found that five one-hourly samples during the season accurately reflected the CH4 emission calculated based on all 136 hourly samples. This new sampling scheme is simple and more efficient than current sampling practices. Previously reported sampling schemes yielded estimates 9 to 32% higher than the measured CH4 emission, while our suggested scheme yielded an estimate that was only 5% different from that based on all 136-h samples. The sampling scheme proposed in this study can be used in rice paddy fields in Korea and extended worldwide to countries that use similar farming practices. This sampling scheme will help in producing more accurate global methane budget from rice paddy fields.

  5. Ecotoxicological effects of rice field waters on selected planktonic species: comparison between conventional and organic farming.

    Science.gov (United States)

    Suárez-Serrano, Andrea; Ibáñez, Carles; Lacorte, Silvia; Barata, Carlos

    2010-11-01

    The aim of this study was to assess the ecotoxicological effects of water coming from untreated organic and conventional rice field production areas in the Ebro Delta (Catalonia, Spain) treated with the herbicides oxadiazon, benzofenap, clomazone and bensulfuron-methyl and the fungicides carbendazim, tricyclazole and flusilazole. Irrigation and drainage channels of the study locations were also included to account for potential toxic effects of water coming in and out of the studied rice fields. Toxicity tests included four species (Pseudokirchneriella subcapitata, Desmodesmus subcapitatus, Chlorella vulgaris and Daphnia magna), three endpoints (microalgae growth, D. magna mortality and feeding rates), and two trophic levels: primary producers (microalgae) and grazers (D. magna). Pesticides in water were analyzed by solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Negative effects on algae growth and D. magna feeding rates were detected mainly after application of herbicides and fungicides, respectively, in the conventional rice field. Results indicated that most of the observed negative effects in microalgae and D. magna were explained by the presence of herbicides and fungicides. The above mentioned analyses also denoted an inverse relationship between phytoplankton biomass measured as chlorophyll a and herbicides. In summary, this study indicates that in real field situations low to moderate levels of herbicides and fungicides have negative impacts to planktonic organisms and these effects seem to be short-lived.

  6. Effect of flaring of natural gas in oil fields of Assam on rice cultivation.

    Science.gov (United States)

    Sharma, K K; Hazarika, S; Kalita, B; Sharma, B

    2011-07-01

    Assam (India) is endowed with natural resources like oil, coal and natural gas. The crude oil, one of the most precious natural resources, is found in the districts of upper Assam. During the process of extraction of crude oil, low-pressure natural gas is burnt in the air. Most of the oil wells in upper Assam are located near rice fields and therefore, rice crop grown near the oil wells is exposed to light uninterruptedly causing grain sterility resulting significant loss in grain yield. To identify promising varieties for these areas, we studied the effect of flare on rice varieties with different photoperiod sensitivity. The high light intensity and increased light hours were the factors responsible for substantial loss in grain yield near the flare resulting from delay in flower initiation, reduction of panicle length, having less number of grains per panicle and more grain sterility. To prevent significant loss in yield, photoperiod-sensitive traditional and improved rice varieties should not be grown up to the distance of 80 and 100 m, respectively from the boundary wall of the flare pit. Modern weakly-photoperiod sensitive varieties like Ranjti and Mahsuri can be grown 40 m away from the wall while modern photoperiod insensitive variety like Jaya, can be cultivated 20 m away from the wall without significant loss in yield.

  7. Optical interface created by laser-cooled atoms trapped in the evanescent field surrounding an optical nanofiber

    CERN Document Server

    Vetsch, E; Sagué, G; Schmidt, R; Dawkins, S T; Rauschenbeutel, A

    2009-01-01

    Trapping and optically interfacing laser-cooled neutral atoms is an essential requirement for their use in advanced quantum technologies. Here we simultaneously realize both of these tasks with cesium atoms interacting with a multi-color evanescent field surrounding an optical nanofiber. The atoms are localized in a one-dimensional optical lattice about 200 nm above the nanofiber surface and can be efficiently interrogated with a resonant light field sent through the nanofiber. Our technique opens the route towards the direct integration of laser-cooled atomic ensembles within fiber networks, an important prerequisite for large scale quantum communication schemes. Moreover, it is ideally suited to the realization of hybrid quantum systems that combine atoms with, e.g., solid state quantum devices.

  8. The dominant factors affecting agricultural land use (rice field change in Yogyakarta Special Province

    Directory of Open Access Journals (Sweden)

    Hadi Sabari Yunus

    2013-07-01

    The research shows that the period of 1980 - 2000 in Yogyakarta Special Province has indicated very significantly the increase in population, the development of road and the extension of built up area. For the time being, agricultural land mainly in Sleman Regency, Bantul Regency and Yogyakarta Municipality has decreased. Sleman regency performed the largest decrease of rice field and followed after then by Bantul regency and Yogyakarta Municipality. The regency of Kulon Progo and Gunung Kidul have experienced reverse phenomenon i.e. the increase of rice field during this period. Individually or simultaneously, three variables used in this research (number of people, road's length and built up area have significantly influenced the agricultural land use.

  9. Remote sensing of rice fields and sea pollution by SIR-B

    Science.gov (United States)

    Fugono, N.; Furuhama, Y.; Takasugi, T.; Okamoto, K.; Fujita, M.; Yoshikado, S.; Masuko, H.; Shinozuka, T.; Inomata, H.; Shiro, I.

    1984-01-01

    Sensor calibration, rice fields, and sea pollution are to be investigated with respect to shuttle imaging radar-B (SIR-B). It is planned that the resolution characteristics of the SIR-B be evaluated, the sidelobe characteristics of the SIR-B be investigated, and the relationship between backscatter cross section and image intensity be established. The microwave-scattering characteristics of rice fields are to be studied using SIR-B data. The possibility of classifying crops from SIR-B data is to be explored. The characteristics of the radar image of oil-like surface films under several sea surface conditions are to be determined. The absolute measurement capability of the sea surface scattering cross section is to be estimated using the SIR.

  10. Structural properties and digestibility of pulsed electric field treated waxy rice starch.

    Science.gov (United States)

    Zeng, Feng; Gao, Qun-Yu; Han, Zhong; Zeng, Xin-An; Yu, Shu-Juan

    2016-03-01

    Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm(-1). The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm(-1). Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility.

  11. Pathological Study of Blood Parasites in Rice Field Frogs, Hoplobatrachus rugulosus (Wiegmann, 1834)

    OpenAIRE

    Achariya Sailasuta; Jetjun Satetasit; Malinee Chutmongkonkul

    2011-01-01

    One hundred and forty adult rice field frogs, Hoplobatrachus rugulosus (Wiegmann, 1834), were collected in Srakaew province, Thailand. For blood parasite examination, thin blood smears were made and routinely stained with Giemsa. The results showed that 70% of the frogs (98/140) were infected with 5 species of blood parasites, including a Trypanosoma rotatorium-like organism, Trypanosoma chattoni, Hepatozoon sp. a, Hepatozoon sp. b, and Lankesterella minima. Pathological examination of the li...

  12. Unravelling trophic subsidies of agroecosystems for biodiversity conservation: Food consumption and nutrient recycling by waterbirds in Mediterranean rice fields

    Energy Technology Data Exchange (ETDEWEB)

    Navedo, Juan G., E-mail: jgnavedo@uach.cl [Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Facultad de Ciencias, Campus Isla Teja, 5090000 Valdivia (Chile); Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Hahn, Steffen [Department Bird Migration, Swiss Ornithological Institute, Seerose 1, 6204 Sempach (Switzerland); Parejo, Manuel; Abad-Gómez, José M. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Gutiérrez, Jorge S. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain); Department of Marine Ecology, Royal Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, Texel (Netherlands); Villegas, Auxiliadora; Sánchez-Guzmán, Juan M.; Masero, José A. [Conservation Biology Research Group, Universidad de Extremadura, Avda. Elvas s/n, 06002 Badajoz (Spain)

    2015-04-01

    Waterbirds can reallocate a considerable amount of nutrients within agricultural fields and between agriculture sites and wetlands. However their effects on biogeochemical cycles have rarely been quantified. We estimated bird numbers, diet (from stable isotope analysis), food supply, and the food consumption on rice fields by overwintering waterbirds in one of the most important areas for rice production in southwestern Europe and a key area for various migrating and resident waterbird species. Herein, we modelled the nutrient (N and P) recycling in rice fields, and their transport to reservoirs. The energy consumption by waterbirds (96,605 ± 18,311 individuals) on rice fields during winter averaged at 89.9 ± 39.0 kJ·m{sup −2}, with its majority (89.9%) belonging to foraging on rice seeds. Thus, the birds removed about 26% of rice seeds leftover after harvest (estimated in 932.5 ± 504.7 seeds·m{sup −2} in early winter) wherein common cranes and dabbling ducks (four species) were the most important consumers. Waterbirds foraging and roosting in the rice fields recycled more than 24.1 (1.0 kg·ha{sup −1}) of N and an additional 5.0 tons (0.2 kg·ha{sup −1}) of P in the Extremadura's rice fields during winter. Additionally, we estimated that 2.3 tons of N and 550 kg of P were removed from rice fields and transported to reservoirs. The seasonal foraging of wildlife should result in a direct benefit for rice farmers by improving nutrient recycling through defecation by waterbirds with respect to artificial fertilisation. Additionally, rice fields located in the cranes' core wintering areas can provide sufficient food supply to induce habitat shift from their traditional wintering habitat in ‘dehesas’ to rice fields, which causes indirect socioeconomic benefit through reduced acorn consumption by cranes. Our modelling approach may thus be especially helpful for management decisions regarding rice agroecosystems in areas which are also important

  13. Effects of Fipronil Insecticide Application on Sympetrum sp. Larvae and Adults in Experimental Rice Paddy Field

    Science.gov (United States)

    Jinguji, Hiroshi; Ueda, Tetsuyuki; Tsunoda, Manami; Aihara, Shoko; Saito, Mitsuo

    The effect of on sowing and before transplanting application of the phenyl pyrazole insecticide, fipronil, on the survivorship Sympetrum spp. was investigated in plots of an experimental rice paddy field. In addition, the effect of two pesticide applications on rice weevils was investigated. A total of nine paddy plots were used in this study: three were treated with fipronil at the before transplanting application , three at the on sowing application, and the three remaining plots were left untreated for use as controls. Fipronil concentrations in paddy water at the time of application in before transplanting and on sowing treatments reached 1.45 and 1.20 μg/L, respectively. A comparison of experimental and control plots revealed a marked absence of Sympetrum frequens larvae, exuviae and adults from fipronil-treated fields. Adult density of Sympetrum sp. and members of Lestidae in paddy fields before transplanting application were considerably lower than in control plots. Our results show that before transplanting application is more effective than on sowing application for treating rice weevils, but that on sowing application may still be harm against dragonflies.

  14. Development of specific chromosomal DNA pool for rice field eel and their application to gene mapping

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The chromosomes 1, 3, 5, 6, 7, 10 and 12 of rice field eel (Monopterus albus Zuiew) have been microdissected successfully from meiosis I diakinesis spreads by using glass microneedle under an inverted microscope. And the DOP-PCR products of the single chromosome dotted on the nylon membrane as "specific chromosomal DNA pool", have been hybridized with 6 probes to map these genes. The mapping results show that Zfa has been mapped to chromosome 1, rDNA to chromosomes 3 and 7, both Gh and Pdeg to chromosome 10, Hsl to chromosome 5 and Hox genes have been detected on chromosomes 1, 3, 6 and 10 meantime. It has initiatively been suggested that chromosome 10 of rice field eel might possess the commom conserved synteny to that on chromosome 17 of human, chromosome 11 of mouse,chromosome 12 of pig and chromosome 19 of bovine. And so chromosome 3 of rice field eel might also contain the commom conserved synteny to that on chromosome 2 of zebrafish. Our study is an attempt to establish a new and feasible method to advance the study of gene mapping and chromosome evolution in fish, and also to provide a new idea to distinguish each chromosome on the base of molecular markers for fish.

  15. Rice Fields Mapping in Fragmented Area Using Multi-Temporal HJ-1A/B CCD Images

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2015-03-01

    Full Text Available Rice is one of the most important crops in the world; meanwhile, the rice field is also an important contributor to greenhouse gas methane emission. Therefore, it is important to get an accurate estimation of rice acreage for both food production and climate change related studies. The eastern plain region is one of the major single-cropped rice (SCR growing areas in China. Subjected to the topography and intensified human activities, the rice fields are generally fragmented and irregular. How remote sensing can meet this challenge to accurately estimate the acreage of the rice in this region using medium-resolution imagery is the topic of this study. In this study, the applicability of the Chinese HJ-1A/B satellites and a two-band enhanced vegetation index (EVI2 was investigated. Field campaigns were carried out during the rice growing season and ground-truth data were collected for classification accuracy assessments in 2012. A stepwise classification strategy utilizing the EVI2 signatures during key phenology stages, i.e., the transplanting and the vegetative to reproductive transition phases, of the SCR was proposed, and the overall classification accuracy was 91.7%. The influence of the mixed pixel and boundary effects to classification accuracy was also investigated. This work demonstrates that the Chinese HJ-1A/B data are suitable data source to estimating SCR cropping area under complex land cover composition.

  16. Methane emissions from rice fields under continuous straw return in the middle-lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Pengfu Hou; Ganghua Li; Shaohua Wang; Xin Jin; Yiming Yang; Xiaoting Chen; Chengqiang Ding

    2013-01-01

    A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane (CH4) emissions from rice fields in which,the rice-wheat rotation system is the most dominant planting pattern.The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year.The analyses for the present study were conducted in the second (2011) and third (2012) rice growing seasons.Four treatments,namely,the continuous return of wheat straw and rice straw in every season (WR),of rice straw but no wheat straw return (R),of wheat straw but no rice straw return (W) and a control with no straw return (CK),were laid out in a randomized split-plot design.The total seasonal CH4 emissions ranged from 107.4 to 491.7 kg/ha (2011) and 160.3 to 909.6 kg/ha (2012).The increase in CH4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year,respectively,in relation to CK.We observed less methane emissions in the treatment R than in CK by 14%-43%,but not statistically significant.Treatment R could increase rice productivity while no more CH4 emission occurs.The difference in the total CH4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season,which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.

  17. Comparative Metagenomics of Anode-Associated Microbiomes Developed in Rice Paddy-Field Microbial Fuel Cells

    Science.gov (United States)

    Kouzuma, Atsushi; Kasai, Takuya; Nakagawa, Gen; Yamamuro, Ayaka; Abe, Takashi; Watanabe, Kazuya

    2013-01-01

    In sediment-type microbial fuel cells (sMFCs) operating in rice paddy fields, rice-root exudates are converted to electricity by anode-associated rhizosphere microbes. Previous studies have shown that members of the family Geobacteraceae are enriched on the anodes of rhizosphere sMFCs. To deepen our understanding of rhizosphere microbes involved in electricity generation in sMFCs, here, we conducted comparative analyses of anode-associated microbiomes in three MFC systems: a rice paddy-field sMFC, and acetate- and glucose-fed MFCs in which pieces of graphite felt that had functioned as anodes in rice paddy-field sMFC were used as rhizosphere microbe-bearing anodes. After electric outputs became stable, microbiomes associated with the anodes of these MFC systems were analyzed by pyrotag sequencing of 16S rRNA gene amplicons and Illumina shotgun metagenomics. Pyrotag sequencing showed that Geobacteraceae bacteria were associated with the anodes of all three systems, but the dominant Geobacter species in each MFC were different. Specifically, species closely related to G. metallireducens comprised 90% of the anode Geobacteraceae in the acetate-fed MFC, but were only relatively minor components of the rhizosphere sMFC and glucose-fed MFC, whereas species closely related to G. psychrophilus were abundantly detected. This trend was confirmed by the phylogenetic assignments of predicted genes in shotgun metagenome sequences of the anode microbiomes. Our findings suggest that G. psychrophilus and its related species preferentially grow on the anodes of rhizosphere sMFCs and generate electricity through syntrophic interactions with organisms that excrete electron donors. PMID:24223712

  18. Comparative metagenomics of anode-associated microbiomes developed in rice paddy-field microbial fuel cells.

    Science.gov (United States)

    Kouzuma, Atsushi; Kasai, Takuya; Nakagawa, Gen; Yamamuro, Ayaka; Abe, Takashi; Watanabe, Kazuya

    2013-01-01

    In sediment-type microbial fuel cells (sMFCs) operating in rice paddy fields, rice-root exudates are converted to electricity by anode-associated rhizosphere microbes. Previous studies have shown that members of the family Geobacteraceae are enriched on the anodes of rhizosphere sMFCs. To deepen our understanding of rhizosphere microbes involved in electricity generation in sMFCs, here, we conducted comparative analyses of anode-associated microbiomes in three MFC systems: a rice paddy-field sMFC, and acetate- and glucose-fed MFCs in which pieces of graphite felt that had functioned as anodes in rice paddy-field sMFC were used as rhizosphere microbe-bearing anodes. After electric outputs became stable, microbiomes associated with the anodes of these MFC systems were analyzed by pyrotag sequencing of 16S rRNA gene amplicons and Illumina shotgun metagenomics. Pyrotag sequencing showed that Geobacteraceae bacteria were associated with the anodes of all three systems, but the dominant Geobacter species in each MFC were different. Specifically, species closely related to G. metallireducens comprised 90% of the anode Geobacteraceae in the acetate-fed MFC, but were only relatively minor components of the rhizosphere sMFC and glucose-fed MFC, whereas species closely related to G. psychrophilus were abundantly detected. This trend was confirmed by the phylogenetic assignments of predicted genes in shotgun metagenome sequences of the anode microbiomes. Our findings suggest that G. psychrophilus and its related species preferentially grow on the anodes of rhizosphere sMFCs and generate electricity through syntrophic interactions with organisms that excrete electron donors.

  19. Comparative metagenomics of anode-associated microbiomes developed in rice paddy-field microbial fuel cells.

    Directory of Open Access Journals (Sweden)

    Atsushi Kouzuma

    Full Text Available In sediment-type microbial fuel cells (sMFCs operating in rice paddy fields, rice-root exudates are converted to electricity by anode-associated rhizosphere microbes. Previous studies have shown that members of the family Geobacteraceae are enriched on the anodes of rhizosphere sMFCs. To deepen our understanding of rhizosphere microbes involved in electricity generation in sMFCs, here, we conducted comparative analyses of anode-associated microbiomes in three MFC systems: a rice paddy-field sMFC, and acetate- and glucose-fed MFCs in which pieces of graphite felt that had functioned as anodes in rice paddy-field sMFC were used as rhizosphere microbe-bearing anodes. After electric outputs became stable, microbiomes associated with the anodes of these MFC systems were analyzed by pyrotag sequencing of 16S rRNA gene amplicons and Illumina shotgun metagenomics. Pyrotag sequencing showed that Geobacteraceae bacteria were associated with the anodes of all three systems, but the dominant Geobacter species in each MFC were different. Specifically, species closely related to G. metallireducens comprised 90% of the anode Geobacteraceae in the acetate-fed MFC, but were only relatively minor components of the rhizosphere sMFC and glucose-fed MFC, whereas species closely related to G. psychrophilus were abundantly detected. This trend was confirmed by the phylogenetic assignments of predicted genes in shotgun metagenome sequences of the anode microbiomes. Our findings suggest that G. psychrophilus and its related species preferentially grow on the anodes of rhizosphere sMFCs and generate electricity through syntrophic interactions with organisms that excrete electron donors.

  20. Lime and Phosphate Amendment Can Significantly Reduce Uptake of Cd and Pb by Field-Grown Rice

    Directory of Open Access Journals (Sweden)

    Rongbo Xiao

    2017-03-01

    Full Text Available Agricultural soils are suffering from increasing heavy metal pollution, among which, paddy soil polluted by heavy metals is frequently reported and has elicited great public concern. In this study, we carried out field experiments on paddy soil around a Pb-Zn mine to study amelioration effects of four soil amendments on uptake of Cd and Pb by rice, and to make recommendations for paddy soil heavy metal remediation, particularly for combined pollution of Cd and Pb. The results showed that all the four treatments can significantly reduce the Cd and Pb content in the late rice grain compared with the early rice, among which, the combination amendment of lime and phosphate had the best remediation effects where rice grain Cd content was reduced by 85% and 61%, respectively, for the late rice and the early rice, and by 30% in the late rice grain for Pb. The high reduction effects under the Ca + P treatment might be attributed to increase of soil pH from 5.5 to 6.7. We also found that influence of the Ca + P treatment on rice production was insignificant, while the available Cd and Pb content in soil was reduced by 16.5% and 11.7%, respectively.

  1. Estimation of the rice-planting field in Bangladesh by satellite remote sensing

    Science.gov (United States)

    Furuta, E.; Suzuki, G.; Yamassaki, M.; Teraoka, T.; Fujiwara, H.; Ogino, Y.; Akashi, M.; Lahrita, L.; Naruse, N.; Takahashi, Y.

    2016-12-01

    In Bangladesh, price of rice has been unstable due to a large increase in production. To control the price can become a political issue, because rice agriculture is one of the most important industries in Bangladesh, whereas the total area of the paddy field is accurately unknown, owing to unsustainable and on-site surveys for the area (1). Satellite remote sensing is an effective solution to research the all area of domestic paddy field. Microwave satellite imaging has a large merit to be observable regardless of the weather conditions, however, research institutions have been limited to observing continuously since the cost is high for developing countries, such as Bangladesh. This study aims to establish the way to grasp the paddy field using optical satellite images for free of charge (Landsat-8). We have focused on seasonal changes in the water and the vegetation indices obtained from paddy fields. We have performed image calculations of Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) of the well-known paddy field in Bangladesh Rice Research Institute. We found that there are seasonal changes of NDVI and NDWI calculated from paddy field. The characteristics are as follows; the NDVI and the NDWI values varies by 0.17-0.25 up and 0.11-0.19 down, respectively, at the transition from the dry to the rainy season, on the other hand, the NDVI and the NDWI changes by 0.21-0.29 down and 0.09-0.17 up from the rainy to the dry season. These features make us to distinguish the paddy field from the other cultivated area. The decrease of NDVI means that rice bares, The increase of NDWI can be interpreted that the paddy field is covered with water for the preparation for planting it. Our estimated area of paddy field in Bangladesh (85,900km ) corresponds well with the previous reported value of 117,700km (1). We have established the way to grasp the paddy field using optical satellite images for free of charge, on the bases of the

  2. Genetic and field management strategies to enhance the nutritional value of rice grains and limit accumulation of undesirable elements such as arsenic

    Science.gov (United States)

    Enhancing the nutritional value of rice grains is of particular interest because rice is a primary dietary component for more than half of the world’s population, and is a primary source of nutrients in many underdeveloped countries. Because rice can be grown under both flooded and unflooded field ...

  3. A digital photography and analysis system for estimation of root and shoot development in rice weed suppression studies in the field

    Science.gov (United States)

    Rice germplasm with an inherent ability to suppress weeds can potentially improve the economics and sustainability of weed control in rice. We devised a simple, rapid, and inexpensive digital imaging system to quantify several shoot and root growth characteristics in field-grown rice plants that ha...

  4. Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy

    Directory of Open Access Journals (Sweden)

    A. Meijide

    2011-09-01

    Full Text Available Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4, the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem.

    For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd. was installed in an eddy-covariance field set-up in a rice paddy field in the Po Valley (Northern Italy. Methane fluxes were measured during the rice growing season, both with EC and with manually operated closed chambers. Methane fluxes were strongly influenced by the presence of the water table, with emissions peaking when it was above 10–12 cm. Further studies are required to evaluate if water table management could decrease CH4 emissions. The development of rice plants and soil temperature were also responsible of the seasonal variation on the fluxes. The EC measured showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between both measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.8 g CH4 m−2

  5. Use of Forward-Scattering Algorithm for Growth Stage Determination of Rice Fields

    Science.gov (United States)

    Yuzugullu, Onur; Erten, Esra; Hajnsek, Irena

    2015-04-01

    Rice is one of the major crops that is highly consumed worldwide. Therefore, there is a requirement for frequent monitoring. The aim of the growth stage monitoring is to optimize crop management practices and reduce the environmental impacts. This study aims to provide a novel approach to determine the growth stage of rice fields by means of polarimetric Synthetic Aperture Radar (PolSAR) data. To estimate the growth stage of rice fields, firstly a hyper space is simulated using a forward scattering model. Then, by assuming that the plant morphology for different polarimetric channels have to be similar, to reduce the size of the simulated hyper space, a set of constraints are applied. Finally, to determine the most possible growth stage the probabilities of the morphological parameters in the minimized hyper spaces are calculated. The proposed method is tested over co-polar TerraSAR-X (TSX) data by exploiting a single acquisition and a priori information. Results of the analysis show that, proposed method is able to estimate growth stage with a ± 5 BBCH accuracy.

  6. Aquaporins are major determinants of water use efficiency of rice plants in the field.

    Science.gov (United States)

    Nada, Reham M; Abogadallah, Gaber M

    2014-10-01

    This study aimed at specifying the reasons of unbalanced water relations of rice in the field at midday which results in slowing down photosynthesis and reducing water use efficiency (WUE) in japonica and indica rice under well-watered and droughted conditions. Leaf relative water content (RWC) decreased in the well-watered plants at midday in the field, but more dramatically in the droughted indica (75.6 and 71.4%) than japonica cultivars (85.5 and 80.8%). Gas exchange was measured at three points during the day (9:00, 13:00 and 17:00). Leaf internal CO2 (Ci) was not depleted when midday stomatal depression was highest indicating that Ci was not limiting to photosynthesis. Most aquaporins were predominantly expressed in leaves suggesting higher water permeability in leaves than in roots. The expression of leaf aquaporins was further induced by drought at 9:00 without comparable responses in roots. The data suggest that aquaporin expression in the root endodermis was limiting to water uptake. Upon removal of the radial barriers to water flow in roots, transpiration increased instantly and photosynthesis increased after 4h resulting in increasing WUE after 4h, demonstrating that WUE in rice is largely limited by the inadequate aquaporin expression profiles in roots.

  7. Simulation of future global warming scenarios in rice paddies with an open-field warming facility

    Directory of Open Access Journals (Sweden)

    Rehmani Muhammad

    2011-12-01

    Full Text Available Abstract To simulate expected future global warming, hexagonal arrays of infrared heaters have previously been used to warm open-field canopies of upland crops such as wheat. Through the use of concrete-anchored posts, improved software, overhead wires, extensive grounding, and monitoring with a thermal camera, the technology was safely and reliably extended to paddy rice fields. The system maintained canopy temperature increases within 0.5°C of daytime and nighttime set-point differences of 1.3 and 2.7°C 67% of the time.

  8. Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy

    Directory of Open Access Journals (Sweden)

    A. Meijide

    2011-12-01

    Full Text Available Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4, the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem.

    For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd. was installed in a rice paddy field in the Po Valley (Northern Italy. Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10–12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.7 g CH4 m−2 measured with chambers and EC respectively and even greater differences are found if shorter periods with high chamber sampling

  9. Comparative analysis of the genomes of two field isolates of the rice blast fungus Magnaporthe oryzae.

    Directory of Open Access Journals (Sweden)

    Minfeng Xue

    Full Text Available Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice worldwide. The fungal pathogen is notorious for its ability to overcome host resistance. To better understand its genetic variation in nature, we sequenced the genomes of two field isolates, Y34 and P131. In comparison with the previously sequenced laboratory strain 70-15, both field isolates had a similar genome size but slightly more genes. Sequences from the field isolates were used to improve genome assembly and gene prediction of 70-15. Although the overall genome structure is similar, a number of gene families that are likely involved in plant-fungal interactions are expanded in the field isolates. Genome-wide analysis on asynonymous to synonymous nucleotide substitution rates revealed that many infection-related genes underwent diversifying selection. The field isolates also have hundreds of isolate-specific genes and a number of isolate-specific gene duplication events. Functional characterization of randomly selected isolate-specific genes revealed that they play diverse roles, some of which affect virulence. Furthermore, each genome contains thousands of loci of transposon-like elements, but less than 30% of them are conserved among different isolates, suggesting active transposition events in M. oryzae. A total of approximately 200 genes were disrupted in these three strains by transposable elements. Interestingly, transposon-like elements tend to be associated with isolate-specific or duplicated sequences. Overall, our results indicate that gain or loss of unique genes, DNA duplication, gene family expansion, and frequent translocation of transposon-like elements are important factors in genome variation of the rice blast fungus.

  10. Rice field agroecosystem investigation : environmental and toxicological assessment; Indagine su una risaia campione: analisi ambientali e chimico-tossicologiche

    Energy Technology Data Exchange (ETDEWEB)

    Bari, A.; Minciardi, M.; Rossi, G. [ENEA, Centro Ricerche Saluggia, Vercelli (Italy). Dip. Ambiente; Bonotto, F.; Paonessa, F.; Troiani, F. [ENEA, Centro Ricerche Saluggia, Vercelli (Italy). Dip. Energia; Rosa, S. [ENEA, Centro Ricrche Casaccia, Rome (Italy). Dip. Ambiente; Cormegna, M. [Ente Nazionale Risi, Centro Ricerche sul Riso, Castello d`Agogna, Pavia (Italy)

    1995-10-01

    The rice-field agroecosystem, even if deeply anthropically determined, can be considered substitute of the plain wet lands, now almost all disappeared in the part of the territory has been considering. The aim of the research we started was the analysis and the ecological characterization of this environment and the assessment of the effects of the different agronomical practices, relating to the conservation of the biodiversity in a plain wetland. The ENEA Environmental Biology and Nature Conservation Division of Saluggia (VC) and Casaccia (Roma), in co-operation with ENEA ERG-RAD-LAB Division of Saluggia and the Rice Research Center of Castello d`Agogna (PV) associated to Rice National Society, started a preliminary research on a sample rice field, aiming to evaluate, using different methodologies, the destiny of the chemical substances (herbicides, fungicidals, heavy metals and other chemical compounds) introduced through cultivation practices or arrived by irrigation systems.

  11. Field-mapping and petrographic analysis of volcanoes surrounding the Lake Natron Homo sapiens footprint site, northern Tanzania

    Science.gov (United States)

    Hewitt, S. M.; Zimmer, B.; Liutkus, C.; Carmichael, S. K.; McGinnis, K.

    2010-12-01

    The Lake Natron Homo sapiens footprint site is located in northern Tanzania along the East African Rift escarpment. The site is positioned south of Lake Natron within an ephemeral channel of the Engare Sero River. The hominid footprints are preserved in a tuff, which originated from one of the volcanic centers surrounding the site. Two large volcanoes in the surrounding region, including the active carbonatite producing Oldoinyo L’engai and the now extinct Kerimasi are possible sources. This area also contains over 30 smaller tuff cones and tuff rings that have been poorly mapped and not analyzed in detail. The site is significant as it is the oldest modern human trackway in East Africa and one of the largest collections of hominid footprints in the world. Determining the source of the footprinted volcanic ash requires detailed field mapping, and both petrographic and geochemical analyses. Extensive field-mapping of the region revealed multiple regional beds that stratigraphically overlay the footprinted layer. Age dating as well as geochemical analysis is being conducted to relate these beds to the footprinted layer. Field-mapping showed that the footprinted tuff is over 35 cm thick, suggesting a large, sustained eruption. The bulk of the tuff cones examined in the field visibly varied in composition to the footprinted tuff and, based on proximity to the footprint site, are too small to produce the requisite volume of ash. Field analysis of samples collected from Oldoinyo L’engai reveal the most similar mineral assemblages to the footprinted layer, and the large volcano provides a source substantial enough to create a thick ash bed 10 km north of the summit. Preliminary research reveals that the footprinted tuff is a phonolite, characterized by silica depletion and the presence of sanidine, augite, and annite with interstitial calcite. XRD analysis of samples collected from Oldoinyo L’engai reveal a nepheline-rich phonolite with zeolites (ie. phillipsite

  12. Runoff of pesticides from rice fields in the Ile de Camargue (Rhone river delta, France): Field study and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Comoretto, Laetitia; Arfib, Bruno; Talva, Romain; Chauvelon, Philippe; Pichaud, Marc; Chiron, Serge [Laboratoire Chimie et Environnement, Universite de Provence, Case 29, 3, Place Victor Hugo, F-13331 Marseille Cedex 3 (France); Hoehener, Patrick [Laboratoire Chimie et Environnement, Universite de Provence, Case 29, 3, Place Victor Hugo, F-13331 Marseille Cedex 3 (France)], E-mail: hoehener@up.univ-mrs.fr

    2008-02-15

    A field study on the runoff of pesticides was conducted during the cultivation period in 2004 on a hydraulically isolated rice farm of 120 ha surface with one central water outlet. Four pesticides were studied: Alphamethrin, MCPA, Oxadiazon, and Pretilachlor. Alphamethrin concentrations in runoff never exceeded 0.001 {mu}g L{sup -1}. The three other pesticides were found in concentrations between 5.2 and 28.2 {mu}g L{sup -1} in the runoff water shortly after the application and decreased thereafter. The data for MCPA compared reasonably well with predictions by an analytical runoff model, accounting for volatilization, degradation, leaching to groundwater, and sorption to soil. The runoff model estimated that runoff accounted for as much as 18-42% of mass loss for MCPA. Less runoff is observed and predicted for Oxadiazon and Pretilachlor. It was concluded that runoff from rice paddies carries important loads of dissolved pesticides to the wetlands in the Ile de Camargue, and that the model can be used to predict this runoff. - Runoff of dissolved pesticides was measured on a rice farm in the Camargue (France) and modeled with an analytical model.

  13. Mosquito (Diptera: Culicidae) and predator abundance in irrigated and rain-fed rice fields in north Sulawesi, Indonesia.

    Science.gov (United States)

    Mogi, M; Memah, V; Miyagi, I; Toma, T; Sembel, D T

    1995-05-01

    Immature mosquito species composition and abundance were studied in irrigated and rain-fed rice fields of North Sulawesi, Indonesia. Irrigated rice fields were characterized by the prevalence of aquatic macrophytes and cyprinodont larvivorous fish, Aplocheilus panchax (Hamilton), but abundance per dip of most aquatic insect predators was lower than that in rain-fed rice fields. Anopheles peditaeniatus (Leicester), Culex vishnui Theobald, and Culex tritaeniorhynchus Giles, were dominant in both irrigated and rain-fed fields, but the abundance of the Culex species was lower in irrigated fields. The effect of irrigation system introduction on regional mosquito abundance cannot be evaluated by the enlarged surface water area alone. Changes in habitat quality, expressed as the abundance per dip (index of density per unit water area), also need to be considered.

  14. Microbial, physical and chemical properties of irrigation water in rice fields of Southern Brazil

    Directory of Open Access Journals (Sweden)

    MARIA HELENA L.R. RECHE

    2016-03-01

    Full Text Available ABSTRACT This paper presents the results of the statistical analysis of microbiological, physical and chemical parameters related to the quality of the water used in rice fields in Southern Brazil. Data were collected during three consecutive crop years, within structure of a comprehensive monitoring program. The indicators used were: potential hydrogen, electrical conductivity, turbidity, nitrogen, phosphorus, potassium, calcium, total and fecal coliforms. Principal Component and Discriminant Analysis showed consistent differences between the water irrigation and drainage, as the temporal variation demonstrated a clear reduction in the concentration of most of the variables analyzed. The pattern of this reduction is not the same in the two regions - that is, the importance of each of the different variables in the observed differentiation is modified in two locations. These results suggested that the variations in the water quality utilized for rice irrigation was influenced by certain specific aspects of each rice region in South Brazilian - such as anthropic action or soil/climate conditions in each hydrographic basin.

  15. Microbial, physical and chemical properties of irrigation water in rice fields of Southern Brazil.

    Science.gov (United States)

    Reche, Maria Helena L R; Machado, Vilmar; Saul, Danilo A; Macedo, Vera R M; Marcolin, Elio; Knaak, Neiva; Fiuza, Lidia M

    2016-03-01

    This paper presents the results of the statistical analysis of microbiological, physical and chemical parameters related to the quality of the water used in rice fields in Southern Brazil. Data were collected during three consecutive crop years, within structure of a comprehensive monitoring program. The indicators used were: potential hydrogen, electrical conductivity, turbidity, nitrogen, phosphorus, potassium, calcium, total and fecal coliforms. Principal Component and Discriminant Analysis showed consistent differences between the water irrigation and drainage, as the temporal variation demonstrated a clear reduction in the concentration of most of the variables analyzed. The pattern of this reduction is not the same in the two regions - that is, the importance of each of the different variables in the observed differentiation is modified in two locations. These results suggested that the variations in the water quality utilized for rice irrigation was influenced by certain specific aspects of each rice region in South Brazilian - such as anthropic action or soil/climate conditions in each hydrographic basin.

  16. Feasibility of Field Evaluation of Rice Nitrogen Status From Reflectance Spectra of Canopy

    Institute of Scientific and Technical Information of China (English)

    WANGRENCAHO; WANGKE; 等

    1998-01-01

    Techniques for measurement of the N status of rice can be an aid to making manaement decisions with economic and environmental implications.A field experiment was conuced to identify spectral variables most sensitive to N deficiency detection in rice canopy with the possibiliy for their use as a management tool. Spectral and agronomic measurements were collected in the evaluation experiment of N status from rice canopy under vive N treatments in a silt loam soil ,Nitroen fertilization effects were seen across the entire wavelength measured .Red refectance decreased and near infrared reflectance increased with increasing N fertilizer application.Spectral differences between treatments were seen throughout the test period.The naer infrared refectnce/red reflectance ration (RVI) differed mored between treatment than between single bands.Variations in canopy reflectances due to other environmental factors were reduced by the use of RVI.In the spectral variables examined ,the RVI separated the treatments most effectively,and three or four treatments can be separated.Differences in spetral responses betwenn the treatments were attributable to leaf area index ,leaf chlorophyll concentration and phtomass,wich all changed with N fertilization.

  17. Rice Crop Field Monitoring System with Radio Controlled Helicopter Based Near Infrared Cameras Through Nitrogen Content Estimation and Its Distribution Monitoring

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-03-01

    Full Text Available Rice crop field monitoring system with radio controlled helicopter based near infrared cameras is proposed together with nitrogen content estimation method for monitoring its distribution in the field in concern. Through experiments at the Saga Prefectural Agricultural Research Institute: SPARI, it is found that the proposed system works well for monitoring nitrogen content in the rice crop which indicates quality of the rice crop and its distribution in the field in concern. Therefore, it becomes available to maintain the rice crop fields in terms of quality control.

  18. Ammonia Volatilization and Nitrogen Utilization Efficiency in Response to Urea Application in Rice Fields of the Taihu Lake Region, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 (control), 100, 200, 300, or 350 kg N ha-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates (300 and 350 kg N ha-1) showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.

  19. [China's rice field greenhouse gas emission under climate change based on DNDC model simulation].

    Science.gov (United States)

    Tian, Zhan; Niu, Yi-long; Sun, Lai-xiang; Li, Chang-sheng; Liu, Chun-jiang; Fan, Dong-li

    2015-03-01

    In contrast to a large body of literature assessing the impact of agriculture greenhouse gas (GHG) emissions on climate change, there is a lack of research examining the impact of climate change on agricultural GHG emissions. This study employed the DNDC v9.5, a state-of-art biogeochemical model, to simulate greenhouse gas emissions in China' s rice-growing fields during 1971-2010. The results showed that owing to temperature rising (on average 0.49 °C higher in the second 20 years than in the first 20 year) and precipitation increase (11 mm more in the second 20 years than in the first 20 years) during the rice growing season, CH4 and N2O emissions in paddy field increased by 0.25 kg C . hm-2 and 0.25 kg N . hm-2, respectively. The rising temperature accelerated CH4 emission and N2O emission increased with precipitation. These results indicated that climate change exerted impact on the mechanism of GHG emissions in paddy field.

  20. Morphological Variation of Six Pigmented Rice Local Varieties Grown in Organic Rice Field in Sengguruh Village, Kepanjen District, Malang Regency

    Directory of Open Access Journals (Sweden)

    Shinta

    2014-05-01

    Full Text Available Indonesia is the third richest country for pigmented rice source such as Wojalaka black rice of East Nusa Tenggara (NTT, Manggarai of NTT, Toraja of South Sulawesi, Cempo Ireng of Central Java and red rice of Aek Sibundong (leading variety and Baubau of Southeast Sulawesi. However, the morphological character of pigmented rice in Indonesia is less reported. The objective of research was to compare the morphological variation of root, stem, leaf, panicle, floret and the colour of milk mature grain and mature grain by observing the vegetative and generative parts of six local rice varieties. Research had been conducted from February 2012 to February 2014 in Sengguruh Village, Kepanjen District, Malang Regency. This study type was quasi-experiment with eleven replications. Group Random Design was used. The observation was given upon vegetative, reproductive and maturity phases as groups. Independent variables in this study were six rice varieties, while the dependent variable was morphological variation (root, stem, leaf, panicle, floret, milk mature grain and mature grain. The analysis of multivariate data in cluster and bip lot was carried out with PAST. The result of the study indicated that there was morphological difference on stem, leaf, panicle, floret, milk mature grain and mature grain. The colour of the stem in Aek Sibundong variety was purple, while that of other varieties was green. Toraja and Manggarai varieties had the highest height with 163-168 cm, followed by Cempo Ireng with 139 cm, Wojalaka and Baubau with 110-112 cm. Aek Sibundong Variety had the lowest height with 99 cm. Aek Sibundong and Wojalaka varieties had 6-7 internodes which were the greatest number of internode, while other varieties only had 4-5 internodes. Some varieties, such as Aek Sibundong, Wojalaka and Baubau had short and small leaf. The leaflet angle of Aek Sibundong and Baubau were 14o and it might be said as upright, while that of Wojalaka was 43o or moderate

  1. Evaluating health of paddy rice field ecosystem with remote sensing and GIS in Lower Yangtze River Plain, China

    Science.gov (United States)

    Li, Jingjing; Qin, Zhihao; Li, Wenjuan; Lin, Lu

    2008-10-01

    A paddy rice ecosystem is a farming system composed of paddy, animals, microbes and other environmental factors in specific time and space, with particular temporal and spatial dynamics. Since paddy rice is a main grain crop to feed above half of population in China, the performance of paddy rice ecosystem is highly concerned to yield level of paddy and food supply safety in China. Therefore, monitoring the performance of paddy rice ecosystem is very important to obtain the required information for evaluation of ecosystem health. In the study we intend to develop an approach to monitor the ecosystem performance spatially and dynamically in a regional scale using MODIS remote sensing data and GIS spatial mapping. On the basis of key factors governing the paddy rice ecosystem, we accordingly develop the following three indicators for the evaluation: Crop growing index (CGI), environmental Index (EI), and pests-diseases index (PDI). Then, we integrated the three indicators into a model with different weight coefficients to calculate Comprehensive ecosystem health index (CEHI) to evaluate the performance and functioning of paddy rice ecosystem in a regional scale. CGI indicates the health status of paddy rice calculated from the normalizing enhanced vegetation Index (EVI) retrieved from MODIS data. EI is estimated from temperature Index (TI) and precipitation Index (PI) indicating heat and water stress on the rice field. PDI reflects the damage brought by pests and diseases, which can be estimated using the information obtained from governmental websites. Applying the approach to Lower Yangtze River Plain, we monitor and evaluate the performance of paddy rice ecosystem in various stages of rice growing period in 2006. The results indicated that the performance of the ecosystem was generally very encouraging. During booting stage and heading and blooming stage, the health level was the highest in Anhui province, which is the main paddy rice producer in the region

  2. Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields.

    Science.gov (United States)

    Mutero, C M; Ng'ang'a, P N; Wekoyela, P; Githure, J; Konradsen, F

    2004-01-01

    Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block, and the fertiliser and control treatments allocated randomly among the ponds. Student's two-sample unpaired t-test was used to test for the significance of differences between the relative counts of larvae in fertiliser and control treatments. The results showed a significant overall increase in the larval populations of An. arabiensis (Price fields, thereby making them visually more attractive for egg-laying by An. arabiensis and culicine mosquitoes.

  3. LiDAR, geophysical and field surveys at Ancient Epomanduodurum site and its surrounding country (Doubs, Eastern France)

    Science.gov (United States)

    Laplaige, Clement; Bossuet, Gilles; Thivet, Matthieu

    2010-05-01

    understand the connections, both in time and in space, between human occupation and the surrounding region, not only at the Roman period and the late Iron Age, but also during prehistoric, medieval and modern periods. In that way, we have defined a square window of 80 km², surrounding the Ancient site of Epomanduodurum This study is based on the LIDAR (Light Detection And Ranging) technology, particularly adapted for the detection and location of cultural resources (ancient fields, buried structures, graves) in forested environment and a multi-data crossing, including: - Geophysical prospecting (principally magnetic, electromagnetic and electric) - Studies of ancient maps, plans (18th and 19th) and archaeological inventories in order to spot the location of vestiges and the utilisation of former soils - Aerial and satellite picture analysis - Field walking and metal detector prospection in order to precise micro topographic anomalies obtained by LiDAR survey. We received first LiDAR results during August 2009 and the use of part of this data allows us to find new sites from different periods. We will present some results, mainly in an Ancient artisanal district built on a Latenian necropolis, on hilltop sites and also on mine plant.

  4. Fipronil application on rice paddy fields reduces densities of common skimmer and scarlet skimmer.

    Science.gov (United States)

    Kasai, Atsushi; Hayashi, Takehiko I; Ohnishi, Hitoshi; Suzuki, Kazutaka; Hayasaka, Daisuke; Goka, Koichi

    2016-03-16

    Several reports suggested that rice seedling nursery-box application of some systemic insecticides (neonicotinoids and fipronil) is the cause of the decline in dragonfly species noted since the 1990s in Japan. We conducted paddy mesocosm experiments to investigate the effect of the systemic insecticides clothianidin, fipronil and chlorantraniliprole on rice paddy field biological communities. Concentrations of all insecticides in the paddy water were reduced to the limit of detection within 3 months after application. However, residuals of these insecticides in the paddy soil were detected throughout the experimental period. Plankton species were affected by clothianidin and chlorantraniliprole right after the applications, but they recovered after the concentrations decreased. On the other hand, the effects of fipronil treatment, especially on Odonata, were larger than those of any other treatment. The number of adult dragonflies completing eclosion was severely decreased in the fipronil treatment. These results suggest that the accumulation of these insecticides in paddy soil reduces biodiversity by eliminating dragonfly nymphs, which occupy a high trophic level in paddy fields.

  5. Genome analysis of rice-blast fungus Magnaporthe oryzae field isolates from southern India

    Directory of Open Access Journals (Sweden)

    Malali Gowda

    2015-09-01

    Full Text Available The Indian subcontinent is the center of origin and diversity for rice (Oryza sativa L.. The O. sativa ssp. indica is a major food crop grown in India, which occupies the first and second position in area and production, respectively. Blast disease caused by Magnaporthe oryzae is a major constraint to rice production. Here, we report the analysis of genome architecture and sequence variation of two field isolates, B157 and MG01, of the blast fungus from southern India. The 40 Mb genome of B157 and 43 Mb genome of MG01 contained 11,344 and 11,733 predicted genes, respectively. Genomic comparisons unveiled a large set of SNPs and several isolate specific genes in the Indian blast isolates. Avr genes were analyzed in several sequenced Magnaporthe strains; this analysis revealed the presence of Avr-Pizt and Avr-Ace1 genes in all the sequenced isolates. Availability of whole genomes of field isolates from India will contribute to global efforts to understand genetic diversity of M. oryzae population and to track the emergence of virulent pathotypes.

  6. Uncertainties in the national inventory of methane emissions from rice cultivation: field measurements and modeling approaches

    Science.gov (United States)

    Zhang, Wen; Sun, Wenjuan; Li, Tingting

    2017-01-01

    Uncertainties in national inventories originate from a variety of sources, including methodological failures, errors, and insufficiency of supporting data. In this study, we analyzed these sources and their contribution to uncertainty in the national inventory of rice paddy methane emissions in China and compared the differences in the approaches used (e.g., direct measurements, simple regressions, and more complicated models). For the 495 field measurements we collected from the scientific literature, the area-weighted 95 % CI (confidence interval) ranged from 13.7 to 1115.4 kg CH4 ha-1, and the histogram distribution of the measurements agreed well with parameterized gamma distributions. For the models, we compared the performance of methods of different complexity (i.e., the CH4MOD model, representing a complicated method, and two less complex statistical regression models taken from literature) to evaluate the uncertainties associated with model performance as well as the quality and accessibility of the regional datasets. Comparisons revealed that the CH4MOD model may perform worse than the comparatively simple regression models when no sufficient input data for the model is available. As simulated by CH4MOD with data of irrigation, organic matter incorporation, and soil properties of rice paddies, the modeling methane fluxes varied from 17.2 to 708.3 kg CH4 ha-1, covering 63 % of the range of the field measurements. When applying the modeling approach to the 10 km × 10 km gridded dataset of the model input variables, the within-grid variations, made via the Monte Carlo method, were found to be 81.2-95.5 % of the grid means. Upscaling the grid estimates to the national inventory, the total methane emission from the rice paddies was 6.43 (3.79-9.77) Tg. The fallacy of CH4MOD contributed 56.6 % of the total uncertainty, with the remaining 43.4 % being attributed to errors and the scarcity of the spatial datasets of the model inputs. Our analysis reveals the

  7. Measurement of Ammonia Emission Following Surface Application of Urea Fertilizer from Irrigated Paddy Rice Fields

    Institute of Scientific and Technical Information of China (English)

    Md.Toufiq Iqbal; TIAN Guang-ming; LIANG Xin-qiang; Fatima Rukshana

    2005-01-01

    Ammonia emission is one of the most important pathways of nitrogen loss from agricultural cultivated field. In this paper, we report the measurement of ammonia emission from paddy rice field obtained by surface application of urea fertilizer with water management. The main objective of the present study were to assess the amount of NH3 emission and the loss of nitrogen from paddy field as affected by various N doses, i.e., 0 (control), 90 (N1), 180 (N2), 270 (N3) and 360 (N4) kg ha-1, following field surface application of urea fertilizer with water management. Ammonia emissions were measured by continuous airflow enclosure method from plots fertilized with the application of surface urea. Increase in urea-N dosage increased NH3 emission thatwas measured from paddy rice field. Ammonia emission started immediately and was almost complete within 12 days after top dressing of urea application to the soils. Ammonia emissions were nearly constant in all treatments from 12 days after fertilizer application. Highest ammonia emission rate was 28 g/day and total amount of ammonia emission was 56.21 kg ha-1 for 360 kg N ha-1 dose. No remarkable observation was found about temperature for ammonia emission. Due to proper water management practices less emission was observed throughout the experiment period. The results also show that N loss through NH3 emission accounted for 11 to 16% during the ricegrowing season. These magnitudes of loss of N appear to be most important for environmental point of view.

  8. Weed-Suppressing Effect and Mechanism of Allelopathic Rice Accessions

    Institute of Scientific and Technical Information of China (English)

    HU Fei; KONG Chui-hua; XU Xiao-hua; ZHANG Chao-xian; CHEN Xiong-hui

    2004-01-01

    Two allelopathic rice accessions, PI312777 and Allelopathyl, significantly suppressedthe growth of associated weeds in the field. Moreover, their weed-suppressing effectswere correlated with the cultivation patterns. The weed-suppressing effects of throwingand transplanting were more effective than that of direct seeding. Furthermore, theamounts of allelochemicals (resorcinols, flavones and hydroxamic acids) produced andreleased from two allelopathic rice accessions were much higher than that from a non-allelopathic rice variety Hua-Jing-Xian 1, and reached the maximum concentration at the6th leaf stage. Differences in the weed-suppressing effects of rice accessions appear toresult from the accessions producing and releasing different amounts of allelochemicalsin the field. Further research confirmed that in PI312777 plants, allelochemicals weresynthesized by the above-ground parts, and then secreted through the root tissues. Roottissues of PI312777 plants never produced the allelochemicals. Root exudates fromPI312777 could significantly inhibit the growth of E. crus-galli surrounding rice plantsin water culture. However, when activated carbon was added to the culture solution, whichcould absorb allelochemicals from root exudates, the growth of E. crus-galli was nolonger significantly inhibited. Weed-suppressing effects of rice accessions depended onallelopathy, cultivation patterns and other factors in rice fields, while allelopathywas one of important factors. Interestingly, the amounts of allelochemicals produced andreleased from allelopathic rice plants may be induced by the presence of E. crus-galli.This suggests that there is a possible chemical recognition between rice and E. crus-galli.

  9. Evaluation of holistic approaches to predicting the concentrations of metals in field-cultivated rice.

    Science.gov (United States)

    Tian, Yuan; Wang, Xiaorong; Luo, Jun; Yu, Hongxia; Zhang, Hao

    2008-10-15

    Measurements of metals in soils by diffusive gradients in thin films (DGT) have previously been shown to be linearly related to metals measured in shoots of plants grown in pots. We examine the relationships between metals measured by DGT and other techniques with metals in the roots and unpolished grains of rice cultivated under field conditions at 18 sites in Jiangsu province, China. Rhizosphere soils of rice were collected and the concentrations of Cd, Cu, Pb, and Zn were determined on soil solution, acetic acid, and calcium chloride (CaCl2) extractions and by DGT. Simple linear regression analyses between concentrations of metals in plants and those measured using DGT and chemical extractions showed a very good fit for DGT measurements of the concentrations of all four metals in both rice roots and unpolished grains. Good fits were also found using soil solution and acetic acid extractions, but the correlation coefficients were lower than those obtained by DGT. CaCl2 extractions provided the poorest fits for all four metals. Multivariate analyses were used to assess the impact of pH, dissolved organic carbon (DOC), soil organic carbon (SOC), cation exchange capacity (CEC), and texture. Two principal components were extracted. The first was well correlated with SOC, DOC, and clay proportion and is therefore representative of "organic matter". The second primarily correlated positively with pH and negatively with CEC and is representative of "inorganic ions". When these principle components were included in multiple linear regression, correlation coefficients for plots involving metals in soil solution and in extractions using acetic acid and CaCl2 were improved, but there was little change in the correlation coefficients for comparable plots using metals measured by DGT. These results show for the first time that the DGT measurement quantitatively incorporates the main factors affecting bioavailability.

  10. [Occurrence dynamics of migratory pest insects Cnaphalocrocis medinalis and Sogatella furcifera in transgenic Bt rice field in Xing'an County of Guangxi Province].

    Science.gov (United States)

    Sui, He; Li, Zhi-Yi; Xu, Yan-Bo; Han, Chao; Han, Lan-Zhi; Chen, Fa-Jun

    2011-11-01

    An investigation was conducted in Xing' an County of Guangxi Province in 2010 to study the occurrence and damage characteristics of two unique migratory pest insects, rice leaffolder (Cnaphalocrocis medinalis) and white-backed planthopper (Sogatella furcifera), in a transgenic Bt rice (cv. HH1 with dual Cry1Ab+Cry1Ac genes) field, taking the corresponding non-transgenic parent (cv. MH63) field as the control. No significant differences were observed in the abundance of C. medinalis eggs and larvae in the two fields, but the percentage of fold-leaf plants and the fold-leaf rate per plant were significantly lower in transgenic Bt rice field than in the control, suggesting that transgenic Bt rice had higher resistance against the target pest insect C. medinalis. As for S. furcifera, its occurrence dynamics of nymphs, adults (including macro- and brachypterous forms), and whole population had no significant differences between the two fields, but the abundance of the nymphs and brachypterous adults at the peak stage of S. furcifera occurrence was obviously higher in transgenic Bt rice field than in the control, while the macropterous abundance was in adverse. The sex ratio of female of the macropterous adults at the late growth stage of rice was generally lower in transgenic Bt rice field than in the control. These results suggested that under the background of large area commercial production of transgenic Bt rice, the occurrence and harm of the non-target pest insect S. furcifera could become more complicated.

  11. Spatial Distribution and Minimum Sample Size for Overwintering Larvae of the Rice Stem Borer Chilo suppressalis (Walker) in Paddy Fields.

    Science.gov (United States)

    Arbab, A

    2014-10-01

    The rice stem borer, Chilo suppressalis (Walker), feeds almost exclusively in paddy fields in most regions of the world. The study of its spatial distribution is fundamental for designing correct control strategies, improving sampling procedures, and adopting precise agricultural techniques. Field experiments were conducted during 2011 and 2012 to estimate the spatial distribution pattern of the overwintering larvae. Data were analyzed using five distribution indices and two regression models (Taylor and Iwao). All of the indices and Taylor's model indicated random spatial distribution pattern of the rice stem borer overwintering larvae. Iwao's patchiness regression was inappropriate for our data as shown by the non-homogeneity of variance, whereas Taylor's power law fitted the data well. The coefficients of Taylor's power law for a combined 2 years of data were a = -0.1118, b = 0.9202 ± 0.02, and r (2) = 96.81. Taylor's power law parameters were used to compute minimum sample size needed to estimate populations at three fixed precision levels, 5, 10, and 25% at 0.05 probabilities. Results based on this equation parameters suggesting that minimum sample sizes needed for a precision level of 0.25 were 74 and 20 rice stubble for rice stem borer larvae when the average larvae is near 0.10 and 0.20 larvae per rice stubble, respectively.

  12. [Distribution characteristics of soil profile nitrous oxide concentration in paddy fields with different rice-upland crop rotation systems].

    Science.gov (United States)

    Liu, Ping-li; Zhang, Xiao-lin; Xiong, Zheng-qin; Huang, Tai-qing; Ding, Min; Wang, Jin-yang

    2011-09-01

    To investigate the dynamic distribution patterns of nitrous oxide (N2O) in the soil profiles in paddy fields with different rice-upland crop rotation systems, a special soil gas collection device was adopted to monitor the dynamics of N2O at the soil depths 7, 15, 30, and 50 cm in the paddy fields under both flooding and drainage conditions. Two rotation systems were installed, i.e., wheat-single rice and oilseed rape-double rice, each with or without nitrogen (N) application. Comparing with the control, N application promoted the N2O production in the soil profiles significantly (P cropping treatments. The soil N2O concentrations in the treatments without N application peaked in the transitional period from the upland crops cropping to rice planting, while those in the treatments with N application peaked right after the second topdressing N of upland crops. Relatively high soil N2O concentrations were observed at the transitional period from the upland crops cropping to rice planting.

  13. Lead pollution from waterfowl hunting in wetlands and rice fields in Argentina.

    Science.gov (United States)

    Romano, Marcelo; Ferreyra, Hebe; Ferreyroa, Gisele; Molina, Fernando V; Caselli, Andrea; Barberis, Ignacio; Beldoménico, Pablo; Uhart, Marcela

    2016-03-01

    The pollution of wetlands by lead derived from waterfowl hunting with lead shot was investigated. We determined soil pellet density and Pb concentration in soil, water and vegetation in natural wetlands and rice fields in central-eastern Santa Fe province, Argentina. Pellet density varied greatly among hunting sites (between 5.5-141 pellets/m(2)) and pellets were present in some control sites. Soil Pb concentration in most hunting sites (approximately 10-20 mg kg(-1)) was not much higher than in control sites (~5-10 mg kg(-1)), with the exception of the site with highest pellet density, which also had a high Pb soil concentration. In water, on the other hand, Pb concentration was similar in all sites (~4-7 μg L(-1)), both control and hunting, and higher than reference values for aquatic media. Lead was also present in vegetation, including grasses and rice crops, in almost all cases. Most soil-collection sites were slightly acidic, and were frequently flooded. These results strongly suggest that metallic Pb from spent shot is oxidized and dissolved due to wetland conditions. Thus, the pollutant is readily mobilized and distributed across all wetland areas, effectively homogenizing its concentration in locations with and without hunting activities. The replacement of lead by nontoxic materials in pellets appears to be the only effective way to prevent Pb pollution in wetlands.

  14. Rapid detection of Aspergillus flavus in rice using biofunctionalized carbon nanotube field effect transistors.

    Science.gov (United States)

    Villamizar, Raquel A; Maroto, Alicia; Rius, F Xavier

    2011-01-01

    In the present study, we have used carbon nanotube field effect transistors (FET) that have been functionalized with protein G and IgG to detect Aspergillus flavus in contaminated milled rice. The adsorbed protein G on the carbon nanotubes walls enables the IgG anti-Aspergillus antibodies to be well oriented and therefore to display full antigen binding capacity for fungal antigens. A solution of Tween 20 and gelatine was used as an effective blocking agent to prevent the non-specific binding of the antibodies and other moulds and also to protect the transducer against the interferences present in the rice samples. Our FET devices were able to detect at least 10 μg/g of A. flavus in only 30 min. To evaluate the selectivity of our biosensors, Fusarium oxysporum and Penicillium chrysogenum were tested as potential competing moulds for A. flavus. We have proved that our devices are highly selective tools for detecting mycotoxigenic moulds at low concentrations in real samples.

  15. Do NERICA rice cultivars express resistance to Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze under field conditions?

    Science.gov (United States)

    Rodenburg, Jonne; Cissoko, Mamadou; Kayeke, Juma; Dieng, Ibnou; Khan, Zeyaur R; Midega, Charles A O; Onyuka, Enos A; Scholes, Julie D

    2015-01-01

    The parasitic weeds Striga asiatica and Striga hermonthica cause high yield losses in rain-fed upland rice in Africa. Two resistance classes (pre- and post-attachment) and several resistant genotypes have been identified among NERICA (New Rice for Africa) cultivars under laboratory conditions (in vitro) previously. However, little is known about expression of this resistance under field conditions. Here we investigated (1) whether resistance exhibited under controlled conditions would express under representative Striga-infested field conditions, and (2) whether NERICA cultivars would achieve relatively good grain yields under Striga-infested conditions. Twenty-five rice cultivars, including all 18 upland NERICA cultivars, were screened in S. asiatica-infested (in Tanzania) and S. hermonthica-infested (in Kenya) fields during two seasons. Additionally, a selection of cultivars was tested in vitro, in mini-rhizotron systems. For the first time, resistance observed under controlled conditions was confirmed in the field for NERICA-2, -5, -10 and -17 (against S. asiatica) and NERICA-1 to -5, -10, -12, -13 and -17 (against S. hermonthica). Despite high Striga-infestation levels, yields of around 1.8 t ha(-1) were obtained with NERICA-1, -9 and -10 (in the S. asiatica-infested field) and around 1.4 t ha(-1) with NERICA-3, -4, -8, -12 and -13 (in the S. hermonthica-infested field). In addition, potential levels of tolerance were identified in vitro, in NERICA-1, -17 and -9 (S. asiatica) and in NERICA-1, -17 and -10 (S. hermonthica). These findings are highly relevant to rice agronomists and breeders and molecular geneticists working on Striga resistance. In addition, cultivars combining broad-spectrum resistance with good grain yields in Striga-infested fields can be recommended to rice farmers in Striga-prone areas.

  16. Studies on mosquitoes (Diptera: Culicidae and anthropicenvironment: 5- Breeding of Anopheles albitarsis in flooded rice fields in South-Eastern Brazil

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    Forattini Oswaldo Paulo

    1994-01-01

    Full Text Available Studies on breeding Anopheles albitarsis and association with rice growth in irrigated paddy fields were carried out during the rice cultivation cycle from December 1993 to March 1994. This period corresponded to the length of time of permanent paddy flooding. Breeding occurred in the early stage up until five weeks after transplantation when rice plant height was small. That inverse correlation may give potential direction to control measures.

  17. Field and laboratory studies on the impact of two Bt rice lines expressing a fusion protein Cry1Ab/1Ac on aquatic organisms.

    Science.gov (United States)

    Wang, Yongmo; Huang, Jiacheng; Hu, Huawei; Li, Jianhong; Liu, Biao; Zhang, Guoan

    2013-06-01

    Genetically modified (GM) rice expressing Bt toxins is at the edge of commercial release in China. However, little information is available concerning the impact of Bt rice on aquatic organisms which are abundant in paddy field. A two-year study was conducted to assess the effects of two GM rice lines expressing a fusion protein Cry1Ab/1Ac (Bt rice) on three groups of zooplankton, rotifers, cladocerans and copepods in field conditions. Multi-factor ANOVA revealed that the population densities of rotifers, cladocerans and copepods in paddy field varied significantly between years and rice developmental stages, but did not differ significantly between Bt and non-Bt rice treatments. In all the field investigations, only one significant difference was found on copepods in the tillering stage of 2009, but the difference was not related to the presence of the Cry toxin. Under open-air conditions, we simulated the farming practice of straw mulch, using Bt rice straw as a food source for the water flea Daphnia hyalina. After one and two months of culture, the density of D. hyalina did not differ between Bt rice treatments and non-Bt rice treatments. A laboratory experiment found that purified Bt toxins Cry1Ab and Cry1Ac had no toxic effect on D. hyalina even in the treatment in which the Bt toxin concentration was as high as 2500ng/ml. Those above results indicate that the two Bt rice lines have no negative effect on the three groups of zooplankton. However, further studies are needed to compare the effects of Bt rice and non-Bt rice on the paddy zooplankton community in the context of integrated pest management which includes the use of pesticides.

  18. Studies on mosquitoes (Diptera: Culicidae and anthropicenvironment: 5- Breeding of Anopheles albitarsis in flooded rice fields in South-Eastern Brazil

    Directory of Open Access Journals (Sweden)

    Oswaldo Paulo Forattini

    1994-10-01

    Full Text Available Studies on breeding Anopheles albitarsis and association with rice growth in irrigated paddy fields were carried out during the rice cultivation cycle from December 1993 to March 1994. This period corresponded to the length of time of permanent paddy flooding. Breeding occurred in the early stage up until five weeks after transplantation when rice plant height was small. That inverse correlation may give potential direction to control measures.

  19. Azolla-Anabaena as a Biofertilizer for Rice Paddy Fields in the Po Valley, a Temperate Rice Area in Northern Italy

    Directory of Open Access Journals (Sweden)

    Stefano Bocchi

    2010-01-01

    Full Text Available Azolla is a floating pteridophyte, which contains as endosymbiont the nitrogen-fixing cyanobacterium Anabaena azollae (Nostocaceae family. Widely cultivated in the Asian regions, Azolla is either incorporated into the soil before rice transplanting or grown as a dual crop along with rice. To examine the feasibility of its use in flooded rice fields sited in the Temperate European Areas, we carried out a series of experiments in PVC tanks during 2000–2002 in Po Valley (northern Italy conditions, to study the growth-development dynamics and the resistance/tolerance to low temperatures and to commonly used herbicides of several different Azolla strains. Three out of five strains tested survived the winter, with an increase in biomass from March to May producing approximately 30–40 kg ha−1 of nitrogen. One of these strains, named “Milan”, emerged as the most resistant to herbicide and the most productive. Of the herbicides tested, Propanil permitted the survival of growing Azolla.

  20. Impacts of Bt rice expressing Cry1C or Cry2A protein on the performance of nontarget leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae), under laboratory and field conditions.

    Science.gov (United States)

    Lu, Z B; Tian, J C; Wang, W; Xu, H X; Hu, C; Guo, Y Y; Peng, Y F; Ye, G Y

    2014-02-01

    Transgenic rice expressing Bacillus thuringiensis Berliner (Bt) protein can effectively control target insects including stem borers and leaf folders. However, the potential effects of Bt rice on nontarget organisms including nontarget herbivores have not been fully evaluated. In the current study, ecological fitness parameters of the nontarget herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae), fed on T1C-19 (Cry1C) or T2A-1 (Cry2A) rice were compared with non-Bt rice (MH63) under laboratory conditions. A 2-yr field trial was also conducted to monitor the population dynamics of N. cincticeps in the Bt and control rice plots using the vacuum-suction machine and yellow sticky card traps. Laboratory results showed that there were no significant differences in some of biological parameters including egg developmental duration, adult fresh weight, adult longevity, and oviposition period when N. cincticeps fed on Bt or non-Bt rice was compared. However, the survival rate of N. cincticeps nymphs fed on T2A-1 Bt rice plants was significantly higher than that on the control. When N. cincticeps fed on T1C-19 Bt rice plants, its nymphal duration was significantly longer and fecundity significantly lower compared with those fed on both T2A-1 Bt and non-Bt rice plants; the preoviposition period of N. cincticeps fed on T1C-19 and T2A-1 Bt rice was also significantly shorter than those on non-Bt rice. Nonetheless, both seasonal density and population dynamics of N. cincticeps adults and nymphs were similar between Bt (T1C-19 and T2A-1) and non-Bt rice plots under field conditions. In conclusion, our results indicate that our two tested Bt rice lines would not lead to higher population of N. cincticeps. Long-term experiments to monitor the population dynamics of N. cincticeps at large scale need to be carried out to confirm the current results.

  1. Field Efficacy Trial and Optimum Control Period of Rice False Smut(Ustilaginoidea virens) in Single Cropping Middle-late Rice

    Institute of Scientific and Technical Information of China (English)

    Liu; Huaizhen; Li; Kanghuo; Huang; Qing; Lu; Xiuming; Zhang; Bin; Li; Huifeng; Zou; Jixiang; Zhou; Shaochuan

    2014-01-01

    [Objective]The paper was to study optimum chemical agents and control periods against rice false smut( Ustilaginoidea virens) in single cropping middle-late rice. [Method]Taking chemical agents( triadimefon,armure,Jinggangmycin) as main treatments and spraying periods( within 7 d before initial heading stage,within 7 d before initial heading stage + initial heading stage,initial heading stage) as assisted treatments,the field efficacy trial and optimum control period of U. virens in single cropping middle-late rice were studied using Huanghuazhan and Jinnongsimiao as experimental materials in 2013. [Result] Three chemical agents,triadimefon,armure,Jinggangmycin,extremely reduced diseased panicle rate and disease index of U. virens,but there was no significant difference among three chemical agents. Spraying period did not have significant impact on diseased panicle rate and disease index of U. virens,whereas spraying within7 d before initial heading stage and during initial heading stage had relatively good control effect. Yield increased significantly after application of three chemical agents,and armure led to greater increase. The reason for yield increase was that seed setting rate was significantly increased,and the number of filled grains per panicle was significantly increased. Although spraying period influenced yield,the difference was not significant. [Conclusion] Triadimefon,armure and Jinggangmycin had good control effects against U. virens in single cropping middle-late rice,of which armure had better control effects. Spraying chemical agents increased seed setting rate,and further increased the number of filled grains per panicle and yield. Spraying within 7 d before initial heading stage and during initial heading stage had relatively better control effect against U. virens.

  2. Effects of field high temperature on grain yield and quality of a subtropical type japonica rice—Pon-Lai rice

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    Yi-Chien Wu

    2016-01-01

    Full Text Available Typical japonica type rice is sensitive to high temperature. Pon-Lai rice is a special japonica type with adaptation to the subtropical climate in Taiwan. Facing climate change, rising temperatures would damage the yield and quality of rice production. This research was conducted using Pon-Lai rice in the field of a subtropical climate. We conducted 2 experiments, including a year-round experiment and collection of samples from different districts for building different temperature conditions. We analyzed the correlation between rising temperature and rice yield or quality. In our results, the critical period of temperature effect is 0–15 days after heading (H15. The threshold of high temperature damage in yield and appearance quality was 25–27 °C. Grain weight decreased about 2–6%, while the temperature of H15 was raised 1 °C above the thresholds. Perfect grain ratio and chalky grain ratio decreased and increased, respectively, while the temperature of H15 was raised above the thresholds. However, the high temperature in H15 affected the physicochemical characteristics. In addition, we found positive correlation between grain length to width ratio and perfect grain ratio. Grain length to width ratio could be an index of temperature effects for grain quality. In our study, when the temperature was below 30 °C, a rising temperature of H15 could damage rice yield and appearance quality, and change grain shape. Our results could provide reference for dealing with the warming future in other temperate rice-cultivated countries.

  3. Exploring a suitable nitrogen fertilizer rate to reduce greenhouse gas emissions and ensure rice yields in paddy fields

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yiming; Wang, Xiaopeng; Yang, Jingping, E-mail: jpyang@zju.edu.cn; Zhao, Xing; Ye, Xinyi

    2016-09-15

    The application rate of nitrogen fertilizer was believed to dramatically influence greenhouse gas (GHG) emissions from paddy fields. Thus, providing a suitable nitrogen fertilization rate to ensure rice yields, reducing GHG emissions and exploring emission behavior are important issues for field management. In this paper, a two year experiment with six rates (0, 75, 150, 225, 300, 375 kg N/ha) of nitrogen fertilizer application was designed to examine GHG emissions by measuring carbon dioxide (CO{sub 2}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O) flux and their cumulative global warming potential (GWP) from paddy fields in Hangzhou, Zhejiang in 2013 and 2014. The results indicated that the GWP and rice yields increased with an increasing application rate of nitrogen fertilizer. Emission peaks of CH{sub 4} mainly appeared at the vegetative phase, and emission peaks of CO{sub 2}, and N{sub 2}O mainly appeared at reproductive phase of rice growth. The CO{sub 2} flux was significantly correlated with soil temperature, while the CH{sub 4} flux was influenced by logging water remaining period and N{sub 2}O flux was significantly associated with nitrogen application rates. This study showed that 225 kg N/ha was a suitable nitrogen fertilizer rate to minimize GHG emissions with low yield-scaled emissions of 3.69 (in 2013) and 2.23 (in 2014) kg CO{sub 2}-eq/kg rice yield as well as to ensure rice yields remained at a relatively high level of 8.89 t/ha in paddy fields. - Highlights: • Exploiting co-benefits of rice yield and reduction of greenhouse gas emission. • Global warming potential and rice yield increased with nitrogen fertilizer rate up. • Emission peaks of CH{sub 4,} CO{sub 2} and N{sub 2}O appeared at vegetative and reproductive phase. • 225 kg N/ha rate benefits both rice yields and GWP reduction.

  4. Field-based high throughput phenotyping rapidly identifies genomic regions controlling yield components in rice

    Science.gov (United States)

    Tanger, Paul; Klassen, Stephen; Mojica, Julius P.; Lovell, John T.; Moyers, Brook T.; Baraoidan, Marietta; Naredo, Maria Elizabeth B.; McNally, Kenneth L.; Poland, Jesse; Bush, Daniel R.; Leung, Hei; Leach, Jan E.; McKay, John K.

    2017-01-01

    To ensure food security in the face of population growth, decreasing water and land for agriculture, and increasing climate variability, crop yields must increase faster than the current rates. Increased yields will require implementing novel approaches in genetic discovery and breeding. Here we demonstrate the potential of field-based high throughput phenotyping (HTP) on a large recombinant population of rice to identify genetic variation underlying important traits. We find that detecting quantitative trait loci (QTL) with HTP phenotyping is as accurate and effective as traditional labor-intensive measures of flowering time, height, biomass, grain yield, and harvest index. Genetic mapping in this population, derived from a cross of an modern cultivar (IR64) with a landrace (Aswina), identified four alleles with negative effect on grain yield that are fixed in IR64, demonstrating the potential for HTP of large populations as a strategy for the second green revolution. PMID:28220807

  5. Field-based high throughput phenotyping rapidly identifies genomic regions controlling yield components in rice.

    Science.gov (United States)

    Tanger, Paul; Klassen, Stephen; Mojica, Julius P; Lovell, John T; Moyers, Brook T; Baraoidan, Marietta; Naredo, Maria Elizabeth B; McNally, Kenneth L; Poland, Jesse; Bush, Daniel R; Leung, Hei; Leach, Jan E; McKay, John K

    2017-02-21

    To ensure food security in the face of population growth, decreasing water and land for agriculture, and increasing climate variability, crop yields must increase faster than the current rates. Increased yields will require implementing novel approaches in genetic discovery and breeding. Here we demonstrate the potential of field-based high throughput phenotyping (HTP) on a large recombinant population of rice to identify genetic variation underlying important traits. We find that detecting quantitative trait loci (QTL) with HTP phenotyping is as accurate and effective as traditional labor-intensive measures of flowering time, height, biomass, grain yield, and harvest index. Genetic mapping in this population, derived from a cross of an modern cultivar (IR64) with a landrace (Aswina), identified four alleles with negative effect on grain yield that are fixed in IR64, demonstrating the potential for HTP of large populations as a strategy for the second green revolution.

  6. Diversity of Bacillus thuringiensis in the rice field soils of different ecologies in India.

    Science.gov (United States)

    Das, J; Dangar, T K

    2007-12-01

    Diversity of the Bacillus thuringiensis (Bt) in the rice field soils of different ecologies viz. the island (Port Blair), the Himalayan (Srinagar), brackish water (Mahe) and coastal mesophilic (Mangalore) habitats was analyzed by phenotypic characterization of 5, 66, 14 and 54 Bt isolates, respectively. The Bt isolates produced either monotypic (bipyramidal or spherical) or heterotypic (polymorphic-bipyramidal or bipyramidal-rhomboidal) crystals. The organisms were generally resistant to the penicillin group of antibiotics, tolerated 5-12% NaCl and 0.5M Na-acetate. The Bt isolates contained 1-5 plasmids of 0.89-58.61 kbp sizes. The plasmid profiles had no correlation with crystal morphology or salt tolerance of different bacteria. Each soil was inhabited by different types of Bt. Two Bt strains of Mangalore and one strain each of the other places were phenotypically similar. One Bt strain each of Port Blair and Srinagar was different from all other strains.

  7. Construction and analysis of gonad suppression subtractive hybridization libraries for the rice field eel, Monopterus albus.

    Science.gov (United States)

    Qu, Xiancheng; Jiang, Jiaoyun; Shang, Xiaoli; Cheng, Cui; Feng, Long; Liu, Qigen

    2014-04-25

    The objective of this study was to investigate gene transcription profiles of the stage IV ovary and the ovotestis of the rice field eel (Monopterus albus) in an attempt to uncover genes involved in sex reversal and gonad development. Suppression subtractive hybridization (SSH) libraries were constructed using mRNA from the stage IV ovary and the ovotestis. In total 100 positive clones from the libraries were selected at random and sequenced, and then expressed sequence tags (ESTs) were used to search against sequences in the GenBank database using the BLASTn and BLASTx search algorithms. High quality SSH cDNA libraries and 90 ESTs were obtained. Of these ESTs, 43 showed high homology with genes of known function and these are associated with energy metabolism, signal transduction, transcription regulation and so on. The remaining 47 ESTs shared no homology with any genes in GenBank and are thus considered to be hypothetical genes. Furthermore, the four genes F11, F63, R11, and R47 from the forward and reverse libraries were analyzed in gonad, brain, heart, spleen, liver, kidney and muscle tissues. The results showed that the transcription of the F11 and F63 genes was significantly increased while the expression of the R11 and R47 genes was significantly decreased from IV or V ovary. In addition, the results also indicated that the four genes' expression was not gonad-tissue specific. This results strongly suggested that they may be involved in the rice field eel gonad development and/or sex reversal.

  8. Diet and resource partitioning among anurans in irrigated rice fields in Pantanal, Brazil

    Directory of Open Access Journals (Sweden)

    L. Piatti

    Full Text Available Artificial ponds or irrigated systems scattered throughout farmlands can offer important habitats for anurans and can be interesting sites for research on species resources use in a changing landscape. This study describes the diet and resource partitioning among anurans inhabiting irrigated rice fields in the Pantanal region. Twenty categories of prey were found in the stomachs of Leptodactylus chaquensis, L. elenae, L. podicipinus and Rhinella bergi, the most frequent being Coleoptera, Hymenoptera, larvae of Hexapoda, Hemiptera, Diptera and Orthoptera. The great differences found in the diet of these species in rice fields compared to other locations, according to available records in the literature, was the increased importance of Hemipitera and Orthoptera and the decrease in importance of Hymenoptera in the diet of leptodactylids. These differences might be attributed to changes in the availability of resources in response to habitat modification. Although diet composition was very similar among species, niche overlap was larger than expected by chance, suggesting that the competition for food resources is not, or has not been, a significant force in determining the structure of this frog community. Two non-exclusive hypotheses could be considered as a justification for this result: 1 the high niche overlap could result from resource availability, which is sufficient to satisfy all species without any strong competition; 2 or the high values of niche overlap could be a selective force driving species to compete, but there has not been enough time to express a significant divergence in the species diet because the study area is characterised as a dynamic habitat influenced by frequent and cyclical changes.

  9. Changes of field incurred chlorpyrifos and its toxic metabolite residues in rice during food processing from-RAC-to-consumption.

    Science.gov (United States)

    Zhang, Zhiyong; Jiang, Wayne W; Jian, Qiu; Song, Wencheng; Zheng, Zuntao; Wang, Donglan; Liu, Xianjin

    2015-01-01

    The objectives of this study were to determine the effects of food processing on field incurred residues levels of chlorpyrifos and its metabolite 3,5,6-Trichloro-2-pyridinol (TCP) in rice. The chlorpyrifos and TCP were found to be 1.27 and 0.093 mg kg-1 in straw and 0.41 and 0.073 mg kg-1 in grain, respectively. It is observed that the sunlight for 2 hours does not decrease the chlorpyrifos and TCP residues in grain significantly. Their residues in rice were reduced by up to 50% by hulling. The cooking reduced the chlorpyrifos and TCP in rice to undetectable level (below 0.01 mg kg-1). Processing factors (PFs) of chlorpyrifos and TCP residues in rice during food processing were similar. Various factors have impacts on the fates of chlorpyrifos and TCP residues and the important steps to reduce their residues in rice were hulling and cooking. The results can contribute to assure the consumer of a safe wholesome food supply.

  10. The effect of motor vehicle emission towards lead (Pb content of rice field soil with different clay content

    Directory of Open Access Journals (Sweden)

    C.C.Wati

    2015-10-01

    Full Text Available Motor vehicle gas emission contains lead (Pb which is a hazardous and toxic substance. Agricultural land, especially rice field, which is located nearby roads passed by many motor vehicle, are susceptible to the accumulation of Pb. If Pb is permeated by plants cultivated in the rice field, it will be very hazardous for humans as they are the final consumers. Hence, it is essential to identify Pb content of rice-field soil initiated by motor vehicle gas emission. This study was aimed to identify the effects of motor vehicle density, the distance between rice-field and road, and the clay content of soil towards Pb content of soils in Blitar and Ngawi Regencies of East Java. The method used for the study was survey method managed by using three-factor nested design with three replicates. The results of this study showed that motor vehicle density and the distance of rice field to road provide significant affected the total of Pb content of soil. However, the dissemination pattern of Pb in the soil was irregular due to the factors of climate and environment. Before Pb reached soil surface, Pb was spread out in the air due to the effect of temperature, wind velocity, vehicle velocity, size of vehicle, and road density. Consequently, the location with low motor vehicle density and positioned faraway to the road had higher total rate of Pb than the location with high motor vehicle density and positioned nearby the road. Clay content affected the total rate of Pb content as much as 37%, every 1% increase of clay content increased the total rate of Pb as much as 0.08 mg/kg.

  11. Mexican rice borer (Lepidoptera: Crambidae) injury to corn greater than to sorghum and sugarcane under field conditions.

    Science.gov (United States)

    Showler, Allan T; Wilson, Blake E; Reagan, Thomas E

    2012-10-01

    The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is the key pest of sugarcane (Saccharum spp.) in Texas; it can attack several grassy crop and noncrop host plants and has spread into Louisiana. Through small-plot, commercial field, and pheromone trap experiments, this study demonstrates that the pest uses corn, Zea mays L., more than sugarcane and sorghum, Sorghum bicolor (L.) Moench, but when corn is harvested in late summer, injury to nearby sugarcane strongly increases during the next approximately equal to 2 mo to harvest. Corn was more infested than sugarcane and sorghum in commercial fields regardless of whether sampling occurred on field edges or farther into field interiors. Differences in numbers of infested stalks and in numbers of larval entry holes between field edges and interiors were not detected. We found that Mexican rice borer infestation of corn can cause loss of ears, and lodging, shattering, and complete destruction of maturing stalks. The larger quantities of adult Mexican rice borers captured in pheromone-based traps placed at corn field edges compared with sorghum and sugarcane field edges further indicates that corn is preferred to sugarcane and sorghum. The basis for the pest's attraction to corn and implications to potential range expansion to other U.S. sugarcane-growing regions are discussed.

  12. Function of controlled release fertilizer in maintaining high agronomic use efficiency and minimizing environmental pollution in rice field of southern China

    Institute of Scientific and Technical Information of China (English)

    Ji Xionghui; Luo Lanfang; Zheng Shengxian

    2006-01-01

    Development and use of controlled release fertilizer (CRF) in southern China, potential advantages of CRF in increasing rice yield and nutrient use efficiency were introduced, as well as its role of minimizing rice field's environmental contamination was discussed. Meanwhile, some suggestions were proposed.

  13. Field Monitoring of Deformations and Internal Forces of Surrounding Rocks and Lining Structures in the Construction of the Gangkou Double-Arched Tunnel—A Case Study

    Directory of Open Access Journals (Sweden)

    Qixiang Yan

    2017-02-01

    Full Text Available Double-arched tunnel is a special and complex underground structure which needs to be monitored carefully during construction. Taking the Gangkou tunnel as the engineering background, this paper presents a case study of field monitoring of a representative double-arched tunnel. Typical cross sections were chosen in each class of surrounding rock masses in the tunnel area and different types of sensors were embedded in designed locations, and the deformations and forces of both surrounding rocks and lining structures were monitored systematically. The dynamic evolution as well as the spatial distribution characteristics of the monitoring data including the internal displacements of surrounding rocks and the contact pressures between surrounding rocks and primary linings, the axial forces in rock bolts and the internal forces in both steel arches and secondary linings were analyzed. The monitoring and analysis results show that the deformations and forces of both surrounding rocks and lining structures are directly related to the construction procedures, geological conditions and locations in the double-arched tunnel. According to the results, some reasonable suggestions were provided for the improvement of the tunnel construction. This study will provide useful reference and guidance for the design, construction and monitoring of similar engineering projects in future.

  14. Spatial variability of N, P, and K in rice field in Sawah Sempadan, Malaysia

    Directory of Open Access Journals (Sweden)

    Saeed Mohamed Eltaib

    2002-04-01

    Full Text Available The variability of soil chemical properties such as total N, available P, and exchangeable K were examined on a 1.2 ha rice (Oryza sativa field. The soil (n = 72 samples were systematically taken from individual fields in Sawah Sempadan in thirty-six locations at two depths (0-20 and 20-30 cm. The Differential Global Positioning System (DGPS was used for locating the sample position. Geostatistical techniques were used to analyze the soil chemical properties variability of the samples that assist in site-specific management of the field. Results showed that areas of similarity were much greater for the soil chemical properties measured at the depth of (0-20 cm than that of the second lower (20- 30 cm. The ranges of the semivariogram for total N, available P, and exchangeable K were 12, and 13 m (0-20 cm, 12 and 38 m (20-30 cm, respectively. Point kriging calculated from the semivariogram was employed for spatial distribution map. The results suggested that soil chemical properties measured may be spatially dependent even within the small.

  15. Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields

    Science.gov (United States)

    Arai-Sanoh, Yumiko; Takai, Toshiyuki; Yoshinaga, Satoshi; Nakano, Hiroshi; Kojima, Mikiko; Sakakibara, Hitoshi; Kondo, Motohiko; Uga, Yusaku

    2014-01-01

    To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study. PMID:24988911

  16. Exposure to tebuconazol in rice field and laboratory conditions induces oxidative stress in carp (Cyprinus carpio).

    Science.gov (United States)

    Toni, Cândida; Loro, Vania Lucia; Santi, Adriana; de Menezes, Charlene Cavalheiro; Cattaneo, Roberta; Clasen, Bárbara Estevão; Zanella, Renato

    2011-01-01

    Pesticides can have an effect on the biochemical and physiological functions of living organisms. The changes seen in fish and their response to pesticides can be used as an example for vertebrate toxicity. In this study, carp fish (Cyprinus carpio) were exposed to different concentrations of tebuconazol fungicide, by rice field (31.95 μg/L) and laboratory (33.47 and 36.23 μg/L) conditional testing, during a 7 day period. Parameters such thiobarbituric acid-reactive substance levels (TBARS), protein carbonyl, catalase, glutathione S-transferase and acetylcholinesterase activities were studied, using the liver, brain and white muscle of the fish. The field experiment showed that the TBARS levels were increased in all the analyzed tissues. Similarly, the protein carbonyl of the liver and the brain AChE activity increased after 7 days. The laboratory experiment demonstrated that the TBARS levels in the liver were increased in both of the concentration tests. TBARS levels in the muscle increased only by the lowest test concentration. On the other hand, the protein carbonyl was increased only by the highest concentration. The results indicate that the tebuconazol exposure from the field and laboratory conditions directly affected the health of the fish, showing the occurrence of oxidative stress.

  17. Clostridium oryzae sp. nov., from soil of a Japanese rice field.

    Science.gov (United States)

    Horino, Haruka; Ito, Miyuki; Tonouchi, Akio

    2015-03-01

    An obligately anaerobic bacterial strain designated KC3(T) was isolated from a rice straw-degrading culture, for which soil of a Japanese rice field was used as the inoculum. Cells of strain KC3(T) were determined to be non-cellulolytic, Gram-stain-positive, non-motile, ellipsoidal, spore-forming rods, 0.8-1×4-25 µm. Endospores were formed at a terminal position in elongated cells (12-25 µm, mean 15 µm). The temperature range for growth was 20-50 °C, with an optimum at 37 °C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.0 (slightly acidophilic). Strain KC3(T) fermented cellobiose to lactate, butyrate, acetate, formate, hydrogen and carbon dioxide. The major cellular fatty acids (>10 %) were C14 : 0, C16 : 0 and C19 : 0 cyclo 11,12 dimethylacetal. The DNA G+C content of strain KC3(T) was 37.5 mol%. 16S rRNA gene sequence analysis revealed that strain KC3(T) shared low sequence similarity (Clostridium sensu stricto (Clostridium rRNA cluster I). Analyses of the DNA gyrase A and ATP synthase beta subunit sequences supported the affiliation of strain KC3(T) to the genus Clostridium sensu stricto. The evidence presented here indicates that strain KC3(T) represents a novel species of the genus Clostridium, for which the name Clostridium oryzae sp. nov. is proposed. The type strain of Clostridium oryzae is KC3(T) ( = DSM 28571(T) = NBRC 110163(T)).

  18. Chemolithotrophic acetogenic H2/CO2 utilization in Italian rice field soil.

    Science.gov (United States)

    Liu, Fanghua; Conrad, Ralf

    2011-09-01

    Acetate oxidation in Italian rice field at 50 °C is achieved by uncultured syntrophic acetate oxidizers. As these bacteria are closely related to acetogens, they may potentially also be able to synthesize acetate chemolithoautotrophically. Labeling studies using exogenous H(2) (80%) and (13)CO(2) (20%), indeed demonstrated production of acetate as almost exclusive primary product not only at 50 °C but also at 15 °C. Small amounts of formate, propionate and butyrate were also produced from (13)CO(2). At 50 °C, acetate was first produced but later on consumed with formation of CH(4). Acetate was also produced in the absence of exogenous H(2) albeit to lower concentrations. The acetogenic bacteria and methanogenic archaea were targeted by stable isotope probing of ribosomal RNA (rRNA). Using quantitative PCR, (13)C-labeled bacterial rRNA was detected after 20 days of incubation with (13)CO(2). In the heavy fractions at 15 °C, terminal restriction fragment length polymorphism, cloning and sequencing of 16S rRNA showed that Clostridium cluster I and uncultured Peptococcaceae assimilated (13)CO(2) in the presence and absence of exogenous H(2), respectively. A similar experiment showed that Thermoanaerobacteriaceae and Acidobacteriaceae were dominant in the (13)C treatment at 50 °C. Assimilation of (13)CO(2) into archaeal rRNA was detected at 15 °C and 50 °C, mostly into Methanocellales, Methanobacteriales and rice cluster III. Acetoclastic methanogenic archaea were not detected. The above results showed the potential for acetogenesis in the presence and absence of exogenous H(2) at both 15 °C and 50 °C. However, syntrophic acetate oxidizers seemed to be only active at 50 °C, while other bacterial groups were active at 15 °C.

  19. Influence of rice field agrochemicals on the ecological status of a tropical stream

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Jes Jessen, E-mail: jr@bios.au.dk [Aarhus University, Department of Bioscience, Vejlsøvej 25, 8600 Silkeborg (Denmark); Reiler, Emilie Marie [University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Carazo, Elizabeth; Matarrita, Jessie [Centro de Investigación en Contaminación Ambiental, Ciudad Universidad de Costa Rica Universitaria Rodrigo Facio, San José (Costa Rica); Muñoz, Alejandro [Centro de Investigación en Contaminación Ambiental, Ciudad Universidad de Costa Rica Universitaria Rodrigo Facio, San José (Costa Rica); Escuela de Biología, Ciudad Universitaria Rodrigo Facio, San José (Costa Rica); Cedergreen, Nina [University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark)

    2016-01-15

    Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area with conventional rice production and a downstream protected nature reserve; Mata Redonda. Three sites were sampled: 1) an upstream control, 2) in the rice production area and 3) a downstream site in Mata Redonda. We sampled benthic macroinvertebrates and pesticides in water and sediments along with supporting physical and chemical data. Pesticide concentrations in water exceeded current safety thresholds at sites 2 and 3, especially during the rainy season, and sediment associated pesticide concentrations exceeded current safety thresholds in three of six samples. Importantly, the highest predicted pesticide toxicity in sediments was observed at site 3 in the Mata Redonda confirming that the nature reserve received critical levels of pesticide pollution from upstream sections. The currently used macroinvertebrate index in Costa Rica (BMWP-CR) and an adjusted version of the SPecies At Risk index (SPEAR) were not significantly correlated to any measure of anthropogenic stress, but the Average Score Per Taxon (ASPT) index was significantly correlated with the predicted pesticide toxicity (sumTU{sub D.magna}), oxygen concentrations and substrate composition. Our results suggest that pesticide pollution was likely involved in the impairment of the ecological status of the sampling sites, including site 3 in Mata Redonda. Based on our results, we give guidance to biomonitoring in Costa Rica and call for increased focus on pesticide transport from agricultural regions to protected areas. - Highlights: • Pesticides are transported via streams to protected downstream nature reserves. • Pesticide concentrations were highest during the rainy season due to flooded fields. • Pesticide concentrations in the protected area exceeded safety thresholds.

  20. Method for NIR Reflectance Estimation with Visible Camera Data based on Regression for NDVI Estimation and its Application for Insect Damage Detection of Rice Paddy Fields

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2016-10-01

    Full Text Available Method for Near Infrared: NIR reflectance estimation with visible camera data based on regression for Normalized Vegetation Index: NDVI estimation is proposed together with its application for insect damage detection of rice paddy fields. Through experiments at rice paddy fields which is situated at Saga Prefectural Agriculture Research Institute SPARI in Saga city, Kyushu, Japan, it is found that there is high correlation between NIR reflectance and Green color reflectance. Therefore, it is possible to estimate NIR reflectance with visible camera data which results in possibility of estimation of NDVI with drone mounted visible camera data. As is well known that the protein content in rice crops is highly correlated with NIR intensity, or reflectance of rice leaves, it is possible to estimate rice crop quality with drone based visible camera data.

  1. Effects of winter cover crops residue returning on soil enzyme activities and soil microbial community in double-cropping rice fields.

    Science.gov (United States)

    Hai-Ming, Tang; Xiao-Ping, Xiao; Wen-Guang, Tang; Ye-Chun, Lin; Ke, Wang; Guang-Li, Yang

    2014-01-01

    Residue management in cropping systems is useful to improve soil quality. However, the studies on the effects of residue management on the enzyme activities and microbial community of soils in South China are few. Therefore, the effects of incorporating winter cover crop residue with a double-cropping rice (Oryza sativa L.) system on soil enzyme activities and microbial community in Southern China fields were studied. The experiment has conducted at the experimental station of the Institute of Soil and Fertilizer Research, Hunan Academy of Agricultural Science, China since winter 2004. Four winter cropping systems were used: rice-rice-ryegrass (Lolium multiflorum L.) (R-R-Ry), rice-rice-Chinese milk vetch (Astragalus sinicus L.) (R-R-Mv), rice-rice-rape (Brassica napus L.) (R-R-Ra) and rice-rice with winter fallow (R-R-Fa). The result indicated that the enzyme activities in the R-R-Ry, R-R-Mv and R-R-Ra systems were significantly higher (Pwinter cover crops into rotations may increase enzyme activities and microbial community in soil and therefore improve soil quality.

  2. Automated Counting of Rice Planthoppers in Paddy Fields Based on Image Processing

    Institute of Scientific and Technical Information of China (English)

    YAO Qing; XIAN Ding-xiang; LIU Qing-jie; YANG Bao-jun; DIAO Guang-qiang; TANG Jian

    2014-01-01

    A quantitative survey of rice planthoppers in paddy ifelds is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy ifelds are time-consuming, fatiguing and tedious. This paper describes a handheld device for easily capturing planthopper images on rice stems and an automatic method for counting rice planthoppers based on image processing. The handheld device consists of a digital camera with WiFi, a smartphone and an extrendable pole. The surveyor can use the smartphone to control the camera, which is ifxed on the front of the pole by WiFi, and to photograph planthoppers on rice stems. For the counting of planthoppers on rice stems, we adopt three layers of detection that involve the following:(a) the ifrst layer of detection is an AdaBoost classiifer based on Haar features;(b) the second layer of detection is a support vector machine (SVM) classiifer based on histogram of oriented gradient (HOG) features;(c) the third layer of detection is the threshold judgment of the three features. We use this method to detect and count whiteback planthoppers (Sogatella furcifera) on rice plant images and achieve an 85.2%detection rate and a 9.6%false detection rate. The method is easy, rapid and accurate for the assessment of the population density of rice planthoppers in paddy ifelds.

  3. Reducing rice field algae and cyanobacteria abundance by altering phosphorus fertilizer applications

    Science.gov (United States)

    In California’s water seeded rice systems algal/cyanobacterial biomass can be a problem during rice establishment. Algal/cyanobacterial growth may be stimulated by phosphorus (P) additions in freshwater habitats, so we set up experiments to evaluate the effects of fertilizer P management on algal/cy...

  4. Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

    Science.gov (United States)

    Iron (Fe) and zinc (Zn) deficiencies are the most prevalent micronutrient malnutrition globally1. Fe in rice has proven efficacious in improving serum ferritin concentration and body Fe levels2. Rapid progress in biofortification demonstrates the feasibility to enhance Fe in polished rice by expre...

  5. Aerobic versus Anaerobic Microbial Degradation of Clothianidin under Simulated California Rice Field Conditions.

    Science.gov (United States)

    Mulligan, Rebecca A; Tomco, Patrick L; Howard, Megan W; Schempp, Tabitha T; Stewart, Davis J; Stacey, Phillip M; Ball, David B; Tjeerdema, Ronald S

    2016-09-28

    Microbial degradation of clothianidin was characterized under aerobic and anaerobic California rice field conditions. Rate constants (k) and half-lives (DT50) were determined for aerobic and anaerobic microcosms, and an enrichment experiment was performed at various nutrient conditions and pesticide concentrations. Temperature effects on anaerobic degradation rates were determined at 22 ± 2 and 35 ± 2 °C. Microbial growth was assessed in the presence of various pesticide concentrations, and distinct colonies were isolated and identified. Slow aerobic degradation was observed, but anaerobic degradation occurred rapidly at both 25 and 35 °C. Transformation rates and DT50 values in flooded soil at 35 ± 2 °C (k = -7.16 × 10(-2) ± 3.08 × 10(-3) day(-1), DT50 = 9.7 days) were significantly faster than in 25 ± 2 °C microcosms (k= -2.45 × 10(-2) ± 1.59 × 10(-3) day(-1), DT50 = 28.3 days). At the field scale, biodegradation of clothianidin will vary with extent of oxygenation.

  6. The availabilities of arsenic and cadmium in rice paddy fields from a mining area: The role of soil extractable and plant silicon.

    Science.gov (United States)

    Yu, Huan-Yun; Ding, Xiaodong; Li, Fangbai; Wang, Xiangqin; Zhang, Shirong; Yi, Jicai; Liu, Chuanping; Xu, Xianghua; Wang, Qi

    2016-08-01

    Adequate silicon (Si) can greatly boost rice yield and improve grain quality through alleviating stresses associated with heavy metals and metalloids such as arsenic (As) and cadmium (Cd). The soil plant-available Si is relatively low in South China due to severe desilicification and allitization of the soils in this region. Conversely, pollution of heavy metals and metalloids in the soils of this region occurs widely, especially As and Cd pollution in paddy soil. Therefore, evaluating the plant availability of Si in paddy soil of South China and examining its correlation with the availability of heavy metals and metalloids are of great significance. Accordingly, in our study, 107 pairs of soil and rice plant samples were collected from paddy fields contaminated by As and Cd in South China. Significantly positive correlations between Si in rice plants and Si fractions in soils extracted with citric acid, NaOAc-HOAc buffer, and oxalate-ammonium oxalate buffer suggest that these extractants are more suitable for use in extracting plant-available Si in the soils of our present study. Significantly negative correlations between different Si fractions and As or Cd in rice plant tissues and negative exponential correlations between the molar ratios of Si to As/Cd in rice roots, straws, husks or grains and As/Cd in rice grains indicate that Si can significantly alleviate the accumulation of As/Cd from soils to the rice plants. Finally, a contribution assessment of soil properties to As/Cd accumulation in rice grains based on random forest showed that in addition to Si concentrations in soil or rice plants, other factors such as Fe fractions and total phosphorus also contributed largely to As/Cd accumulation in rice grains. Overall, Si exhibited its unique role in mitigating As or Cd stress in rice, and our study results provide strong field evidence for this role.

  7. Populations of Rice Grain Bug, Paraeuscosmetus pallicomis, (Hemiptera: Lygaeidae) in Weed-free Paddy Field, Weedy Paddy Field and Paddy Dykes.

    Science.gov (United States)

    Abdullah, Tamrin; Nasruddin, Andi; Agus, Nurariaty

    2017-07-01

    Research on the populations of rice grain bug Paraeuscosmetus pallicomis Dallas (Hemiptera: Lygaeidae) in paddy field ecosystems was performed with the aim to determine the populations of rice grain bug in weed-free paddy field, weedy paddy field, and paddy dykes. Experiment was carried out in the village of Paccellekang in the district of Patallasang of Gowa Regency in South Sulawesi, Indonesia. Observations were performed during the milky grain stage (85 days after planting), the mature grain stage (105 days after planting), and one day after harvest (115 days after transplanting). Results showed that 85 days after the transplanting, the populations of rice grain bug was significantly higher in the weedy paddy field compared to weed-free field and paddy dykes with total numbers of 1.75, 3.53, and 0.31 insects per 2 hills, respectively. Similarly, 105 days after the transplanting, 2.53, 5.53, and 0.11 insects per hill, respectively. However, one day after the harvest (115 days after transplanting) the number of insects in weed-free field decreased, while in the dykes increased, and the weedy plot still had the highest number of insects per 2 hills. Our results suggested that weeds played an important role in regulating the bug population by providing alternative shelter and foods for the insect.

  8. Effects of straw incorporation along with microbial inoculant on methane and nitrous oxide emissions from rice fields.

    Science.gov (United States)

    Liu, Gang; Yu, Haiyang; Ma, Jing; Xu, Hua; Wu, Qinyan; Yang, Jinghui; Zhuang, Yiqing

    2015-06-15

    Incorporation of straw together with microbial inoculant (a microorganism agent, accelerating straw decomposition) is being increasingly adopted in rice cultivation, thus its effect on greenhouse gas (GHG) emissions merits serious attention. A 3-year field experiment was conducted from 2010 to 2012 to investigate combined effect of straw and microbial inoculant on methane (CH4) and nitrous oxide (N2O) emissions, global warming potential (GWP) and greenhouse gas intensity (GHGI) in a rice field in Jurong, Jiangsu Province, China. The experiment was designed to have treatment NPK (N, P and K fertilizers only), treatment NPKS (NPK plus wheat straw), treatment NPKSR (NPKS plus Ruilaite microbial inoculant) and treatment NPKSJ (NPKS plus Jinkuizi microbial inoculant). Results show that compared to NPK, NPKS increased seasonal CH4 emission by 280-1370%, while decreasing N2O emission by 7-13%. When compared with NPKS, NPKSR and NPKSJ increased seasonal CH4 emission by 7-13% and 6-12%, respectively, whereas reduced N2O emission by 10-27% and 9-24%, respectively. The higher CH4 emission could be attributed to the higher soil CH4 production potential triggered by the combined application of straw and microbial inoculant, and the lower N2O emission to the decreased inorganic N content. As a whole, the benefit of lower N2O emission was completely offset by increased CH4 emission, resulting in a higher GWP for NPKSR (5-12%) and NPKSJ (5-11%) relative to NPKS. Due to NPKSR and NPKSJ increased rice grain yield by 3-6% and 2-4% compared to NPKS, the GHGI values for NPKS, NPKSR and NPKSJ were comparable. These findings suggest that incorporating straw together with microbial inoculant would not influence the radiative forcing of rice production in the terms of per unit of rice grain yield relative to the incorporation of straw alone.

  9. Degradation Behavior of Moroxydine Hydrochloride in Rice Plant and Field Water Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    ZHAO Lin

    2014-10-01

    Full Text Available Through field experiments, which were conducted in Zhaodong County of Heilongjiang Province, Zhulou County of Henan Province and Jurong County of Jiangsu Province, the degradation dynamics of moroxydine hydrochloride in rice plant and field water were investigated.The detection was performed by tandem mass spectrometry with electrospray ionization in positive mode(ESI+. The results showed that the average recoveries of rice plant and field water at three spiked levels (0.005, 0.05, 0.5 mg·kg -1were found in the range of 92.50%-109.20% with RSD 6.10%-6.90% and 86.40%-107.2% with RSD 0.73%-3.10%, respectively. Limits of detection(LODof plant and water were 0.005 mg·kg -1. The degradation kinetic equation showed that the half-life of moroxydine hydrochloride in rice plant and field water was 1.2-4.7 d,1.0-3.5 d, respectively. The moroxydine hydrochloride was proved to be an easily degradable pesticide.

  10. [Effect of a strong constant magnetic field and a hypomagnetic surrounding medium on histochemical indices of albino rat liver].

    Science.gov (United States)

    Shust, I V; Kostinik, I M

    1975-01-01

    The paper presents histochemical measurements of the liver of white rats exposed to strong and weak constant magnetic fields. A repeated influence (30 min a day) of the strong magnetic field of 912 ersted for 16 days inhibits synthetic processes in the liver tissue. A more prolonged (30 days) exposure to the field produces insignificant histochemical changes which seem to be induced by the occuring compensatory reaction. It is shown that a month long stay of animals in the environment shielded from the geomagnetic field may enhance synthetic processes in some cells and inhibit them in others.

  11. Rice field flora and vegetation in the provinces of Valencia and Tarragona

    Directory of Open Access Journals (Sweden)

    Carretero, J. L.

    1988-01-01

    Full Text Available Twenty nine emergent and twenty floating or submerged taxa , were found in the rice fields in Valencia and Tarragona provinces. Eleven of the se taxa, all them emergent, are alien Of introduced ones. Echinochloa oryzoides and E. oryzicola are the most important in both areas, together with Cyperus difformis and Echinochloa hispidula in Valencia. The remaining thirty eight taxa belong to the native flora. There are predominantly the emergent Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli and Paspalum distichum; the floating Lemna minor and L. gibba; the submersed Potamogeton nodosus; Zannichellia palustris and Najas minor; and the macroscopical algae Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme, Spirogyra spp., Pithophora oedogania and Hydrodictyon reticulatum. The flora evolution during the last years is analyzed and the present weed communities are studied. The contribution of the different phytosociological classes to the rice field weed flora is presented.

    De los 49 táxones registrados (29 emergentes y 20 flotantes o sumergidos 11 son exóticos introducidos, de los cuales los más importantes son Echinochloa oryzoides y E. oryzicolaen ambas zonas, además de Cyperus difformis y Echinochloa hispidula en Valencia, y el resto propios de la flora autóctona, predominando Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli y Paspalum distichum como emergentes, Lemna minor y L. gibba como flotantes, Potamogeton nodosus, Zannichellia palustris y Najas minor como sumergidos y Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme. Spirogyra spp., Pirhophora oedogonia e Hydrodictyon reticulatum como algas macroscópicas. Se analiza la evolución experimentada por la flora en los últimos años, además de estudiar las

  12. Determination of the mineral stability field of evolving groundwater in the Lake Bosumtwi impact crater and surrounding areas

    Science.gov (United States)

    Loh, Yvonne Sena Akosua; Yidana, Sandow Mark; Banoeng-Yakubo, Bruce; Sakyi, Patrick Asamoah; Addai, Millicent Obeng; Asiedu, Daniel Kwadwo

    2016-09-01

    Conventional graphical techniques, mass balance geochemical modelling, and multivariate statistical methods were jointly applied to hydrogeochemical data of groundwater from the fractured rock aquifer system, and surface water in the Bosumtwi and surrounding areas to reveal evolutionary trends and the characteristics of evolving groundwater in the area. Four clusters distinguished from the Q-mode hierarchical cluster analysis (HCA) comprised three main groundwater associations and one surface water group (lake water). Although both water resources are of low mineralization (TDS dolomite, gypsum, k-felspar and talc, and supersaturation with respect to gibbsite, kaolinite, Ca-montmorillonite and k-mica in the area. The PCA and other geochemical interpretation identify weathering of feldspars and carbonate mineral dissolution as predominantly influencing the hydrochemistry of the groundwater. Hydrolysis of the aluminosilicates causes the groundwater to reach equilibrium with kaolinite. In addition to dissolution of silicates, the chemical composition of the lake water has been influenced by evaporation and consequent carbonate saturation.

  13. Dynamics of bacterial communities in rice field soils as affected by different long-term fertilization practices.

    Science.gov (United States)

    Ahn, Jae-Hyung; Lee, Shin Ae; Kim, Jeong Myeong; Kim, Myung-Sook; Song, Jaekyeong; Weon, Hang-Yeon

    2016-11-01

    Fertilization and the response of the soil microbial community to the process significantly affect crop yield and the environment. In this study, the seasonal variation in the bacterial communities in rice field soil subjected to different fertilization treatments for more than 50 years was investigated using 16S rRNA sequencing. The simultaneous application of inorganic fertilizers and rice straw compost (CAPK) maintained the species richness of the bacterial communities at levels higher than that in the case of non-fertilization (NF) and application of inorganic fertilizers only (APK) in the initial period of rice growth. The seasonal variation in the bacterial community structure in the NF and APK plots showed cyclic behavior, suggesting that the effect of season was important; however, no such trend was observed in the CAPK plot. In the CAPK plot, the relative abundances of putative copiotrophs such as Bacteroidetes, Firmicutes, and Proteobacteria were higher and those of putative oligotrophs such as Acidobacteria and Plactomycetes were lower than those in the other plots. The relative abundances of organotrophs with respiratory metabolism, such as Actinobacteria, were lower and those of chemoautotrophs that oxidize reduced iron and sulfur compounds were higher in the CAPK plot, suggesting greater carbon storage in this plot. Increased methane emission and nitrogen deficiency, which were inferred from the higher abundances of Methylocystis and Bradyrhizobium in the CAPK plot, may be a negative effect of rice straw application; thus, a solution for these should be considered to increase the use of renewable resources in agricultural lands.

  14. Mapping rice field anopheline breeding habitats in Mali, West Africa, using Landsat ETM+ sensor data.

    Science.gov (United States)

    Diuk-Wasser, M A; Bagayoko, M; Sogoba, N; Dolo, G; Touré, M B; Traoré, S F; Taylor, C E

    2004-01-01

    The aim of this study was to determine whether remotely sensed data could be used to identify rice-related malaria vector breeding habitats in an irrigated rice growing area near Niono, Mali. Early stages of rice growth show peak larval production, but Landsat sensor data are often obstructed by clouds during the early part of the cropping cycle (rainy season). In this study, we examined whether a classification based on two Landsat Enhanced Thematic Mapper (ETM)+ scenes acquired in the middle of the season and at harvesting times could be used to map different land uses and rice planted at different times (cohorts), and to infer which rice growth stages were present earlier in the season. We performed a maximum likelihood supervised classification and evaluated the robustness of the classifications with the transformed divergence separability index, the kappa coefficient and confusion matrices. Rice was distinguished from other land uses with 98% accuracy and rice cohorts were discriminated with 84% accuracy (three classes) or 94% (two classes). Our study showed that optical remote sensing can reliably identify potential malaria mosquito breeding habitats from space. In the future, these 'crop landscape maps' could be used to investigate the relationship between cultivation practices and malaria transmission.

  15. Non-Destructive Monitoring of Rice by Hyperspectral In-Field Spectrometry and Uav-Based Remote Sensing: Case Study of Field-Grown Rice in North Rhine-Westphalia Germany

    Science.gov (United States)

    Willkomm, M.; Bolten, A.; Bareth, G.

    2016-06-01

    In the context of an increasing world population, the demand for agricultural crops is continuously rising. Especially rice plays a key role in food security, not only in Asia. To increase crop production of rice, either productivity of plants has to be improved or new cultivation areas have to be found. In this context, our study investigated crop growth of paddy rice (Oryza Sativa J.) in Germany. An experimental field in the vegetation period of 2014 with two nitrogen treatments was conducted using remote sensing methods. The research project focussed on two main aspects: (1) the potential of UAV-based and hyperspectral remote sensing methods to monitor selected growth parameters at different phenological stages; (2) the potential of paddy rice cultivation under the present climate condition in western Germany. We applied a low-cost UAV-system (Unmanned Aerial Vehicle) to generate high resolution Crop Surface Models (CSM). These were compared with hyperspectral in-field measurements and directly measured agronomic parameters (fresh and dry aboveground biomass (AGB), leaf-area-index (LAI) and plant nitrogen concentration (PNC)). For all acquisition dates we could determine single in-field structures in the CSM (e.g. distribution of hills) and different growth characteristics between the nitrogen treatments. Especially in the second half of the growing season, the plants with higher nitrogen availability were about 25 - 30 % larger. The plant height in the CSM correlates particularly with fresh AGB and the LAI (R2 > 0.8). Thus, the conducted methods for plant growth monitoring can be a contribution for precision agriculture approaches.

  16. Environmental and biological factors influence the relationship between a predator fish, Gambusia holbrooki, and its main prey in rice fields of the Lower Mondego River Valley (Portugal)

    OpenAIRE

    Cabral, J.; Mieiro, C.; Marques, J.

    1998-01-01

    Abstract We studied the relationships between a predator fish, Gambusia holbrooki, and its main food prey, within the content of a rice field food web. The influence of some environmental and biological factors on these trophic interactions, in combination with existent quantitative information, allowed us to evaluate the ecological viability of using a non-ionic surfactant, Genapol OXD-080, to control a plague caused by crayfish (Procambarus clarkii) populations in the rice fields. In the L...

  17. A Record of Small-Clawed Otters (Aonyx cinereus) Foraging on an Invasive Pest Species, Golden Apple Snails (Pomacea canaliculata) in a West Sumatra Rice Field

    OpenAIRE

    Jabang; Wilson Novarino; Aadrean

    2011-01-01

    A small-clawed otter (Aonyx cinereus) survey in West Sumatran rice fields was conducted from April to September 2010. During this survey, golden apple snail (Pomacea canaliculata) shell remains were found on a rice field bank as suspected prey remains of small-clawed otters. This suspicion was later proved by the occurrence of snail material (pieces of operculum and shell) in otter spraints. This is the first evidence of small-clawed otters foraging on this invasive pest species. Characterist...

  18. Activity and population dynamics of heterotrophic and ammonia-oxidizing microorganisms in soil surrounding sludge bands spiked with linear alkylbenzene sulfonate: a field study.

    Science.gov (United States)

    Brandt, Kristian Koefoed; Krogh, Paul Henning; Sørensen, Jan

    2003-04-01

    Recent research has documented soil microorganisms to be rather sensitive to linear alkylbenzene sulfonates (LAS), which may enter the soil environment in considerable quantities following sewage sludge disposal. We here report field effects of LAS on selected microbial populations present in a sandy soil surrounding well-defined sludge bands spiked with high but realistic LAS levels (7.1 or 31.3 g/kg). Surprisingly, LAS had no effect on heterotrophic respiration in the sludge compartment per se but stimulated activity and metabolic quotient (microbial activity per unit of biomass) in the surrounding soil. By contrast, autotrophic ammonia oxidation was initially inhibited in the LAS-spiked sludge. This led to dramatic transient increases of NH4+ availability in the sludge and surrounding soil, subsequently stimulating soil ammonia oxidizers. As judged from a Nitrosomonas europaea bioluminescence toxicity assay, however, LAS or other sludge components never accumulated to toxic levels in the soil compartments and the LAS tolerance of the indigenous microbes further remained unchanged following LAS exposure. LAS effects on the investigated microbial populations largely occurred during the first two months and were confined to soil closer than 30 mm from LAS-spiked sludge. Our results strongly suggest that disposal of LAS-contaminated sludge does not pose a major risk to the function of the soil microbial community under field conditions.

  19. Phenotypic and molecular characterisation of efficient nitrogen-fixing Azotobacter strains from rice fields for crop improvement.

    Science.gov (United States)

    Sahoo, Ranjan K; Ansari, Mohammad W; Dangar, Tushar K; Mohanty, Santanu; Tuteja, Narendra

    2014-05-01

    Biological nitrogen fixation (BNF) is highly effective in the field and potentially useful to reduce adverse effects chemical fertilisers. Here, Azotobacter species were selected via phenotypic, biochemical and molecular characterisations from different rice fields. Acetylene reduction assay of Azotobacter spp. showed that Azotobacter vinelandii (Az3) fixed higher amount of nitrogen (121.09 nmol C2H4 mg(-1) bacteria h(-1)). Likewise, its plant growth functions, viz. siderophore, hydrogen cyanide, salicylic acid, IAA, GA3, zeatin, NH3, phosphorus solubilisation, ACC deaminase and iron tolerance, were also higher. The profile of gDNA, plasmid DNA and cellular protein profile depicted inter-generic and inter-specific diversity among the isolates of A. vinelandii. The PCR-amplified genes nifH, nifD and nifK of 0.87, 1.4 and 1.5 kb , respectively, were ascertained by Southern blot hybridisation in isolates of A. vinelandii. The 16S rRNA sequence from A. vinelandii (Az3) was novel, and its accession number (JQ796077) was received from NCBI data base. Biofertiliser formulation of novel A. vinelandii isolates along with commercial one was evaluated in rice (Oriza sativa L. var. Khandagiri) fields. The present finding revealed that treatment T4 (Az3) (A. vinelandii) are highly efficient to improved growth and yield of rice crop.

  20. Methyl fluoride affects methanogenesis rather than community composition of methanogenic archaea in a rice field soil.

    Science.gov (United States)

    Daebeler, Anne; Gansen, Martina; Frenzel, Peter

    2013-01-01

    The metabolic pathways of methane formation vary with environmental conditions, but whether this can also be linked to changes in the active archaeal community structure remains uncertain. Here, we show that the suppression of aceticlastic methanogenesis by methyl fluoride (CH(3)F) caused surprisingly little differences in community composition of active methanogenic archaea from a rice field soil. By measuring the natural abundances of carbon isotopes we found that the effective dose for a 90% inhibition of aceticlastic methanogenesis in anoxic paddy soil incubations was <0.75% CH(3)F (v/v). The construction of clone libraries as well as t-RFLP analysis revealed that the active community, as indicated by mcrA transcripts (encoding the α subunit of methyl-coenzyme M reductase, a key enzyme for methanogenesis), remained stable over a wide range of CH(3)F concentrations and represented only a subset of the methanogenic community. More precisely, Methanocellaceae were of minor importance, but Methanosarcinaceae dominated the active population, even when CH(3)F inhibition only allowed for aceticlastic methanogenesis. In addition, we detected mcrA gene fragments of a so far unrecognised phylogenetic cluster. Transcription of this phylotype at methyl fluoride concentrations suppressing aceticlastic methanogenesis suggests that the respective organisms perform hydrogenotrophic methanogenesis. Hence, the application of CH(3)F combined with transcript analysis is not only a useful tool to measure and assign in situ acetate usage, but also to explore substrate usage by as yet uncultivated methanogens.

  1. Methyl fluoride affects methanogenesis rather than community composition of methanogenic archaea in a rice field soil.

    Directory of Open Access Journals (Sweden)

    Anne Daebeler

    Full Text Available The metabolic pathways of methane formation vary with environmental conditions, but whether this can also be linked to changes in the active archaeal community structure remains uncertain. Here, we show that the suppression of aceticlastic methanogenesis by methyl fluoride (CH(3F caused surprisingly little differences in community composition of active methanogenic archaea from a rice field soil. By measuring the natural abundances of carbon isotopes we found that the effective dose for a 90% inhibition of aceticlastic methanogenesis in anoxic paddy soil incubations was <0.75% CH(3F (v/v. The construction of clone libraries as well as t-RFLP analysis revealed that the active community, as indicated by mcrA transcripts (encoding the α subunit of methyl-coenzyme M reductase, a key enzyme for methanogenesis, remained stable over a wide range of CH(3F concentrations and represented only a subset of the methanogenic community. More precisely, Methanocellaceae were of minor importance, but Methanosarcinaceae dominated the active population, even when CH(3F inhibition only allowed for aceticlastic methanogenesis. In addition, we detected mcrA gene fragments of a so far unrecognised phylogenetic cluster. Transcription of this phylotype at methyl fluoride concentrations suppressing aceticlastic methanogenesis suggests that the respective organisms perform hydrogenotrophic methanogenesis. Hence, the application of CH(3F combined with transcript analysis is not only a useful tool to measure and assign in situ acetate usage, but also to explore substrate usage by as yet uncultivated methanogens.

  2. Novel cyanophage photosynthetic gene psbA in the floodwater of a Japanese rice field.

    Science.gov (United States)

    Wang, Guanghua; Murase, Jun; Asakawa, Susumu; Kimura, Makoto

    2009-10-01

    The gene psbA, encoding the D1 protein involved in photosynthesis, was recently found in a number of cultured cyanophages infecting marine Synechococcus and Prochlorococcus and in environmental samples from marine and freshwaters. In this study, viral concentrates were prepared by sampling the floodwaters from each of four plots in a Japanese rice field: (1) no fertilizer; (2) P and K chemical fertilizers; (3) N, P and K chemical fertilizers; and (4) chemical fertilizers with compost. Fragments of the cyanophage psbA gene were amplified by PCR from DNA in the viral concentrates, with primers psbA-F and psbA-R. Double denaturing gradient gel electrophoresis was conducted to obtain different psbA clones. Phylogenetic analyses indicated that the majority of the psbA sequences in the floodwater formed two unique groups, with their sequences being more closely related to those from freshwater samples than the sequences obtained from marine waters, suggesting that psbA genes in terrestrial aquatic environments are different from those in marine environments.

  3. Field dissipation and environmental hazard assessment of clomazone, molinate, and thiobencarb in Australian rice culture.

    Science.gov (United States)

    Quayle, Wendy C; Oliver, Danielle P; Zrna, Sharyn

    2006-09-20

    The fates of clomazone [2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone], molinate (S-ethyl hexahydro-1-H-azepine-1-carbothioate), and thiobencarb {S-[(4-chlorophenyl)methyl]diethylcarbamothioate} applied to rice were studied at two locations in New South Wales (Australia). Rates of dissipation (DT50) from floodwaters and soils were measured. Dissipation of the three herbicides from water and soil can be best explained by a first-order decay process. DT(50) values for clomazone, molinate, and thiobencarb were 7.2, 5.1, and 3.5 days, respectively, in water and 14.6, 23.9, and >46 days, respectively, in surface soil. Maximum measured concentrations of clomazone, molinate, and thiobencarb in floodwaters were 202, 1042, and 148 microg/L, respectively, taking 18.4, 26.4, and 21.4 days to dissipate to concentrations set to protect aquatic ecosystems. A hazard assessment identified clomazone as presenting a low environmental hazard while molinate and thiobencarb presented a medium environmental hazard when used at registered field rates.

  4. Selective grazing of methanotrophs by protozoa in a rice field soil.

    Science.gov (United States)

    Murase, Jun; Frenzel, Peter

    2008-09-01

    Biological methane oxidation is a key process in the methane cycle of wetland ecosystems. The methanotrophic biomass may be grazed by protozoa, thus linking the methane cycle to the soil microbial food web. In the present study, the edibility of different methanotrophs for soil protozoa was compared. The number of methanotroph-feeding protozoa in a rice field soil was estimated by determining the most-probable number (MPN) using methanotrophs as food bacteria; naked amoebae and flagellates were the dominant protozoa. Among ten methanotrophic strains examined as a food source, seven yielded a number of protozoa comparable with the yield with Escherichia coli [10(4) MPN (g soil dry weight)(-1)], and three out of four Methylocystis spp. yielded significantly fewer numbers [10(2)-10(3) MPN (g soil dry weight)(-1)]. The lower edibility of the Methylocystis spp. was not explained either by their growth phase or by harmful effects on protozoa. Incubation of the soil under methane resulted in a higher number of protozoa actively grazing on methanotrophs, especially on the less-edible group. Protozoa isolated from the soil demonstrated a grazing preference on the different methanotrophs consistent with the results of MPN counts. The results indicate that selective grazing by protozoa may be a biological factor affecting the methanotrophic community in a wetland soil.

  5. Stroemgren - near-infrared photometry of the Baade's Window. I. The bulge globular cluster NGC6528 and the surrounding field

    CERN Document Server

    Calamida, Annalisa; Lagioia, Edoardo P; Milone, Antonino P; Fabrizio, Michele; Saviane, Ivo; Bidin, Christian Moni; Mauro, Francesco; Buonanno, Roberto; Ferraro, Ivan; Iannicola, Giacinto; Zoccali, Manuela

    2014-01-01

    We present Stroemgren-NIR photometry of NGC6528 and its surroundings in the Baade's Window. uvby images were collected with EFOSC2@NTT, while NIR catalogs are based on VIRCAM@VISTA and SOFI@NTT data. The matching with HST photometry allowed us to obtain proper-motion-cleaned samples of cluster and bulge stars. The huge color sensitivity of Stroemgren-NIR CMDs helped us in disentangling age and metallicity effects. The RGB of NGC6528 is reproduced by scaled-solar isochrones with solar abundance or alpha-enhanced isochrones with the same iron content, and an age of t = 11+/-1 Gyr. These findings support literature age estimates for NGC6528. We also performed a theoretical metallicity calibration based on the Stroemgren index m1 and on visual-NIR colors for RGs, by adopting scaled-solar and alpha-enhanced models. We applied the calibration to estimate the metallicity of NGC6528, finding [Fe/H] = -0.04+/-0.02, with an intrinsic dispersion of 0.27 dex (by averaging abundances based on the scaled-solar [m], y - J a...

  6. Effects of Cropping System Change for Paddy Field with Double Harvest Rice on the Crops Growth and Soil Nutrient

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of the cropping system change for paddy field with double harvest rice on crops growth and soil nutrient in red soil were studied. The results indicated that the economic benefit and the ratio of the output to input were all increased in terms of the market price for the crops under various treatments. The greatest economic benefit was obtained in the treatment of paddy-upland rotation, and the corresponding economic benefit was increased by 34.7, 21.4, and 2.2% in comparison with that of control (rice-rice-astragali), pasture, and upland cropping treatments. The economic benefits in pasture and upland cultivation treatments were increased by 11.0 and 31.8%, respectively, when compared with that of the control treatment (CK). The ratio of output to input in pasture, paddy-upland rotation, and upland cropping treatments was enhanced by 0.9, 0.6, and 0.3, respectively, in comparison with that of control. To grow pasture is beneficial for improving soil fertility since the contents of soil organic matter, total nitrogen, total phosphorus, and available phosphorus are all enhanced significantly. However, the concentrations of the soil available nitrogen, the total potassium, the available potassium were somewhat reduced in all the treatments, suggesting that increasing the input of nitrogen,particularly potassium, was necessary under the present fertilization level. Based on the conditions of fertility, climate,cultivation, and management of paddy field with double harvest rice in red soil regions, it is feasible to alter the cultivation system of paddy field with bad irrigation condition. In particular, cultivation systems such as pasture and paddy-upland rotation can be selected to extend because better economic benefit and improvement of soil fertility in the purpose region were obtained.

  7. Screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer.

    Science.gov (United States)

    Singh, Surendra; Datta, Pallavi

    2006-01-01

    Periodic applications of heavy dosages of herbicides in modern rice-agriculture are a necessary evil for obtaining high crop productivity. Such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. It is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice-field herbicides that can be further improved by mutational techniques to make biofertilizer technology a viable one. Therefore, efforts have been made to screen five dominant diazotrophic cyanobacterial forms e.g. filamentous heterocystous Nostoc punctiforme , Nostoc calcicola , Anabaena variabilis and unicellular Gloeocapsa sp. and Aphanocapsa sp. along with standard laboratory strain Nostoc muscorum ISU against increasing concentrations (0-100 mg l(-1) of four commercial grade common rice-field herbicides i.e. Arozin, Butachlor, Alachlor and 2,4-D under diazotrophic growth conditions. The lethal and IGC(50) concentrations for all four herbicides tested were found highest for A. variabilis as compared to other test cyanobacteria. The lowest reduction in chlorophyll a content, photosynthetic oxygen evolution, and N(2)-fixation was found in A. variabilis as compared to other rice field isolates and standard laboratory strain N. muscorum ISU. On the basis of prolong survival potential and lowest reductions in vital metabolic activities tested at IGC(50) concentration of four herbicides, it is concluded that A. variabilis is the most potent and promising cyanobacterial isolate as compared with other forms. This could be further improved by mutational techniques for exploitation as most potential and viable biofertilizer strain.

  8. Influence of water management and fertilizer application on (137)Cs and (133)Cs uptake in paddy rice fields.

    Science.gov (United States)

    Wakabayashi, Shokichi; Itoh, Sumio; Kihou, Nobuharu; Matsunami, Hisaya; Hachinohe, Mayumi; Hamamatsu, Shioka; Takahashi, Shigeru

    2016-06-01

    Cesium-137 derived from the Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident contaminated large areas of agricultural land in Eastern Japan. Previous studies before the accident have indicated that flooding enhances radiocesium uptake in rice fields. We investigated the influence of water management in combination with fertilizers on (137)Cs concentrations in rice plants at two fields in southern Ibaraki Prefecture. Stable Cs ((133)Cs) in the plants was also determined as an analogue for predicting (137)Cs behavior after long-term aging of soil (137)Cs. The experimental periods comprised 3 y starting from 2012 in one field, and 2 y from 2013 in another field. These fields were divided into three water management sections: a long-flooding section without midsummer drainage, and medial-flooding, and short-flooding sections with one- or two-week midsummer drainage and earlier end of flooding than the long-flooding section. Six or four types of fertilizer subsections (most differing only in potassium application) were nested in each water management section. Generally, the long-flooding treatment led to higher (137)Cs and (133)Cs concentrations in both straw and brown rice than medial- and short-flooding treatments, although there were some notable exceptions in the first experimental year at each site. Effects of differing potassium fertilizer treatments were cumulative; the effects on (137)Cs and (133)Cs concentrations in rice plants were not obvious in 2012 and 2013, but in 2014, these concentrations were highest where potassium fertilizer had been absent and lowest where basal dressings of K had been tripled. The relationship between (137)Cs and (133)Cs in rice plants was not correlative in the first experimental year at each site, but correlation became evident in the subsequent year(s). This study demonstrates a novel finding that omitting midsummer drainage and/or delaying drainage during the grain-filling period enhances

  9. Effects of raising frogs and putting pest-killing lamps in paddy fields on the prevention of rice pests and diseases

    Science.gov (United States)

    Teng, Qing; Hu, Xue-Feng; Luo, Fan; Cao, Ming-Yang

    2014-05-01

    Frogs in paddy fields become less and less due to applying large amounts of pesticides and human hunting for a long time, which causes the aggravation of rice pests and diseases. A field experiment was carried out in the suburb of Shanghai to study the effects of artificially raising frogs and putting frequency oscillation pest-killing lamps in paddy fields on the prevention of rice pests and diseases. The field experiment includes three treatments. Treatment I: 150 frogs, each 20 g in weight, per 100 m2 were put in the fields; Treatment II: a frequency oscillation pest-killing lamp was put in the fields; Treatment III: no frogs and pest-killing lamps were put in the fields. All the experimental fields were operated based on the organic faming system. The amount of organic manure, 7500 kg/hm2, was applied to the fields as base fertilizer before sowing in early June, 2013. No any chemical fertilizers and pesticides were used during the entire period of rice growth. Each treatment is in triplicate and each plot is 67 m2 in area. The results are as follows: (1) During the entire growth period, the incidences of rice pests and diseases with Treatment I and II are significantly lower than those with CK (Treatment III). The incidence of chilo suppressalis with Treatment I, II and III is 0, 0.46% and 1.69%, respectively; that of cnaphalocrocis medinalis is 7.67%, 6.62% and 10.10%, respectively; that of rice sheath blight is 0, 11.11% and 5.43%, respectively; that of rice planthopper is 4.25 per hill, 5.75 per hill and 11 per hill, respectively. (2) The grain yield of the three treatments is significantly different. That of Treatment I, II and III is 5157.73 kg/hm2, 4761.60 kg/hm2 and 3645.14kg/hm2 on average, respectively. (3) Affected by frog activities, the contents of NH4-N, available P and available K in the soil with Treatment I are significantly raised. All the above suggest that artificially raising frogs in paddy fields could effectively prevent rice pests and

  10. Effects of straw incorporation along with microbial inoculant on methane and nitrous oxide emissions from rice fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang; Yu, Haiyang [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Jing [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China); Xu, Hua, E-mail: hxu@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing 210008 (China); Wu, Qinyan; Yang, Jinghui; Zhuang, Yiqing [Zhenjiang Institute of Agricultural Science of Hilly Regions in Jiangsu, Jurong 212400 (China)

    2015-06-15

    Incorporation of straw together with microbial inoculant (a microorganism agent, accelerating straw decomposition) is being increasingly adopted in rice cultivation, thus its effect on greenhouse gas (GHG) emissions merits serious attention. A 3-year field experiment was conducted from 2010 to 2012 to investigate combined effect of straw and microbial inoculant on methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) emissions, global warming potential (GWP) and greenhouse gas intensity (GHGI) in a rice field in Jurong, Jiangsu Province, China. The experiment was designed to have treatment NPK (N, P and K fertilizers only), treatment NPKS (NPK plus wheat straw), treatment NPKSR (NPKS plus Ruilaite microbial inoculant) and treatment NPKSJ (NPKS plus Jinkuizi microbial inoculant). Results show that compared to NPK, NPKS increased seasonal CH{sub 4} emission by 280–1370%, while decreasing N{sub 2}O emission by 7–13%. When compared with NPKS, NPKSR and NPKSJ increased seasonal CH{sub 4} emission by 7–13% and 6–12%, respectively, whereas reduced N{sub 2}O emission by 10–27% and 9–24%, respectively. The higher CH{sub 4} emission could be attributed to the higher soil CH{sub 4} production potential triggered by the combined application of straw and microbial inoculant, and the lower N{sub 2}O emission to the decreased inorganic N content. As a whole, the benefit of lower N{sub 2}O emission was completely offset by increased CH{sub 4} emission, resulting in a higher GWP for NPKSR (5–12%) and NPKSJ (5–11%) relative to NPKS. Due to NPKSR and NPKSJ increased rice grain yield by 3–6% and 2–4% compared to NPKS, the GHGI values for NPKS, NPKSR and NPKSJ were comparable. These findings suggest that incorporating straw together with microbial inoculant would not influence the radiative forcing of rice production in the terms of per unit of rice grain yield relative to the incorporation of straw alone. - Highlights: • This paper presents 3-year measurements of CH

  11. Probing the IGM/Galaxy Connection IV: The LCO/WFCCD Galaxy Survey of 20 Fields Surrounding UV Bright Quasars

    CERN Document Server

    Prochaska, J Xavier; Chen, H -W; Cooksey, K L; Mulchaey, J S

    2011-01-01

    We publish the survey for galaxies in 20 fields containing ultraviolet bright quasars (with z_em 0.1 to 0.5) that can be used to study the association between galaxies and absorption systems from the low-z intergalactic medium (IGM). The survey is magnitude limited (R~19.5 mag) and highly complete out to 10' from the quasar in each field. It was designed to detect dwarf galaxies (L ~ 0.1 L*) at an impact parameter rho 1Mpc (z=0.1) from a quasar. The complete sample (all 20 fields) includes R-band photometry for 84718 sources and confirmed redshifts for 2800 sources. This includes 1198 galaxies with 0.005 < z < (z_em - 0.01) at a median redshift of 0.18, which may associated with IGM absorption lines. All of the imaging was acquired with cameras on the Swope 40" telescope and the spectra were obtained via slitmask observations using the WFCCD spectrograph on the Dupont 100" telescope at Las Campanas Observatory (LCO). This paper describes the data reduction, imaging analysis, photometry, and spectral ana...

  12. Tissue biochemical alterations of Cyprinus carpio exposed to commercial herbicide containing clomazone under rice-field conditions.

    Science.gov (United States)

    Cattaneo, Roberta; Moraes, Bibiana Silveira; Loro, Vania Lucia; Pretto, Alexandra; Menezes, Charlene; Sartori, Gerson Meneghetti Sarzi; Clasen, Bárbara; de Avila, Luis Antonio; Marchesan, Enio; Zanella, Renato

    2012-01-01

    Field and laboratory experiments were performed to evaluate toxicological responses of Cyprinus carpio exposed to the commercial herbicide clomazone (500 mg l(-1)). Fish were exposed to 0.5 mg l(-1) of the formulated herbicide for 7, 30, and 90 days. Fish were exposed to clomazone in field conditions (7, 30, or 90 days trapped in submersed cages together with rice crops) and in laboratory conditions where the fish were placed in 45-l tanks with tap water only for 7 days. Fish exposed for 7, 30, or 90 days showed no alterations in acetylcholinesterase (AChE) activity under field conditions. Under laboratory conditions, decreased muscle AChE activity was observed only after 7 days of exposure. During the same evaluation period (7 days), oxidative stress parameters changed under both field and laboratory conditions; however, metabolic parameters were altered only under field conditions. Disorders in oxidative stress parameters and metabolism were evident in different tissues up to day 90 after treatment. These overall results show that AChE activity changed only under laboratory conditions. Oxidative stress, along with metabolic parameters, may be good indicators of herbicide contamination in C. carpio under rice-field conditions.

  13. Phosphorus Concentration and Forms in Surface and Subsurface Drainage Water from Wetland Rice Fields in the Shaoxing Plain

    Institute of Scientific and Technical Information of China (English)

    ZHANG MINGKUI; JIANG HONG; LIU XINGMEI

    2003-01-01

    Phosphorus (P) is the limiting factor for eutrophication in most freshwater ecosystems. In China, Ptransported from intensively cultivated land has been reported as an important source of P in surface waters.In this study, we investigated P concentration and forms in surface and subsurface drainage from wetland ricefields in the Shaoxing plain, Zhejiang Province, China. From selected rice fields, surface drainage sampleswere collected at rice-growing, non-growing and fertilization periods, and subsurface drainage samples atdrought and rewetting (irrigation or precipitation after 5~10 d drought period in the surface soils) and wet(drainage under long-term wet soil condition) periods. Water samples were characterized for their totalreactive P (TRP), dissolved reactive P (DRP) and particulate reactive P (PRP). Concentrations of the TRPand DRP in the surface drainage ranged from 0.08 to 1.50 and 0.06 to 1.27 mg L-1, respectively. The TRPand DRP were dependent on field operation activities, and decreased in the order of fertilization period >rice-growing period > non-growing period. Phosphorus concentration of runoff receiving P fertilizer can bean environmental concern. The PRP concentration in the surface drainage, ranging from 0.01 to 0.57 mgL-1, accounted for 8%~78% of the TRP. Concentration of the TRP in the subsurface drainage was from0.026 to 0.090 mg L-1, consisting of 29%~90 % of the DRP and 10%~71% of the PRP. In the droughtand rewetting period, the PRP accounted for, on average, 63% of the TRP, much higher than in the wetperiod (23%), suggesting that there was transport of P in preferential flow during drainage events after ashort-term drought period in the surface soils. Therefore, P losses in particulate form may be importantin the subsurface drainage from rice fields when surface soils form cracks and favor rapid flow downwardthrough the soil profiles, suggesting the important role of water-dispersible colloid particles in mediating andco

  14. Effect of timing of joint application of hydroquinone and dicyandiamide on nitrous oxide emission from irrigated lowland rice paddy field.

    Science.gov (United States)

    Li, Xianglan; Zhang, Guangbin; Xu, Hua; Cai, Zucong; Yagi, Kazuyuki

    2009-06-01

    A field experiment was conducted to study the effect of timing of joint application of urease inhibitor hydroquinone (HQ) and nitrification inhibitor dicyandiamide (DCD) on N(2)O emission from irrigated lowland rice paddy field. Four treatments including Treatment CK (the control with urea alone), HQ/DCD-1 (application of HQ and DCD together with fertilizer before transplanting), HQ/DCD-2 (HQ and DCD with fertilizer at tillering stage) and HQ/DCD-3 (HQ and DCD with fertilizer at panicle initiation stage) were designed and implemented separately during rice growth period. Seasonal peaks of N(2)O flux occurred during midseason drainage and significant negative correlation between N(2)O flux and water layer depth was observed (r=-0.69 to -0.75, P<0.01). Mean N(2)O flux was the highest in the control with urea alone, while joint addition of HQ and DCD with urea lowered mean N(2)O flux considerably (P<0.05). Total N(2)O emission during rice growth season in Treatment CK, HQ/DCD-1, HQ/DCD-2 and HQ/DCD-3 was 3.90, 2.98, 1.73 and 3.23kgN(2)O-N ha(-1), respectively. Application of HQ and DCD together with basal fertilizer, tillering fertilizer and panicle initiation fertilizer decreased the total N(2)O emission by 24%, 56% and 17%, respectively, while increased grain yield by 10%, 18% and 6%, respectively. Effect of application of inhibitors on N(2)O emission during the continuous period from incorporation of HQ and DCD to rice harvest was also studied, where results indicating that the highest inhibiting efficiency of inhibitors on N(2)O emission was recorded when HQ and DCD applied with fertilizer at tillering stage.

  15. [Influence of paddy rice-upland crop rotation of cold-waterlogged paddy field on crops produc- tion and soil characteristics].

    Science.gov (United States)

    Wang, Fei; Li, Qing-hua; Lin, Cheng; He, Chun-mei; Zhong, Shao-jie; Li, Yu; Lin, Xin-jian; Huang, Jian-cheng

    2015-05-01

    Two consecutive years (4-crop) experiments were conducted to study the influence of different paddy rice-upland crop rotation in cold-waterlogged paddy field on the growth of crops and soil characteristics. The result showed that compared with the rice-winter fallow (CK) pattern, the two-year average yield of paddy rice under four rotation modes, including rape-rice (R-R), spring corn-rice (C-R), Chinese milk vetch-rice (M-R) and bean-rice (B-R), were increased by 5.3%-26.7%, with significant difference observed in C-R and R-R patterns. Except for M-R pattern, the annual average total economic benefits were improved by 79.0%-392.4% in all rotation pattern compared with the CK, and the ration of output/input was enhanced by 0.06-0.72 unit, with the most significant effect found in the C-R pattern. Likewise, compared with the CK, the contents of chlorophyll and carotenoid, and net photosynthetic rate (Pn) of rice plant were all increased during the full-tillering stage of rice in all rotation patterns. The rusty lines and rusty spots of soils were more obvious compared with the CK during the rice harvest, particularly in R-R, C-R and B-R patterns. The ratio of water-stable soil macro aggregates of plough layer of soil (> 2 mm) decreased at different levels in all rotation patterns while the ratios of middle aggregate (0.25-2 mm, expect for M-R) and micro aggregate of soil (benefits, and soil physical and chemical properties were improved.

  16. A GIS-based Upscaling Estimation of Nutrient Runoff Losses from Rice Paddy Fields to a Regional Level.

    Science.gov (United States)

    Sun, Xiaoxiao; Liang, Xinqiang; Zhang, Feng; Fu, Chaodong

    2016-11-01

    Nutrient runoff losses from cropping fields can lead to nonpoint source pollution; however, the level of nutrient export is difficult to evaluate, particularly at the regional scale. This study aimed to establish a novel yet simple approach for estimating total nitrogen (TN) and total phosphorus (TP) runoff losses from regional paddy fields. In this approach, temporal changes of nutrient concentrations in floodwater were coupled with runoff-processing functions in rice ( L.) fields to calculate nutrient runoff losses for three site-specific field experiments. Validation experiments verified the accuracy of this method. The geographic information system technique was used to upscale and visualize the TN and TP runoff losses from field to regional scales. The results indicated that nutrient runoff losses had significant spatio-temporal variation characteristics during rice seasons, which were positively related to fertilizer rate and precipitation. The average runoff losses over five study seasons were 20.21 kg N ha for TN and 0.76 kg P ha for TP. Scenario analysis showed that TN and TP losses dropped by 7.64 and 3.0%, respectively, for each 10% reduction of fertilizer input. For alternate wetting and drying water management, the corresponding reduction ratio was 24.7 and 14.0% respectively. Our results suggest that, although both water and fertilizer management can mitigate nutrient runoff losses, the former is significantly more effective. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas

    Science.gov (United States)

    Acevedo, R. D.; Rabassa, J.; Ponce, J. F.; Martínez, O.; Orgeira, M. J.; Prezzi, C.; Corbella, H.; González-Guillot, M.; Rocca, M.; Subías, I.; Vásquez, C.

    2012-10-01

    The Bajada del Diablo astrobleme-strewn field is a huge domain of enigmatic circular structures located in central Patagonia. Three more localities are herein described, adding to the first area studied so far. Taking into consideration the four areas, a single, blurred crater dispersion ellipse has been identified. The four sectors now have been investigated, mapped, and georreferenced. Their circular structures, with a total of 185 (some of which are partially obliterated by erosion or sediment accumulation), were identified by remote sensing techniques, but many have been evaluated in situ and interpreted as impact craters. Moreover, two of the structures have been surveyed in detail in the field using a total station instrument. In addition to the previously known occurrence of circular structures on the Eruptive Complex Quiñelaf (Miocene basalts), the Pampa Sastre Fm. (Pliocene conglomerates), and of the Pleistocene pediment gravels and sands, and the geomorphological inferences that have suggested the extra-terrestrial origin of this event, we should now add that the recurrent absence of the cited Pliocene stratigraphic unit at the bottom of the craters is found in the pediment gravel and sands. Its removal has been interpreted as directly related to the impact, according to the magnetometric record of existing magnetic anomalies. Other preliminary observations on the collected samples (glass, breccias, and, most relevant, Fe-Ni-bearing spherules picked up within the impact zones) are herein discussed. Two hypotheses have been put forward about the nature of the possible impacting object that formed these astroblemes which, fragmented into hundreds of pieces, hit the surface of the Earth most likely in middle Pleistocene times. One of these hypotheses is related to the impact of a disintegrated asteroid of the rubble pile type, whereas a second hypothesis refers to the collision of a split comet with the Earth surface. The latter hypothesis is favoured since

  18. Covariation between Spike and LFP Modulations Revealed with Focal and Asynchronous Stimulation of Receptive Field Surround in Monkey Primary Visual Cortex.

    Science.gov (United States)

    Kim, Kayeon; Kim, Taekjun; Yoon, Taehwan; Lee, Choongkil

    2015-01-01

    A focal visual stimulus outside the classical receptive field (RF) of a V1 neuron does not evoke a spike response by itself, and yet evokes robust changes in the local field potential (LFP). This subthreshold LFP provides a unique opportunity to investigate how changes induced by surround stimulation leads to modulation of spike activity. In the current study, two identical Gabor stimuli were sequentially presented with a variable stimulus onset asynchrony (SOA) ranging from 0 to 100 ms: the first (S1) outside the RF and the second (S2) over the RF of primary visual cortex neurons, while trained monkeys performed a fixation task. This focal and asynchronous stimulation of the RF surround enabled us to analyze the modulation of S2-evoked spike activity and covariation between spike and LFP modulation across SOA. In this condition, the modulation of S2-evoked spike response was dominantly facilitative and was correlated with the change in LFP amplitude, which was pronounced for the cells recorded in the upper cortical layers. The time course of covariation between the SOA-dependent spike modulation and LFP amplitude suggested that the subthreshold LFP evoked by the S1 can predict the magnitude of upcoming spike modulation.

  19. Covariation between Spike and LFP Modulations Revealed with Focal and Asynchronous Stimulation of Receptive Field Surround in Monkey Primary Visual Cortex.

    Directory of Open Access Journals (Sweden)

    Kayeon Kim

    Full Text Available A focal visual stimulus outside the classical receptive field (RF of a V1 neuron does not evoke a spike response by itself, and yet evokes robust changes in the local field potential (LFP. This subthreshold LFP provides a unique opportunity to investigate how changes induced by surround stimulation leads to modulation of spike activity. In the current study, two identical Gabor stimuli were sequentially presented with a variable stimulus onset asynchrony (SOA ranging from 0 to 100 ms: the first (S1 outside the RF and the second (S2 over the RF of primary visual cortex neurons, while trained monkeys performed a fixation task. This focal and asynchronous stimulation of the RF surround enabled us to analyze the modulation of S2-evoked spike activity and covariation between spike and LFP modulation across SOA. In this condition, the modulation of S2-evoked spike response was dominantly facilitative and was correlated with the change in LFP amplitude, which was pronounced for the cells recorded in the upper cortical layers. The time course of covariation between the SOA-dependent spike modulation and LFP amplitude suggested that the subthreshold LFP evoked by the S1 can predict the magnitude of upcoming spike modulation.

  20. Effects of elevated ozone on growth and yield of field-grown rice in Yangtze River Delta,China

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhan; WANG Xiaoke; FENG Zhaozhong; ZHENG Feixiang; DUAN Xiaonan; YANG Wenrui

    2008-01-01

    With rapid industrialization and urbanization in the Yangtze Delta,China,the tropospheric ozone concentration has increased to levels that induce orop yield loss.Rice,a widely grown crop in China,was investigated in field-established,open-top chambers.Four treatments were used:charcoal-filtered air (CF),non-charcoal-filtered air (NF),and charcoal-filtered air with two levels of additional ozone (O3-1 and O3-2).The AOT40s (accumulated hourly mean ozone concentration above 40 ppbv) were 0,0.91,23.24,and 39.28 ppmv.h for treatraent of CF,NF,O3-1,and O3-2,respectively.The rice height and biomass were reduced in the elevated ozone concentration.Less organic matter partitioning to roots under the elevated ozone significantly decreased rice root activity.The yield loss was 14.3% and 20.2% under O3-1 and O3-2 exposure,respectively.This was largely caused by a reduction in grain weight per panicle.

  1. Water footprint assessment for crop production based on field measurements: A case study of irrigated paddy rice in East China.

    Science.gov (United States)

    Xinchun, Cao; Mengyang, Wu; Rui, Shu; La, Zhuo; Dan, Chen; Guangcheng, Shao; Xiangping, Guo; Weiguang, Wang; Shuhai, Tang

    2018-01-01

    Water footprint (WF) is a comprehensive measure of water consumption by human activities and can be used to assess the impact on both water volume and quality. This study aims to explore the feasibility of evaluating green, blue and grey WFs of crop production based on field measurements. The irrigated paddy rice grown in three different experimental sites in different typical irrigation districts in Huai'an, East China over 2011 to 2014 was taken as study case. With fixed irrigation and fertilization, on the basis of measuring field water and fertilizer balance at daily step, we calculated WF of crop production under different test treatments. Results show that crop water requirement of rice was measured as 667.1mm and 6.2% of the total nitrogen (T-N) was washed away from farmland accompany with drainage and percolation. Average annual WF of paddy rice during 2011-2014 in Huai'an was 1.760m(3)/kg (33.3% green, 25.8% blue and 40.9% grey). The level of WF and blue water proportion in different locations (irrigation districts) and different years changed slightly, while the proportion of green and grey WF changed with the variance of precipitation. Green water proportion was 25.1%, 34.2 and 44.2%, while 48.0%, 40.2% and 31.0% for grey water proportion under precipitation levels of 400, 600 and 800mm, respectively. The reduced grey WF was due to increased drainage. This study not only proved the feasibility of assessing WF of crop production with field experiments, but also provided a new method for WF calculation based on field water and fertilizer migration processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. P3-9: Roles of Subthreshold LFP Induced by Receptive Field Surround for Response Modulation in Monkey V1

    Directory of Open Access Journals (Sweden)

    Kayeon Kim

    2012-10-01

    Full Text Available A focal stimulus outside the receptive field robustly induces LFP change, while the same stimulus evokes no spike activity. We determined how this subthreshold LFP change interacted with spike response to the RF stimulus. Specifically, we sequentially presented two identical Gabor stimuli with a variable stimulus onset asynchrony (SOA; the first one (S1 was presented outside RF inducing a subthreshold LFP change, and the second one (S2 was subsequently presented within RF generating a spiking response. This enabled us to manipulate the temporal relation between subthreshold LFP and evoked spike activity and to determine whether subthreshold LFP contributed to modulation of spike activity in a SOA-dependent manner. We found that the subthreshold LFP propagated a considerably long distance, estimated to be more than 10 mm of cortical distance. The cross-correlation between the time course of subthreshold LFP and the pattern of SOA-dependency of spike activity was significant. These results indicate that signal integration is farther beyond the RF than previously estimated based on spike-triggered average, and suggest that subthreshold LFP modulate spike activity in a SOA-dependent manner.

  3. Mitigation options for methane emissions from rice fields in the Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Lantin, R.S.; Buendia, L.V.; Wassmann, R. [International Rice Research Institute, Laguna (Philippines)] [and others

    1996-12-31

    The contribution of Philippine rice production to global methane emission and breakthroughs in methane emission studies conducted in the country are presented in this paper. A significant impact in the reduction of GHG emissions from agriculture can be achieved if methane emissions from ricefields can be abated. This study presents the contribution of Philippine rice cultivation to global methane emission and breakthroughs in methane emission studies in the country which address the issue of mitigation. Using the derived emission factors from local measurements, rice cultivation contributes 566.6 Gg of methane emission in the Philippines. This value is 62% of the total methane emitted from the agriculture sector. The emission factors employed which are 78% of the IPCC value for irrigated rice and 95% for rainfed rice were derived from measurements with an automatic system taken during the growth duration in the respective ecosystems. Plots drained for 2 weeks at midtillering and before harvest gave a significant reduction in methane emission as opposed to continuously flooded plots and plots drained before harvest. The cultivar Magat reduced methane emission by 50% as compared to the check variety IR72. The application of ammonium sulfate instead of urea reduced methane emission by 10% to 34%. Addition of 6 t ha{sup {minus}1} phosphogypsum in combination with urea reduced emission by 74% as opposed to plots applied with urea alone. It is also from the results of such measurements that abatement strategies are based as regards to modifying treatments such as water management, fertilization, and choice of rice variety. It is not easy to identify and recommend mitigation strategies that will fit a particular cropping system. However, the identified mitigation options provide focus for the abatement of methane emission from ricefields.

  4. Field phenotyping strategies and breeding for adaptation of rice to drought.

    Science.gov (United States)

    Fischer, Ken S; Fukai, Shu; Kumar, Arvind; Leung, Hei; Jongdee, Boonrat

    2012-01-01

    This paper is a section of the book "Drought phenotyping in crops: from theory to practice" (Monneveux Philippe and Ribaut Jean-Marcel eds, published by CGIAR Generation Challenge Programme. Texcoco, Mexico). The section describes recent experience in drought phenotyping in rice which is one of the most drought-susceptible crops. The section contains genetic and genomic resources for drought adaptation and methods for selection of drought-resistant varieties in rice. In appendix, there is experience from Thailand on integration of direct selection for grain yield and physiological traits to confer drought resistance.

  5. Field Phenotyping Strategies and Breeding for Adaptation of Rice to Drought†

    Science.gov (United States)

    Fischer, Ken S.; Fukai, Shu; Kumar, Arvind; Leung, Hei; Jongdee, Boonrat

    2012-01-01

    This paper is a section of the book “Drought phenotyping in crops: from theory to practice” (Monneveux Philippe and Ribaut Jean-Marcel eds, published by CGIAR Generation Challenge Programme. Texcoco, Mexico). The section describes recent experience in drought phenotyping in rice which is one of the most drought-susceptible crops. The section contains genetic and genomic resources for drought adaptation and methods for selection of drought-resistant varieties in rice. In appendix, there is experience from Thailand on integration of direct selection for grain yield and physiological traits to confer drought resistance. PMID:22934036

  6. Field phenotyping strategies and breeding for adaptation of rice to drought

    Directory of Open Access Journals (Sweden)

    Shu eFukai

    2012-07-01

    Full Text Available This paper is a section of the book ‘Drought phenotyping in crops: from theory to practice (Monneveux Philippe and Ribaut Jean-Marcel eds, published by CGIAR Generation Challenge Programme. Texcoco, Mexico. The section describes recent experience in drought phenotyping in rice which is one of the most drought susceptible crops. The section contains genetic and genomic resources for drought adaptation and methods for selection of drought resistant varieties in rice. In appendix, there is experience from Thailand on integration of direct selection for grain yield and physiological traits to confer drought resistance.

  7. Using natural Chinese zeolite to remove ammonium from rainfall runoff following urea fertilization of a paddy rice field.

    Science.gov (United States)

    Wang, Xiao-Ling; Qiao, Bin; Li, Song-Min; Li, Jian-Sheng

    2016-03-01

    The potential of natural Chinese zeolite to remove ammonium from rainfall runoff following urea applications to a paddy rice field is assessed in this study. Laboratory batch kinetic and isotherm experiments were carried out first to investigate the ammonium adsorption capacity of the natural zeolite. Field experiments using zeolite adsorption barriers installed at drain outlets in a paddy rice field were also carried out during natural rainfall events to evaluate the barrier's dynamic removal capacity of ammonium. The results demonstrate that the adsorption kinetics are accurately described by the Elovich model, with a coefficient of determination (R (2)) ranging from 0.9705 to 0.9709, whereas the adsorption isotherm results indicate that the Langmuir-Freundlich model provides the best fit (R (2) = 0.992) for the equilibrium data. The field experiments show that both the flow rate and the barrier volume are important controls on ammonium removal from rainfall runoff. A low flow rate leads to a higher ammonium removal efficiency at the beginning of the tests, while a high flow rate leads to a higher quantity of ammonium adsorbed over the entire runoff process.

  8. GM RICE COMMERCIALIZATION AND ITS IMPACT ON THE GLOBAL RICE ECONOMY

    OpenAIRE

    Durand-Morat, Alvaro; Chavez, Eddie; Wailes, Eric

    2015-01-01

    Genetically-modified (GM) rice is an important technology surrounded with controversy and uncertainty, hence it warrants more in-depth analysis. While GM rice is considered by its supporters as having promising potential, many still remain passionately against its use. This study assesses the impacts of GM rice commercialization on the global rice market. We use the Arkansas Global Rice Model (AGRM) and the RICEFLOW model to provide stochastic and dynamic analyses. Scenarios of adoption, diff...

  9. Investigating Within-Field Variability of Rice from High Resolution Satellite Imagery in Qixing Farm County, Northeast China

    Directory of Open Access Journals (Sweden)

    Quanying Zhao

    2015-02-01

    Full Text Available Rice is a primary staple food for the world population and there is a strong need to map its cultivation area and monitor its crop status on regional scales. This study was conducted in the Qixing Farm County of the Sanjiang Plain, Northeast China. First, the rice cultivation areas were identified by integrating the remote sensing (RS classification maps from three dates and the Geographic Information System (GIS data obtained from a local agency. Specifically, three FORMOSAT-2 (FS-2 images captured during the growing season in 2009 and a GIS topographic map were combined using a knowledge-based classification method. A highly accurate classification map (overall accuracy = 91.6% was generated based on this Multi-Data-Approach (MDA. Secondly, measured agronomic variables that include biomass, leaf area index (LAI, plant nitrogen (N concentration and plant N uptake were correlated with the date-specific FS-2 image spectra using stepwise multiple linear regression models. The best model validation results with a relative error (RE of 8.9% were found in the biomass regression model at the phenological stage of heading. The best index of agreement (IA value of 0.85 with an RE of 13.6% was found in the LAI model, also at the heading stage. For plant N uptake estimation, the most accurate model was again achieved at the heading stage with an RE of 11% and an IA value of 0.77; however, for plant N concentration estimation, the model performance was best at the booting stage. Finally, the regression models were applied to the identified rice areas to map the within-field variability of the four agronomic variables at different growth stages for the Qixing Farm County. The results provide detailed spatial information on the within-field variability on a regional scale, which is critical for effective field management in precision agriculture.

  10. Weed-Suppressing Effect and Mechanism of Allelopathic Rice Accessions

    Institute of Scientific and Technical Information of China (English)

    HUFei; KONGChui-hua; XUXiao-hua; ZHANGChao-xian; CHENXiong-hui

    2004-01-01

    Two allelopathic rice accessions, PI312777 and Allelopathy i, significantly suppressed the growth of associated weeds in the field. Moreover, their weed-suppressing effects were correlated with the cultivation patterns. The weed-suppressing effects of throwing and transplanting were more effective than that of direct seeding. Furthermore, the amounts of allelochemicals (resorcinols, flavones and hydroxamic acids) produced and released from two allelopathic rice accessions were much higher than that from a nonallelopathic rice variety Hua-Jing-Xian i, and reached the maximum concentration at the 6th leaf stage. Differences in the weed-suppressing effects of rice accessions appear to result from the accessions producing and releasing different amounts of allelochemicals in the field. Further research confirmed that in PI312777 plants, allelochemicals were synthesized by the above-ground parts, and then secreted through the root tissues. Root tissues of PI312777 plants never produced the allelochemicals. Root exudates from PI312777 could significantly inhibit the growth of E. crus-galli surrounding rice plants in water culture. However, when activated carbon was added to the culture solution, which could absorb allelochemicals from root exudates, the growth of E. crus-galli was no longer significantly inhibited. Weed-suppressing effects of rice accessions depended on allelopathy, cultivation patterns and other factors in rice fields, while allelopathy was one of important factors. Interestingly, the amounts of allelochemicals produced and released from allelopathic rice plants may be induced by the presence of E. crus-galli.This suggests that there is a possible chemical recognition between rice and E. crus-galli.

  11. Numerical optimization of nitrogen application to rice. Part II. Field evaluations

    NARCIS (Netherlands)

    Berge, ten H.F.M.; Qinghua, S.; Zhiming, Z.; Rao, K.S.; Riethoven, J.J.M.; Zhong, X.

    1997-01-01

    The MANAGE-N model (Part I; Ten Berge et al., this issue) was tested by comparing predicted and measured final crop biomass production for 48 rice cultivars under application of 0, 30–40, 60–80 and 90 to 120 kg urea-N per ha at Cuttack, India, during seven consecutive wet seasons. The overall coeffi

  12. Optimizing rice plant photosynthate allocation reduces N2O emissions from paddy fields

    Science.gov (United States)

    Jiang, Yu; Huang, Xiaomin; Zhang, Xin; Zhang, Xingyue; Zhang, Yi; Zheng, Chengyan; Deng, Aixing; Zhang, Jun; Wu, Lianhai; Hu, Shuijin; Zhang, Weijian

    2016-07-01

    Rice paddies are a major source of anthropogenic nitrous oxide (N2O) emissions, especially under alternate wetting-drying irrigation and high N input. Increasing photosynthate allocation to the grain in rice (Oryza sativa L.) has been identified as an effective strategy of genetic and agronomic innovation for yield enhancement; however, its impacts on N2O emissions are still unknown. We conducted three independent but complementary experiments (variety, mutant study, and spikelet clipping) to examine the impacts of rice plant photosynthate allocation on paddy N2O emissions. The three experiments showed that N2O fluxes were significantly and negatively correlated with the ratio of grain yield to total aboveground biomass, known as the harvest index (HI) in agronomy (P < 0.01). Biomass accumulation and N uptake after anthesis were significantly and positively correlated with HI (P < 0.05). Reducing photosynthate allocation to the grain by spikelet clipping significantly increased white root biomass and soil dissolved organic C and reduced plant N uptake, resulting in high soil denitrification potential (P < 0.05). Our findings demonstrate that optimizing photosynthate allocation to the grain can reduce paddy N2O emissions through decreasing belowground C input and increasing plant N uptake, suggesting the potential for genetic and agronomic efforts to produce more rice with less N2O emissions.

  13. Numerical optimization of nitrogen application to rice. Part II. Field evaluations

    NARCIS (Netherlands)

    Berge, ten H.F.M.; Qinghua, S.; Zhiming, Z.; Rao, K.S.; Riethoven, J.J.M.; Zhong, X.

    1997-01-01

    The MANAGE-N model (Part I; Ten Berge et al., this issue) was tested by comparing predicted and measured final crop biomass production for 48 rice cultivars under application of 0, 30–40, 60–80 and 90 to 120 kg urea-N per ha at Cuttack, India, during seven consecutive wet seasons. The overall

  14. Numerical optimization of nitrogen application to rice. Part II. Field evaluations

    NARCIS (Netherlands)

    ten Berge, H.F.M.; Qinghua, S.; Zhiming, Z.; Rao, K.S.; Riethoven, J.J.M.; Zhong, X.

    1997-01-01

    The MANAGE-N model (Part I; Ten Berge et al., this issue) was tested by comparing predicted and measured final crop biomass production for 48 rice cultivars under application of 0, 30–40, 60–80 and 90 to 120 kg urea-N per ha at Cuttack, India, during seven consecutive wet seasons. The overall coeffi

  15. Predicting As, Cd and Pb uptake by rice and vegetables using field data from China

    Institute of Scientific and Technical Information of China (English)

    Hongzhen Zhang; Yongming Luo; Jing Song; Haibo Zhang; Jiaqi Xia; Qiguo Zhao

    2011-01-01

    Plant uptake factor (PUF), single-variable regression of natural log-transformed concentrations in rice grain/vegetables versus natural log-transformed concentrations in soil and multiple-variable regression with soil concentrations and pH, was derived, validated and compared based on the paired crop and soil data collected from studies regarding As, Cd and Pb contaminated croplands in China.Results showed that the median value of PUF did not present deterministic prediction. But after natural logarithm transformation, the PUF followed Gaussian distribution which could be useful in risk assessment. The single-variable regression models were significant for As, Cd and Pb uptake both by rice and vegetables; however, the standard errors of all the regressions were comparatively large.Soil pH as a variable was generally significant but it only contributed positively to model fit for Cd uptake. After model comparison and selection, the upper 95% prediction limits of the multiple regression model for Cd uptake by rice was recommended to calculate screening value of Cd for paddy soil based on the limit for Cd concentration in rice grain.

  16. TOXICITY OF TWO HERBICIDES 2,4 -D DIMETHYLAMINE AND BENSULFURON METHYL TO RICE FIELD CHIRONOMUS KIIENSIS (TOKUNAGA) ( DIPTERA: CHIRONOMIDAE)

    Institute of Scientific and Technical Information of China (English)

    Al-Shami S A; Che Salmah M R; Siti Azizah M N; Abu Hassan A; Azmi M

    2006-01-01

    Fourth instar larvae of Chironomus kiiensis(Tokunaga) were exposed to various concentrations of two commonly used herbicides: 2,4 - D Dimethylamine and Bensulfuron methyl in the rice fields. The bioassay experiment was carried out in a rearing unit in the laboratory at a room temperature ( (27 ± 2) ℃ ). A thin layer of sand sediments and tissue papers were provided as substrate in each unit. Each concentration of all herbicides was prepared in 250 mL distilled water. The experiment was performed in triplicate and 20 chironomid larvae were placed in each rearing unit. The larvae were fed with fish food (Sanyuichiban(R)) at 2 d intervals and all units were aerated by air pumps. The experiment was monitored every 24 h for mortality of C. kiiensis. The 2,4 - D Dimethylamine bioassay was carried out for 24 h while Bensulfuron methyl was run for 72 h. Dead larvae, pupae and living or dead adults were counted and removed daily.The LC50 of 2,4 - D Dimethylamine was 2 638 mg ai L-1, more than 2 000 times higher than the recommended dose of 0.753 mg ai L-1 used for controlling weeds in the rice field. Bensulfuron methyl was more toxic than the 2,4 - D Dimethylamine. The LC50 of the Bensulfuron methyl was recorded at 1.29 mg ai L-1, and approximately was more 20 times than that of the recommended dose of 0. 057 mg ai L-1. Bensulfuron methyl was found to be slow acting. The mortality of the larvae was only observed after 72 h. However, this herbicide interfered with the emergence of C. kiiensis to adults at and above the recommended dose used in the rice fields. Based on their LC50 values, this study showed that applying these herbicides in the rice fields at doses recommended by the manufacturers was safe for C. kiiensis and presumably to other living organisms in the water.

  17. Geobacter, Anaeromyxobacter and Anaerolineae populations are enriched on anodes of root exudate-driven microbial fuel cells in rice field soil.

    Science.gov (United States)

    Cabezas, Angela; Pommerenke, Bianca; Boon, Nico; Friedrich, Michael W

    2015-06-01

    Plant-based sediment microbial fuel cells (PMFCs) couple the oxidation of root exudates in living rice plants to current production. We analysed the composition of the microbial community on anodes from PMFC with natural rice field soil as substratum for rice by analysing 16S rRNA as an indicator of microbial activity and diversity. Terminal restriction fragment length polymorphism (TRFLP) analysis indicated that the active bacterial community on anodes from PMFCs differed strongly compared with controls. Moreover, clones related to Deltaproteobacteria and Chloroflexi were highly abundant (49% and 21%, respectively) on PMFCs anodes. Geobacter (19%), Anaeromyxobacter (15%) and Anaerolineae (17%) populations were predominant on anodes with natural rice field soil and differed strongly from those previously detected with potting soil. In open circuit (OC) control PMFCs, not allowing electron transfer, Deltaproteobacteria (33%), Betaproteobacteria (20%), Chloroflexi (12%), Alphaproteobacteria (10%) and Firmicutes (10%) were detected. The presence of an electron accepting anode also had a strong influence on methanogenic archaea. Hydrogenotrophic methanogens were more active on PMFC (21%) than on OC controls (10%), whereas acetoclastic Methanosaetaceae were more active on OC controls (31%) compared with PMFCs (9%). In conclusion, electron accepting anodes and rice root exudates selected for distinct potential anode-reducing microbial populations in rice soil inoculated PMFC.

  18. Methanocella conradii sp. nov., a thermophilic, obligate hydrogenotrophic methanogen, isolated from Chinese rice field soil.

    Directory of Open Access Journals (Sweden)

    Zhe Lü

    Full Text Available BACKGROUND: Methanocellales contributes significantly to anthropogenic methane emissions that cause global warming, but few pure cultures for Methanocellales are available to permit subsequent laboratory studies (physiology, biochemistry, etc.. METHODOLOGY/PRINCIPAL FINDINGS: By combining anaerobic culture and molecular techniques, a novel thermophilic methanogen, strain HZ254(T was isolated from a Chinese rice field soil located in Hangzhou, China. The phylogenetic analyses of both the 16S rRNA gene and mcrA gene (encoding the α subunit of methyl-coenzyme M reductase confirmed its affiliation with Methanocellales, and Methanocella paludicola SANAE(T was the most closely related species. Cells were non-motile rods, albeit with a flagellum, 1.4-2.8 µm long and by 0.2-0.3 µm in width. They grew at 37-60 °C (optimally at 55 °C and salinity of 0-5 g NaCl l(-1 (optimally at 0-1 g NaCl l(-1. The pH range for growth was 6.4-7.2 (optimum 6.8. Under the optimum growth condition, the doubling time was 6.5-7.8 h, which is the shortest ever observed in Methanocellales. Strain HZ254(T utilized H(2/CO(2 but not formate for growth and methane production. The DNA G+C content of this organism was 52.7 mol%. The sequence identities of 16S rRNA gene and mcrA gene between strain HZ254(T and SANAE(T were 95.0 and 87.5% respectively, and the genome based Average Nucleotide Identity value between them was 74.8%. These two strains differed in phenotypic features with regard to substrate utilization, possession of a flagellum, doubling time (under optimal conditions, NaCl and temperature ranges. Taking account of the phenotypic and phylogenetic characteristics, we propose strain HZ254(T as a representative of a novel species, Methanocella conradii sp. nov. The type strain is HZ254(T ( = CGMCC 1.5162(T = JCM 17849(T = DSM 24694(T. CONCLUSIONS/SIGNIFICANCE: Strain HZ254(T could potentially serve as an excellent laboratory model for studying Methanocellales due to its

  19. Effects of winter cover crops residue returning on soil enzyme activities and soil microbial community in double-cropping rice fields.

    Directory of Open Access Journals (Sweden)

    Tang Hai-Ming

    Full Text Available Residue management in cropping systems is useful to improve soil quality. However, the studies on the effects of residue management on the enzyme activities and microbial community of soils in South China are few. Therefore, the effects of incorporating winter cover crop residue with a double-cropping rice (Oryza sativa L. system on soil enzyme activities and microbial community in Southern China fields were studied. The experiment has conducted at the experimental station of the Institute of Soil and Fertilizer Research, Hunan Academy of Agricultural Science, China since winter 2004. Four winter cropping systems were used: rice-rice-ryegrass (Lolium multiflorum L. (R-R-Ry, rice-rice-Chinese milk vetch (Astragalus sinicus L. (R-R-Mv, rice-rice-rape (Brassica napus L. (R-R-Ra and rice-rice with winter fallow (R-R-Fa. The result indicated that the enzyme activities in the R-R-Ry, R-R-Mv and R-R-Ra systems were significantly higher (P<0.05 than in the R-R-Fa system during the early and late rice season. The β-glucosidase activities reached peak values at the tillering stage after residue application, and alkaline phosphatase activities reached peak values at the booting stage after residue application, respectively, the activities of β-glucosidase and alkaline phosphatase gradually decreased after this. Arylsulfatase activities reached peak values at the maturity stage. Arylamidase activities reached peak values at the maturity stage. The numbers of aerobic bacteria, actinomycete and fungus of residue treatments were significantly higher (P<0.05 than that the R-R-Ra system. However, the number of anaerobic bacteria under the R-R-Ry and R-R-Mv systems was significantly lower (P<0.05 than that under the R-R-Fa system during early rice and late rice growth stage. Thus, incorporation of winter cover crops into rotations may increase enzyme activities and microbial community in soil and therefore improve soil quality.

  20. Role of Remote Sensing and Geographyc Information System Mapping for Protected Areas Land Rice Field Subak, Buffer Zones, and Area Conversion (Case Studies In Gianyar Regency, Bali Province)

    Science.gov (United States)

    Lanya, Indayati; Netera Subadiyasa, N.

    2016-11-01

    Conversion of rice fields in Bali 2579 ha/year, Law Number 41 of 2009 [1] and five of Government Regulation (GR), mandates the Local Government (LG) has a Regional Regulation (RR) or Rule Regent/Mayor, on the protection of agricultural land sustainable food (PALSF). Yet none provincial government of Bali has PALSF; although Subak as world cultural heritage. Similarly, Gianyar regency development strategy directed to integrate agriculture with tourism. Landsat 8 images, Word View Coverage 2015 Gianyar district and ArcGIS 10.3 software used for of rice field mapping and zoning of land protection Subak. Ten thematic maps (watersheds, land use, irrigation, relief/slope, rainfall, spatial planning, land suitability, productivity, the distance from downtown) as a variable parameter, weighted and balanced numerically. Numerical classification agricultura land using for the overlay menu and reselek. The total value of >125 as rice need to be protected, 100-125 value for buffer zone, and the value of 100, 50-100 and sustainable of rice field protection, buffer and can be converted in a row for the next 20 years is 10973 ha, 3855 ha and 311 ha. For the next 40 years Subak conserved of rice field (8019 ha), buffer (5855 ha), and can be converted (3124 ha). Subak land pattern of spread can be converted to an supply of land for non-agricultural development of the region downstream to the access road Ida Bagus Matera (Jln. Province / national) in the coastal areas of Gianyar.

  1. Genotypic Variation in Grain P Loading across Diverse Rice Growing Environments and Implications for Field P Balances

    Science.gov (United States)

    Vandamme, Elke; Wissuwa, Matthias; Rose, Terry; Dieng, Ibnou; Drame, Khady N.; Fofana, Mamadou; Senthilkumar, Kalimuthu; Venuprasad, Ramaiah; Jallow, Demba; Segda, Zacharie; Suriyagoda, Lalith; Sirisena, Dinarathna; Kato, Yoichiro; Saito, Kazuki

    2016-01-01

    More than 60% of phosphorus (P) taken up by rice (Oryza spp.) is accumulated in the grains at harvest and hence exported from fields, leading to a continuous removal of P. If P removed from fields is not replaced by P inputs then soil P stocks decline, with consequences for subsequent crops. Breeding rice genotypes with a low concentration of P in the grains could be a strategy to reduce maintenance fertilizer needs and slow soil P depletion in low input systems. This study aimed to assess variation in grain P concentrations among rice genotypes across diverse environments and evaluate the implications for field P balances at various grain yield levels. Multi-location screening experiments were conducted at different sites across Africa and Asia and yield components and grain P concentrations were determined at harvest. Genotypic variation in grain P concentration was evaluated while considering differences in P supply and grain yield using cluster analysis to group environments and boundary line analysis to determine minimum grain P concentrations at various yield levels. Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g−1. Minimum grain P concentrations associated with grain yields of 150, 300, and 500 g m−2 varied between 1.2 and 1.7, 1.3 and 1.8, and 1.7 and 2.2 mg g−1 among genotypes respectively. Two genotypes, Santhi Sufaid and DJ123, were identified as potential donors for breeding for low grain P concentration. Improvements in P balances that could be achieved by exploiting this genotypic variation are in the range of less than 0.10 g P m−2 (1 kg P ha−1) in low yielding systems, and 0.15–0.50 g P m−2 (1.5–5.0 kg P ha−1) in higher yielding systems. Improved crop management and alternative breeding approaches may be required to achieve larger reductions in grain P concentrations in rice. PMID:27729916

  2. Zonal disintegration phenomenon in enclosing rock mass surrounding deep tunnels Elasto-plastic analysis of stress field of enclosing rock mass

    Institute of Scientific and Technical Information of China (English)

    WU Hao; FANG Qin; ZHANG Ya-dong; GONG Zi-ming

    2009-01-01

    The zonal disintegration phenomenon (ZDP) is a typical phenomenon in deep block rock masses. In order to investigate the mechanism of ZDP, an improved non-linear Hock-Brown strength criterion and a bi-linear constitutive model of rock mass were used to analyze the elasto-plastic stress field of the enclosing rock mass around a deep round tunnel. The radius of the plastic region and stress of the enclosing rock mass were obtained by introducing dimensionless parameters of radial distance. The results show that tunneling in deep rock mass causes a maximum stress zone to appear in the vicinity of the boundary of the elastic and the plas-tic zone in the surrounding rock mass. Under the compression of a large tangential force and a small radial force, the rock mass in the maximum stress zone was in an approximate uniaxial loading state, which could lead to a split failure in the rock mass.

  3. Impact of volunteer rice infestation on yield and grain quality of rice.

    Science.gov (United States)

    Singh, Vijay; Burgos, Nilda R; Singh, Shilpa; Gealy, David R; Gbur, Edward E; Caicedo, Ana L

    2017-03-01

    Volunteer rice (Oryza sativa L.) grains may differ in physicochemical traits from cultivated rice, which may reduce the quality of harvested rice grain. To evaluate the effect of volunteer rice on cultivated rice, fields were surveyed in Arkansas in 2012. Cropping history that included hybrid cultivars in the previous two years (2010 and 2011) had higher volunteer rice infestation (20%) compared with fields planted previously with inbred rice (5.5%). The total grain yield of rice was reduced by 0.4% for every 1% increase in volunteer rice density. The grain quality did not change in fields planted with the same cultivar for three years. Volunteer rice density of at least 7.6% negatively impacted the head rice and when infestation reached 17.7%, it also reduced the rice grain yield. The protein and amylose contents of rice were not affected until volunteer rice infestation exceeded 30%. Crop rotation systems that include hybrid rice are expected to have higher volunteer rice infestation than systems without hybrid rice. It is predicted that, at 8% infestation, volunteer rice will start to impact head rice yield and will reduce total yield at 18% infestation. It could alter the chemical quality of rice grain at >30% infestation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  4. NUMERICAL SIMULATION OF METHANE EMISSIONS FROM RICE PADDY FIELDS IN THE YANGTZE DELTA OF CHINA

    Institute of Scientific and Technical Information of China (English)

    刘建栋; 周秀骥; 张宇

    2001-01-01

    A numerical simulation model is presented in this paper, which comprises the processes of crop growth, soil organic carbon decomposition, and methane emissions in agroecosystems.Simulation results show that the model can simulate the main process of methane emissions well,and the correlation coefficient between the simulated values and observed data is 0. 79 with 239 samples, which passed a significance test of 0. 01. The average error of methane emission simulation in whole growth period is about 15%. Numerical analysis of the model indicates that the average temperature during rice growth period has much impacts on methane emissions, and the basic trend of interannual methane emissions is similar to that of average temperature. The amount of methane emissions reduces about 34. 93%, when the fertilizer is used instead of manure in single rice paddy.

  5. Tissue distribution of hepatopancreatic parvo-like virus of shrimp in freshwater rice-field crab, Paratelphusa hydrodomous (Herbst).

    Science.gov (United States)

    Madan, N; Rajkumar, T; Sundar Raj, N; Farook, M A; Nambi, K S N; Abdul Majeed, S; Sahul Hameed, A S

    2014-11-01

    An attempt was made to determine the replication efficiency of hepatopancreatic parvo-like virus (HPV) of shrimp in different organs of freshwater rice-field crab Paratelphusa hydrodomous (Herbst) using bioassay, PCR, RT-PCR, ELISA, Western blot and q-PCR analyses. Another attempt was made to use this crab as an alternative to penaeid shrimp for the large-scale production of HPV. This crab was found to be highly susceptible to HPV by intramuscular injection. The systemic HPV infection was confirmed by PCR and Western blot analyses in freshwater crab. The expression of capsid protein gene in different organs of infected crab was revealed by RT-PCR analysis. Indirect ELISA was used to quantify the capsid protein in different organs of the crab. The copy number of HPV in different organs of the infected crab was quantified by q-PCR. The results revealed a steady decrease in CT values in different organs of the infected crab during the course of infection. The viral inoculum that was prepared from different organs of the infected crab caused significant mortality in post-larvae of tiger prawn, Penaeus monodon (Fabricius). The results revealed that this rice-field crab could be used as an alternative host for HPV replication and also for large-scale production of HPV.

  6. Study of Environmental Impacts Before and After Using the Organic-Chemical Fertilizer in Rice Paddy Fields

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    Wipawee KHAMWICHIT

    2006-01-01

    Full Text Available The environmental impact of an organic-chemical fertilizer developed by the Institute of National Science and Technology has been studied at Bansrangsabaeng Posai Ubonratchathani. The study revealed that the values of pH, EC, OC, total N, available P, and exchangeable K in soils from two varieties of rice tested Kor-Khor 10 and         Kor-Khor 15 paddy fields are almost the same. The concentrations of VOC, NH3, and CH4 in the air from the rice paddy fields mentioned above are lower than 0.001 mg/m3 indicating no air pollution problems. Analysis of the water supply (ground water and surface water within the studied area before and after using organic-chemical fertilizer, found that most of the water supply parameters including pH, Total Hardness, TDS, SS, Fe, Mn, and   NO3-N were not significantly changed and all of them met water supply standards. In terms of surface water quality, slightly different values of pH, TDS, SS, NO3-N, TKN, PO4-P, BOD, COD, and DO were observed compared with a standard fertilizer. In conclusion, the organic-chemical fertilizer is a viable alternative to standard chemical fertilizer and may help to reduce the environmental impact of such chemicals upon the land.

  7. [Effects of no-tillage and stubble-remaining on soil enzyme activities in broadcasting rice seedlings paddy field].

    Science.gov (United States)

    Ren, Wan-Jun; Huang, Yun; Wu, Jin-Xiu; Liu, Dai-Yin; Yang, Wen-Yu

    2011-11-01

    A field experiment was conducted to study the effects of four cultivation modes (conventional tillage, no-tillage, conventional tillage + stubble-remaining, and no-tillage + stubble-remaining) on the activities of urease, acid phosphatase, protease, and cellulose in different soil layers in a broadcasting rice seedlings paddy field. Under the four cultivation modes, the activities of test enzymes were higher in upper than in deeper soil layers, and had a greater difference between the soil layers under no-tillage + stubble-remaining. In upper soil layers, the activities of test enzymes were higher in the treatments of no-tillage than in the treatments of conventional tillage, being the highest under no-tillage + stubble-remaining and the lowest under conventional tillage. In deeper soil layers, the test enzyme activities were the highest under conventional tillage + stubble-remaining, followed by no-tillage + stubble-remaining, no-tillage, and conventional tillage. During the growth period of rice, soil urease and cellulose activities were lower at tillering stage, increased to the maximum at booting stage, and decreased then, soil acid phosphatase activity was higher at tillering stage but lower at elongating stage, whereas soil protease activity peaked at tillering and heading stages.

  8. Influence of nitrogen loading and plant nitrogen assimilation on nitrogen leaching and N₂O emission in forage rice paddy fields fertilized with liquid cattle waste.

    Science.gov (United States)

    Riya, Shohei; Zhou, Sheng; Kobara, Yuso; Sagehashi, Masaki; Terada, Akihiko; Hosomi, Masaaki

    2015-04-01

    Livestock wastewater disposal onto rice paddy fields is a cost- and labor-effective way to treat wastewater and cultivate rice crops. We evaluated the influence of nitrogen loading rates on nitrogen assimilation by rice plants and on nitrogen losses (leaching and N2O emission) in forage rice fields receiving liquid cattle waste (LCW). Four forage rice fields were subjected to nitrogen loads of 107, 258, 522, and 786 kg N ha(-1) (N100, N250, N500, and N750, respectively) using basal fertilizer (chemical fertilizer) (50 kg N ha(-1)) and three LCW topdressings (each 57-284 kg N ha(-1)). Nitrogen assimilated by rice plants increased over time. However, after the third topdressing, the nitrogen content of the biomass did not increase in any treatment. Harvested aboveground biomass contained 93, 60, 33, and 31 % of applied nitrogen in N100, N250, N500, and N750, respectively. The NH4 (+) concentration in the pore water at a depth of 20 cm was less than 1 mg N L(-1) in N100, N250, and N500 throughout the cultivation period, while the NH4 (+) concentration in N750 increased to 3 mg N L(-1) after the third topdressing. Cumulative N2O emissions ranged from -0.042 to 2.39 kg N ha(-1); the highest value was observed in N750, followed by N500. In N750, N2O emitted during the final drainage accounted for 80 % of cumulative N2O emissions. This study suggested that 100-258 kg N ha(-1) is a recommended nitrogen loading rate for nitrogen recovery by rice plants without negative environmental impacts such as groundwater pollution and N2O emission.

  9. Effects of tire rubber ash and zinc sulfate on crop productivity and cadmium accumulation in five rice cultivars under field conditions.

    Science.gov (United States)

    Fahad, Shah; Hussain, Saddam; Khan, Fahad; Wu, Chao; Saud, Shah; Hassan, Shah; Ahmad, Naeem; Gang, Deng; Ullah, Abid; Huang, Jianliang

    2015-08-01

    Cadmium (Cd) is among the most widespread and toxic heavy metals becoming a severe threat to humans. A field study was conducted to examine the role of various zinc (Zn) fertilization treatments and cultivars on crop productivity and Zn and Cd concentrations in brown rice and rice straw. The Zn fertilization treatments included an unfertilized control, foliar applied Zn sulfate (ZnSO4) at panicle initiation stage, foliar applied ZnSO4 at milky stage, soil application of rubber ash, and soil-applied ZnSO4, while five rice cultivars were Swat-1, Shadab, Shua-92, Swat-2, and Sada Hayat. All the Zn fertilization treatments resulted in significantly higher number of panicles, number of spikelets per panicles, spikelet fertility, 1,000-grain weight, grain yield, brown rice and rice straw Zn concentrations, and significantly lower Cd concentrations. Soil application of rubber ash remained the best among all Zn fertilization treatments as it resulted in 73% higher grain yield and reduced Cd concentration by 51% as compared with control. Variations were also apparent among cultivars, and Shua-92 and Swat-2 performed better in terms of all studied attributes as compared with other cultivars. Conclusively, cultivar selection and Zn application are effective strategies to improve rice grain yield as well as quality. Rubber ash appeared a viable source of Zn having the ability to increase yield along with reducing Cd accumulation.

  10. Field transcriptome revealed critical developmental and physiological transitions involved in the expression of growth potential in japonica rice

    Directory of Open Access Journals (Sweden)

    Kamatsuki Kaori

    2011-01-01

    Full Text Available Abstract Background Plant growth depends on synergistic interactions between internal and external signals, and yield potential of crops is a manifestation of how these complex factors interact, particularly at critical stages of development. As an initial step towards developing a systems-level understanding of the biological processes underlying the expression of overall agronomic potential in cereal crops, a high-resolution transcriptome analysis of rice was conducted throughout life cycle of rice grown under natural field conditions. Results A wide range of gene expression profiles based on 48 organs and tissues at various developmental stages identified 731 organ/tissue specific genes as well as 215 growth stage-specific expressed genes universally in leaf blade, leaf sheath, and root. Continuous transcriptome profiling of leaf from transplanting until harvesting further elucidated the growth-stage specificity of gene expression and uncovered two major drastic changes in the leaf transcriptional program. The first major change occurred before the panicle differentiation, accompanied by the expression of RFT1, a putative florigen gene in long day conditions, and the downregulation of the precursors of two microRNAs. This transcriptome change was also associated with physiological alterations including phosphate-homeostasis state as evident from the behavior of several key regulators such as miR399. The second major transcriptome change occurred just after flowering, and based on analysis of sterile mutant lines, we further revealed that the formation of strong sink, i.e., a developing grain, is not the major cause but is rather a promoter of this change. Conclusions Our study provides not only the genetic basis for functional genomics in rice but also new insight into understanding the critical physiological processes involved in flowering and seed development, that could lead to novel strategies for optimizing crop productivity.

  11. Optimization of Field Investigation of Major Rice Pests%水稻主要害虫田间调查实践优化

    Institute of Scientific and Technical Information of China (English)

    尤伟群; 侯平扬

    2013-01-01

    病虫害田间调查是测报的基础性工作,提高病虫害田间调查数据的准确性,有赖于田间调查方法的规范性和操作技能的提升.本文优化总结了基层测报技术人员对水稻主要害虫稻飞虱、稻纵卷叶螟、二化螟的田间调查实践,归纳出对3种害虫田间调查方法的要点,并提出了田间调查的注意事项.%Field investigations of plant diseases and pests are the basis for forecasting,improving the accuracy of field investigation data,depends on normative and operational skills of field investigation methods improved.This paper sum optimizes and summarizes the major pests in rice field investigations practice of grass-roots forecasting technicians on the rice planthopper,rice leaf-roller and Asiatic rice striped borer,summarized to 3 kinds of pests field investigation methods,and made notes on field investigations.

  12. Quantifying methane emissions from rice fields in Tai-Lake region, China by coupling detailed soil database with biogeochemical model

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2008-12-01

    Full Text Available China's paddy rice accounts for about 22% of the world's rice fields, therefore it is crucial to accurately estimate the CH4 emissions at regional scale to gauge their contribution to global greenhouse gas effect. This paper reports an application of a biogeochemical model, DeNitrification and DeComposition or DNDC, for quantifying CH4 emissions from rice fields in Tai-Lake region of China by linking DNDC to a 1:50 000 soil database, which was derived from 1107 paddy soil profiles in the Second National Soil Survey of China in the 1980s–1990s. The modeled results estimate that the 2.34 M ha of paddy rice fields in Tai-Lake region emitted about CH4 of 5.67 Tg C for the period of 1982–2000, with the average CH4 flux ranged from 114 to 138 kg C ha−1y−1. The highest emission rate (659.24 kg C ha−1 y−1 occurred in the subgroup of "gleyed paddy soils", while the lowest (90.72 kg C ha−1y−1 were associated with the subgroup "degleyed paddy soils". The subgroup "hydromorphic paddy soils" accounted for about 52.82% of the total area of paddy soils, the largest of areas of all the soil subgroups, with the CH4 flux rate of 106.47 kg C ha−1y−1. On a sub-regional basis, the annual average CH4 flux in the Tai-Lake plain soil region and alluvial plain soil region was higher than that in low mountainous and hilly soil region and polder soil region. The model simulation was conducted with two databases using polygon or county as the basic unit. The county-based database contained soil information coarser than the polygon system built based on the 1:50 000 soil database. The modeled results with the two databases found similar spatial patterns CH4 emissions in Tai-Lake region. However, discrepancies exist between the results from the two methods, the relative deviation is

  13. Methylmercury Bioaccumulation in Rice and Wetland Biota: employing integrated indices of processes that drive methylmercury risk

    Science.gov (United States)

    Eagles-Smith, C.; Ackerman, J.; Windham-Myers, L.; Fleck, J.

    2013-12-01

    Wetlands often are associated with elevated methylmercury (MeHg) production and food web bioaccumulation, making them potentially important sources of Hg to surrounding waters and to wetland-dependent fish and wildlife. However, the cycling of MeHg through wetlands can vary markedly with wetland type. Agricultural wetlands such as rice fields can exhibit particularly pronounced MeHg concentrations and bioaccumulation because their biogeochemical, hydrological, and ecological characteristics facilitate the conversion of inorganic mercury (Hg) to MeHg. Rice fields are characterized by a series of seasonal extreme wetting and drying cycles, sulfate-containing fertilizers, and high levels of labile organic carbon, all of which are key processes in the Hg cycle. Rice fields comprise approximately 20% of freshwater habitats and 11% of cultivated land area globally, providing critical wildlife habitat while offering substantial economic, human health, and ecosystem benefits. Thus, there is strong impetus to better understand the drivers of Hg cycling in rice fields and to develop useful management approaches for minimizing Hg risk associated with rice agriculture without compromising rice production. We examined the role of rice wetlands on MeHg bioaccumulation through foodwebs by employing biosentinel caged fish as integrators of MeHg cycling processes. With experimental field studies in California's Central Valley, we placed biosentinel fishes into nine rice wetlands that were subjected to three different harvest strategies, and into nine managed wetlands that encompassed three different hydrological regimes. We simultaneously measured a suite of biogeochemical processes in surface water, sediment, and pore water in order to link the response in fish Hg bioaccumulation with within-field processes that regulate MeHg cycling. Our preliminary results indicate that fish Hg concentrations were 1.6 times higher in rice wetlands than in managed wetlands. Additionally, fish Hg

  14. Rice Yield and the Fate of Fertilizer Nitrogen as Affected by Addition of Earthworm Casts Collected from Oilseed Rape Fields: A Pot Experiment.

    Science.gov (United States)

    Huang, Min; Zhou, Xuefeng; Xie, Xiaobing; Zhao, Chunrong; Chen, Jiana; Cao, Fangbo; Zou, Yingbin

    2016-01-01

    The mechanism associated with improvement of soil nutritional status by oilseed rape crop, leading to better performance of rice crop, in rice-oilseed rape cropping systems is little known. The present study was aimed to test the hypothesis that earthworm casts produced during oilseed rape-growing season have positive effects on grain yield and fertilizer nitrogen (N) utilization in the subsequent flooded rice crop. A 15N-tracing pot experiment was conducted to determine the effects of earthworm casts collected from oilseed rape fields on yield attributes in rice and the fate of fertilizer N. Soil treated with earthworm casts (soil: earthworm casts = 4: 1, w/w) (EC1) produced 39% higher grain yield than soil only (EC0). EC1 had 18% more panicle number and 10% higher spikelet filling percentage than EC0. Aboveground biomass and harvest index were higher in EC1 than in EC0 by 20% and 15%, respectively. SPAD values in flag leaves were 10% and 22% higher under EC1 than EC0 at 15 and 20 days after heading, respectively. EC1 had 19% higher total N uptake and 18% higher physiological N-use efficiency than EC0. These positive effects of earthworm casts on yield attributes offset negative effects of decreasing N rate from 0.74 g pot-1 (equivalent to the recommended field rate of 150 kg ha-1) to 0.44 g pot-1 (equivalent to 60% of the recommended rate). Fertilizer N retention rate was 7% higher while fertilizer N loss rate was 6% lower in EC1 than in EC0. Our study suggests that earthworm casts produced during oilseed rape-growing season are expected to have the following benefits on the subsequent flooded rice system: (1) improving growth and physiological processes in rice plants and consequently increasing rice grain yield, and (2) increasing fertilizer N retention rate and hence decreasing fertilizer N loss rate and reducing environmental risk.

  15. Nitrogen Fertilizer Optimization and Cultivar Selection for Rice Grown near Mountainous Slopes in Orissa, India-A Field Experiment and Simulation Model Study

    Institute of Scientific and Technical Information of China (English)

    D. K. Swain; S. Herath; A. Pathirana; R. N. Dash

    2005-01-01

    Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia,is suffering from lack of suitable cultivar and N fertilizer management, when grown near mountainous slopes under rain-fed agro-ecosystem.An investigation through a field experiment and simulation study was conducted at United Nations University, Tokyo to select suitable rice cultivars and N fertilizer level for the rice grown near mountainous slopes in Orissa, India. The field experiment was conducted during wet season (June to November) of 2001 at Kasiadihi village of Dhenkanal district, Orissa,India with eight popular rice cultivars of medium (120~130 d) and long duration (135~150 d) group and Ranjit of long duration group followed by 4,730group, across N levels. CERES-Rice model was used to simulated grain yield of these two selected cultivars using historical weather data of the past 18years (1983~2000). Long duration cultivar Ranjit registered higher yield with lower stability as compared medium duration cultivar Mahamaya over the past 18 years. An optimum N fertilizer level of 80rain-fed ecosystem near mountainous slopes in Orissa,India to attain optimum yield potential of cultivar.

  16. Preliminary Study of Phylogenetic Relationship of Rice Field Chironomidae (Diptera Inferred From DNA Sequences of Mitochondrial Cytochrome Oxidase Subunit I

    Directory of Open Access Journals (Sweden)

    Salman A. Al-Shami

    2009-01-01

    Full Text Available Problem statement: Chironomidae have been recorded in rice fields throughout the world including in many countries such as India, Australia and the USA. Although some studies provide the key to genera level and note the difficulty of identifying the larvae to species level. Chironomid researches have been hindered because of difficulties in specimen preparation, identification, morphology and literature. Systematics, phylogenetics and taxonomic studies of insects developed quickly with emergence of molecular techniques. These techniques provide an effective tool toward more accurate identification of ambiguous chironomid species. Approach: Samples of chironomids larvae were collected from rice plots at Bukit Merah Agricultural Experimental Station (BMAES, Penang, Malaysia. A 710 bp fragment of mitochondrial gene Cytochrome Oxidase subunit I (COI was amplified and sequenced. Results: Five species of Chironomidae; three species of subfamily Chironominae, Chironomus kiiensis, Polypedilum trigonus, Tanytarsus formosanus, two species of subfamily Tanypodinae, Clinotanypus sp and Tanypus punctipennis were morphologically identified. The phylogenetic relationship among these species was been investigated. High sequence divergence was observed between two individuals of the presumed C. kiiensis and it is suggested that more than one species may be present. However the intraspecific sequence divergence was lower between the other species of Tanypodinae subfamily. Interestingly, Tanytarsus formosanus showed close phylogenetic relationship to Tanypodinae species and this presumably reflect co-evolutionary traits of different subfamilies. Conclusion: The sequence of the mtDNA cytochrome oxidase subunit I gene has proven useful to investigate the phylogenetic relationship among the ambiguous species of chironomids.

  17. Characterization of Nivalenol-Producing Fusarium culmorum Isolates Obtained from the Air at a Rice Paddy Field in Korea

    Directory of Open Access Journals (Sweden)

    Da-Woon Kim

    2016-06-01

    Full Text Available Together with the Fusarium graminearum species complex, F. culmorum is a major member of the causal agents of Fusarium head blight on cereals such as wheat, barley and corn. It causes significant yield and quality losses and results in the contamination of grain with mycotoxins that are harmful to humans and animals. In Korea, F. culmorum is listed as a quarantine fungal species since it has yet to be found in the country. In this paper, we report that two isolates (J1 and J2 of F. culmorum were collected from the air at a rice paddy field in Korea. Species identification was confirmed by phylogenetic analysis using multi-locus sequence data derived from five genes encoding translation elongation factor, histone H3, phosphate permease, a reductase, and an ammonia ligase and by morphological comparison with reference strains. Both diagnostic PCR and chemical analysis confirmed that these F. culmorum isolates had the capacity to produce nivalenol, the trichothecene mycotoxin, in rice substrate. In addition, both isolates were pathogenic on wheat heads and corn stalks. This is the first report on the occurrence of F. culmorum in Korea.

  18. Biodiversity Conservation in Rice Paddies in China: Toward Ecological Sustainability

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    Yufeng Luo

    2014-09-01

    Full Text Available Rice paddies are artificial wetlands that supply people with food and provide wildlife with habitats, breeding areas, shelters, feeding grounds and other services, and rice paddies play an important part in agricultural ecological systems. However, modern agricultural practices with large-scale intensive farming have significantly accelerated the homogenization of the paddy field ecosystem. Modern agriculture mostly relies on chemically-driven modern varieties and irrigation to ensure high production, resulting in the deterioration and imbalance of the ecosystem. Consequently, outbreaks of diseases, insects and weeds have become more frequent in paddy fields. This paper describes the current situation of rice paddy biodiversity in China and analyzes the community characteristics of arthropods and weedy plants. Meanwhile, we discuss how biodiversity was affected by modern agriculture changes, which have brought about a mounting crisis threatening to animals and plants once common in rice paddies. Measures should be focused to firstly preventing further deterioration and, then, also, promoting restoration processes. Ecological sustainability can be achieved by restoring paddy field biodiversity through protecting the ecological environment surrounding the paddy fields, improving paddy cropping patterns, growing rice with less agricultural chemicals and chemical fertilizers, constructing paddy systems with animals and plants and promoting ecological education and public awareness.

  19. Simulation on the Use of LOSAT Data for Rice Field Mapping

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    Bambang H. Trisasongko

    2011-05-01

    Full Text Available Since the launch of LAPAN-TUBSAT satellite in 2007, Indonesia has been developing mission on earth observation missions for various applications. The next generation mission, called LAPAN-ORARI Satellite (LOSAT, is currently under development and expected to be launched in 2011. In order to facilitate the applications, a thorough assessment of the sensor should be made. This paper presents an examination of simulated LOSAT data for rice monitoring and mapping purposes coupled with QUEST statistical tree. We found that three-band simulated LOSAT data were suitable for the task with reasonably high accuracy.

  20. Hyperspectral measurements for estimating biophysical parameters and CO2 exchanges in a rice field

    Science.gov (United States)

    Rossini, M.; Migliavacca, M.; Meroni, M.; Manca, G.; Cogliati, S.; Busetto, L.; Picchi, V.; Galvagno, M.; Colombo, R.; Seufert, G.

    2009-04-01

    The objective of this work was to monitor the main biophysical and structural parameters as well as the CO2 exchanges between atmosphere and a terrestrial ecosystem from remote and high spectral resolution spectroradiometric measurements. Estimation of photosynthetic rate or gross primary productivity from remotely sensed data is based on the light use efficiency model (LUE), which states that carbon exchange is a function of the photosynthetically active radiation absorbed by vegetation (APAR) and the radiation use efficiency (ɛ) which represents the conversion efficiency of energy to fixed carbon. Hyperspectral data were used in this study in order to derived both the APAR of green vegetation and the ɛ term. The experimental site was a rice paddy field in North Italy equipped with an Eddy Covariance (EC) flux measurement tower (Castellaro IES-JRC site). Intensive field campaigns were conducted during summer 2007 and 2008. In each sampling day, canopy optical properties, canopy structure, biophysical and ecophysiological parameters were measured. EC fluxes were calculated with a time step of 30 minutes according to EUROFLUX methodology. Measured half-hourly net ecosystem exchange (NEE) was partitioned to derive half hourly gross ecosystem production (GEP). Canopy reflectance spectra were collected under clear sky conditions using two portable spectrometers (HR4000, OceanOptics, USA) characterised by different spectral resolutions. A spectrometer characterised by a Full Width at Half Maximum (FWHM) of 0.13 nm was used to estimate steady-state fluorescence (F) and a second one with a FWHM of 2.8 nm was used for the computation of traditional vegetation indices (e.g. NVDI, Normalized Difference Vegetation Index and SAVI, Soil Adjusted Vegetation Index) and PRI (Photochemical Reflectance Index, Gamon et al. 1992). F was estimated by exploiting a variation of the Fraunhofer Line Depth (FLD) principle (Plascyk 1975): the spectral fitting method described in Meroni

  1. Comparison of greenhouse gas emissions from rice paddy fields under different nitrogen fertilization loads in Chongming Island, Eastern China.

    Science.gov (United States)

    Zhang, Xianxian; Yin, Shan; Li, Yinsheng; Zhuang, Honglei; Li, Changsheng; Liu, Chunjiang

    2014-02-15

    Rice is one of the major crops of southern China and Southeast Asia. Rice paddies are one of the largest agricultural greenhouse gas (GHG) sources in this region because of the application of large quantities of nitrogen (N) fertilizers to the plants. In particular, the production of methane (CH4) is a concern. Investigating a reasonable amount of fertilizers to apply to plants is essential to maintaining high yields while reducing GHG emissions. In this study, three levels of fertilizer application [high (300 kg N/ha), moderate (210 kg N/ha), and low (150 kg N/ha)] were designed to examine the effects of variation in N fertilizer application rate on carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions from the paddy fields in Chongming Island, Shanghai, China. The high level (300 kg N/ha) represented the typical practice adopted by the local farmers in the area. Maximum amounts of CH4 and N2O fluxes were observed upon high-level fertilizer application in the plots. Cumulative N2O emissions of 23.09, 40.10, and 71.08 mg N2O/m(2) were observed over the growing season in 2011 under the low-, moderate-, and high-level applications plots, respectively. The field data also indicated that soil temperatures at 5 and 10 cm soil depths significantly affected soil respiration; the relationship between Rs and soil temperature in this study could be described by an exponential model. Our study showed that reducing the high rate of fertilizer application is a feasible way of attenuating the global-warming potential while maintaining the optimum yield for the studied paddy fields.

  2. Population Dynamics and Survival of Rhizoctonia solani AG-1 in Field Soil Under Rice-Wheat Rotation

    Institute of Scientific and Technical Information of China (English)

    LI Shi-dong

    2004-01-01

    A field under rice-wheat rotation was selected near Chengdu, China, to study the population of Rhizoctonia solani anastomosis group 1 (AG-l), pathogen causing rice sheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered from the field were divided into three types, i.e., sclerotia, free mycelium retained in the soil passed through a 0.355mm sieve, and colonized plant debris which was subdivided into small colonized debris retained between 2.00 and 0.355mm sieves and large colonized debris retained on 2.00mm sieve after wet screening. Quantitative estimation of the three types of inocula in one year indicated that small colonized debris was the dominant inoculum type for most of the time. The population peaked in March and September at 1 210and 480 colonized debris 100 g-1 air-dry soil respectively, and fell down in December and August to 0 and 177 colonized debris 100 g-1 air-dry soil respectively. Free mycelium was only detectable in March, September and October with 1 209, 7.9 and 14.5 μg fresh wt myceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the second highest level of small debris density in the year. Viable sclerotia and large colonized debris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for large colonized debris 100 g-1 air-dry soil, but were the main structures to survive over winter. It was expected that soil temperature was the main factor determining population dynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasing is predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicated that 60.9% sclerotia could survive after 265 d being buried in natural sandy loam in field conditions in Beijing, while colonized rice straw debris (0.5 - 1.0 cm long) could not yield the fungus on medium plates after 88d of being buried under the same conditions.

  3. Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing.

    Science.gov (United States)

    Pareja, Lucía; Colazzo, Marcos; Pérez-Parada, Andrés; Besil, Natalia; Heinzen, Horacio; Böcking, Bernardo; Cesio, Verónica; Fernández-Alba, Amadeo R

    2012-05-09

    The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS. The distribution of pesticide residues was uneven among the different matrices. Ten different pesticide residues were found in paddy rice, seven in brown rice, and eight in rice bran. The highest concentrations were detected in paddy rice. These results provide information regarding the fate of pesticides in the rice food chain and its safety for consumers.

  4. Methane mitigation in transplanting and direct-wet seeding rice fields treated with fertilizers under condition of alternately flooding and soil aerating

    Directory of Open Access Journals (Sweden)

    Sanwangsi, M.

    2006-05-01

    Full Text Available Rice is main staple crop of the world. Growing rice in flooded water entails methane (CH4 emission. CH4 is one of greenhouse gases contributing to global warming. The experiment aimed to clarify the influence of fertilizer and water management on total methane emission (TME, methane mitigation and rice yields (RY. The experimental design was a split - split plot with 3 replications taking 2 cultivation in main plots, transplanting (TP rice and direct-wet seeding (DWS rice fields; 2 basal fertilizers, 16-16-8, 20 kg/rai and chicken manure pallet (CMP, 105 kg/rai in sub plots; and 3 top dressing fertilizers 1 none, 2 urea (46% N, 15 kg/rai and 3 ammonium sulfate (AS, 21% N, 30 kg/rai in sub-sub plots. It also examined relationship between quantity of paddy-soil water, TME and RY of both cultivations. Methane emission rate (MER occurred during the whole growth period and was characterized by 2 large peaks: one from after transplanting or broadcasting to maximum tillering stage and the other from flowering to yellow ripening stage. Rapid declines of MER were dictated by soil aeration recognized as 3-5 days cracks. In TP rice plot based with CMP, 105 kg/rai, topped with AS, 30 kg/rai, TME decreased to 73.0% and RY increased to 14.7% over that of untreated plots with top dressing fertilizer, while in that topped with urea, 15 kg/rai, TME decreased to 68.9% and RY increased to 16.9%. In all of DWS rice plots which were topped with AS or urea, declines of TME ranged from 27.3 to 56.4% and increase of RY ranged from 31.3 to 47.9% over those without top dressing. In both TP and DWS plots, TMEs were closely correlated with the quantity of paddy-soil water (r = 0.83 and 0.86, respectively and with submergence days (r = 0.94 and 0.89, respectively. Hence, saturated condition in paddy soil is a primary factor for methanogenesis. Moreover, for TP rice, the relationship between TME and RY was weakly positive (r = 0.16, whereas that for DWS rice was obviously

  5. Influence of rice field agrochemicals on the ecological status of a tropical stream.

    Science.gov (United States)

    Rasmussen, Jes Jessen; Reiler, Emilie Marie; Carazo, Elizabeth; Matarrita, Jessie; Muñoz, Alejandro; Cedergreen, Nina

    2016-01-15

    Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area with conventional rice production and a downstream protected nature reserve; Mata Redonda. Three sites were sampled: 1) an upstream control, 2) in the rice production area and 3) a downstream site in Mata Redonda. We sampled benthic macroinvertebrates and pesticides in water and sediments along with supporting physical and chemical data. Pesticide concentrations in water exceeded current safety thresholds at sites 2 and 3, especially during the rainy season, and sediment associated pesticide concentrations exceeded current safety thresholds in three of six samples. Importantly, the highest predicted pesticide toxicity in sediments was observed at site 3 in the Mata Redonda confirming that the nature reserve received critical levels of pesticide pollution from upstream sections. The currently used macroinvertebrate index in Costa Rica (BMWP-CR) and an adjusted version of the SPecies At Risk index (SPEAR) were not significantly correlated to any measure of anthropogenic stress, but the Average Score Per Taxon (ASPT) index was significantly correlated with the predicted pesticide toxicity (sumTUD.magna), oxygen concentrations and substrate composition. Our results suggest that pesticide pollution was likely involved in the impairment of the ecological status of the sampling sites, including site 3 in Mata Redonda. Based on our results, we give guidance to biomonitoring in Costa Rica and call for increased focus on pesticide transport from agricultural regions to protected areas.

  6. In-vitro screening and field validation of rice (Oryza sativa L. genotypes for drought tolerance

    Directory of Open Access Journals (Sweden)

    S. Utharasu1* and C. R. Anandakumar1

    2014-03-01

    Full Text Available In vitro screening using polyethylene glycol (PEG was performed with matured seed-derived callus from six elite rice varieties and eight advanced cultures to understand the response to drought stress. Murashige and Skoog medium supplemented with 2 mg l-1 of 1-napthaleneacetic acid and 5, 10, 15 and 20 g l-1 of PEG 6000 were used to induce drought stress in callus. Significant differences were observed among the genotypes, treatments and their interactions for callus morphology and fresh weight. The genotypes PMK3, RMD(R1, ARB6 , ARB7 and ARB8 were identified as the most tolerant to drought stress using principal component analysis (PCA. A total of 48 crosses made from these genotypes showed significant yield increase over their respective parents. The hybrids RMD(R1/ARB7, PMK3/ARB7 and PMK3/ARB8 were identified as drought tolerant using PCA analysis. From the study it is proved that in vitro screening method can be used to identify drought tolerant rice genotypes.

  7. N2O Emission from Paddy Field under Different Rice Planting Modes

    Institute of Scientific and Technical Information of China (English)

    WANG Yuying; ZHU Bo; WANG Yanqiang; GAO Meirong; MA Xiumei

    2006-01-01

    Measurements of N2O emissions from conventional rice cultivation (CRC), CRC with straw mulching, system of rice intensification (SRI) and SRI with plastic film mulching were conducted through static chamber/gas-chromatography techniques. The results show that daily fluctuation of N2O emissions in jointing stage are much higher than in others. A type peak of N2O seasonal emission presented between jointing and bearing stages companying with high daily average temperature and low precipitation. Biomass and leaf stomatal conductance were observed. Total quantities of N2O emission were budgeted. The results showed that after jointing stage the average N2O emission flux of SRI with plastic film mulching increased significantly than CRC with straw mulching and SRI, the leaf stomatal conductance of those showed the same trend (p<0.05). Yield and total quantity of N2O emission in CRC with straw mulching enhanced 13.7% and 10.7% compared with those of CRC, respectively. The total quantity of N2O emissions reduced 3.6% in SRI with plastic film mulching compared with CRC, however, the yield increase of that was not significant.

  8. Assessment of Rice Cultivars in China for Field Resistance to Aphelenchoides besseyi

    Institute of Scientific and Technical Information of China (English)

    FENG Hui; WEI Li-hui; LIN Mao-song; ZHOU Yi-jun

    2014-01-01

    The effect of Aphelenchoides besseyi on 27 cultivars of rice (23 japonica and 4 indica) was assessed in the ifeld for two seasons during 2010 and 2011. The vigorous pathogenic nematodes culturing on Botrytis cinerea were used for this experiment. Inoculation was carried out at the tilling stage;the growth parameters and nematode population were recorded at the end of growth of rice plants. The results showed that the cultivars differed in their response to infection. Most of cultivars were lack of the characteristic symptom of white tip, which was seen less frequently than the other two symptoms, namely small grains and erect panicles;moreover, the expression of symptoms was probably hereditary. The infection lowered the values of all the measured biological parameters, namely length of the stem and of the panicle, the number of iflled grains per panicle, and 100-grain weight, in all the cultivars. The ifnal nematode population indicated that the threshold of economic damage had also been exceeded in 10 cultivars, and none of them was immune. Three japonica cultivars proved most vulnerable whereas Tetep, an indica type, showed a level of resistance potentially useful in controlling A. besseyi.

  9. Proposal for Reference Soil Concentrations of Radiocesium Applicable to Accidentally Contaminated Rice and Soybean Fields

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Ho; Lim, Kwang-Muk; Jun, In; Kim, Byung-Ho; Keum, Dong-Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Radionuclides in arable soil can be transferred to food plants via root uptake. If radionuclide concentrations in food plants to be grown in contaminated soil are estimated to be higher than the authorized food standards, their culture needs to be cancelled or ameliorating practices need to be taken. Therefore, it is necessary to establish soil concentration limits or reference soil concentrations of radiocesium standing with the food standards in preparation for potential severe NPP accidents in this and adjacent countries. In the present study, reference soil concentrations of radiocesium for rice and soybean, two of the most important food plants in Korea, were provisionally established using all relevant domestic data of soil-to-plant transfer factor (TF). The reference soil concentrations of radiocesium for rice and soybean were calculated using available domestic TF data, and were proposed for provisional use at the time of a severe NPP accident. The present RSCs are based on limited numbers of {sup 137}Cs TF values. More amounts of relevant TF data should be produced to have more reliable RSCs. For other staple-food plants such as Chinese cabbage and radish, RSCs of radiocesium should also be established. However, only a couple of relevant domestic TF values are available for these vegetables.

  10. [N2O and CH4 emission from Japan rice fields under different long-term fertilization patterns and its environmental impact].

    Science.gov (United States)

    Luo, Liang-guo; Kondo, Motohiko; Itoh, Sumio

    2010-12-01

    This study intended to investigate the greenhouse gases emission from Japan single cropping paddy fields after 75-year continuous application of ammonium sulfate, composted rice straw with soybean cake, and fresh clover, as well as the environmental impact of the emission. During this long period, field management remained constant in terms of rice cultivation density, irrigation, and equivalent net N fertilization. No significant differences were observed in N2O emission among the fertilization treatments, but the CH4 emission differed significantly between organic amendment and ammonium sulfate application, indicating that long-term organic fertilization didn' t increase N2O emission but promoted CH4 emission. The cumulative global warming potential (GWP) of the CH4 and NO2O from the paddy ecosystem was the greatest (310.7 g CO2e x m(-2)) under fresh clover application, followed by composted rice straw plus soybean cake addition (151 g CO2e x m(-2)), and the least (60.6 g CO2e x m(-2)) under ammonium sulfate application. This study showed that for paddy system, it was CH4 instead of N2O the major factor affecting global warming, and thereby, to control and reduce the CH4 emission from paddy system would be the core in mitigating greenhouse gases emission from paddy field. Long-term consecutive application of composted rice straw plus soybean cake could increase soil organic matter, improve soil fertility, promote rice high-yielding, and as well, mitigate CH4 emission, being the recommendable paddy rice production mode in practice.

  11. The Properties of Humic Acids Extracted from Four Sources of Organic Matters and Their Ability to Bind Fe2+ at New Established Rice Field

    Directory of Open Access Journals (Sweden)

    Herviyanti

    2010-09-01

    Full Text Available In order to identify the properties of humic acid extracted from four kinds of organic matters (a peat soil, a stable manure, a compost of rice straw and a municipal waste and their potentiality to bind Fe2+ at new established rice field, a series of experiment was done in Soil Laboratory Faculty of Agriculture, Andalas University Padang. First step was characterization of functional groups and other chemical properties of humic acids, and their reaction with Fe2+. The second step was to examine the ability of humic acids to bind Fe2+ solution at new established rice field by conducting incubation experiments. The experiment used a completely randomized design with three replications. The 450 ppm Fe solution was treated with 0, 50, 100, 150, 200, 250, 300, 350, 400, and 450 ppm humic acids and incubated for 24 hours. While top soil samples taken from Sitiung, West Sumatera were treated with 0,100, 200, 300, and 400 ppm humic acids, flooded with deionized water, and incubated for 6 weeks. The result showed that the functional group and other chemical characteristic of humic acid from rice straw compost and peat soil were better than those of manure and municipal waste compost. Functional group of both humic acids was dominated by COO-. High reactivity of the humic acid had been found when humic acids were added to Fe solution with ratio 1 : 1. Use of humic acid extracted from peat soil with the levels from 0 to 100, 200, 300, and 400 ppm decreased the Fe2+ concentration from 1.361 ppm to 910, 860, 831, and 776 ppm, respectively at new established rice field. While the use of humic acid extracted from rice straw compost with the same levels as above decreased the Fe2+ concentration from 1361 to 770, 701, 612, and 600 ppm, respectively, after four weeks of flooding.

  12. [Effects of different fertilization regimes on weed communities in wheat fields under rice-wheat cropping system].

    Science.gov (United States)

    Yuan, Fang; Li, Yong; Li, Fen-hua; Sun, Guo-jun; Han, Min; Zhang, Hai-yan; Ji, Zhong; Wu, Chen-yu

    2016-01-01

    To reveal the effects of different fertilization regimes on weed communities in wheat fields under a rice-wheat rotation system, a survey was conducted before wheat harvest in 2014 after a 4-year long-term recurrent fertilization scheme. Weed species types, density, height and diversity index under different fertilization and straw-returning schemes in wheat fields were studied and complemented with a canonical correspondence analysis on weed community distribution and soil nutrient factors. Twenty weed species were recorded among 36 wheat fields belonging to 19 genera and 11 families. Beckmannia syzigachne, Hemistepta lyrata, Malachium aquaticum and Cnidium monnieri were widely distributed throughout the sampled area. Long-term fertilization appeared to reduce weed species richness and density, particularly for broadleaf weeds, but increased weed height. Diversity and evenness indices of weed communities were lower and dominance indices were higher in fields where chemical fertilizers were applied alone or combined with organic fertilizers, especially, where organic-inorganic compound fertilizer was used, in which it readily caused the outbreak of a dominant species and severe damage. Conversely, diversity and evenness indices of weed communities were higher and dominance indices were lower when the straw was returned to the field combined with chemical or organic fertilizers, in which weed community structures were complex and stable with lower weed density. Under these conditions weeds only caused slight reduction of wheat growth.

  13. Microeukaryotic community and oxygen response in rice field soil revealed using a combined rRNA-gene and rRNA-based approach.

    Science.gov (United States)

    Murase, Jun; Takenouchi, Yuriko; Iwasaki, Kazufumi; Kimura, Makoto

    2014-01-01

    Irrigated rice field soil is subjected to frequent changes in oxygen status due to the water regime by agricultural management. In this study, the community response of microeukaryotes in rice field soil to the oxygen status was explored in a microcosm experiment under defined conditions. Water-saturated soil was incubated under a two-level factorial design of oxygen and organic enrichment with plant residue. The eukaryotic microbial community composition, which was either present or potentially active in the soils, was analyzed using denaturing gradient gel electrophoresis (DGGE) targeting the 18S rRNA gene or reverse-transcribed 18S rRNA. Oxygen availability was a primary factor shaping the microeukaryotic community in both DNA- and RNA-based analyses, revealing a shift within a week of incubation. Plant residue also affected the microeukaryotic community, which was more notable in the active community showing rRNA expression with time. Sequences of amplicons in DGGE bands indicated that protozoa (ciliates, flagellates, and amoebae) were the most prominent microeukaryotes in water-saturated rice field soil both in DNA- and RNA-based analyses. The use of a modified primer for soil protozoa suggested the functional importance of Heterolobosea amoeba in rice field soil, particularly in anoxic soil with organic enrichment.

  14. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    Science.gov (United States)

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2017-06-01

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  15. Characteristics of cylindrical surrounding-gate GaAs x Sb1-x /In y Ga1-y As heterojunction tunneling field-effect transistors

    Science.gov (United States)

    Guan, Yun-He; Li, Zun-Chao; Luo, Dong-Xu; Meng, Qing-Zhi; Zhang, Ye-Fei

    2016-10-01

    A III-V heterojunction tunneling field-effect transistor (TFET) can enhance the on-state current effectively, and GaAs x Sb1-x /In y Ga1-y As heterojunction exhibits better performance with the adjustable band alignment by modulating the alloy composition. In this paper, the performance of the cylindrical surrounding-gate GaAs x Sb1-x /In y Ga1-y As heterojunction TFET with gate-drain underlap is investigated by numerical simulation. We validate that reducing drain doping concentration and increasing gate-drain underlap could be effective ways to reduce the off-state current and subthreshold swing (SS), while increasing source doping concentration and adjusting the composition of GaAs x Sb1-x /In y Ga1-y As can improve the on-state current. In addition, the resonant TFET based on GaAs x Sb1-x /In y Ga1-y As is also studied, and the result shows that the minimum and average of SS reach 11 mV/decade and 20 mV/decade for five decades of drain current, respectively, and is much superior to the conventional TFET. Project supported by the National Natural Science Foundation of China (Grant Nos. 61176038 and 61474093), the Science and Technology Planning Project of Guangdong Province, China (Grant No. 2015A010103002), and the Technology Development Program of Shaanxi Province, China (Grant No. 2016GY-075).

  16. Effect of Vermicompost Alone and Its Combination with Recommended Dose of Fertilizers on Available Nitrogen, Phosphorus, Potassium in Rice Field.

    Science.gov (United States)

    Shwetha, S; Narayana, J

    2014-01-01

    Rice variety KMP101 was treated with both organic and inorganic manure. The field and experimental studies were conducted, before applying organic and inorganic manures.The values obtained for available nitrogen, phosphorous and potassium were 360 kg/ha, 12 kg/ha and 166 kg/ha respectively. After treatment and harvest there was a gradual increase in available nitrogen, phosphorus and potassium ranging between 335-415, 14 -23 and 173- 235 kg/ha respectively among the treatments. Applying 15 t of vermicompost /ha and 10 t of vermicompost /ha and recommended dose of fertilizer showed a greater availability of nitrogen and phosphorus. It is revealed that after addition of organics into the soil year-wise, the soil became more stable. Also, the biological activity increased in the soil and was influenced to maintain the available nitrogen in the soil. Therefore, it is evident that vermicompost significantly increases the availability of available nutrients.

  17. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Wahid, Ahmad Nazrul Abd, E-mail: a-nazrul@nuclearmalaysia.gov.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahim, Sahibin Abd, E-mail: haiyan@ukm.edu.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Rahim, Khairuddin Abdul; Harun, Abdul Rahim [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2015-09-25

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

  18. Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using 15N isotopic tracer technique

    Science.gov (United States)

    Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

    2015-09-01

    This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct 15N isotope tracer method was used in this study, whereby the 15N isotope was utilized as a tracer for nitrogen nutrient uptake. 15N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. 15N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

  19. Preliminary Information on the Vertebrate Fauna (Animalia: Vertebrata of the NATURA2000 Site “Rice Fields Tsalapitsa” (Bulgaria

    Directory of Open Access Journals (Sweden)

    Ivayla L. Klimentova

    2011-12-01

    Full Text Available The study was carried out by tree visits in different areas of the Natura 2000 site “Rice Fields Tsalapitsa” BG 0002086 (West of Plovdiv city, near village of Tsalapitsa. Our preliminary research showed that in the area vertebrates with high conservation status occurred included in the Bulgarian Bidiversity Act, Appendix II and III, Appendix II of the Bern convention, Natura 2000 species list, the Bonn convention, Appendix II, the Convention of the International Trade of Endangered Species, and the list of the International Union for Conservation of the Nature. This information will help in future preparation of the management plan of the Natura 2000 site and showed the need of studies focused on such areas which will help undertaking adequate measures for their proper way of conservation.

  20. Identification of nif genes in N2-fixing bacterial strains isolated from rice fields along the Yangtze River Plain.

    Science.gov (United States)

    Xie, Guang Hui; Cui, Zongjun; Yu, Jun; Yan, Jing; Hai, Weili; Steinberger, Yosef

    2006-01-01

    The aim of this research was to identify nifH and nifHDKYE ' genes in twenty strains of N2-fixing heterotrophic bacteria isolated from rice fields in the Yangtze River Plain. Southern hybridization of the total DNA from each strain was performed with the Klebsiella pneumoniae nifHDKYE ' gene probe (6.2 kb Eco RI fragment from pSA30) and the Azospirillum brasilense nifH gene probe (0.6 kb Eco RI-Hin dIII fragment from pHU8). We found that Eco RI fragments of total DNA from Aeromonas hydrophila HY2, Bacillus azotoformans FD, Bacillus licheniformis NCH1, NCH5, WH4, Bacillus brevis NC2, Bacillus pumilus NC12, Bacillus cereus NCH2, Citrobacter freundii HY5, HY9, Derxia gummosa HZ5, Pseudomonas mendocina HZ1 and Pseudomonas pseudoalcaligenes WH3 were positively hybridized with both of the probes. Agrobacterium radiobacter HY17, Corynebacterium sp. HY12, YZ and Pseudomonas sp. HY11 had Eco RI fragments hybridized with the K. pneumoniae nifHDKYE ' gene probe. An Eco RI fragment of total DNA from Bacillus megaterium YY4 was positively hybridized to the A. brasilense nifH gene probe. No hybridization sign was found in the total DNA fragments from Alcaligenes cupidus YY6 and Corynebacterium sp. NC11 hybridized with either of the gene probes. The data provide the number and size of EcoRI fragments of the total DNA hybridized with the nif gene probes for these strains of rarely studied species, suggesting additional evidence for N2 fixing and nif gene diversity of N2-fixing bacteria in rice fields along the Yangtze River Plain.

  1. A three-season field study on the in-situ remediation of Cd-contaminated paddy soil using lime, two industrial by-products, and a low-Cd-accumulation rice cultivar.

    Science.gov (United States)

    Yan-Bing, He; Dao-You, Huang; Qi-Hong, Zhu; Shuai, Wang; Shou-Long, Liu; Hai-Bo, He; Han-Hua, Zhu; Chao, Xu

    2017-02-01

    To mitigate the serious problem of Cd-contaminated paddy soil, we investigated the remediation potential of combining in-situ immobilization with a low-Cd-accumulation rice cultivar. A three-season field experiment compared the soil pH, available Cd and absorption of Cd by three rice cultivars with different Cd accumulation abilities grown in Cd-contaminated paddy soil amended with lime (L), slag (S), and bagasse (B) alone or in combination. The three amendments applied alone and in combination significantly increased soil pH, reduced available Cd and absorption of Cd by rice with no effect on grain yield. Among these, the LS and LSB treatments reduced the brown rice Cd content by 38.3-69.1% and 58.3-70.9%, respectively, during the three seasons. Combined with planting of a low-Cd-accumulation rice cultivar (Xiang Zaoxian 32) resulted in a Cd content in brown rice that met the contaminant limit (≤0.2mgkg(-1)). However, the grain yield of the low-Cd-accumulation rice cultivar was approximately 30% lower than the other two rice cultivars. Applying LS or LSB as amendments combined with planting a low-Cd-accumulation rice cultivar is recommended for the remediation of Cd-contaminated paddy soil. The selection and breeding of low-Cd-accumulation rice cultivars with high grain production requires further research.

  2. [Observation for CH4 and N2O emissions under different rates of nitrogen and phosphate fertilization in double rice fields].

    Science.gov (United States)

    Shi, Sheng-Wei; Li, Yu-E; Wan, Yun-Fan; Qin, Xiao-Bo; Gao, Qing-Zhu

    2011-07-01

    Two non-CO2 greenhouse gas emissions (methane and nitrous oxide) and related environmental factors were measured within rice growing season under five treatments including non-fertilization (CK), balanced fertilization (BF), decreased nitrogen and phosphate 1 (DNP1), decreased nitrogen and phosphate 2 (DNP2) and increased nitrogen and phosphate 1 (INP) in double rice fields of red clay soil in 2009, using the method of static chamber-gas chromatograph techniques. The results showed that the average CH4 emission fluxes for treatments of BF, DNP1, DNP2 and INP were 4.57, 5.42, 4.70 and 4.65 mg x (m2 x h)(-1) during early rice growing period, which increased by 39%, 49%, 41% and 40% compared with non-fertilizer treatment, respectively. The average CH4 emission fluxes in late rice growing season was higher than preseason's. Compared to CK, CH4 emission increased by 11%, 1%, 26% and - 4% in treatments of BF, DNP1, DNP2 and INP within late rice growing season. Applying nitrogen and phosphate enhanced CH4 emission in turning green period for early and late rice. No significant difference was observed between the CH4 emissions of five treatments during early and late rice growing season (p > 0.05). N2O emission was very little during mid-seasonal drainage period. In contrast, N2O emission peaks were observed in period of alternation of wetting and drying after mid-seasonal drainage in this experiment. N2O emission was, on average, equivalent to 0.18% of the nitrogen applied in double rice growing season. Statistically, air temperature, soil Eh and soil moisture (water-filled pore space, WFPS) at 0-10cm depth significantly affected the fluctuations of the seasonal CH4 flux, but no significant correlationship has been found between N2O flux and related environmental factors. CH4 was the dominated greenhouse gas in double rice fields which contributed approximately 90% for the integrated global warming potential of CH4 and N2O released during the rice growing season

  3. Suppression of Rice Stem Borer, Chilo suppressalis by Mass Trapping Using Synthetic Sex Pheromone in Paddy Field

    Institute of Scientific and Technical Information of China (English)

    SU Jian-wei; XUAN Wei-jian; SHENG Cheng-fa; GE Feng

    2003-01-01

    Suppressing effects of mass trapping using synthetic sex pheromone with main active ingredients of Z-11-hexadecenal, Z-13-octadecenal and Z-9-hexadecenal on the rice stem borer, Chilo suppressalis were investigated during the flight periods of the overwintering and 1st generation in the paddy area of 60 ha in 1999. Population density of C. suppressalis in the pheromone-treated fields was lower than that in control. The egg masses decreased by 74.39% and population size of adult males of the 1st generation decreased by 61.64% in the treated fields as compared to control. Meanwhile, the damage by C.suppressalis larvae was significantly lower in the treated fields than control (t-test, P=0.05). Percentages of brownish leaf sheath, dead heart, and white head in the treated fields were decreased by 70.90%, 57.01% and 44.30%, respectively in contrast to control. The present study demonstrated that mass trapping to C. suppressalis using synthetic sex pheromone shows great potential as an alternative measure in an environment-friendly pest management and at the same challenging the insecticide use that has some environment impacts.

  4. Effect of limestone, lignite and biochar applied alone and combined on cadmium uptake in wheat and rice under rotation in an effluent irrigated field.

    Science.gov (United States)

    Rehman, Muhammad Zia Ur; Khalid, Hinnan; Akmal, Fatima; Ali, Shafaqat; Rizwan, Muhammad; Qayyum, Muhammad Farooq; Iqbal, Muhammad; Khalid, Muhammad Usman; Azhar, Muhammad

    2017-08-01

    Cadmium (Cd) uptake and accumulation in crop plants, especially in wheat (Triticum aestivum) and rice (Oryza sativa) is one of the main concerns for food security worldwide. A field experiment was done to investigate the effects of limestone, lignite, and biochar on growth, physiology and Cd uptake in wheat and rice under rotation irrigated with raw effluents. Initially, each treatment was applied alone at 0.1% and combined at 0.05% each and wheat was grown in the field and then, after wheat harvesting, rice was grown in the same field without additional application of amendments. Results showed that the amendments applied increased the grain and straw yields as well as gas exchange attributes compared to the control. In both crops, highest Cd concentrations in straw and grains and total uptake were observed in control treatments while lowest Cd concentrations was observed in limestone + biochar treatment. No Cd concentrations were detected in wheat grains with the application of amendments except limestone (0.1%). The lowest Cd harvest index was observed in limestone + biochar and lignite + biochar treatments for wheat and rice respectively. Application of amendments decreased the AB-DTPA extractable Cd in the soil while increasing the Cd immobilization index after each crop harvest. The benefit-cost ratio and Cd contents in plants revealed that limestone + biochar treatment might be an effective amendment for increasing plant growth with lower Cd concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Potencial de emissão de metano em lavouras de arroz irrigado Methane emission potential in flooded rice fields

    Directory of Open Access Journals (Sweden)

    Dirceu Agostinetto

    2002-12-01

    responsible for such phenomenon. The main gases that cause the greenhouse effect are carbon dioxide (CO2, methane (CH4, nitrous oxide (N2O, and chlorofluorocarbons (CFCs. Methane stands out amongst them by the amount produced and by its activity in the absorbing atmospheric heat. The main methane producing sources are soils naturally flooded or cultivated under flooding conditions, which represent approximately 40% of the total methane emitted; from this amount, 37% is emitted by rice cultivated under flooding conditions. In this context, the present review has as main purposes to describe processes responsible for methane production and emission, as well as to discuss management practices and rice plant characteristics which affect emission of this gas. From the total methane originated in rice fields during its growth cycle, between 60 to 90% comes from rice plants. Although methane is not the main gas responsible for the greenhouse effect and rice crop does not represent the main methane source, the reduction in the emission could be accomplished through changes in rice cultural practices. Amongst alternatives that can be worked out are management of irrigation water and fertilizer applied, and cropping of rice cultivars that present lower number of aerenchyma and lower biomass production, whereas maintaining rice grain yields potential.

  6. Field population abundance of leafhopper (Homoptera: Cicadelidae) and planthopper (Homoptera: Delphacidae) as affected by rice growth stages

    Science.gov (United States)

    Hafizal, M. M.; Idris, A. B.

    2013-11-01

    The leafhopper (Homoptera: Delphacidae) and planthopper (Homoptera: Cicadelidae) are considered as important rice pest in Asia including Malaysia. As phloem-feeders, they can cause loss to rice growth development and their population abundance is thought to be influenced by rice growth stages. This study was conducted to examine the population of Delphacidae and Cicadelidae between different rice growth stages, i.e. before and after rice planting periods. Monthly sampling was conducted in three sites in Kuala Selangor at before planting, vegetative, reproductive, maturing stages and post-harvest period using sweeping net and light traps. Population abundance of Delphacidae and Cicadelidae were found to be significantly different and positively correlated with different rice growth stages (ppopulation of these two homopterans indicated adaptive feeding strategy to reduce food competition.

  7. Changes in Grain Yield of Rice and Emission of Greenhouse Gases from Paddy Fields after Application of Organic Fertilizers Made from Maize Straw

    Institute of Scientific and Technical Information of China (English)

    MA Yi-hu; GU Dao-jian; LIU Li-jun; WANG Zhi-qin; ZHANG Hao; YANG Jian-chang

    2014-01-01

    A field experiment was conducted at the farm of Yangzhou University, Yangzhou, China, to study the effects of organic fertilizers made from maize straw on rice grain yield and the emission of greenhouse gases. Four organic fertilizer treatments were as follows:maize straw (MS), compost made from maize straw (MC), methane-generating maize residue (MR), and black carbon made from maize straw (BC). These organic fertilizers were applied separately to paddy fields before rice transplanting. No organic fertilizer was applied to the control (CK). The effects of each organic fertilizer on rice grain yield and emission of greenhouse gases were investigated under two conditions, namely, no nitrogen (N) application (0N) and site-specific N management (SSNM). Rice grain yields were significantly higher in the MS, MC and MR treatments than those in CK under either 0N or SSNM. The MS treatment resulted in the highest grain yield and agronomic N use efficiency. However, no significant difference was observed for these parameters between the BC treatment and CK. The changes in the emissions of methane (CH4), carbon dioxide (CO2), or nitrous oxide (N2O) from the fields were similar among all organic fertilizer treatments during the entire rice growing season. The application of each organic fertilizer significantly increased the emission of each greenhouse gas (except N2O emission in the BC treatment) and global warming potential (GWP). Emissions of all the greenhouse gases and GWP increased under the same organic fertilizer treatment in the presence of N fertilizer, whereas GWP per unit grain yield decreased. The results indicate that the application of organic fertilizer (MS, MC or MR) could increase grain yield, but also could enhance the emissions of greenhouse gases from paddy fields. High grain yield and environmental efficiency could be achieved by applying SSNM with MR.

  8. Dynamic variability of the heading-flowering stages of single rice in China based on field observations and NDVI estimations.

    Science.gov (United States)

    Zhang, Zhao; Song, Xiao; Chen, Yi; Wang, Pin; Wei, Xing; Tao, Fulu

    2015-05-01

    Although many studies have indicated the consistent impact of warming on the natural ecosystem (e.g., an early flowering and prolonged growing period), our knowledge of the impacts on agricultural systems is still poorly understood. In this study, spatiotemporal variability of the heading-flowering stages of single rice was detected and compared at three different scales using field-based methods (FBMs) and satellite-based methods (SBMs). The heading-flowering stages from 2000 to 2009 with a spatial resolution of 1 km were extracted from the SPOT/VGT NDVI time series data using the Savizky-Golay filtering method in the areas in China dominated by single rice of Northeast China (NE), the middle-lower Yangtze River Valley (YZ), the Sichuan Basin (SC), and the Yunnan-Guizhou Plateau (YG). We found that approximately 52.6 and 76.3 % of the estimated heading-flowering stages by a SBM were within ±5 and ±10 days estimation error (a root mean square error (RMSE) of 8.76 days) when compared with those determined by a FBM. Both the FBM data and the SBM data had indicated a similar spatial pattern, with the earliest annual average heading-flowering stages in SC, followed by YG, NE, and YZ, which were inconsistent with the patterns reported in natural ecosystems. Moreover, diverse temporal trends were also detected in the four regions due to different climate conditions and agronomic factors such as cultivar shifts. Nevertheless, there were no significant differences (p > 0.05) between the FBM and the SBM in both the regional average value of the phenological stages and the trends, implying the consistency and rationality of the SBM at three scales.

  9. Spatial Distribution and Coexisting Patterns of Adults and Nymphs of Tibraca limbativentris (Hemiptera: Pentatomidae) in Paddy Rice Fields.

    Science.gov (United States)

    Alves, Tavvs M; Maia, Aline H N; Barrigossi, José A F

    2016-12-01

    The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is a primary insect pest of paddy rice in South America. Knowledge of its spatial distribution can support sampling plans needed for timely decisions about pest control. This study aimed to investigate the spatial distribution of adults and nymphs of T. limbativentris and determine the spatial coexistence of these stages of development. Fifteen paddy rice fields were scouted once each season to estimate insect densities. Scouting was performed on regular grids with sampling points separated by ∼50 m. Moran's I and semivariograms were used to determine spatial distribution patterns. Spatial coexistence of nymphs and adults was explored via spatial point process. Here, adults and nymphs had typically contrasting spatial distribution patterns within the same field; however, the frequency of aggregation was not different between these developmental stages. Adults and nymphs were aggregated in seven fields and randomly distributed in the other eight fields. Uniform distribution of adults or nymphs was not observed. The study-wide semivariogram ranges were ∼40 m for adults and ∼55 m for nymphs. Nymphs and adults spatially coexisted on 67% of the fields. Coexisting patterns were classified using one of the following processes: stage-independent, bidirectional attractive, unidirectional attractive, bidirectional inhibiting, or unidirectional inhibiting. The information presented herein can be important for developing sampling plans for decision-making, implementing tactics for site-specific management, and monitoring areas free of T. limbativentrisResumoO percevejo-do-colmo Tibraca limbativentris Stål (Hemiptera: Pentatomidae) é uma praga primária na cultura do arroz irrigado na América do Sul. O conhecimento de sua distribuição espacial é essencial para desenvolver planos de amostragem e para o controle desta praga. Nosso objetivo foi investigar a distribuição espacial de

  10. Drainage and tillage practices in the winter fallow season mitigate CH4 and N2O emissions from a double-rice field in China

    Science.gov (United States)

    Zhang, Guangbin; Yu, Haiyang; Fan, Xianfang; Yang, Yuting; Ma, Jing; Xu, Hua

    2016-09-01

    Traditional land management (no tillage, no drainage, NTND) during the winter fallow season results in substantial CH4 and N2O emissions from double-rice fields in China. A field experiment was conducted to investigate the effects of drainage and tillage during the winter fallow season on CH4 and N2O emissions and to develop mitigation options. The experiment had four treatments: NTND, NTD (drainage but no tillage), TND (tillage but no drainage), and TD (both drainage and tillage). The study was conducted from 2010 to 2014 in a Chinese double-rice field. During winter, total precipitation and mean daily temperature significantly affected CH4 emission. Compared to NTND, drainage and tillage decreased annual CH4 emissions in early- and late-rice seasons by 54 and 33 kg CH4 ha-1 yr-1, respectively. Drainage and tillage increased N2O emissions in the winter fallow season but reduced it in early- and late-rice seasons, resulting in no annual change in N2O emission. Global warming potentials of CH4 and N2O emissions were decreased by 1.49 and 0.92 t CO2 eq. ha-1 yr-1, respectively, and were reduced more by combining drainage with tillage, providing a mitigation potential of 1.96 t CO2 eq. ha-1 yr-1. A low total C content and high C / N ratio in rice residues showed that tillage in the winter fallow season reduced CH4 and N2O emissions in both early- and late-rice seasons. Drainage and tillage significantly decreased the abundance of methanogens in paddy soil, and this may explain the decrease of CH4 emissions. Greenhouse gas intensity was significantly decreased by drainage and tillage separately, and the reduction was greater by combining drainage with tillage, resulting in a reduction of 0.17 t CO2 eq. t-1. The results indicate that drainage combined with tillage during the winter fallow season is an effective strategy for mitigating greenhouse gas releases from double-rice fields.

  11. Genome wide association mapping of grain arsenic, copper, molybdenum and zinc in rice (Oryza sativa L. grown at four international field sites.

    Directory of Open Access Journals (Sweden)

    Gareth J Norton

    Full Text Available The mineral concentrations in cereals are important for human health, especially for individuals who consume a cereal subsistence diet. A number of elements, such as zinc, are required within the diet, while some elements are toxic to humans, for example arsenic. In this study we carry out genome-wide association (GWA mapping of grain concentrations of arsenic, copper, molybdenum and zinc in brown rice using an established rice diversity panel of ∼ 300 accessions and 36.9 k single nucleotide polymorphisms (SNPs. The study was performed across five environments: one field site in Bangladesh, one in China and two in the US, with one of the US sites repeated over two years. GWA mapping on the whole dataset and on separate subpopulations of rice revealed a large number of loci significantly associated with variation in grain arsenic, copper, molybdenum and zinc. Seventeen of these loci were detected in data obtained from grain cultivated in more than one field location, and six co-localise with previously identified quantitative trait loci. Additionally, a number of candidate genes for the uptake or transport of these elements were located near significantly associated SNPs (within 200 kb, the estimated global linkage disequilibrium previously employed in this rice panel. This analysis highlights a number of genomic regions and candidate genes for further analysis as well as the challenges faced when mapping environmentally-variable traits in a highly genetically structured diversity panel.

  12. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    Science.gov (United States)

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Review on greenhouse gases emission and the reduction technology in rice fields%稻田温室气体排放与减排研究综述

    Institute of Scientific and Technical Information of China (English)

    邵美红; 孙加焱; 阮关海

    2011-01-01

    水稻是我国最重要的粮食作物之一,甲烷和氧化亚氮作为稻田两大温室气体,在全球温室效应中起着很大作用.文章综述了水分管理条件、施肥方式、品种选择差异、农作模式差异及土壤气候条件等因素对稻田甲烷和氧化亚氮排放的主要因素,并从综合温室效应方面提出品种和栽培措施、合理施肥和用药、改进农作制度、发展农村沼气能等技术措施,为发展稻田低碳提供一定的参考.%Rice is one of the most important food crops in our country. Two major greenhouse gases, methane ( CH4 ) and nitrous oxide ( N2O) , play significant roles in global greenhouse effect. This paper reviewed the effects of irrigation, fertilization, rice varieties, cropping patterns, soil-climatic conditions and other factors on emissions of CH4 and N2O from rice fields. Considering the synthetic greenhouse effect, some measures of reducing greenhouse gas emission in rice fields were also put forward such as varieties and cultivation, fertilization and pesticide application, improving farming system, development of biogas energy technologies, etc. This paper might provide some references for developing low carbon technology in rice field.

  14. Genetic diversity of rice sheath blight isolates (Rhizoctonia solani AG-1 IA) from different rice cultivars

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Rhizoctonia solani AG 1 IA, the non specific, soil borne, and plant casual agent of rice sheath blight, occurring world widely in rice fields, has become a major disease to rice. In this study,relationships among R. solani AG 1 IA isolates, collected from different rice cultivars were reported.

  15. Comparison of greenhouse gas emissions from rice paddy fields under different nitrogen fertilization loads in Chongming Island, Eastern China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xianxian [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Yin, Shan, E-mail: yinshan@sjtu.edu.cn [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Li, Yinsheng [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Zhuang, Honglei [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Li, Changsheng [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Morse Hall, College Road, NH 03824-3525 (United States); and others

    2014-02-01

    Rice is one of the major crops of southern China and Southeast Asia. Rice paddies are one of the largest agricultural greenhouse gas (GHG) sources in this region because of the application of large quantities of nitrogen (N) fertilizers to the plants. In particular, the production of methane (CH{sub 4}) is a concern. Investigating a reasonable amount of fertilizers to apply to plants is essential to maintaining high yields while reducing GHG emissions. In this study, three levels of fertilizer application [high (300 kg N/ha), moderate (210 kg N/ha), and low (150 kg N/ha)] were designed to examine the effects of variation in N fertilizer application rate on carbon dioxide (CO{sub 2}), methane (CH{sub 4}), and nitrous oxide (N{sub 2}O) emissions from the paddy fields in Chongming Island, Shanghai, China. The high level (300 kg N/ha) represented the typical practice adopted by the local farmers in the area. Maximum amounts of CH{sub 4} and N{sub 2}O fluxes were observed upon high-level fertilizer application in the plots. Cumulative N{sub 2}O emissions of 23.09, 40.10, and 71.08 mg N{sub 2}O/m{sup 2} were observed over the growing season in 2011 under the low-, moderate-, and high-level applications plots, respectively. The field data also indicated that soil temperatures at 5 and 10 cm soil depths significantly affected soil respiration; the relationship between Rs and soil temperature in this study could be described by an exponential model. Our study showed that reducing the high rate of fertilizer application is a feasible way of attenuating the global-warming potential while maintaining the optimum yield for the studied paddy fields. - Highlights: • In Chongming Island, Shanghai, GHG emissions were measured under different nitrogen fertilizer rates from the paddy. • Low nitrogen fertilizer application reduced CH{sub 4} and N{sub 2}O emissions. • The study showed that 210 kg N/ha was the suitable fertilizer application rate.

  16. How smallholder farmers in Uttarakhand reworked the system of rice intensification: innovations from sociotechnical interactions in fields and villages

    NARCIS (Netherlands)

    Sen, D.

    2015-01-01

    The System of Rice Intensification (SRI) is presented in Asia and other parts of the world as an alternative ‘agro-ecological’ and ‘farm-based’ innovation in rice production. SRI calls for modifications in crop-management practices without relying on external inputs, which ma

  17. Bt rice harbouring cry genes controlled by a constitutive or wound-inducible promoter: protection and transgene expression under Mediterranean field conditions.

    Science.gov (United States)

    Breitler, Jean Christophe; Vassal, Jean Michel; del Mar Catala, Maria; Meynard, Donaldo; Marfà, Victoria; Melé, Enric; Royer, Monique; Murillo, Isabel; San Segundo, Blanca; Guiderdoni, Emmanuel; Messeguer, Joaquima

    2004-09-01

    Seven homozygous transgenic lines of two European commercial cultivars of rice (Ariete (A) and Senia (S)), harbouring the cry1B or cry1Aa Bacillus thuringiensis (Bt) delta-endotoxin genes, were field evaluated for protection from striped stem borer (SSB) (Chilo suppressalis) damage during the 2001 and 2002 summer crop seasons in the Delta de l'Ebre region, Spain. The plant codon-optimized toxin gene was placed under the control of the promoter of either the constitutive ubi1 gene or the wound-inducible mpi gene from maize. Stable, high-level, insecticidal protein accumulation was observed throughout root, leaf and seed tissues of field-grown plants harbouring the cry1B (lines A64.1, A33.1, A3.4 and S98.9) or cry1Aa (lines S05.1 and A19.14) genes under the control of the ubi1 promoter. Conversely, no toxin was detected in unwounded vegetative tissues of the A9.1 line harbouring the cry1B gene controlled by the mpi promoter, indicating that natural environmental stresses did not trigger the activity of the wound-inducible promoter. However, the toxin accumulated at 0.2% total soluble proteins in A9.1 sheath tissue exhibiting brown lesions resulting from SSB damage. The agronomical traits and performance of the transgenic lines were generally comparable with parental controls, except in the two lines accumulating Cry1Aa, which exhibited a high frequency of plants non-true to type. Natural infestation was assisted with manual infestations of L2/L3 SSB larvae in border control plants surrounding the experimental plots, which served as a reservoir for the second-cycle SSB population. The observation of damage (brown lesions and dead hearts) during the crop season and dissection of plants at harvest stage revealed a range of protection amongst the transgenic lines, which was highly consistent with the level of toxin accumulation and with previous experience in greenhouse assays. Lines A3.4 and S05.1 were found to exhibit stable and full protection against SSB attacks

  18. Susceptibility to Insecticides and Ecological Fitness in Resistant Rice Varieties of Field Nilaparvata lugens Stål Population Free from Insecticides in Laboratory

    Institute of Scientific and Technical Information of China (English)

    YANG Ya-jun; DONG Bi-qin; XU Hong-xing; ZHENG Xu-song; K.L.HEONG; LU Zhong-xian

    2014-01-01

    A population of rice brown planthopper (BPH) Nilaparvata lugens collected from a paddy field in Hangzhou was successively reared on susceptible rice Taichung Native 1 (TN1) in a laboratory free from insecticides for more than 14 generations. The changes in susceptibility to insecticides and ecological fitness on different resistant rice varieties were monitored in each generation. The resistance ratio to imidacloprid sharply declined with the succession of rearing generations without insecticides from 359.94-fold at F1 to 6.50-fold at F14 compared with the susceptible strain, and the resistance ratio to chlorpyrifos was from 9.90-fold at F1 to 5.94-fold at F14. Nymphal duration and weights of newly hatched female adults were significantly affected by rice variety, generation and their interactions, but nymphal survival was significantly affected by the generation only. The ratio of brachypterous adults in males was affected by the generation and generation × variety interaction, whereas no difference was found in females. Nymphal duration extended with increasing generations, and the female nymphal duration was shorter in the susceptible variety TN1 than those in the resistant varieties IR26 and IR36. In addition, the female adult weight in TN1 was higher than those in IR26 and IR36. These results indicated that the resistance of field BPH population to insecticides was reversed after several generations of no-exposure to insecticides, and the ecological fitness in TN1 was higher than those in IR26 and IR36. These findings suggested the rational and reduced use of insecticides in combination with the manipulation of resistant rice varieties would be effective for BPH management.

  19. Limited fitness advantages of crop-weed hybrid progeny containing insect-resistant transgenes (Bt/CpTI in transgenic rice field.

    Directory of Open Access Journals (Sweden)

    Xiao Yang

    Full Text Available BACKGROUND: The spread of insect-resistance transgenes from genetically engineered (GE rice to its coexisting weedy rice (O. sativa f. spontanea populations via gene flow creates a major concern for commercial GE rice cultivation. Transgene flow to weedy rice seems unavoidable. Therefore, characterization of potential fitness effect brought by the transgenes is essential to assess environmental consequences caused by crop-weed transgene flow. METHODOLOGY/PRINCIPAL FINDINGS: Field performance of fitness-related traits was assessed in advanced hybrid progeny of F(4 generation derived from a cross between an insect-resistant transgenic (Bt/CpTI rice line and a weedy strain. The performance of transgene-positive hybrid progeny was compared with the transgene-negative progeny and weedy parent in pure and mixed planting of transgenic and nontransgenic plants under environmental conditions with natural vs. low insect pressure. Results showed that under natural insect pressure the insect-resistant transgenes could effectively suppress target insects and bring significantly increased fitness to transgenic plants in pure planting, compared with nontransgenic plants (including weedy parent. In contrast, no significant differences in fitness were detected under low insect pressure. However, such increase in fitness was not detected in the mixed planting of transgenic and nontransgenic plants due to significantly reduced insect pressure. CONCLUSIONS/SIGNIFICANCE: Insect-resistance transgenes may have limited fitness advantages to hybrid progeny resulted from crop-weed transgene flow owning to the significantly reduced ambient target insect pressure when an insect-resistant GE crop is grown. Given that the extensive cultivation of an insect-resistant GE crop will ultimately reduce the target insect pressure, the rapid spread of insect-resistance transgenes in weedy populations in commercial GE crop fields may be not likely to happen.

  20. Variations and constancy of mercury and methylmercury accumulation in rice grown at contaminated paddy field sites in three Provinces of China.

    Science.gov (United States)

    Li, B; Shi, J B; Wang, X; Meng, M; Huang, L; Qi, X L; He, B; Ye, Z H

    2013-10-01

    Many paddy fields have been contaminated by mercury (Hg) in mining areas of China. In this study, twenty-six rice cultivars and three Hg contaminated paddy fields in different geographic regions were selected for field trials and aimed to investigate the variations and similarities in total Hg (THg) and methylmercury (MeHg) accumulations in brown rice (seeds) across sites. Our results revealed widescale cultivar variation in THg (13-52 ng g(-1) at Wanshan) and MeHg (3.5-23 ng g(-1)) accumulation and %MeHg (17.7-89%) in seeds. The ability to translocate is an important factor in the levels of THg and MeHg in seed. Cultivar tended to stability in THg accumulation across sites. Some cultivars accumulated lower concentrations of both THg and MeHg in seeds at fields seriously contaminated by Hg. Present results suggest that appropriate cultivar selection is a possible way to reduce THg and MeHg accumulation in seeds of rice grown in Hg-contaminated regions.

  1. Effect of vegetation of transgenic Bt rice lines and their straw amendment on soil enzymes, respiration, functional diversity and community structure of soil microorganisms under field conditions.

    Science.gov (United States)

    Fang, Hua; Dong, Bin; Yan, Hu; Tang, Feifan; Wang, Baichuan; Yu, Yunlong

    2012-01-01

    With the development of transgenic crops, there is an increasing concern about the possible adverse effects of their vegetation and residues on soil environmental quality. This study was carried out to evaluate the possible effects of the vegetation of transgenic Bt rice lines Huachi B6 (HC) and TT51 (TT) followed by the return of their straw to the soil on soil enzymes (catalase, urease, neutral phosphatase and invertase), anaerobic respiration activity, microbial utilization of carbon substrates and community structure, under field conditions. The results indicated that the vegetation of the two transgenic rice lines (HC and TT) and return of their straw had few adverse effects on soil enzymes and anaerobic respiration activity compared to their parent and distant parent, although some transient differences were observed. The vegetation and subsequent straw amendment of Bt rice HC and TT did not appear to have a harmful effect on the richness, evenness and community structure of soil microorganisms. No different pattern of impact due to plant species was found between HC and TT. It could be concluded that the vegetation of transgenic Bt rice lines and the return of their straw as organic fertilizer may not alter soil microbe-mediated functions.

  2. Effect of vegetation of transgenic Bt rice lines and their straw amendment on soil enzymes, respiration, functional diversity and community structure of soil microorganisms under field conditions

    Institute of Scientific and Technical Information of China (English)

    Hua Fang; Bin Dong; Hu Yan; Feifan Tang; Baichuan Wang; Yunlong Yu

    2012-01-01

    With the development of transgenic crops,there is an increasing concern about the possible adverse effects of their vegetation and residues on soil environmental quality.This study was carried out to evaluate the possible effects of the vegetation of transgenic Bt rice lines Huachi B6 (HC) and TT51 (TT) followed by the return of their straw to the soil on soil enzymes (catalase,arease,neutral phosphatase and invertase),anaerobic respiration activity,microbial utilization of carbon substrates and community structure,under field conditions.The results indicated that the vegetation of the two transgenic rice lines (HC and TT) and return of their straw had few adverse effects on soil enzymes and anaerobic respiration activity compared to their parent and distant parent,although some transient differences were observed.The vegetation and subsequent straw amendment of Bt rice HC and TT did not appear to have a harmful effect on the richness,evenness and community structure of soil microorganisms.No different pattern of impact due to plant species was found between HC and TT.It could be concluded that the vegetation of transgenic Bt rice lines and the return of their straw as organic fertilizer may not alter soil microbe-mediated functions.

  3. Ground beetles (Coleoptera: Carabidae of rice field banks and restored habitats in an agricultural area of the Po Plain (Lombardy, Italy

    Directory of Open Access Journals (Sweden)

    Nicola Pilon

    2013-11-01

    Full Text Available An entomological investigation was carried out in an agricultural area, mainly rice fields, of the Po river plain, located in the municipalities of Lacchiarella (MI and Giussago (PV (Lombardy, Italy. In 2009 and 2010, ground beetles (Coleoptera: Carabidae were sampled along rice field banks and in restored habitats, by means of pitfall traps. The area appeared as species-rich, compared to other anthropogenic habitats in the Po river pain. Most of the collected Carabids were species with a wide distribution in the Paleartic region, eurytopic and common in European agroecosystems. The assemblages were dominated by small-medium, macropterous species, with summer larvae. No endemic species were found. Species with southern distribution, rarely found north of the Po river, were also sampled. Amara littorea is recorded for the first time in Italy.

  4. Eficiência de Metarhizium anisopliae no controle do Percevejo-do-Colmo Tibraca limbativentris (Heteroptera: Pentatomidae em lavoura de arroz irrigado Efficiency of Metarhizium anisopliae on rice stem bug Tibraca limbativentris (Heteroptera: Pentatomidae control in flooded rice field

    Directory of Open Access Journals (Sweden)

    José Francisco da Silva Martins

    2004-12-01

    , pode provavelmente reduzir a taxa de disseminação do fungo nos arrozais e, por conseqüência, ser desfavorável à ocorrência de epizootias.The rice stem bug, Tibraca limbativentris Stal, 1860 (Heteroptera: Pentatomidae, is an important pest of rice (Oryza sativa L. in Brazil, mainly in flooded system of cultivation. The effect of two ways of application (conidia in aqueous suspension and on rice grain of Metarhizium anisopliae strain 172 for the control of the rice stem bug, was evaluated in three experiments conducted in 1991, 1992 and 1994 in commercial irrigated rice. In 1991, the spraying of conidia suspension and manual distribution of rice grain covered with fungal material at dose of 7.2 x 10(13 conidia.ha-1, on soil and among rice stems, where the bugs were located, reduced significantly the insect natural population with control efficiencies of 52.6 and 61.8%, respectively. Studies about establishment and persistence of fungal conidia in soil, using the colony forming unity (CFU counts, indicated that the fungus persisted in the soil between two rice crop seasons, up to 216 days after application, when new rice crops were established. The number of CFU was greater in the plots treated with rice grain covered with fungal material. The linear growth of CFU in the control plots showed that the fungus spread to the untreated areas of the rice field. Significant control efficiency was obtained in 1993 for grain and aqueous fungus treatment with 48.2% and 51.8%, respectively. In 1994, the conidial suspension at dose of 5x10(13 conidia.ha-1 resulted in control efficiency of 39.5%. The level of insect mycosis, however, was low in both 1993 and 1994, reaching a maximum of 20% mycosis in 1993. The low numbers of insect with mycosis compared with the level of mortality, may probably reduce the rate of fungal dissemination in rice fields and, consequently, be detrimental to the occurrence of epizootics.

  5. The potential of community fish refuges (CFRs) in rice field agro-ecosystems for improving food and nutrition security in the Tonle Sap region

    OpenAIRE

    Brooks, A.; Sieu, C.

    2016-01-01

    The fisheries sector in Cambodia contributes 8%–12% to national GDP and 25% - 30% to agricultural GDP, with an estimated 4.5 million people involved in fishing and associated trades. Fish and other aquatic animals are important food sources, contributing an estimated national average of 60% - 70% of total animal protein intake. Of the 2013 total fish production, 550,000 metric tons were harvested from freshwater habitats, of which rice field fisheries and small-scale family fisheries contribu...

  6. First record of epizootics in the ocola skipper, Panoquina ocola (Lepidopera: Hesperiidae), caused by Isaria tenuipes in flooded rice fields of Central Brazil.

    Science.gov (United States)

    Mascarin, G M; Dunlap, C A; Barrigossi, J A F; Quintela, E D; de Noronha, N C

    2017-04-01

    We report the first occurrence of an epizootic of the ascomycete fungus, Isaria tenuipes (teleomorph Cordyceps takaomontana), on the ocola skipper Panoquina ocola (Lepidoptera: Hesperiidae), an insect pest affecting rice in Brazil. Field surveys in flooded rice fields in the state of Goiás in Brazil were conducted, and a fungal pathogen of a caterpillar pest (P. ocola) was serendipitously found. This fungus inflicted high infection levels (average 86·2%) mainly to the pupal stage during warm, humid growing conditions. Typically, mycosed pupal cadavers produced milky-white to pale yellow synnemata bearing an average of 1·1 ± 0·2 × 10(9) conidia per cadaver. Based on phylogenetic analysis using beta-tubulin gene sequences, we confirmed that all 12 isolates obtained from field-mummified pupae were identifiable as I. tenuipes. Our data expand our knowledge on the host and geographical ranges of this mycopathogen and underscore its epizootic potential to affect a lepidopterous insect pest on rice in Brazil. This finding may facilitate the exploitation of this fungus as a mycoinsecticide. Isaria tenuipes may be used as an effective and environmentally friendly bioinsecticide against agricultural caterpillar pests due to its epizootic potential, as well as explored for medicinal purposes by pharmaceutical industry. © 2016 The Society for Applied Microbiology.

  7. Isolation of a new heterolobosean amoeba from a rice field soil: Vrihiamoeba italica gen. nov., sp. nov.

    Science.gov (United States)

    Murase, Jun; Kawasaki, Michio; De Jonckheere, Johan F

    2010-08-01

    A heterolobosean amoeba strain 6_5F was isolated from an Italian rice field soil. Although 18S rRNA gene sequence analysis demonstrated that the new isolate was closely related to Stachyamoeba sp. ATCC 50324, further molecular analysis and morphological observation showed distinct differences amongst the two. The 5.8S rRNA gene was successfully amplified and sequenced for strain 6_5F but not for strain ATCC 50324. Trophozoites of strain ATCC 50324 transform into flagellate forms in the late stage of incubation before encystment, while strain 6_5F do not show flagellate forms under different conditions of the flagellation test. Light and electron microscopic observation showed the structural difference of cysts of strain 6_5F from strain ATCC 50324 and also from the type strain Stachyamoeba lipophora. The results show that the strain 6_5F is distinct from Stachyamoeba spp. and we propose a new genus and species for this isolate, Vrihiamoeba italica gen. nov., sp. nov.

  8. Water-requirement Characteristics and Water-saving Irrigation Indices of Dry-raised Rice Seedlings in Paddy Field

    Institute of Scientific and Technical Information of China (English)

    YANG Jian-chang; WANG Wei; WANG Zhi-qin; LIU Li-jun; DING Zhi-jia; ZHU Qing-sen

    2001-01-01

    The dry-raised seedlings (D-RS)of rice had obvious superiority in tillering and growth after transplanting. Especially under the condition of water-saving irrigation or low soil moisture, D-RS had more productive tillers, higher dry matter accumulation, larger grain-filling rate, slower senescence of leaves and stronger root activity during ripening, and higher grain yield, compared with the moist-raised seedlings (MRS). D-RS had smaller yield reduction than M-RS when subject to heavy water stress. The results suggested that D-RS had the ability to adapt to lower soil moisture in paddy field. Basedon the response of D-RS to soil moisture at each growth stage, the water-saving and high-yielding irrigation indices through controlling lowlimit soil water potential were proposed, i.e. soil water potential was - 15 - - 20 kPa from the recovery to the criticalleaf-age of productive tillering, - 20 - - 40 kPa from the critical leaf-age of productive tillering to secondary branch-differentiating stage, - 15 - - 25 kPa from secondary branch-differentiating stage to 20 days after heading and - 25 - - 35 kPa from 21 to 45 days after heading.

  9. Responses of a rice-field cyanobacterium Anabaena siamensis TISTR-8012 upon exposure to PAR and UV radiation.

    Science.gov (United States)

    Rastogi, Rajesh P; Incharoensakdi, Aran; Madamwar, Datta

    2014-10-15

    The effects of PAR and UV radiation and subsequent responses of certain antioxidant enzymatic and non-enzymatic defense systems were studied in a rice field cyanobacterium Anabaena siamensis TISTR 8012. UV radiation resulted in a decline in growth accompanied by a decrease in chlorophyll a and photosynthetic efficiency. Exposure of cells to UV radiation significantly affected the differentiation of vegetative cells into heterocysts or akinetes. UV-B radiation caused the fragmentation of the cyanobacterial filaments conceivably due to the observed oxidative stress. A significant increase of reactive oxygen species in vivo and DNA strand breaks were observed in UV-B exposed cells followed by those under UV-A and PAR radiation, respectively. The UV-induced oxidative damage was alleviated due to an induction of antioxidant enzymatic/non-enzymatic defense systems. In response to UV irradiation, the studied cyanobacterium exhibited a significant increase in antioxidative enzyme activities of superoxide dismutase, catalase and peroxidase. Moreover, the cyanobacterium also synthesized some UV-absorbing/screening substances. HPLC coupled with a PDA detector revealed the presence of three compounds with UV-absorption maxima at 326, 331 and 345 nm. The induction of the biosynthesis of these UV-absorbing compounds was found under both PAR and UV radiation, thus suggesting their possible function as an active photoprotectant.

  10. RICE CROSSES

    African Journals Online (AJOL)

    Spikelet sterility is the greatest barrier to rice hybridization. ... sterility, Hybridization, Duplicate recessive epis- tasis ' ... hybrid fertility of intra-subspecific crosses, i.e., indica by ..... 'Germ 59(1) 293$ ' ' male sterility and fertility restoration in rice.

  11. Using the Surface Renewal Technique to Estimate CO2 Exchange from a Rice Field to the Atmosphere

    Science.gov (United States)

    Suvocarev, K.; Reba, M. L.; Runkle, B.

    2015-12-01

    Measuring CO2 emissions as surface fluxes is crucial for climate change predictions. One major set of techniques to measure surface fluxes is through continuous micrometeorological observations over different landscapes. Recent approaches of the surface renewal method (SR) are becoming important for their capacity to independently measure sensible (H) and latent heat (LE) fluxes while avoiding some of the shortcomings of the eddy covariance method (EC). Unlike EC, SR avoids orientation limitations, leveling requirements and instrumentation separation and shadowing issues. The main advantage of SR over EC method is in its applicability in both roughness and inertial sub-layers. Therefore, SR measurements can be planned in cases where fetch requirements are not adequate for EC application. We applied the recent approach as suggested by Castellvi et al. (2008) over two months (May to July, 2015) of high-frequency data collected by EC equipment from a rice field in Arkansas. The main goal was to extend this SR application to CO2 fluxes (Fc) over agricultural fields. The results show high correlation between EC and SR fluxes (H, LE and Fc) when they are compared for all atmospheric stability conditions (R2 > 0.75). Some overestimation is observed for SR with respect to EC fluxes, similar to the findings of Castellvi et al. (2008) for rangeland grass. For all the data, SR analysis results were about 11%, 18% and 17% higher than the EC results for H, LE and Fc, respectively. These higher flux estimates resulted in better energy balance closure. The root mean square error for Fc was 6.55 μmol m-2 s-1. The observed overestimation will be addressed in the future by using additional methods for the turbulent fluxes quantification.

  12. Occurrence and distribution of nematodes in rice fields in Guilan province, Iran and the first record of Mylonchulus polonicus (Stefanski, 1915 Cobb, 1917 (Nematoda: Mononchina

    Directory of Open Access Journals (Sweden)

    Shahabi Soheila

    2016-12-01

    Full Text Available The distribution of nematodes was studied in rice fields in Guilan province, Iran, from 2014 to 2016. Nematode biodiversity of 250 soil and root samples was examined. Thirty nematode species were identified morphologically, including plant parasites, microbivores and mycetophagous and predator species. Molecular techniques were also used for further identification of three plant parasitic species. Indicators of population were also estimated. Spiral nematodes (Helicotylenchus crenacauda Sher, 1966 and H. digitiformis Ivanova, 1967 and stunt nematode (Tylenchorhynchus agri were the predominant parasitic species identified. Among other species, three mononchid species were identified namely Mononchus aquaticus, Mylonchulus sigmaturus and M. polonicus. The species M. polonicus was found and reported in Iran for the first time. The two plant parasitic species T. agri and Xiphinema index were reported in association with rice in Iran for the first time. To evaluate the distribution and incidence of Aphelenchoides besseyi (rice white-tip nematode in different regions of Guilan province, a total of 255 fresh seed samples were collected/inspected, of which, about 40% of them were infested with A. besseyi. Of the 16 studied counties, the highest percentage of infected seeds came from fields around the city of Astara (69.2% and the second highest infection was observed near the city of Anzali (60%.

  13. [Vertical distribution and quantitative dynamics of dominant functional groups of arthropod community in rice fields and estimation of natural enemy effects].

    Science.gov (United States)

    Hao, S; Zhang, X; Cheng, X

    2000-02-01

    The study showed that Lycosid (wolf spider) mainly distributed in the basal part of rice plants, not as wide as we know in past. Tetragnathid did not limited in the upper part of plants, but might translate to middle or lower part when affected by insecticide. The relationship between the vertical distributions of top and basal species was not significant. Besides the amount of natural enemies, the spatial distribution characteristics of natural enemies and brownplanthopper, and the proportion of brownplanthopper to total preys of natural enemies were the factors affecting the role of natural enemies on the population dynamics of brownplanthopper in rice fields. A model to evaluate the effect of natural enemies to brownplanthopper was put forward, which included the message of quantitative dynamics, spatial distribution and feeding characteristics of natural enemies, brownplanthopper and neutral insects.

  14. Can the co-cultivation of rice and fish help sustain rice production?

    Science.gov (United States)

    Hu, Liangliang; Zhang, Jian; Ren, Weizheng; Guo, Liang; Cheng, Yongxu; Li, Jiayao; Li, Kexin; Zhu, Zewen; Zhang, Jiaen; Luo, Shiming; Cheng, Lei; Tang, Jianjun; Chen, Xin

    2016-06-28

    Because rice feeds half of the world's population, a secure global food supply depends on sustainable rice production. Here we test whether the co-cultivation of rice and fish into one "rice-fish system" (RFS; fish refers to aquatic animals in this article) could help sustain rice production. We examined intensive and traditional RFSs that have been widely practiced in China. We found that rice yields did not decrease when fish yield was below a threshold value in each intensive RFS. Below the thresholds, moreover, fish yields in intensive RFSs can be substantially higher than those in traditional RFS without reducing rice yield. Relative to rice monoculture, the use of fertilizer-nitrogen and pesticides decreased, and the farmers' net income increased in RFSs. The results suggest that RFSs can help sustain rice production, and suggest that development of co-culture technologies (i.e. proper field configuration for fish and rice) is necessary to achieve the sustainability.

  15. Model Research on the Effect of Surface Film on Ammonia Volatilization from Rice Field

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Shun-yao; YIN Bin; ZHU Zhao-liang

    2002-01-01

    Pan and field experiments were conducted to investigate the effect of surface film on ammonia volatilization from water and paddy soil. The results showed that the addition of the surface film on floodwater reduced the rate of ammonia volatilization, however, the reduction of the latter varied greatly with its rates of addition. Jayaweera-Mikkelsen ammonia volatilization model with the introduction of a parameter Kf, a relative measure of the resistance of the surface film on ammonia volatilization, was used to elucidate the effectiveness of the surface film on lowering ammonia volatilization. The Kf value was calculated from the results obtained in the pan experiment with different rates of surface film addition. With the modified model and the optimized Kf value, the effects of the surface film in reducing ammonia volatilization under different environmental conditions were simulated and analyzed. However, it was found that the simulation was not satisfactory in the field experiment and the parameter Kf should be further tuned so as to improve the simulation and to optimize the addition rate of the surface film in field conditions.

  16. Net global warming potential and greenhouse gas intensity in rice agriculture driven by high yields and nitrogen use efficiency: a 5 year field study

    Science.gov (United States)

    Zhang, X.; Zhou, Z.; Liu, Y.; Xu, X.; Wang, J.; Zhang, H.; Xiong, Z.

    2015-11-01

    Our understanding of how net global warming potential (NGWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a 5 year field experiment was conducted in China to evaluate the effects of integrated soil-crop system management (ISSM) on NGWP and GHGI after accounting for carbon dioxide (CO2) emissions from all sources (methane, CH4, and nitrous oxide, N2O, emissions, agrochemical inputs, Ei, and farm operations, Eo) and sinks (i.e., soil organic carbon, SOC, sequestration). For the improvement of rice yield and agronomic nitrogen use efficiency (NUE), four ISSM scenarios consisting of different nitrogen (N) fertilization rates relative to the local farmers' practice (FP) rate were carried out, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios, i.e., N1, N2, N3 and N4, significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 86 and 82 %, respectively. In addition, compared with the FP, the N1 and N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar NGWPs. The N3 and N4 scenarios remarkably increased the NGWP and GHGI by an average of 67 and 36 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.

  17. Using chromosome introgression lines to map quantitative trait loci for photosynthesis parameters in rice (Oryza sativa L.) leaves under drought and well-watered field conditions.

    Science.gov (United States)

    Gu, Junfei; Yin, Xinyou; Struik, Paul C; Stomph, Tjeerd Jan; Wang, Huaqi

    2012-01-01

    Photosynthesis is fundamental to biomass production, but sensitive to drought. To understand the genetics of leaf photosynthesis, especially under drought, upland rice cv. Haogelao, lowland rice cv. Shennong265, and 94 of their introgression lines (ILs) were studied at flowering and grain filling under drought and well-watered field conditions. Gas exchange and chlorophyll fluorescence measurements were conducted to evaluate eight photosynthetic traits. Since these traits are very sensitive to fluctuations in microclimate during measurements under field conditions, observations were adjusted for microclimatic differences through both a statistical covariant model and a physiological approach. Both approaches identified leaf-to-air vapour pressure difference as the variable influencing the traits most. Using the simple sequence repeat (SSR) linkage map for the IL population, 1-3 quantitative trait loci (QTLs) were detected per trait-stage-treatment combination, which explained between 7.0% and 30.4% of the phenotypic variance of each trait. The clustered QTLs near marker RM410 (the interval from 57.3 cM to 68.4 cM on chromosome 9) were consistent over both development stages and both drought and well-watered conditions. This QTL consistency was verified by a greenhouse experiment under a controlled environment. The alleles from the upland rice at this interval had positive effects on net photosynthetic rate, stomatal conductance, transpiration rate, quantum yield of photosystem II (PSII), and the maximum efficiency of light-adapted open PSII. However, the allele of another main QTL from upland rice was associated with increased drought sensitivity of photosynthesis. These results could potentially be used in breeding programmes through marker-assisted selection to improve drought tolerance and photosynthesis simultaneously.

  18. Effects of N loading rate on CH4 and N2O emissions during cultivation and fallow periods from forage rice fields fertilized with liquid cattle waste.

    Science.gov (United States)

    Riya, S; Zhou, S; Kobara, Y; Sagehashi, M; Terada, A; Hosomi, M

    2015-09-15

    The use of liquid cattle waste (LCW) as a fertilizer for forage rice is important for material recycling because it can promote biomass production, and reduce the use of chemical fertilizer. Meanwhile, increase in emission of greenhouse gases (GHGs), especially CH4 and N2O would be concerned. We conducted a field study to determine the optimum loading rate of LCW as N to promote forage rice growth with lower GHG emissions. The LCW was applied to forage rice fields, N100, N250, N500, and N750, at four different N loading rates of 107, 258, 522, and 786 kg N ha(-1), respectively, including 50 kg N ha(-1) of basal chemical fertilizer. The above-ground biomass yields increased 14.6-18.5 t ha(-1) with increases in N loading rates. During the cultivation period, both the CH4 and N2O fluxes increased with increases in LCW loading rates. In the treatments of N100, N250, N500, and N750, the cumulative CH4 emissions during the entire period, including cultivation and fallow period were 29.6, 18.1, 54.4, and 67.5 kg C ha(-1), respectively, whereas those of N2O were -0.15, -0.02, 1.49, and 5.82 kg N ha(-1), respectively. Considering the greenhouse gas emissions and above-ground biomass, the yield-scaled CO2-equivalents (CO2-eqs) were 66.3, 35.9, 161, and 272 kg CO2 t(-1) for N100, N250, N500, and N750, respectively. These results suggest that N250 is the most appropriate LCW loading rate for promoting forage rice production with lower GHG emissions.

  19. Molecular dynamics simulations of hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) using a combined Sorescu-Rice-Thompson AMBER force field.

    Science.gov (United States)

    Agrawal, Paras M; Rice, Betsy M; Zheng, Lianqing; Thompson, Donald L

    2006-12-28

    We present the results of molecular dynamics simulations of crystalline hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) using the SRT-AMBER force field (P. M. Agrawal et al., J. Phys. Chem. B 2006, 110, 5721), which combines the rigid-molecule force field developed by Sorescu-Rice-Thompson (D. C. Sorescu, B. M. Rice, and D. L. Thompson, J. Phys. Chem. B 1997, 101, 798) with the intramolecular interactions obtained from the Generalized AMBER Force Field (Wang et al., J. Comput. Chem. 2004, 25, 1157). The calculated crystal density at room conditions is about 10% lower than the measured value, while the lattice parameters and thermodynamic melting point are within about 5% at ambient pressure. The chair and inverted chair conformation, bond lengths, and bond angles of the RDX molecule are accurately predicted; however, there are some inaccuracies in the calculated orientations of the NO2 groups. The SRT-AMBER force field predicts overall reasonable results, but modifications, probably in the torsional parameters, are needed for a more accurate force field.

  20. Practices Surrounding Event Photos

    NARCIS (Netherlands)

    Vyas, Dhaval; Nijholt, Antinus; van der Veer, Gerrit C.; Kotzé, P.; Marsden, G.; Lindgaard, G.; Wesson, J.; Winckler, M.

    Sharing photos through mobile devices has a great potential for creating shared experiences of social events between co-located as well as remote participants. In order to design novel event sharing tools, we need to develop indepth understanding of current practices surrounding these so called

  1. Crop Species Recognition and Discrimination Paddy-Rice from Reaped-Fields by the Radar Vegetation Index (rvi) of ALOS-2/PALSAR2

    Science.gov (United States)

    Yamada, Y.

    2016-06-01

    The Japanese ALOS-2 satellite was launched on May 24th, 2014. It has the L-band SAR, PALSAR-2. Kim,Y. and van Zyl, J.J. proposed a kind of Radar Vegetation Index (RVI) as RVI = 8 * σ0hv / (σ0hh + σ0vv + 2* σ0hv) by L-band full-polarimetric radar data. Kim, Y. and Jackson, T.J., et al. applied the equation into rice and soybean by multi-frequency polarimetric scatterometer above 4.16 meters from the ground. Their report showed the L-band was the most promising wave length for estimating LAI and NDVI from RVI. The author tried to apply the analysis to the actual paddy field areas, both Inashiki region and Miyagi region in the eastern main island, "Honshu", areas of Japan by ALOS-2/PALSAR-2 full-polarimetry data in the summer season, the main crop growing time, of 2015. Judging from conventional methods, it will be possible to discriminate paddy rice growing fields from reaped fields or the other crops growing fields by the PALSAR-2 data. But the RVI value is vaguely related to such land use or biomass at the present preliminary experiment. The continuous research by the additional PALSAR-2 full-polarimetry data should be desired.

  2. Preliminary Report on Effectiveness of Four Mixtures of Herbicide and Rice BB Fertilizer in Control of Weeds in Rice Fields and Their Safety%水稻除草复混肥防除稻田杂草 效果及安全性试验初报

    Institute of Scientific and Technical Information of China (English)

    李保同; 潘晓华; 方加海; 季梦成

    2001-01-01

    对4种水稻除草复混肥防除稻田杂草效果及安全性研究表明,丁苄复混肥具有高效、水稻安全、省工、使用方便等特点,符合一次用药肥、全季有效的化学除草和施肥目标,是稻田一次性化学除草、施肥的优选配方。%Effectiveness of four mixtures of herbicide and rice BB fertilizer in control of weeds in rice fields and their safety were studied. The results showed that the mixture of butachlor and bensulfuron-methyl and rice BB fertilizer is highly effective in control of weeds, safe to rice growth, convenient for use and labour-saving. It conforms the objective of chemical weeding and fertilizing, and it is good for the whole season of rice growth when it is used once only. It is the best directive for chemical weeding and fertilizing once only in rice field.

  3. Elucidation of molecular dynamics of invasive species of rice

    Science.gov (United States)

    Cultivated rice fields are aggressively invaded by weedy rice in the U.S. and worldwide. Weedy rice results in loss of yield and seed contamination. The molecular dynamics of the evolutionary adaptive traits of weedy rice are not fully understood. To understand the molecular basis and identify the i...

  4. Simulations of H 2O 2 concentration profiles in the water surrounding spent nuclear fuel taking mixed radiation fields and bulk reactions into account

    Science.gov (United States)

    Nielsen, Fredrik; Jonsson, Mats

    2008-02-01

    To simulate the dynamics of the concentration gradient of hydrogen peroxide in groundwater surrounding spent nuclear fuel under various conditions, a model has been developed. The model treats the water volume as a sequence of volume elements, and applies the processes that affect hydrogen peroxide concentration to each volume element. The surface steady-state concentrations of H 2O 2, and the time to reach steady-state, have been determined under different conditions. The processes accounted for in the model are radiolytic production of H 2O 2 from α- and β-radiation, surface reactions consuming H 2O 2, homogeneous reactions consuming H 2O 2, and diffusion. The system has been modeled mainly for different surface reaction rate constants and homogeneous (bulk) reaction rate constants. The simulations show that the surface concentration of H 2O 2 approaches the steady-state concentration very rapidly and that the impact of homogeneous (bulk) reactions consuming H 2O 2 on the steady-state concentration is significant.

  5. TECHNICAL ECONOMIC FEASIBILITY OF PADDY RICE FIELDS VARIETY OF APPROACH PTT SPECIFIC LOCATIONS IN PAPUA (Case Jayapura

    Directory of Open Access Journals (Sweden)

    Afrizal Malik

    2013-01-01

    Full Text Available Study aims to determine technical economically feasibility of irrigration rice in village of Sumbe, Namblong District, Jayapura on-farm research involving farmers with an area of 2.50 ha cooperators, July to November 2011. Technology introduced: PTT, 4:1 legowo systems, seed varieties Inpari labeled 1, 2, 4, 6, 7, 9, 10, and Sintanur. Fertilizer: urea 150 kg +100 kg +100 kg SP-36 Phonska KCl +50 kg per ha. Variables: height and number of tillers 35 and 65 dap, weight of 1000 seeds, productivity, input, and output. Data were analyzed descriptively. Highest productivity in varieties Inpari 7 (7.925 tonnes per ha Milled Rice (MR and lowest Sintanur varieties (4.625 tonnes per ha MR. Pest stand: rice leaffolder and stinky rice pest. Lowest expenditure on non-cooperators Ciherang farmers IDR 12.15 million per ha per Growing Season (GS and highest in varieties Inpari 7 (IDR 15,005,000 per ha per GS. Lowest Acceptance Ciherang farmers on non-cooperators, IDR 16.4 million per ha per GS and highest in varieties Inpari 7, IDR 27.7 million per ha per GS. If farmers apply recommendation technologies using Inpari 7 varieties, farmers receiving IDR 3,173,750 per month (greater than Regional Minimum Wage of Jayapura. Need government support in order to minimize dependence on outside

  6. A two-year field measurement of methane and nitrous oxide fluxes from rice paddies under contrasting climate conditions

    Science.gov (United States)

    Sun, Huifeng; Zhou, Sheng; Fu, Zishi; Chen, Guifa; Zou, Guoyan; Song, Xiangfu

    2016-06-01

    The effects of three irrigation levels (traditional normal amount of irrigation [NA100%], 70%, and 30% of the normal amount [NA70% and NA30%]) and two rice varieties (Oryza sativa L. Huayou14 and Hanyou8) on CH4 and N2O emissions were investigated over two years under contrasting climate conditions (a ‘warm and dry’ season in 2013 and a normal season in 2014). Hanyou8 was developed as a drought-resistant variety. The mean seasonal air temperature in 2013 was 2.3 °C higher than in 2014, while the amount of precipitation from transplanting to the grain-filling stage in 2013 was only 36% of that in 2014. CH4 emission rose by 93-161%, but rice grain yield fell by 7-13% in 2013, compared to 2014 under the NA100% conditions. Surface standing water depths (SSWD) were higher in Hanyou8 than in Huayou14 due to the lower water demand by Hanyou8. A reduction in the amount of irrigation water applied can effectively reduce the CH4 emissions regardless of the rice variety and climate condition. However, less irrigation during the ‘warm and dry’ season greatly decreased Huayou14 grain yield, but had little impact on Hanyou8. In contrast, N2O emission depended more on fertilization and SSWD than on rice variety.

  7. Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain

    Directory of Open Access Journals (Sweden)

    Mas-Coma Santiago

    2010-07-01

    Full Text Available Abstract Background International travel and immigration have been related with an increase of imported malaria cases. This fact and climate change, prolonging the period favouring vector development, require an analysis of the malaria transmission resurgence risk in areas of southern Europe. Such a study is made for the first time in Spain. The Ebro Delta historically endemic area was selected due to its rice field landscape, the presence of only one vector, Anopheles atroparvus, with densities similar to those it presented when malaria was present, in a situation which pronouncedly differs from already assessed potential resurgence areas in other Mediterranean countries, such as France and Italy, where many different Anopheles species coexist and a different vector species dominates. Methods The transmission risk was assessed analysing: 1 climate diagrams including the minimum temperature for Plasmodium falciparum and Plasmodium vivax development; 2 monthly evolution of the Gradient Model Risk (GMR index, specifying transmission risk period and number of potential Plasmodium generations; 3 ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI; 4 evaluation of A. atroparvus population dynamics. Results Climatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for P. falciparum, and from May until October for P. vivax. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and A. atroparvus maximum abundance correspond to months with maximum growth of the rice fields. Conclusions The Ebro Delta

  8. Long-term behaviours of {sup 54}Mn, {sup 60}Co, {sup 85}Sr and {sup 137}Cs in a simulated rice field

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y. H.; Lim, K. M.; Park, H. G; Park, D. W.; Lee, W. Y. [KAERI, Taejon (Korea, Republic of)

    1999-07-01

    or studying long-term behaviours of major fission and activation products in the paddy field, greenhouse experiments were carried out for 4 years with rice plants grown in a simulated paddy field. A radioactive solution containing {sup 54}Mn, {sup 60}Co, {sup 85}Sr and {sup 137}Cs was mixed with the topsoil in a flooded lysimeter 1 day before transplanting rice seedlings in 1993. Soil-to-plant transfer factor (TFs) of {sup 54}Mn and {sup 85}Sr were 1-2 orders of magnitude higher than those of {sup 60}Co and {sup 137}Cs. TFs of {sup 54}Mn and {sup 137}Cs tended to decrease year by year but that of {sup 60}Co decreased a little only in the second year. Negligible amounts of {sup 54}Mn, {sup 60}Co and {sup 137}Cs were leached out of the lysimeter. Leaching of {sup 60}Co and {sup 137}Cs decreased by factors of 10 and 7, respectively, in 3 years. Downward migration was the greatest in {sup 85}Sr. In the fourth year, radioactivity distributed rather uniformly over the top 15 cm layer of soil. The present results can be utilized for assessing the radiological impact and deciding counter-measures when the paddy field is contaminated with those radionuclides. (author). 13 refs., 2 tabs., 4 figs.

  9. 3D lithospheric mapping of the Iberian Peninsula and surrounding Atlantic and Mediterranean margins from 3D joint inversion of potential field and elevation data.

    Science.gov (United States)

    Torne, Montserrat; Zeyen, Hermann; Jimenez-Munt, Ivone; Fernandez, Manel; Vergés, Jaume

    2017-04-01

    We investigate the lithospheric density structure of the Iberian Peninsula and the surrounding Atlantic and Mediterranean margins from a 3D joint inversion of free-air, geoid and elevation data, based on a Bayesian approach. In addition, the crustal structure has been further constrained by incorporating about 750 Moho values from DSS investigations and RF analysis covering the entire region. Our preliminary results shows a significant lithospheric deformation along the plate boundaries, the Bay of Biscay-Pyrenees to the North and the Azores-Gibraltar to the south, where the CMB and LAB are located at depths more than 45 and 150 km, respectively. Noteworthy is the arcuate lithospheric thickening located at the westernmost end of the Gibraltar Arc system showing the presence of the NW-to-Westward retreated Gibraltar Arc slab that has given rise to the formation of the Betics-Rif Alpine belt system and the back arc Alboran basin. To the west, the stable-slightly deformed Iberian massif shows a quasi-flat CMB and LAB topography (30 to 32 km and about 110 km, respectively). The crust and mantle lithosphere thin towards the Mediterranean and Atlantic margins, with the exception of its northern margin where lithospheric thickening extends offshore to the Gulf of Biscay. In the western Mediterranean the SE-Neogene slab retreat has resulted in a significant thinning of the crust and mantle lithosphere. Thin lithosphere is also observed in the Tagus-Horseshoe abyssal plain region where the LAB shallows to less than 90 km. This work has been funded by the Spanish projects MITE (CGL2014-59516-P) and WEME-CSIC project 201330E11.

  10. Spatial variation of present-day stress field and tectonic regime in Tunisia and surroundings from formal inversion of focal mechanisms: Geodynamic implications for central Mediterranean

    Science.gov (United States)

    Soumaya, A.; Ben Ayed, N.; Delvaux, D.; Ghanmi, M.; Zargouni, F.; Khayati Ammar, H.; Kadri, A.

    2015-12-01

    We compiled 123 focal mechanisms from various sources for Tunisia and adjacent regions up toSicily, to image the current stress field in the Maghrebides chain (from Tunisia to Sicily) and its foreland. Stressinversion of all the available data provides a first-order stress field with a N150°E horizontal compression(SHmax) and a transpressional tectonic regime, but the obtained stress tensor poorly fit to the data set.Weseparated them into regional subsets (boxes) in function of their geographical proximity, kinematicregime, homogeneity of kinematic orientations, and tectonic setting. Their respective inversion evidencessecond- and third-order spatial variations in tectonic regime and horizontal stress directions. The stressfield gradually changes from compression in the Maghrebides thrust belt to transpression and strike slipin the Atlassic and Pelagian foreland, respectively, where preexisting NW-SE to E-W deep faults systemare reactivated. This spatial variation of the sismotectonic stress field and tectonic regime is consistentwith the neotectonic stress field determined by others from fault slip data. The major Slab Transfer EdgePropagator faults (i.e., North-South Axis-Hammamet relay and Malte Escarpment), which laterally delimitthe subducting slabs, play an active role in second- and third-order lateral variations of the tectonicregime and stress field orientations over the Tunisian/Sicilian domain. The past and current tectonicdeformations and kinematics of the central Mediterranean are subordinately guided by the plateconvergence (i.e., Africa-Eurasia), controlled or influenced by lateral slab migration/segmentation andby deep dynamics such as lithosphere-mantle interaction.

  11. Effects of cultivation patterns on rice yield and soil properties in cold waterlogged paddy fields%耕作模式对冷浸田水稻产量和土壤特性的影响

    Institute of Scientific and Technical Information of China (English)

    王思潮; 曹凑贵; 李成芳; 熊又升; 汪金平

    2014-01-01

    为探明不同耕作模式对冷浸田的影响机制,挖掘冷浸田的生产潜力,以冷浸田为研究对象,通过田间试验,以常规平作模式为对照,研究了垄作和稻鱼共作模式对冷浸田水稻产量以及土壤团聚体、温度、pH及有机质和还原性物质含量以及酶活性的影响。结果表明:相比对照(CK),垄作模式(T1)能显著降低土壤微团聚体(1 mm) and organic matter content increased respectively by 67.6%and 28.0%at rice maturity stage. Treatment T2 had less effect on soil physical and chemical properties in cold waterlogged paddy fields. However, it significantly increased soil available nutrients (mainly available potassium and phosphorus) contents. Soil available potassium content increased 18.2% and 69.2% at booting and mature stages, compared with CK. It provided good soil environment and nutrition for rice growth, promoted rice growth and development, and improved rice yield. Further analysis showed that treatments T1 and T2 significantly improved rice yield in cold waterlogged paddy fields and increased yield in the range of 8.8%-25.8%. The effect of T1 on increasing rice production was the most significant, with actual output reaching 7 623 kg·hm-2. In conclusion, treatment T1 effectively improved soil properties in cold waterlogged paddy fields and increased rice yield. The effect of increasing production of treatment T2 was mainly drived by increased water and soil available nutrients in cold paddy waterlogged fields.

  12. Interaction of genotype x management on vegetative growth and weed suppression of aerobic rice

    NARCIS (Netherlands)

    Zhao, D.L.; Bastiaans, L.; Atlin, G.N.; Spiertz, J.H.J.

    2007-01-01

    Water shortage in drought-prone rice-growing areas of the world is threatening conventional irrigated rice production systems, in which rice is transplanted into fields where standing water is maintained until harvest. Aerobic rice production systems, in which rice is grown as a direct-seeded upland

  13. Screening of Rhizosphere Bacteria From Rice Fields in The Coastal Area as Acc-Deaminase and Auxin Producer

    Directory of Open Access Journals (Sweden)

    Annisyia Zarina Putri

    2015-02-01

    Full Text Available Salinity and drought stress results in the production of ethylene. Rhizosphere bacterial activity suppresses the production of ethylene through the activity of 1-aminocycopropane-1-carboxylate (ACC deaminase. In this study,a sampel of rhizosphere bacteria from coastal rice plant area was tested. The method used was acc deaminase activity test performed on Dworkin - Foster (DF media and PCR acdS gene using specific primers of ACC and a quantitative analysis of the production of auxin (IAA. Of 47 isolatees obtained, 8 were positively have acdS activity. The positive result was indicated by the presence of 1080 bp amplicon. Quantitative analysisshowed the highest yield of 10.6 ppm of auxin. The results prove that there are some bacteria originated from coastal rice plant area which have acc deaminase activity.

  14. Trace gas fluxes from intensively managed rice and soybean fields across three growing seasons in the Brazilian Amazon

    Science.gov (United States)

    R.C. Oliveira Junior; Michael Keller; P. Crill; T. Beldini; J. Van Haren; P. Camargo

    2015-01-01

    The emission of gases that may potentially intensify the greenhouse effect has received special attention due to their ability to raise global temperatures and possibly modify conditions for life on earth. The objectives of this study were the quantification of trace gas flux (N2O, CO2 and CH4) in soils of the lower Amazon basin that are planted with rice and soybean,...

  15. Community composition of ammonia-oxidizing bacteria and archaea in rice field soil as affected by nitrogen fertilization.

    Science.gov (United States)

    Wang, Yanan; Ke, Xiubin; Wu, Liqin; Lu, Yahai

    2009-02-01

    Little information is available on the ecology of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in flooded rice soils. Consequently, a microcosm experiment was conducted to determine the effect of nitrogen fertilizer on the composition of AOB and AOA communities in rice soil by using molecular analyses of ammonia monooxygenase gene (amoA) fragments. Experimental treatments included three levels of N (urea) fertilizer, i.e. 50, 100 and 150 mgNkg(-1) soil. Soil samples were operationally divided into four fractions: surface soil, bulk soil deep layer, rhizosphere and washed root material. NH(4)(+)-N was the dominant form of N in soil porewater and increased with N fertilization. Cloning and sequencing of amoA gene fragments showed that the AOB community in the rice soil consisted of three major groups, i.e. Nitrosomonas communis cluster, Nitrosospira cluster 3a and cluster 3b. The sequences related to Nitrosomonas were predominant. There was a clear effect of N fertilizer and soil depth on AOB community composition based on terminal restriction fragment length polymorphism fingerprinting. Nitrosomonas appeared to be more abundant in the potentially oxic or micro-oxic fractions, including surface soil, rhizosphere and washed root material, than the deep layer of anoxic bulk soil. Furthermore, Nitrosomonas increased relatively in the partially oxic fractions and that of Nitrosospira decreased with the increasing application of N fertilizer. However, AOA community composition remained unchanged according to the denaturing gradient gel electrophoresis analyses.

  16. Remote and field level quantification of vegetation covariates for malaria mapping in three rice agro-village complexes in Central Kenya

    Directory of Open Access Journals (Sweden)

    Shililu Josephat

    2007-06-01

    Full Text Available Abstract Background We examined algorithms for malaria mapping using the impact of reflectance calibration uncertainties on the accuracies of three vegetation indices (VI's derived from QuickBird data in three rice agro-village complexes Mwea, Kenya. We also generated inferential statistics from field sampled vegetation covariates for identifying riceland Anopheles arabiensis during the crop season. All aquatic habitats in the study sites were stratified based on levels of rice stages; flooded, land preparation, post-transplanting, tillering, flowering/maturation and post-harvest/fallow. A set of uncertainty propagation equations were designed to model the propagation of calibration uncertainties using the red channel (band 3: 0.63 to 0.69 μm and the near infra-red (NIR channel (band 4: 0.76 to 0.90 μm to generate the Normalized Difference Vegetation Index (NDVI and the Soil Adjusted Vegetation Index (SAVI. The Atmospheric Resistant Vegetation Index (ARVI was also evaluated incorporating the QuickBird blue band (Band 1: 0.45 to 0.52 μm to normalize atmospheric effects. In order to determine local clustering of riceland habitats Gi*(d statistics were generated from the ground-based and remotely-sensed ecological databases. Additionally, all riceland habitats were visually examined using the spectral reflectance of vegetation land cover for identification of highly productive riceland Anopheles oviposition sites. Results The resultant VI uncertainties did not vary from surface reflectance or atmospheric conditions. Logistic regression analyses of all field sampled covariates revealed emergent vegetation was negatively associated with mosquito larvae at the three study sites. In addition, floating vegetation (-ve was significantly associated with immature mosquitoes in Rurumi and Kiuria (-ve; while, turbidity was also important in Kiuria. All spatial models exhibit positive autocorrelation; similar numbers of log-counts tend to cluster in

  17. Far-Field Tunable Nano-focusing Based on Metallic Slits Surrounded with Nonlinear-Variant Widths and Linear-Variant Depths of Circular Dielectric Grating

    CERN Document Server

    Cao, Peng-Fei; Zhang, Xiao-Ping; Lu, Wei-Ping; Kong, Wei-Jie; Liang, Xue-Wu

    2013-01-01

    In this work, we design a new tunable nanofocusing lens by the linear-variant depths and nonlinear-variant widths of circular grating for far field practical applications. The constructively interference of cylindrical surface plasmon launched by the subwavelength metallic structure can form a subdiffraction-limited focus, and the focal length of the this structures can be adjusted if the each groove depth and width of circular grating are arranged in traced profile. According to the numerical calculation, the range of focusing points shift is much more than other plasmonic lens, and the relative phase of emitting light scattered by surface plasmon coupling circular grating can be modulated by the nonlinear-variant width and linear-variant depth. The simulation result indicates that the different relative phase of emitting light lead to variant focal length. We firstly show a unique phenomenon for the linear-variant depths and nonlinear-variant widths of circular grating that the positive change and negative ...

  18. The Atlas3D project -- XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images

    CERN Document Server

    Duc, Pierre-Alain; Karabal, Emin; Cappellari, Michele; Alatalo, Katherine; Blitz, Leo; Bournaud, Frederic; Bureau, Martin; Crocker, Alison F; Davies, Roger L; Davis, Timothy A; de Zeeuw, P T; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M; Michel-Dansac, Leo; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Paudel, Sanjaya; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M

    2014-01-01

    Galactic archeology based on star counts is instrumental to reconstruct the past mass assembly of Local Group galaxies. The development of new observing techniques and data-reduction, coupled with the use of sensitive large field of view cameras, now allows us to pursue this technique in more distant galaxies exploiting their diffuse low surface brightness (LSB) light. As part of the Atlas3D project, we have obtained with the MegaCam camera at the Canada-France Hawaii Telescope extremely deep, multi--band, images of nearby early-type galaxies. We present here a catalog of 92 galaxies from the Atlas3D sample, that are located in low to medium density environments. The observing strategy and data reduction pipeline, that achieve a gain of several magnitudes in the limiting surface brightness with respect to classical imaging surveys, are presented. The size and depth of the survey is compared to other recent deep imaging projects. The paper highlights the capability of LSB--optimized surveys at detecting new pr...

  19. H2-Producing Bacterial Community during Rice Straw Decomposition in Paddy Field Soil: Estimation by an Analysis of [FeFe]-Hydrogenase Gene Transcripts.

    Science.gov (United States)

    Baba, Ryuko; Asakawa, Susumu; Watanabe, Takeshi

    2016-09-29

    The transcription patterns of [FeFe]-hydrogenase genes (hydA), which encode the enzymes responsible for H2 production, were investigated during rice straw decomposition in paddy soil using molecular biological techniques. Paddy soil amended with and without rice straw was incubated under anoxic conditions. RNA was extracted from the soil, and three clone libraries of hydA were constructed using RNAs obtained from samples in the initial phase of rice straw decomposition (day 1 with rice straw), methanogenic phase of rice straw decomposition (day 14 with rice straw), and under a non-amended condition (day 14 without rice straw). hydA genes related to Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Thermotogae were mainly transcribed in paddy soil samples; however, their proportions markedly differed among the libraries. Deltaproteobacteria-related hydA genes were predominantly transcribed on day 1 with rice straw, while various types of hydA genes related to several phyla were transcribed on day 14 with rice straw. Although the diversity of transcribed hydA was significantly higher in the library on day 14 with rice straw than the other two libraries, the composition of hydA transcripts in the library was similar to that in the library on day 14 without rice straw. These results indicate that the composition of active H2 producers and/or H2 metabolic patterns dynamically change during rice straw decomposition in paddy soil.

  20. Integrated Emergy, Energy and Economic Evaluation of Rice and Vegetable Production Systems in Alluvial Paddy Fields: Implications for Agricultural Policy in China

    Science.gov (United States)

    China is the largest rice producing and consuming country in the world, but rice production has given way to the production of vegetables during the past twenty years. The government has been trying to stop this land-use conversion and increase the area in rice-vegetable rotation...

  1. Areas to explore surrounding the Cerro Prieto geothermal field, BC; Areas para exploracion en los alrededores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Dumas, Alvaro [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: alvaro.aguilar@cfe.gob.mx

    2009-07-15

    Exploration plays an important role in tapping underground natural resources-whether water, oil, natural gas or minerals. Exploratory data allow us to learn reservoir conditions, increasing probable reserves and reservoir life span. Around the Cerro Prieto geothermal field, BC, and in the Mexicali Valley in general, exploration had almost stopped but recently was resumed by the Studies Division of Comision Federal de ELectricidad (CFE)'s Gerencia de Proyectos Geotermoelectricos. The division sent technical personnel to structurally map the northern and eastern portions of Laguna Salada. The paper offers a general outline of the main zones undergoing exploratory studies-studies perhaps culminating in siting exploratory wells to locate more geothermal resources (and ultimately producing them using binary power plants). CFE also wants to site injection wells west of the current production zone, and this is covered, as well. All activities are meant to increase the productive lifespan of the geothermal reservoir. [Spanish] Cuando se trata de la explotacion de recursos naturales del subsuelo, sea agua, gas, petroleo o minerales, la exploracion juega un papel muy importante, ya que permite conocer las condiciones del yacimiento que pudieran llevar a incrementar las reservas de los recursos explotados y extender su vida util. En las zonas aledanas al campo geotermico de Cerro Prieto, BC, y en general en el Valle de Mexicali, la exploracion estaba practicamente detenida habiendose reactivado a raiz de que la Subgerencia de Estudios de la Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad (CFE) envio personal para realizar mapeos estructurales en las porciones norte y oriente de la Laguna Salada. Este trabajo presenta un panorama general de las areas prioritarias para realizar estudios exploratorios y poder programar, con mas bases, pozos exploratorios enfocados a localizar mas recursos geotermicos, inclusive para generar energia por medio

  2. The ATLAS3D project - XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images

    Science.gov (United States)

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Karabal, Emin; Cappellari, Michele; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Michel-Dansac, Leo; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Paudel, Sanjaya; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2015-01-01

    Galactic archaeology based on star counts is instrumental to reconstruct the past mass assembly of Local Group galaxies. The development of new observing techniques and data reduction, coupled with the use of sensitive large field of view cameras, now allows us to pursue this technique in more distant galaxies exploiting their diffuse low surface brightness (LSB) light. As part of the ATLAS3D project, we have obtained with the MegaCam camera at the Canada-France-Hawaii Telescope extremely deep, multiband images of nearby early-type galaxies (ETGs). We present here a catalogue of 92 galaxies from the ATLAS3D sample, which are located in low- to medium-density environments. The observing strategy and data reduction pipeline, which achieve a gain of several magnitudes in the limiting surface brightness with respect to classical imaging surveys, are presented. The size and depth of the survey are compared to other recent deep imaging projects. The paper highlights the capability of LSB-optimized surveys at detecting new prominent structures that change the apparent morphology of galaxies. The intrinsic limitations of deep imaging observations are also discussed, among those, the contamination of the stellar haloes of galaxies by extended ghost reflections, and the cirrus emission from Galactic dust. The detection and systematic census of fine structures that trace the present and past mass assembly of ETGs are one of the prime goals of the project. We provide specific examples of each type of observed structures - tidal tails, stellar streams and shells - and explain how they were identified and classified. We give an overview of the initial results. The detailed statistical analysis will be presented in future papers.

  3. Diversity of bacteriophages infecting Xanthomonas oryzae pv. oryzae in paddy fields and its potential to control bacterial leaf blight of rice.

    Science.gov (United States)

    Chae, Jong-Chan; Hung, Nguyen Bao; Yu, Sang-Mi; Lee, Ha Kyung; Lee, Yong Hoon

    2014-06-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

  4. Microbial ecology on the microcosm level: Activity and population dynamics of methanotrophic bacteria during early succession in a flooded rice field soil

    Science.gov (United States)

    Krause, S.; Frenzel, P.

    2009-04-01

    Methane oxidizing bacteria (methanotrophs) play an important role in natural wetlands and rice fields preventing large amounts of methane from escaping into the atmosphere. The occurrence of both type I and type II methanotrophs in the soil surface layer has been demonstrated in many studies. However, there is no profound understanding which of them are responsible for the oxidizing activity and how they differ ecologically. Hence, a gradient microcosm system was applied simulating oxic-anoxic interfaces of water saturated soils to unravel population dynamics in early succession of methanotrophs in a flooded rice paddy. Additionally, environmental parameters were analyzed to link environment, populations, and their specific activity. We measured pmoA-based (particulate methane monooxygenase) terminal restriction fragment length polymorphism (T-RFLP) profiles both on transcription and population level. DNA T-RFLP patterns showed no major differences in the methanotrophic community structure remaining relatively constant over time. In contrast the active methanotrophic community structure as detected by pmoA mRNA T-RFLP analysis clearly demonstrated a distinct pattern from DNA T-RFLP profiles. While type II represented the most prominent group on the population level it seems to play a minor role on the transcription level. Furthermore there were no clear implications towards a link between soil parameters (e.g. NH4+ concentration) and methanotrophic community structure.

  5. Suppressive effect of magnesium oxide materials on cadmium accumulation in winter wheat grain cultivated in a cadmium-contaminated paddy field under annual rice-wheat rotational cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Tetsuro, E-mail: tetsu-k@hino.meisei-u.ac.jp [Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Okazaki, Masanori, E-mail: masaok24@cc.tuat.ac.jp [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Motobayashi, Takashi, E-mail: takarice@cc.tuat.ac.jp [Field Science Center for Education and Research, Tokyo University of Agriculture and Technology, 3-7-1 Hommachi, Fuchu, Tokyo 183-0027 (Japan)

    2009-08-30

    The effectiveness of two kinds of magnesium oxide (MgO) materials, commercial MgO (2250 kg ha{sup -1}) and a material derived from MgO and magnesium silicate minerals named 'MgO-SH-A' (2250 and 4500 kg ha{sup -1}1), in suppression of uptake and accumulation of cadmium (Cd) into grain of winter wheat (Triticum aestivum L. cv. Ayahikari) was examined in a Cd-contaminated alluvial paddy field under annual rice-wheat rotational system. The MgO materials were mixed into the plough-layer soil only once prior to the preceding rice cultivation. Cadmium concentration in wheat grain produced from the non-amendment control exceeded the maximum limit of Cd in wheat grain adopted by FAO/WHO (0.2 mg kg{sup -1}). All of the treatments with the MgO materials significantly lowered plant available Cd fraction in the plough-layer soil. However, only the treatment with the commercial MgO at 2250 kg ha{sup -1} produced wheat grain whose Cd concentration was not only significantly lower than that from the control but also less than 0.2 mg kg{sup -1}. It is suggested that the significant suppressive effect of the commercial MgO on Cd accumulation in wheat grain would be mainly attributed to its high soil neutralizing capacity as compared to that of MgO-SH-A.

  6. Additional Burden of Diseases Associated with Cadmium Exposure: A Case Study of Cadmium Contaminated Rice Fields in Mae Sot District, Tak Province, Thailand

    Directory of Open Access Journals (Sweden)

    Nisarat Songprasert

    2015-08-01

    Full Text Available The cadmium (Cd contaminated rice fields in Mae Sot District, Tak Province, Thailand has been one of the major environmental problems in Thailand for the last 10 years. We used disability adjusted life years (DALYs to estimate the burden of disease attributable to Cd in terms of additional DALYs of Mae Sot residents. Cd exposure data included Cd and β2–microglobulin (β2-MG in urine (as an internal exposure dose and estimated cadmium daily intake (as an external exposure dose. Compared to the general Thai population, Mae Sot residents gained 10%–86% DALYs from nephrosis/nephritis, heart diseases, osteoporosis and cancer depending on their Cd exposure type and exposure level. The results for urinary Cd and dietary Cd intake varied according to the studies used for risk estimation. The ceiling effect was observed in results using dietary Cd intake because of the high Cd content in rice grown in the Mae Sot area. The results from β2-MG were more robust with additional DALYs ranging from 36%–86% for heart failure, cerebral infraction, and nephrosis/nephritis. Additional DALYs is a useful approach for assessing the magnitude of environmental Cd exposure. The Mae Sot population lost more healthy life compared to populations living in a non- or less Cd polluted area. This method should be applicable to various types of environmental contamination problems if exposure assessment information is available.

  7. Biological control of golden apple snail, Pomacea canaliculata by Chinese soft-shelled turtle, Pelodiscus sinensis in the wild rice, Zizania latifolia field

    Directory of Open Access Journals (Sweden)

    Shengzhang Dong

    2012-04-01

    Full Text Available The wild rice, Zizania latifolia Turcz, used to be one of the important aquatic vegetables cultivated in China. Recently, the golden apple snail - GAS (Pomacea canaliculata (Lamarck was found to be a major invasive pest attacking Z. latifolia. To control efficiently GAS, predation by the Chinese soft-shelled turtles (Pelodiscus sinensis on GAS was evaluated in laboratory and field trials. P. sinensis had a strong predatory capacity and selectivity for GAS both in laboratory and field conditions. All the sizes of P. sinensis prefer to capture smaller snails. The optimum number of P. sinensis released in Z. latifolia field was dependent on the density of over-wintered GAS, and varied between 30 and 50 turtles per 666.7 m². The number of GAS declined in the fields with turtles as compared to turtle-free field. A pattern of releasing P. sinensis in Z. latifolia fields was developed and widely adopted by farmers because of much more benefit besides biologically controlling GAS.

  8. Aerobic rice mechanization: techniques for crop establishment

    Science.gov (United States)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  9. Dissipation of pencycuron in rice plant

    Institute of Scientific and Technical Information of China (English)

    PAL R.; CHAKRABARTI K.; CHAKRABORTY A.; CHOWDHURY A.

    2005-01-01

    Pencycuron is a non-systemic protective fungicide for controlling sheath blight of rice. However, information on the fate of pencycuron in rice plant is lacking. The degradation of pencycuron in waterlogged tropic rice field was investigated.Pencycuron was applied at recommended field dose (187.5 g a.i./ha) and double recommended dose to cropped plots for three consecutive years. Pencycuron was rapidly degraded in rice plant at all doses of pencycuron application with first order half-lives of 1.57~2.77 d. The study revealed that pencycuron is safe from the human and environmental contamination point of view.

  10. Utilization Of Rice Husk Ash

    Directory of Open Access Journals (Sweden)

    S. D. Nagrale

    2012-07-01

    Full Text Available India is a major rice producing country, and the husk generated during milling is mostly used as a fuel in the boilers for processing paddy, producing energy through direct combustion and / or by gasification. About 20 million tones of Rice Husk Ash (RHA is produced annually. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped. Lots of ways are being thought of for disposing them by making commercial use of this RHA. RHA can be used as a replacement for concrete (15 to 25%.This paper evaluates how different contents of Rice Husk Ash added to concrete may influence its physical and mechanical properties. Sample Cubes were tested with different percentage of RHA and different w/c ratio, replacing in mass the cement. Properties like Compressive strength, Water absorption and Slump retention were evaluated.

  11. On-farm trials with rice fish cultivation in the west Kano rice irrigation scheme, Kenya

    OpenAIRE

    Rasowo, J.; Auma, E.O.

    2006-01-01

    The viability of integrating rice farming with fish culture was studied in ten (10) rice plots. The on-farm research was done during one rice-growing season starting May 2003. The rice variety used was IR 2793-80-1 while the fish species was the Nile tilapia, Oreochromis niloticus. The fish culture period lasted 77 days. An average fish production of 132.4 kg/ha was obtained. The mean recovery rate of tilapia was 43 per cent. Total rice yield from the fields stocked with fish was lower than f...

  12. Impact of the insecticide Alphacypermetrine and herbicide Oxadiazon, used singly or in combination, on the most abundant frog in French rice fields, Pelophylax perezi.

    Science.gov (United States)

    Mesléard, François; Gauthier-Clerc, Michel; Lambret, Philippe

    2016-07-01

    The potential impact of agricultural pesticides is a major concern with regard to biodiversity conservation. Pesticides are considered as one of the main causes of the worldwide decline of Amphibians. They are rarely used singly, but their cumulative impact and interaction are often neglected, as is the importance of the age or stage of the animal on which the impact of the molecules is assessed. We therefore tested the potential cumulative impact of the only authorized insecticide (Alphacypermetrine) and the main herbicide (Oxadiazon) used in French rice fields on four replicates of 25 eggs, young larvae and prometamorphosis tadpoles of the most abundant frog in paddies (Pelophylax perezi). We found no significant effect of the insecticide and herbicide, used singly or in combination, on hatching and young tadpoles. However, we found a strong impact of insecticide and herbicide used singly and a highly deleterious impact of their combined use on prometamorphosis tadpoles. Among the four replicates, only one of the prometamorphosis tadpoles did not reach this adult stage in the control against 9, 9, 6, 4 and 13, 9, 8, 7 with the herbicide and insecticide, respectively. But when the two pesticides were used in combination, only two prometamorphosis tapdoles reached the adult stage. Our results emphasize the potential impact on amphibians of pesticides used in agriculture and highlight the necessity of testing their role as cocktails. They also stress the importance of the age and/or stage of the target organism, the choice of which can lead to contrasting conclusions. Finally, our results suggest a possible underestimation of the impact of pesticides on non-targeted fauna in the rice fields in particular, and on living organisms in general.

  13. Effects of fertilization on microbial abundance and emissions of greenhouse gases (CH4 and N2O) in rice paddy fields.

    Science.gov (United States)

    Fan, Xianfang; Yu, Haiyang; Wu, Qinyan; Ma, Jing; Xu, Hua; Yang, Jinghui; Zhuang, Yiqing

    2016-02-01

    This study is to explore effects of nitrogen application and straw incorporation on abundance of relevant microbes and CH 4 and N2O fluxes in a midseason aerated rice paddy field. Fluxes of CH 4 and N2O were recorded, and abundance of relevant soil microbial functional genes was determined during rice-growing season in a 6-year-long fertilization experiment field in China. Results indicate that application of urea significantly changed the functional microbial composition, while the influence of straw incorporation was not significant. Application of urea significantly decreased the gene abundances of archaeal amoA and mcrA, but it significantly increased the gene abundances of bacterial amoA. CH 4 emission was significantly increased by fresh straw incorporation. Incorporation of burnt straw tended to increase CH 4 emission, while the urea application had no obvious effect on CH 4 emission. N2O emission was significantly increased by urea application, while fresh or burnt straw incorporation tended to decrease N2O emission. The functional microbial composition did not change significantly over time, although the abundances of pmoA, archaeal amoA, nirS, and nosZ genes changed significantly. The change of CH 4 emission showed an inverse trend with the one of the N2O emissions over time. To some extent, the abundance of some functional genes in this study can explain CH 4 and N2O emissions. However, the correlation between CH 4 and N2O emissions and the abundance of related functional genes was not significant. Environmental factors, such as soil Eh, may be more related to CH 4 and N2O emissions.

  14. Agricultural biotechnology. Monsanto donates its share of golden rice.

    Science.gov (United States)

    Normile, D

    2000-08-11

    Monsanto Co. has agreed to provide royalty-free licenses to speed up work on a genetically modified rice that could alleviate vitamin A deficiency around the world. Researchers welcomed last week's announcement, but warn that a thicket of intellectual property claims surrounds the technology and that significant legal hurdles remain before the rice can become widely available to farmers in developing countries.

  15. Integrated emergy, energy and economic evaluation of rice and vegetable production systems in alluvial paddy fields: implications for agricultural policy in China.

    Science.gov (United States)

    Lu, Hongfang; Bai, Yu; Ren, Hai; Campbell, Daniel E

    2010-12-01

    China is the largest rice producing and consuming country in the world, but rice production has given way to the production of vegetables during the past twenty years. The government has been trying to stop this land-use conversion and increase the area in rice-vegetable rotation. Important questions that must be answered to determine what strategy is best for society are, "What is the reason behind this conversion?"; "Which system is more productive and which is more sustainable?"; and "How can economic policy be used to adjust the pattern of farmland use to attain sustainable development?" To answer these questions, a combined evaluation of these agricultural production systems was done using emergy, energy and economic methods. An economic analysis clearly showed that the reason for this conversion was simply that the economic output/input ratio and the benefit density of the vegetable production system were greater than that of rice. However, both energy and emergy evaluations showed that long-term rice was the best choice for sustainable development, followed by rotation systems. The current price of rice is lower than the em-value of rice produced from the long-term rice system, but higher than that of rice produced from the rotation system. Scenario analysis showed that if the government increases the price of rice to the em-value of rice produced from the long-term rice system, US$0.4/kg, and takes the value of soil organic matter into account, the economic output/input ratios of both the rice and rotation systems will be higher than that of the vegetable system. The three methods, energy, emergy and economics, are different but complementary, each revealing a different aspect of the same system. Their combined use shows not only the reasons behind a system's current state or condition, but also the way to adjust these systems to move toward more sustainable states.

  16. The effect of salinity on chlorophyll, proline and mineral nutrients in common weeds of coastal rice fields in Malaysia.

    Science.gov (United States)

    Hakim, M A; Juraimi, Abdul Shukor; Hanafi, M M; Ismail, Mohd Razi; Rafii, M Y; Aslani, Fazad; Selamat, A

    2014-09-01

    Six weed species (Leptochola chinensis, Echinochloa crus-galli, Echinochloa colona, Jussiaea linifolia, Oryza sativa (weedy rice) and Cyperus iria) were tested for their salt tolerant traits in terms of chlorophyll, proline and mineral nutrients accumulation against different salinity levels (0, 4, 8, 16, 24, 32, and 40 dS m(-1)). Chlorophyll a, b and total chlorophyll content, proline and mineral nutrients accumulation were determined. Salt stress showed prominent effect on all the parameters investigated and there were significant variations between the all weed species. Chlorophyll content, K+, Ca(2+) and Mg(2+) ions in both shoots and roots significantly decreased; while proline and Na+ accumulation significantly increased with increasing salinity up to 40 dS m(-1). In terms of overall performance, Cyperus iria and E. crus-galliwere relatively more tolerant; E. colona and J. linifolia were tolerant; L. chinensis and O. sativa L were salt sensitive, respectively.

  17. Heliophilum fasciatum gen. nov. sp. nov. and Heliobacterium gestii sp. nov.: endospore-forming heliobacteria from rice field soils.

    Science.gov (United States)

    Ormerod, J G; Kimble, L K; Nesbakken, T; Torgersen, Y A; Woese, C R; Madigan, M T

    1996-04-01

    Two new taxa of phototrophic heliobacteria are described: Heliobacterium gestii sp. nov. and Heliophilum fasciatum gen. nov. sp. nov. Both organisms were isolated from dry paddy soils. Cells of H. gestii were motile spirilla; cells of H. fasciatum formed cell bundles that were motile as units. Both organisms produced endospores; H. gestii endospores contained dipicolinic acid and elevated levels of calcium. As with other heliobacteria, bacteriochlorophyll g was produced in both organisms and no intracytoplasmic photosynthetic membranes were observed. Growth of H. gestii and H. fasciatum occurred under both photoheterotrophic and chemotrophic conditions; nitrogen fixation also occurred in both organisms. H. gestii and H. fasciatium showed a phylogenetic relationship to the "low GC" line of gram-positive Bacteria, but H. fasciatum was distinct from H. gestii and all other heliobacteria. The ability of H. gestii and H. fasciatum to form endospores might be a significant ecological advantage for survival in their rice soil habitat.

  18. [Effects of combined applications of pig manure and chemical fertilizers on CH4 and N2O emissions and their global warming potentials in paddy fields with double-rice cropping].

    Science.gov (United States)

    Wang, Cong; Shen, Jian-Lin; Zheng, Liang; Liu, Jie-Yun; Qin, Hong-Ling; Li, Yong; Wu, Jin-Shui

    2014-08-01

    A field experiment was carried out to study the effects of combined applications of pig manure and chemical fertilizers on CH4 and N2O emissions, which were measured using the static chamber/gas chromatography method, and their global warming potentials in typical paddy fields with double-rice cropping in Hunan province. The results showed that the combined applications of pig manure and chemical fertilizers did not change the seasonal patterns of CH4 and N2O emissions from paddy soils, but significantly changed the magnitudes of CH4 and N2O fluxes in rice growing seasons as compared with sole application of chemical fertilizers. During the two rice growing seasons, the cumulative CH4 emissions for the pig manure and chemical nitrogen (N) fertilizer each contributing to 50% of the total applied N (1/2N + PM) treatment were higher than those for the treatments of no N fertilizer (ON), half amount of chemical N fertilizer (1/2N) and 100% chemical N fertilizer (N) by 54.83%, 33.85% and 43.30%, respectively (P fertilizers in paddy fields would increase the GWP of CH4 and N2O emissions during rice growing seasons and this effect should be considered in regional greenhouse gases emissions inventory.

  19. Quantifying methane emissions from rice fields in the Taihu Lake region, China by coupling a detailed soil database with biogeochemical model

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2009-05-01

    Full Text Available As China has approximately 22% of the world's rice paddies, the regional quantification of CH4 emissions from these paddies is important in determining their contribution to the global greenhouse gas effect. This paper reports the use of a biogeochemical model (DeNitrification and DeComposition or DNDC for quantifying CH4 emissions from rice fields in the Taihu Lake region of China. For this application, the DNDC model was linked to a 1:50 000 soil database derived from 1107 paddy soil profiles compiled during the Second National Soil Survey of China in the 1980s–1990s. The simulated results showed that the 2.3 Mha of paddy rice fields in the Taihu Lake region emitted the equivalent of 5.7 Tg C from 1982–2000, with the average CH4 flux ranging from 114 to 138 kg C ha−1 y−1. As for soil subgroups, the highest emission rate (660 kg C ha−1 y−1 was linked to gleyed paddy soils accounting for about 4.4% of the total area of paddy soils. The lowest emission rate (91 kg C ha−1 y−1 was associated with degleyed paddy soils accounting for about 18% of the total area of paddy soils. The most common soil in the area was hydromorphic paddy soils, which accounted for about 53% of the total area of paddy soils with a CH4 flux of 106 kg C ha−1 y−1. On a regional basis, the annual averaged CH4 flux in the Taihu Lake plain soil region and alluvial plain soil region were higher than that in the low mountainous and hilly soil region and the polder soil region. The model simulation was conducted with two databases using polygons or counties as the basic units. The county-based database contained soil information coarser than the polygon system built based on the 1:50 000 soil database. The modeled results with the two databases found similar spatial patterns of CH4 emissions in the Taihu

  20. LED multispectral circulation solar insecticidal lamp application in rice field%LED 多光谱间歇发光太阳能杀虫灯对稻田害虫诱杀效果

    Institute of Scientific and Technical Information of China (English)

    涂海华; 唐乃雄; 胡秀霞; 姚志文; 王广利; 魏洪义

    2016-01-01

    pesticide pollution, pest resistance and high cost compared with the chemical prevention. In this paper, we studied the night life regularity of insects and the rhythm of insects to the searchlight trap. For instance, the activity time of rice planthopper, Cnaphalocrocis medinalis and rice stem borer is from 7:00 in evening to 1:00 in the next morning, rice gall midge, brown planthopper, and white-backed planthopper mainly appear in 8:30-10:30 in evening, and Sesamia inferens usually acts from 10:30 in evening to 1:30 in the next morning. In order to overcome the drawbacks that lights were on all night and beneficial insects were captured by the light, we developed the LED multispectral circulating solar insecticidal lamp that can control time cycle and open different spectral peak lamp to kill the corresponding insect at night, which realized the maximization of luring pests and avoided the trapping of beneficial insects to the greatest extent. All experiments started in May and finished in September, 2015, which were carried out in an experimental field in Jiangxi Agricultural University, Shanggao County, Jiangxi Province (longitude of 115°10’ and latitude of 28°25’). We investigated the quantity damage and rate of rice planthopper, Cnaphalocrocis medinalis, rice stem borer, and Tryporyza incertulas in test and control area. Results indicated that the developed lamp had larger trapping force towards rice pests, and trapped a total of 5 orders, 10 families and 19 species, mainly including Lepidoptera, Pyralidae, Cnaphalocrocis medinalis, stem borer, Tryporyza incertulas, and Plecoptera Delphacidae Laodelphax striatellus, brown planthopper, Sogatella furcifera, Diptera, Culicidae giant mosquitoes and rice gall midge. In addition, there were also a few pests of Coleoptera and straight wing. The percentages of the trapped pest were 32.5% for rice leaf folder, 25.6% for Chilo suppressalis, 25.15% for Tryporyza incertulas, 9.35% for rice planthopper, and 6.90% for other

  1. Study of Dynamics of Floodwater Nitrogen and Regulation of Its Runoff Loss in Paddy Field-Based Two-Cropping Rice with Urea and Controlled Release Nitrogen Fertilizer Application

    Institute of Scientific and Technical Information of China (English)

    JI Xiong-hui; ZHENG Sheng-xian; LU Yan-hong; LIAO Yu-lin

    2007-01-01

    The article deals with the effects of urea and controlled release nitrogen fertilizer (CRNF) on dynamics of pH, electronic conductivity (EC), total nitrogen (TN), NH4+-N and NO3--N in floodwater, and the regulation of runoff TN loss from paddy field-based two-cropping rice in Dongting Lake, China, and probes the best fertilization management for controlling N loss. Studies were conducted through modeling alluvial sandy loamy paddy soil (ASP) and purple calcareous clayey paddy soil (PCP) using lysimeter, following the sequence of the soil profiles identified by investigating soil profile. After application of urea in paddy field-based two-cropping rice, TN and NH4+-N concentrations in floodwater reached peak on the 1st and the 3rd day, respectively, and then decreased rapidly over time; all the floodwater NO3--N concentrations were very low; the pH of floodwater gradually rose in case of early rice within 15 d (late rice within 3 d) after application of urea,and EC remained consistent with the dynamics of NH4+-N. The applied CRNF, especially 70% CRNF, led to significantly lower floodwater TN and NH4+ concentrations, pH, and EC values compared with urea within 15 d after application. The monitoring result for N loss due to natural rainfall runoff indicated that the amount of TN lost in runoff from paddy fieldbased two-cropping rice with urea application in Dongting Lake area was 7.47 kg ha-1, which accounted for 2.49% of ureaN applied, and that with CRNF and 70% CRNF application decreased 24.5 and 27.2% compared with urea application,respectively. The two runoff events, which occurred within 20 d after application, contributed significantly to TN loss from paddy field. TN loss due to the two runoffs in urea, CRNF, and 70% CRNF treatments accounted for 72, 70, and 58% of the total TN loss due to runoff over the whole rice growth season, respectively. And the TN loss in these two CRNF treatments due to the first run-off event at the 10th day after application to early

  2. Bioaccumulation of organochlorine pesticides and polychlorinated biphenyls by loaches living in rice paddy fields of Northeast China.

    Science.gov (United States)

    Zhang, Haijun; Lu, Xianbo; Zhang, Yichi; Ma, Xindong; Wang, Shuqiu; Ni, Yuwen; Chen, Jiping

    2016-09-01

    The concentrations of 21 organochlorine pesticide (OCP) residues and 18 polychlorinated biphenyl (PCB) congeners were measured in two loach species (Misgurnus mohoity and Paramisgurnus dabryanus) and the soils of their inhabiting rice paddies from three typical rice production bases of Northeast China to explore the main factors influencing the bioaccumulation. The concentrations of ∑18PCBs and ∑21OCPs in loaches were determined to be in the ranges of 0.14-0.76 ng g(-1) wet weight (ww) and 1.19-78.53 ng g(-1) ww, respectively. Most of loaches showed the considerably high contamination levels of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), which accounted for over 97% of the total OCPs. The much lower maximum allowable loach consumption rates (bioaccumulation potential. The comparisons of BSAF values and the results of multivariate analysis indicated that habitat-specific environmental conditions, mainly the paddy soil contamination levels and average temperature, decisively affected the bioaccumulation of organochlorine contaminants. When the influence of lipid contents was offset, M. mohoity loaches were found to have a higher potential to accumulation PCBs and OCPs than P. dabryanus loaches, while the bioaccumulation potentials did not exhibit significant differences between juvenile and adult loaches and between male and female loaches. The octanol-water partition coefficient (KOW) was the main chemical factor influencing bioaccumulation potentials. The BSAF values presented an increasing tendency with increasing log KOW values from 6.0 to approximately 7.0, followed by a decreasing tendency with a continuous increase in log KOW values. Moreover, loaches exhibited an isomeric-selective bioaccumulation for p,p'-chlorinated DDTs, α-HCH, β-HCH, δ-HCH and cis-chlordane.

  3. Chemical Weed-control Technique in Machine-transplanted Fields of Single Late Rice%单季晚稻机插田化学除草技术

    Institute of Scientific and Technical Information of China (English)

    赵敏; 李荣; 张国忠; 吴传伟; 洪美萍; 徐福寿; 陈建明

    2011-01-01

    [目的]随着小苗机插稻田面积的扩大,机插田草害发生也日益严重,为有效控制机插田杂草的危害,2008-2009年在浙江省桐庐县单季晚稻机插田进行不同施药时期和施药剂量对主要杂草防效试验.[结果]5%丁草胺GR 750 g a.i./hm+10%苄嘧磺隆WP 30 g a.i./hm和20%乙·苄WP 90 g a.i./hm在插后3 d施药.插后50d对总草鲜质量防效极显著高于插后7 d的防效.53%苄嘧·苯噻酰WP 318、477、636 g&iAun~于插后5 d施药,药后30、50 d,对异型莎草、阔叶草、总杂草的防效有差异;而50%苄·丁·异丙隆WP 450、600 g a.i/hm的防效差异均不显著;药后50 d对总草株防效均达93%以上、鲜质量防效99%以上.且增产8.2%~14.4%.上述处理除20%乙·苄WP 90 g a.i./hm在药后15 d内对机插稻有一定影响外,其余均较安全.[结论]在小苗机插后3-5 d,使用5%丁草胺GR 750 g a.i./hm+10%苄嘧磺隆WP 30 g a.i./hm或53%苄嘧·苯噻酰WP 318~636 g a.i./hm,或50%苄·丁·异丙隆WP 450~600 g a.i./hm拌肥或拌土150 kg/hm能有效控制机插田杂草的为害,且对机插稻安全.%[Aims]With the increase of area of machine-transplanted rice fields, occurrence of weeds was also increasingly serious.Field efficacy of different spraying time and spraying doses to major weeds was evaluated in machinetransplanted fields in Tonglu county of Zhejiang province during the years of 2008 to 2009 in order to effectively control the damage of weeds.[Results]Field efficacy of the mixture of butachlor 5% GR 750 g ai./ha and bensulfuron methyl 10% WP 30 g a.i./ha, and acetochlor· bensulfuron-methyl 20% WP 90 g a.i./ha sprayed on the 3rd day after machine-transplanting on fresh weight of total weeds were significantly higher than those on the 7th day after machinetransplanted for 50 days after machine-transplanting.On the 5th day spraying after machine-transplanted, control efficacy of bensulfuron methyl· mefenacet 53% WP at different doses(318, 477

  4. 保试达防除水稻田杂草稻研究%Study on Glufosinate-amonium in Controlling Oryza sativa f. spontanea in Rice Field

    Institute of Scientific and Technical Information of China (English)

    高玉珠; 罗彩莲; 卓晓光; 刘华伟; 邓德海; 翁强; 李国君

    2014-01-01

    Objective The aim was to explore the efficacy and safety of glu-fosinate-ammonium in controlling Oryza sativa f. spontanea in rice field, for pro-viding efficient and safe solution for controlling Oryza sativa f. spontanea. [Method] The research which taking the glufosinate-ammonium as the based phar-maceutical for controlling Oryza sativa f.spontanea was carried out, by se-lecting the middle paddy in which Oryza sativa f. spontanea serious outbroke at perennial as the testing ground, and single-use of glufosinate-ammonium and mix of glufosinate-ammonium and oxadi-azon. [Result] The results showed that glufosinate-ammonium and oxadia-zon had better effects for controlling O-ryza sativa f.spontanea and the main weeds in seeded rice. Supporting use treatment with potassium nitrate, glufosinate-am-monium and oxadiazon had final safety of yield. [Conclusion] The results provid-ed a reference for the rice production.%[目的]明确保试达防除稻田杂草稻的效果及安全性,为稻田杂草稻防除提供高效、安全的解决方案。[方法]开展以保试达为基础药剂对杂草稻防除效果的研究,通过选择常年杂草稻发生严重的中产稻田为试验地和保试达单用、与农思它混用等方法进行试验。[结果]保试达和农思它对杂草稻和直播稻田的主要杂草都有较好的防治效果。硝酸钾、保试达和农思它配套使用处理对产量有最终安全性。[结论]研究结果为水稻生产提供了参考。

  5. Differential Expression of Whitebacked Planthopper Resistance in the japonica/indica Doubled Haploid Rice Population under Field Evaluation and Seedbox Screening Test

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Whitebacked planthopper (WBPH) -resistance in a japonica / indica doubled haploid (DH) rice population established from a cross between WBPH-resistant japonica Chunjiang 06 and susceptible indica TN1, was comparatively evaluated through a field experiment based on the WBPH immigrant density and standardized seedbox screening test (SSST). All the susceptible DH lines in the field experiment behaved accordingly in SSST. However, 35 of resistant 66 lines (53%) in the field, were categorized to susceptible groups in SSST. Likewise, there were no significant differences in WBPH immigrant densities among 70 DH lines that were highly resistant to susceptible in SSST. The results revealed that SSST could not evaluate properly WBPH resistance in the DH lines. Four QTLs for WBPH-resistance phenotyped by the immigrant density were detected on chromosomes 2, 3, 4, and 11. Of them, the QTL on chromosome 4 was the most effective (LOD 21.8, variance 78%). Five QTLs associated with seedling mortality were mapped on chromosomes 2, 3, 4, 5 and 6. In addition to the QTL (LOD 10.5, variance 68%) on chromosome 4, there was another major QTL (LOD 12.7, variance 71%) located on chromosome 5, which was SSST-specific but might be irrespective of the WBPH resistance traits.

  6. EFFECTS OF MULCHING AND TILLAGE ON SOIL FERTILITY OF UPLAND RICE FIELD%不同耕作方式下覆草旱作稻田土壤肥力特征

    Institute of Scientific and Technical Information of China (English)

    王栋; 李辉信; 胡锋

    2011-01-01

    A field experiment was carried out during the period from 2005 to 2007 to investigate the effects of straw mulching and tillage on soil physical, chemical and biological properties of upland rice field that has been under the double-rice cropping system since 2003 in the seasonal arid region of South China (Yujiang County, Jiangxi Province). Results show that there was no significant difference between the treatments, I. E. conventional flooded rice cultivation (CF) , upland rice cultivation with straw mulching (SM) , and non-tillage upland rice cultivation with straw mulching (N-SM) in soil bulk density and total porosity in 0 - 15 cm depth soil layer. But Treatment N-SM significantly increased soil organic matter, total N, alkalystic N and soil basal respiration, and both Treatments SM and N-SM significantly increased soil microbial biomass carbon content and the activities of urease and saccharase, as was compared with Treatment CF. Therefore, the findings suggest that upland rice cultivation with straw mulching and non-tillage upland rice cultivation with straw mulching may be cited as novel water-saving and fertility building rice cultivation models for extrapolation in this region.%通过始建于2003年中国南方季节性干旱区(江西省余江县)的双季稻田定位试验,于2005~2007年研究了水稻覆草旱作和免耕覆草旱作对稻田土壤理化性质和生物学性质的影响.结果表明,覆草旱作、免耕覆草旱作的耕层土壤容重和总孔隙度与常规水作的差异不显著.与常规水作相比,免耕覆草旱作显著提高土壤有机质、全氮、碱解氮和土壤基础呼吸;与常规水作相比,覆草旱作和免耕覆草旱作均显著提高土壤微生物生物量碳含量、脲酶和蔗糖酶活性.由此可知,覆草旱作和免耕覆草旱作可以作为该区积极推行的具有培肥地力作用的节水型稻作栽培模式.

  7. The rice REDUCED CULM NUMBER11 gene controls vegetative growth under low-temperature conditions in paddy fields independent of RCN1/OsABCG5.

    Science.gov (United States)

    Funabiki, Atsushi; Takano, Sho; Matsuda, Shuichi; Tokuji, Yoshihiko; Takamure, Itsuro; Kato, Kiyoaki

    2013-10-01

    Low temperature tolerance during vegetative growth is an important objective in rice (Oryza sativa L.) breeding programs. We isolated a novel reduced culm number mutant, designated reduced culm number11 (rcn11), by screening under low-temperature condition in a paddy fields. Since the shoot architecture of the rcn11 was very similar to that of the rcn1, we examined whether RCN11 is involved in RCN1/OsABCG5-associated vegetative growth control. The rcn11 mutant has no mutation in the RCN1/OsABCG5 gene and rcn11 has no effect on RCN1/OsABCG5 gene expression. In the rcn1 mutant, RCN1/OsABCG5 was upregulated showing that RCN1/OsABCG5 is controlled by negative feedback regulation. Absence of an effect of rcn11 on RCN1/OsABCG5 feedback regulation supported that RCN11 is not involved in the RCN1/OsABCG5-associated transport system. A genetic allelism test and molecular mapping study showed that rcn11 is independent of rcn1 on rice chromosome 3 and located on chromosome 8. The rcn1 rcn11 phenotype suggests that RCN11 acts on vegetative growth independent of RCN1/OsABCG5. A root development comparison between rcn1 and rcn11 in young seedlings represented that rcn11 reduced crown root number and elongation, whereas rcn1 reduced lateral root density and elongation. Thus, rcn11 will shed new light on vegetative growth control under low temperature.

  8. Characteristics of Resistance to Rice Sheath Blight of Zhongda 2, a Transgenic Rice Line as Modified by Gene "RC24"

    Institute of Scientific and Technical Information of China (English)

    YUAN Hong-xu; XU Xin-ping; ZHANG Jian-zhong; GUO Jian-fu; LI Bao-jian

    2004-01-01

    The transgenic rice, Zhongda 2, which was genetically modified from an indica rice line Zhuxian B by rice chitinase gene (RC24), had high resistance to rice sheath blight (Rhizoctonia solani) in laboratory and a two-year field experiment. The pathogen could invade sheath of Zhongda 2 and induce symptoms of the disease. No difference was noted in time of penetration or incubation period between Zhongda 2 and non-transgenic rice control, Zhuxian B, but the hyphae lysate could be observed earlier five non-transgenic rice lines showed higher resistance than donor non-transgenic parents, but the resistance was different along with the different maternal parents.

  9. Effect of la io Predatory Behavior on Pest Occurrence in Rice Field%南蝠捕食行为及其对稻田虫害发生的影响

    Institute of Scientific and Technical Information of China (English)

    韩宝银; 贺红早

    2012-01-01

    The effect of Ia io predatory behavior on pest occurrence in rice field was studied by excrement analysis and the direct-vision method to know the role of Ia io in ecosystem stability of rice field. Ia io is one of effective natural enemies to control pests in rice field. The average rice yield in 2 ~ 3 km radius area was 98. 2 kg/667m2 higher than in 6 ~ 7 km radius area. The diet composition for la io includes Coleoptera, Lepidoptera, Hemiptera, Orthoptera, Hymenoptera, and Acaria etc. besides birds. Because most insect species are spreaders of rice pests and diseases, Ia io can play an important role in maintenance of ecosystem stability in rice field and improvement of rice yield.%为了解南蝠(Ia io)在维持稻田生态系统稳定性中的作用,采用粪便分析和直观法,研究了南蝠的捕食行为及其对稻田虫害发生的影响.结果表明:南蝠是控制农田害虫的有效天敌之一,在其捕食区域内稻田病虫害较轻,2~3 km半径区域水稻的平均产量比6~7 km半径区域增产98.2kg/667m2;南蝠的食物组成除鸟类外,还有鞘翅目、鳞翅目、半翅目、直翅目、膜翅目和蜱螨等昆虫/生物,多数种类昆虫均是水稻害虫或病害的传播者.南蝠在维护稻田生态系统稳定性和提高农作物产量方面具有重要的作用.

  10. Herbicide application techniques in direct seeded rice field with glufosinate-ammonium-resistant transgenic rice ‘Y0003’%抗草铵膦转基因水稻‘Y0003’直播田除草剂施用技术研究

    Institute of Scientific and Technical Information of China (English)

    孙光辉; 强胜; 戴伟民; 宋小玲

    2014-01-01

    In order to provide scientific evidence for safety and effective application of glufosinate-ammonium,the optimum spraying period and effective dosage of glufosinate-ammonium was explored in direct-seeded rice field with glufosinate-ammonium-resistant (GR)transgenic rice ‘Y0003’.Different dosages of glufosinate-ammonium were applied at different spraying periods (three to four leaf stage,five to six leaf stage and tillering stage)in the direct-seeded rice field,and the effect of different spraying periods and dosage of glufosinate-ammonium on weed control and growth of GR transgenic rice were determined.In direct-seeded field,the weed control efficiency were low,and rice yield was reduced significantly at dosage of 0.225 g/hm2 (active ingredient,the same as fol-lows)under three spraying periods.Weed control efficiencies were also low at the dosage of 0.45 g /hm2 and 0.9 g/hm2 under three to four leaf stage and tillering stage.The growth of transgenic rice was inhibited and rice yield reduced significantly compared with the weed-free control.Whereas weed control efficiencies of 0.45 g/hm2 and 0.9 g/hm2 at five to six leaf stage was more than 90%,without injury on rice and influence on the rice yield. Therefore application of 0.45-0.9 g/hm2 glufosinate-ammonium at five to six leaf stage was recommended for weed control in direct-seeded GR transgenic rice ‘Y0003’field.%为给抗草铵膦转基因水稻‘Y0003’商业化生产后除草剂的安全高效施用提供科学依据,探索了该转基因直播稻田草铵膦的最佳施用时期和施用剂量。研究了在直播稻田3~4叶期、5~6叶期以及分蘖期施用0.225、0.45和0.9 g/hm2草铵膦(有效成分,下同)后,草铵膦对杂草的控制效果和对转基因水稻生长的影响。在测试的3个施药时期,施用0.225 g/hm2草铵膦对杂草防除效果都很差,水稻减产严重;在水稻3~4叶期和分蘖期施用0.45和0.9 g/hm2草铵膦对杂草的

  11. Rice production in relation to soil quality under different rice-based cropping systems

    Science.gov (United States)

    Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

    2016-04-01

    Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal soil depth without restriction for rice root elongation

  12. 耕作方式和稻草还田对双季稻田CH4和N2O排放的影响%Effect of tillage and rice residue return on CH4 and N2O emission from double rice field

    Institute of Scientific and Technical Information of China (English)

    秦晓波; 李玉娥; 万运帆; 廖育林; 范美蓉; 高清竹; 刘硕; 马欣

    2014-01-01

    Greenhouse gas intensity (GHGI) (methane and nitrous oxide) of double rice paddy was controlled by various field managements, tillage, and rice straw return to the field. On one hand, the choice of the tillage mode affects the gas permeability of soil during the crop-growing stage. On the other, the incorporation of rice straw can be a critical way to amend the loss of soil carbon. Both of the two practices have their advantages and disadvantages on rice production and environmental effects. In fact, no tillage causes less methane emissions from double rice fields than the field with conventional tillage. Nevertheless, rice straw return to the field increases tremendous methane production and emission of organic carbon. In spite of its promotion on rice productivity and sequestration of soil organic carbon pool, this practice is still under discussion .Therefore, multi-management mode should be considered simultaneously when regional or national policy is made to reduce GHGI from agriculture. To date, the study of the interaction effect of tillage and the rice residue return on GHGI from double rice fields is lacking. Most of the previous studies focused only on one field management and its influence mechanism. Consequently, we conducted a measurement for 4 rice growing seasons on GHGI of a double rice field in Hunan, China to investigate the interaction effect of tillage and rice straw return on both the social-economical and environmental benefits. The improved static chamber-GC (gas chromatography) method was used to monitor the greenhouse gas emissions from the rice paddy. Major improvements made on the chamber include the adjustable sampling tube and the pores in the base. The former was designed to change with the growth of the rice plant and the latter favored the communication of soil water between the inside and outside of the base. Both of them enhanced the accuracy of the field measurement. Four field practices were included in this research, viz. CWS

  13. New technique for identifying varieties resistance to rice blast

    Institute of Scientific and Technical Information of China (English)

    ZHUPeiliang

    1994-01-01

    After 8 yrs lab experiments and field tests, an advanced technique for identifying varieties resistance to rice blast was developed by a research group in Plant Protection Institute, Zhejiang Academy of AgricuLltural Sciences. With this technique, the inoculum was prepared on a maizc-rice-straw-agar media which was suitable for sporulation of most rice blast pathogen isolates.

  14. Feasiblity of collecting naturally leached rice straw for thermal conversion

    NARCIS (Netherlands)

    Bakker, R.R.; Jenkins, B.M.

    2003-01-01

    The practical application of field or natural leaching to rice straw was evaluated with the goal of improving biomass fuel value. Observations on three rice farms in the Sacramento Valley, California indicated that potassium, chlorine and total ash are leached from rice straw by rainfall regardless

  15. Clinical Application of Surrounding Puncture

    Institute of Scientific and Technical Information of China (English)

    GUO Yao-jie; HAN Chou-ping

    2003-01-01

    Surrounding puncture can stop pathogenic qi from spreading, consolidate the connection between local meridians and enrich local qi and blood, which can eventually supplement anti-pathogenic qi and remove pathogenic qi, and consequently remedy diseases. The author of this article summrized and analyzed the clinical application of surrounding puncture for the purpose of studying this technique and improving the therapeutic effect.

  16. Results of an experimental campaign of monitoring of agricultural practice of field combustion of rice straw; Risultati di una campagna sperimentale di monitoraggio della pratica di combustione all`aperto della paglia di riso

    Energy Technology Data Exchange (ETDEWEB)

    Spezzano, P.; Cerea, E.; Massironi, L.; Nocente, M.; Olivetta, A. [ENEA, Centro Ricerche Saluggia, Vercelli (Italy). Dipt. Ambiente; Castellani, C. M.; De Zaiacomo, T. [ENEA, centro Ricerche ``Ezio Clementel``, Bologna (Italy). Dipt. Ambiente

    1997-09-01

    For the evaluation of environmental impact of agricultural practice of field combustion of rice straw following harvest an experimental campaign was performed in a field situated near Rive Vercellese (Vercelli, Italy) by burning the amount of rice straw in a 1.2 hectare piece of ground. Four sampling positions were operated, each one composed of a miniaturized impactor and a battery-powered pump, and an optical monitor was also used to measure aerosuspended aerosol concentration continuously. Experimental results show that after field combustion, resulting ash is depleted in cadmium, copper, lead and zinc while manganese and silica remaining almost quantitatively in the ash. Manganese and silica were the only components attributable to field combustion of rice straw in the atmospheric aerosol collected during this monitoring survey. Aerosuspended mass concentration values obtained by means of both optical measurements and gravimetric determinations are presented. Aerosol granulometric distribution, measured in the vicinity of the experimental field and the parameter values of the log-normal distribution obtained with experimental data are also indicated. Finally, a comparison is made between aerosol granulometric data and respirable fraction as defined by international standards.

  17. The role of momilactones in rice allelopathy.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Peters, Reuben J

    2013-02-01

    Large field screening programs and laboratory experiments in many countries have indicated that rice is allelopathic and releases allelochemical(s) into its environment. A number of compounds, such as phenolic acids, fatty acids, phenylalkanoic acids, hydroxamic acids, terpenes, and indoles, have been identified as potential rice allelochemicals. However, the studies reviewed here demonstrate that the labdane-related diterpenoid momilactones are the most important, with momilactone B playing a particularly critical role. Rice plants secrete momilactone B from their roots into the neighboring environments over their entire life cycle at phytotoxic levels, and momilactone B seems to account for the majority of the observed rice allelopathy. In addition, genetic studies have shown that selective removal of the momilactones only from the complex mixture found in rice root exudates significantly reduces allelopathy, demonstrating that these serve as allelochemicals, the importance of which is reflected in the presence of a dedicated momilactone biosynthetic gene cluster in the rice genome.

  18. Optimization Model for Mitigating Global Warming at the Farm Scale: An Application to Japanese Rice Farms

    OpenAIRE

    Kiyotaka Masuda

    2016-01-01

    In Japan, greenhouse gas emissions from rice production, especially CH4 emissions in rice paddy fields, are the primary contributors to global warming from agriculture. When prolonged midseason drainage for mitigating CH4 emissions from rice paddy fields is practiced with environmentally friendly rice production based on reduced use of synthetic pesticides and chemical fertilizers, Japanese rice farmers can receive an agri-environmental direct payment. This paper examines the economic and env...

  19. Geochemical Modeling of Zinc Bioavailability for Rice

    NARCIS (Netherlands)

    Gao, X.; Schröder, T.J.; Hoffland, E.; Zou, C.; Zhang, F.; Zee, van der S.E.A.T.M.

    2010-01-01

    The transition from anaerobic to aerobic rice (Oryza sativa L.) cultivation has been reported to decrease Zn bioavailability. To determine and understand the differences in plant Zn uptake between anaerobic and aerobic rice cultivation systems, a field plot experiment was conducted with direct-seede

  20. Effects of crop rotation on properties of a Vietnam clay soil under rice-based cropping systems in small-scale farmers' fields

    Science.gov (United States)

    In tropical deltas, intensive monocultures with three rice crops per year have been the standard for decades. In recent years, though, rice-based rotations with one or more upland crops per year are being adopted by several farmers. Their trends of increasing grain yields raise the question whether ...

  1. Cyanobacterial diversity shifts induced by butachlor in selected Indian rice fields in Eastern Uttar Pradesh and Western Bihar analyzed with PCR and DGGE.

    Science.gov (United States)

    Kumari, Nidhi; Narayan, Om Prakash; Rai, Lal Chand

    2012-01-01

    The present study examines the effects of 30 mg/kg butachlor on the cyanobacterial diversity of rice fields in Eastern Uttar Pradesh and Western Bihar in India. A total of 40 samples were grouped into three classes [(i) acidic, (ii) neutral, and (iii) alkaline soils], based on physicochemical and principle component analyses. Acidic soils mainly harbored Westillopsis, Trichormus, Anabaenopsis, and unicellular cyanobacteria; whereas Nostoc, Anabaena, Calothrix, Tolypothrix, and Aulosira were found in neutral and alkaline soils. Molecular characterization using 16S rRNA PCR and DGGE revealed the presence of 13 different phylotypes of cyanobacteria in these samples. Butachlor treatment of the soil samples led to the disappearance of 5 and the emergence of 2 additional phylotypes. A total of 40 DGGE bands showed significant reproducible changes upon treatment with butachlor. Phylogenetic analyses divided the phylotypes into five major clusters exhibiting interesting links with soil pH. Aulosira, Anabaena, Trichormus, and Anabaenopsis were sensitive to butachlor treatment, whereas uncultured cyanobacteria, a chroococcalean member, Westillopsis, Nostoc, Calothrix, Tolypothrix, Rivularia, Gloeotrichia, Fischerella, Leptolyngbya, and Cylindrospermum, appeared to be tolerant against butachlor at their native soil pH. Butachlor-induced inhibition of nitrogen fixation was found to be 65% (maximum) and 33% (minimum) in the soil samples of pH 9.23 and 5.20, respectively. In conclusion, low butachlor doses may prove beneficial in paddy fields having a neutral to alkaline soil pH.

  2. The Use of Rice Varietal Diversity for Rice Blast Control

    Institute of Scientific and Technical Information of China (English)

    ZHU You-yong; LI Zuo-shen; LU Bao-rong; CHEN Hai-ru; FAN Jing-hua; WANG Yun-yue; LI Yan; FAN Jin-xiang; YANG Shi-sheng; MA Guan-liang; CHEN Jian-bin

    2003-01-01

    Field experiments of mixed- (intercropping) and pure-planting (monoculture) of four rice vari-eties, representing improved hybrid varieties (Shanyou63 and Shanyou22) and high-quality traditional varie-ties (Huangkenuo and Zigu) from Yunnan Province, were conducted based on their differences in genetic back-ground and agro-economical characteristics. The results demonstrated that the mixed-planting of the hybridrice and high-quality traditional rice varieties had a significantly greater effect on controlling rice blast diseasethan the monocuiture of these varieties, particularly the traditional ones. It is evident for the highly suscepti-ble traditional varieties in mixed-planting to achieve disease control, with significant decreases in blast inci-dences and severity indexes. The blast control efficiency reached up to 83 - 98 % under such planting model.This suggests that an appropriate mixed-planting of rice varieties with diverse genetic background and agro-e-conomical characteristics is an effective approach for rice blast control. In addition, resistance of the tradi-tional rice varieties to lodging was considerably increased in the plots with mixed-planting, compared with theplots with monoculture. The average rate of grain-yield increase ranged from 6.5 to 9.7 % in the plots withmixed-planting.

  3. 大连地下石油储备库洞室群围岩稳定性及渗流场分析%ANALYSES OF SURROUNDING ROCK STABILITY OF CAVERN GROUP AND SEEPAGE FIELD AT DALIAN UNDERGROUND OIL STORAGE

    Institute of Scientific and Technical Information of China (English)

    于崇; 李海波; 周庆生

    2012-01-01

    为分析水封式大连地下石油储备库洞室群围岩稳定性及渗流场特征,首先基于现场地应力实测结果的回归分析,利用Fish语言编写函数,反演初始地应力场.其次,采用三维离散元程序3DEC生成三维节理网络模型,反演库区初始渗流场的各向异性特征.最后,利用应力与渗流耦合模块实施开挖仿真计算,获取围岩应力场、位移场变化特征.考虑平行、垂直层理面不同材料特性,基于带有抗拉的Mohr-Coulomb强度储备型点安全系数,定量评价洞室群的稳定性.借鉴国外水封效果评价标准,分别从地下水位线和垂直水力坡降2个方面,分析渗流场变化特征.研究表明:在洞室周边平行层理面点安全系数为1.02~1.25,垂直层理面点安全系数为1.95~2.00.在补水隧道及注水孔组成的人工水幕系统作用下,建设期内地下水位下降3~5 m,地下水位距洞室顶55 m.开挖洞室附近平均垂直水力坡降大于1.0,满足设计规范及密封性要求.%Aiming at analyses of surrounding rock stability of cavern group and seepage field characteristics at Dalian water-tight underground oil storage, firstly, based on regression analysis of in-situ stress testing data, initial in-situ stress field inversion is conducted with functions defined with program language Fish. Secondly, after three-dimensional random joint networks with different sizes are generated with 3DEC. a new method of calculating the anisotropy permeability is proposed. Finally, stress field and displacement field of surrounding rocks are gained using coupled fluid and mechanical excavation calculations. Based on point safety factor, whose criterion is the Mohr-Coulomb one with the tensile strength, cavern group stability is quantitatively evaluated considering parallel and vertical bedding planes owing to different materials characteristics. Referring to ideas from abroad, seepage field is analyzed by groundwater table and vertical

  4. 米糠毛油掺伪食用植物油的低场核磁共振检测%Discrimination of Edible Vegetable Oil Adulterated with Rice Bran Crude Oil by Low-field Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    周凝; 刘宝林; 王欣; 汪宏志; 杨培强; 周航

    2011-01-01

    应用低场核磁共振方法分别测定了米糠毛油和3种食用植物油(花生油、橄榄油和葵花籽油)的弛豫图谱,发现在10 ms左右米糠毛油弛豫图谱中出现了-明显特征峰,而其他3种纯油品均未检出,且随着米糠毛油掺入量的增多,该峰面积的比例也随之增大.结果表明,通过测定该特征峰面积比例可定量测出米糠毛油掺伪量.%The relaxation maps of three edible vegetable oils (peanut oil, sunflower seed oil and sunflower seed oil) and rice bran crude oil were detected by low - field nuclear magnetic resonance technology (NMR). An obvious characteristic peak has been determined in the relaxation maps of rice bran crude oil at 10ms, which can not be detected in the other three kinds of pure edible oil. And the area proportion increased with the increase of rice bran crude oil content. Therefore, the detecting of the characteristic peak area can judge the vegetable oil adulterated with rice bran crude oil.

  5. Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    Science.gov (United States)

    Li, Guangsheng; Wang, Yongmo; Liu, Biao; Zhang, Guoan

    2014-01-01

    Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.

  6. Transgenic Bacillus thuringiensis (Bt rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    Directory of Open Access Journals (Sweden)

    Guangsheng Li

    Full Text Available Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.

  7. Visual surround suppression in schizophrenia

    Directory of Open Access Journals (Sweden)

    Marc Samuel Tibber

    2013-02-01

    Full Text Available Compared to unaffected observers patients with schizophrenia show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgements of contrast - a manifestation of weaker surround suppression. To examine the generality of this phenomenon we measured the ability of 24 individuals with schizophrenia to judge the luminance, contrast, orientation and size of targets embedded in contextual surrounds that would typically influence the target’s appearance. Individuals with schizophrenia demonstrated weaker surround suppression compared to matched controls for stimuli defined by contrast or size, but not for those defined by luminance or orientation. As perceived luminance is thought to be regulated at the earliest stages of visual processing our findings are consistent with a suppression deficit that is predominantly cortical in origin. In addition, we propose that preserved orientation surround suppression in schizophrenia may reflect the sparing of broadly tuned mechanisms of suppression. We attempt to reconcile these data with findings from previous studies.

  8. Educational Success and Surrounding Culture

    Science.gov (United States)

    Walters, Garrison

    2016-01-01

    The curriculum, instruction, and services we provide in schools, colleges, and universities matter a lot, but if we continue to ignore our students' "surrounding culture," progress toward a more educated nation will continue to be disappointing.

  9. Educational Success and Surrounding Culture

    Science.gov (United States)

    Walters, Garrison

    2016-01-01

    The curriculum, instruction, and services we provide in schools, colleges, and universities matter a lot, but if we continue to ignore our students' "surrounding culture," progress toward a more educated nation will continue to be disappointing.

  10. Multichannel spatial surround sound system

    Institute of Scientific and Technical Information of China (English)

    RAO Dan; XIE Bosun

    2004-01-01

    Based on the consideration of being compatible with 5.1 channel horizontal surround sound system, a spatial surround sound system is proposed. Theoretical and experimental results show that the system has a wide listening area. It can not only recreate stable image in the front and rear direction, but also eliminate the defect of poor lateral image of 5.1 channel system. The system can be used to reproduce special 3D sound effect and the spaciousness of hall.

  11. Factors Affecting Methane Emission from Rice Paddies

    Institute of Scientific and Technical Information of China (English)

    于心科; 王卫东; 等

    1995-01-01

    A comparative study of rice paddies and the uncovered water field in Taoyuan(Hunan) showed that methane emission from rice-vegetated paddy fields in 1993 was different from that in 1992(I,e,lower in rates and irregular in pattern).Climate has obvious influence on methane emission .And ebullition made a considerable contribution to the total flux of methane emission from rice paddies (45%).This implies that the intensification of paddy cultivation of rice might not be,as was proposed,the main con-tributor to the observed gradual increasing of atmospheric methane.24-hour automatic measurements of atmospheric temperature,air temperature and methane concentration in the static sampling boxes revealed that temperature,in addition to fertilization and irrigation style,is one of the most important factors that control the emission of methane from rice paddies.

  12. Radiocarbon ages of Sorori ancient rice of Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Ja, E-mail: kjkim@kigam.re.kr [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Lee, Yung-Jo; Woo, Jong-Yoon [Institute of Korean Prehistory, Cheongju (Korea, Republic of); Jull, A.J. Timothy [NSF Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-01-15

    Samples of Sorori ancient rice were excavated in 1998 from the Sorori Paleolithic site located at Sorori, Oksan-myeon, Cheong-won County in Chungcheongbuk-do, Korea. We have made new radiocarbon measurements for Sorori samples in 2009 at the NSF Arizona AMS Laboratory. Both ancient rice samples and surrounded peat from the Sorori site were dated. The AMS results confirmed that the ages of the rice and peat soil were 12,520 {+-} 150 and 12,552 {+-} 90 BP, respectively. These radiocarbon ages are consistent with the previously published data of quasi rice measured at Seoul National University and confirm that the Sorori rice is the oldest ancient rice currently reported.

  13. OsNAC5 overexpression enlarges root diameter in rice plants leading to enhanced drought tolerance and increased grain yield in the field.

    Science.gov (United States)

    Jeong, Jin Seo; Kim, Youn Shic; Redillas, Mark C F R; Jang, Geupil; Jung, Harin; Bang, Seung Woon; Choi, Yang Do; Ha, Sun-Hwa; Reuzeau, Christophe; Kim, Ju-Kon

    2013-01-01

    Drought conditions are among the most serious challenges to crop production worldwide. Here, we report the results of field evaluations of transgenic rice plants overexpressing OsNAC5, under the control of either the root-specific (RCc3) or constitutive (GOS2) promoters. Field evaluations over three growing seasons revealed that the grain yield of the RCc3:OsNAC5 and GOS2:OsNAC5 plants were increased by 9%-23% and 9%-26% under normal conditions, respectively. Under drought conditions, however, RCc3:OsNAC5 plants showed a significantly higher grain yield of 22%-63%, whilst the GOS2:OsNAC5 plants showed a reduced or similar yield to the nontransgenic (NT) controls. Both the RCc3:OsNAC5 and GOS2:OsNAC5 plants were found to have larger roots due to an enlarged stele and aerenchyma at flowering stage. Cell numbers per cortex layer and stele of developing roots were higher in both transgenic plants than NT controls, contributing to the increase in root diameter. The root diameter was enlarged to a greater extent in the RCc3:OsNAC5, suggesting the importance of this phenotype for enhanced drought tolerance. Microarray experiments identified 25 up-regulated genes by more than three-fold (P < 0.01) in the roots of both transgenic lines. Also identified were 19 and 18 up-regulated genes that are specific to the RCc3:OsNAC5 and GOS2:OsNAC5 roots, respectively. Of the genes specifically up-regulated in the RCc3:OsNAC5 roots, GLP, PDX, MERI5 and O-methyltransferase were implicated in root growth and development. Our present findings demonstrate that the root-specific overexpression of OsNAC5 enlarges roots significantly and thereby enhances drought tolerance and grain yield under field conditions.

  14. Effects of Metal Ions and Organic Solvents on Alkaline Phosphatase from Rice-field Eel%金属离子·有机溶剂对黄鳝碱性磷酸酶的影响

    Institute of Scientific and Technical Information of China (English)

    黄毅; 唐云明

    2008-01-01

    [Objective]The mechanism of alkaline phcephatase(ALP) was studied to promote rice-field eel aquaculture industry. [Method] The effects of effectors such as multiple metal ions and organic solvents on ALP in viscera of rice-field eel. [ Result] Na+ and K+ didn't generate big influences on en-zyme activity ;Mg2+ and Ca2+ could promote ALP while Li+,Cu2+ and Zn2+ could restrain ALP enzyme activity. Both KPO2-4 and WO3-4 generated by en-zyme catalyzing disodium phenyl phosphate possessed strong inhibitory effects on emzyme, and 9.5 mmol/L HPO2-4 would make enzyme activity decline by 13% while 9.5 mmol/L WO3-4 would make enzyme decline by 34%. The inhibition types of them were both competitive inhibition on enzyme activity. The organic solvents such as methanol,ethanol,ethylene glycol,isopropanol all generated influences on ALP and the order according to their inhibitory effects was isopropanol > ethanol > methanol > ethylene glycol. [Conclusion] The influences of various effectors on ALP activity of rice-field eel were studied from dy-namics perspective to provide theoretical basis for further clarifying ALP mechanism.

  15. Phylogenetic analysis of Pomacea canaliculata isolates collected from rice fields in different origins of China by combined mitochondrial 12S and 16S genes.

    Science.gov (United States)

    Li, Xiao-Yan; Bian, Qing-Qing; Zhao, Guang-Hui

    2015-02-01

    To study the genetic relationships of Pomacea canaliculata collected from rice fields in China, the mitochondrial (mt) 12S and 16S of 9 P. canaliculata isolates from 5 southern provinces in China were sequenced and analyzed. The intra-specific sequence variations of P. canaliculata were 0-1.1% for 12S and 0--0.6% for 16S, while the inter-specific variations among common Pomacea species in mt 12S and 16S were 3.0-11.7% and 2.3-10.1%, respectively. Phylogenetic analysis based on combined sequences of mt 12S and 16S revealed complex genetic structure of P. canaliculata in China. Two phylogenetic groups of P. canaliculata were indicated in China with one group sistered to P. canaliculata isolates from USA, and two groups were even found in the same province. The phylogenetic relationships of Pomacea spp. also could be effectively inferred by combined sequences of mt 12S and 16S. These findings provided basic information for further study of population genetics and diffusion pattern of P. canaliculata in China as well as in the world.

  16. Insect abundance over Chinese rice fields in relation to environmental parameters, studied with a polarization-sensitive CW near-IR lidar system

    Science.gov (United States)

    Zhu, Shiming; Malmqvist, Elin; Li, Wansha; Jansson, Samuel; Li, Yiyun; Duan, Zheng; Svanberg, Katarina; Feng, Hongqiang; Song, Ziwei; Zhao, Guangyu; Brydegaard, Mikkel; Svanberg, Sune

    2017-07-01

    Effective monitoring of flying insects is of major societal importance in view of the role of insects as indispensable pollinators, destructive disease vectors and economically devastating agricultural pests. The present paper reports on monitoring of flying agricultural pests using a continuous-wave lidar system in a rice-field location in Southern China. Using a Scheimpflug arrangement, range resolution over several 100 m long observational paths was achieved. The system operates with two perpendicularly polarized near-infrared lasers, which are activated intermittently, and back-scattered radiation from insects was recorded by a linear array detector placed after a linear polarizer. Our polarization sensitive system was used to monitor the flying insect diurnal activity and also the influence of changes in weather conditions, e.g., the occurrence of rain. Activity strongly peaked at dusk and rose again, although to a lower extent, just before dawn. At the onset of rainfall, a strong increase in insect counts occurred which was interpreted as the rain-induced bringing down of high-altitude migrant insects.

  17. Rice methylmercury exposure and mitigation: a comprehensive review.

    Science.gov (United States)

    Rothenberg, Sarah E; Windham-Myers, Lisamarie; Creswell, Joel E

    2014-08-01

    Rice cultivation practices from field preparation to post-harvest transform rice paddies into hot spots for microbial mercury methylation, converting less-toxic inorganic mercury to more-toxic methylmercury, which is likely translocated to rice grain. This review includes 51 studies reporting rice total mercury and/or methylmercury concentrations, based on rice (Orzya sativa) cultivated or purchased in 15 countries. Not surprisingly, both rice total mercury and methylmercury levels were significantly higher in polluted sites compared to non-polluted sites (Wilcoxon rank sum, p<0.001). However, rice percent methylmercury (of total mercury) did not differ statistically between polluted and non-polluted sites (Wilcoxon rank sum, p=0.35), suggesting comparable mercury methylation rates in paddy soil across these sites and/or similar accumulation of mercury species for these rice cultivars. Studies characterizing the effects of rice cultivation under more aerobic conditions were reviewed to determine the mitigation potential of this practice. Rice management practices utilizing alternating wetting and drying (instead of continuous flooding) caused soil methylmercury levels to spike, resulting in a strong methylmercury pulse after fields were dried and reflooded; however, it is uncertain whether this led to increased translocation of methylmercury from paddy soil to rice grain. Due to the potential health risks, it is advisable to investigate this issue further, and to develop separate water management strategies for mercury polluted and non-polluted sites, in order to minimize methylmercury exposure through rice ingestion.

  18. Laboratory and Field Control Effect of Some Pesticides to Yellow Rice Borer Tryporyza incertulas Walker%几种药剂对三化螟室内与田间防治效果研究

    Institute of Scientific and Technical Information of China (English)

    张振飞; 黄炳超; 张扬; 肖汉祥; 李燕芳; 刘梅凤; 薛皇娃; 范秀其; 周小武

    2011-01-01

    The laboratory control effect of ten pesticides to the yellow rice borer was studied. On above basis, six pesticides were chose to test in the fields. The field control effect, application rate of pesticides, the effect to other important rice pest and natural enemy also were studied. The field results showed that chlorantraniliprole 20% SC had best control effect to yellow rice borer than other tested drugs. And it didn't caused resurgence of brown plant hopper and don't impact the natural enemies largely. Buprofezin + monosultap 58% WP also had good control effect to yellow rice borer. However, it killed natural enemies including spider and plant bugs seriously. Tnazophos 8% EC and imidaclopri + triadimefon 14.5% ME had a little control effect to yellow rice borer, but it caused resurgence of brown plant hopper. Moreover, all of those six types of pesticides must be applied twice to control the yellow rice borer successfully.%通过室内盆栽试验研究了20%氛虫苯甲酰胺SC等10种药剂对水稻三化螟的药效,并在此墓础上,选取6种防效较好的药剂进行大田试验,研究田间防治效果、施药次数对三化螟控制作用以及评价这些药剂对稻田生态系统内其它生物的影响.试验结果表明,20%氯虫苯甲酰胺SC对三化螟防效最好,不会造成褐飞虱的猖獗发生和严重杀伤天敌;58%噻嗪·杀虫单WP对三化螟和稻褐飞虱都具有较好防效,但是时天敌有较大杀伤作用;8%三唑磷EC和14.5%吡虫·杀虫单ME对三化螟具有一定防效,但是造成褐飞虱的猖獗发生.所有6种药剂施药1次均不能有效防治三化螟,而施药2次20%氛虫苯甲酞胺SC等4种药剂对三化螟具有明显控制作用.

  19. Cytoplasmic-genetic male sterility gene provides direct evidence for some hybrid rice recently evolving into weedy rice.

    Science.gov (United States)

    Zhang, Jingxu; Lu, Zuomei; Dai, Weimin; Song, Xiaoling; Peng, Yufa; Valverde, Bernal E; Qiang, Sheng

    2015-05-27

    Weedy rice infests paddy fields worldwide at an alarmingly increasing rate. There is substantial evidence indicating that many weedy rice forms originated from or are closely related to cultivated rice. There is suspicion that the outbreak of weedy rice in China may be related to widely grown hybrid rice due to its heterosis and the diversity of its progeny, but this notion remains unsupported by direct evidence. We screened weedy rice accessions by both genetic and molecular marker tests for the cytoplasmic male sterility (CMS) genes (Wild abortive, WA, and Boro type, BT) most widely used in the production of indica and japonica three-line hybrid rice as a diagnostic trait of direct parenthood. Sixteen weedy rice accessions of the 358 tested (4.5%) contained the CMS-WA gene; none contained the CMS-BT gene. These 16 accessions represent weedy rices recently evolved from maternal hybrid rice derivatives, given the primarily maternal inheritance of this trait. Our results provide key direct evidence that hybrid rice can be involved in the evolution of some weedy rice accessions, but is not a primary factor in the recent outbreak of weedy rice in China.

  20. Characteristics of Growth and Yield Formation of Rice in Rice-Fish Farming System

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; ZHANG Hong-cheng; HU Xiao-jun; DAI Qi-gen; ZHANG Yong-jiang

    2006-01-01

    By using single rice cultivation as a control, the effect of rice-fish culture on growth dynamic, plant type and yield formation of rice was studied. The results showed as follows: rice-fish culture improved the physical-chemical properties of arable layer soil of paddy field, extended growth period of rice, increased dry matter and LAI of different growth stages,improved three top leaves area, deterred the degeneration of leaves function, increased the diameter of stem, promoted the growth of roots and the formation of roots in the extended stem. At the same time, rice-fish culture extended the length of basal internodes, increased the number of internodes, uplifted the gravity of plant, and depressed the root vigor. For the grain yield and yield structure of rice, rice-fish culture decreased ear/tillering ratio, spikelet/panicle and seed set percentage,increased grain weight. If variety choice and cultivation technology were controlled appropriately, rice-fish culture could increase the effective panicles and improve grain yield of rice.

  1. Can the co-cultivation of rice and fish help sustain rice production?

    Science.gov (United States)

    Hu, Liangliang; Zhang, Jian; Ren, Weizheng; Guo, Liang; Cheng, Yongxu; Li, Jiayao; Li, Kexin; Zhu, Zewen; Zhang, Jiaen; Luo, Shiming; Cheng, Lei; Tang, Jianjun; Chen, Xin

    2016-06-01

    Because rice feeds half of the world’s population, a secure global food supply depends on sustainable rice production. Here we test whether the co-cultivation of rice and fish into one “rice-fish system” (RFS; fish refers to aquatic animals in this article) could help sustain rice production. We examined intensive and traditional RFSs that have been widely practiced in China. We found that rice yields did not decrease when fish yield was below a threshold value in each intensive RFS. Below the thresholds, moreover, fish yields in intensive RFSs can be substantially higher than those in traditional RFS without reducing rice yield. Relative to rice monoculture, the use of fertilizer-nitrogen and pesticides decreased, and the farmers’ net income increased in RFSs. The results suggest that RFSs can help sustain rice production, and suggest that development of co-culture technologies (i.e. proper field configuration for fish and rice) is necessary to achieve the sustainability.

  2. A scheme for regional rice yield estimation using ENVISAT ASAR data

    Institute of Scientific and Technical Information of China (English)

    LE; TOAN; Thuy

    2009-01-01

    Information on rice growing areas and rice production is critical for most rice growing countries to make state and economic policies. However, the areas where rice crop is cultivated are often cloudy and rainy, which entails the use of radar remote sensing data for rice monitoring. In this paper, a practical scheme to integrate multi-temporal and multi-polarization ENVISAT ASAR data into rice crop model for regional rice yield estimation has been presented. To achieve this, rice distribution information should be obtained first by rice mapping method to retrieve rice fields from ASAR images, and then an assimilation method is applied to use the observed multi-temporal rice backscattering coefficients which are grouped for each rice pixel to re-initialize ORYZA2000 to predict rice yield. The assimilation method re-initializes the model with optimal input parameters, allowing a better temporal agreement between the rice backscattering coefficients retrieved from ASAR data and the rice backscattering coefficients simulated by a coupled model, i.e., the combination of ORYZA2000 and a semi-empirical rice backscatter model through LAI. The SCE-UA optimization algorithm is employed to determine the optimal set of input parameters. After the re-initialization, rice yield for each rice pixel is calculated, and the yield map over the area of interest is produced. The scheme was validated over Xinghua study area located in the middle of Jiangsu Province of China by using the data set of an experimental campaign carried out during the 2006 rice season. The result shows that the obtained rice yield map generally overestimates the actual rice production by 13% on average and with a root mean square error of approximately 1133 kg/ha on validation sites, but the tendency of rice growth status and spatial variation of the rice yield are well predicted and highly consistent with the actual production variation.

  3. 适宜深泥脚田的2行插秧机试验研究%Study on Two-row Rice Transplanter Suitable for Deep Mud Feet Paddy Field

    Institute of Scientific and Technical Information of China (English)

    易文裕; 应婧; 庹洪章; 熊昌国; 谢祖琪

    2014-01-01

    针对深泥脚田的泥脚深度30 cm以上、田面积水层深浅不一致,以及土壤的硬底层较深、表层土壤流变性大、剪切应力小和运动阻力大等特点,设计研制了一种适应深泥脚田的 SNJ 2行插秧机,并在田间进行了机插秧试验,对SNJ 2行插秧机的秧苗栽插质量(包括漂秧率、漏插率、伤秧率)、插秧效率和产量进行了分析。%This paper research on deep mud feet paddy field when the depth of the mud feet is above 30cm, surface wa-ter layer depth is inconsistent , the substratum of soil is deep , surface of soil rheology is big、shear stress is small and the movement resistance is large , a two-row SNJ rice transplanter adapting to deep mud feet paddy field was designed .On the basis of taking a great number of producing experiments by the two-row SNJ rice transplanter verified that the two-row SNJ rice transplanter is suitable for deep mud feet paddy field .In the meanwhile , this paper analyze transplanting quality which means seedling floating rate , sowing leakage rate and seedling injury rate , transplanting efficiency and rice yields .

  4. The anisotropic properties analysis of the rock mass surrounding the roadway' s in seepage and stress field%巷道围岩渗流场和应力场各向异性特征分析及应用

    Institute of Scientific and Technical Information of China (English)

    杨天鸿; 师文豪; 于庆磊; 李海洲; 郑超; 夏冬

    2012-01-01

    依托范各庄煤矿12号煤层底板的砂岩巷道工程实际,应用岩体结构面非接触测量(Sha-peMetriX3D)系统,对巷道开挖面进行岩体结构面数字摄影测量及识别,得到岩体结构面的几何分布参数;在此基础上,利用Mont-Carlo方法生成裂隙网络,分别利用离散介质渗流方法和几何损伤理论计算岩体的渗透张量和弹性张量,研究了岩体力学参数各向异性和尺度效应;最后,建立了平面应变情况下的巷道围岩各向异性渗流力学模型,采用COMSOL Multiphysics多物理场分析软件,计算得到了可以考虑节理分布特征的巷道围岩应力场和渗流场,并讨论了岩体力学性质主方向对围岩应力场、渗流场及损伤区的影响。研究表明,岩体的各向异性对数值模拟结果影响显著,等效连续介质的各向异性模型能考虑岩体结构面的影响,更符合工程实际。%Depending on the sandstone roadway on the floor of No. 12 coal seam in Fangezhuang Coal Mine,a 3D con- tact-free measuring system, named as ShapeMetriX3D, was employed to capture discontinuities on the face of the road- way and obtain statistical parameters for each set of discontinuities. And then, fracture network was generated by Mont- Carlo method. Permeability tensor of rock mass was calculated by the discrete medium seepage method, and the elastic- ity tensor of rock mass was obtained by geometrical damage theory. Then, scale effect and anisotropic behaviors of rock mass were studied. Finally, an anisotropic percolation mechanics model of surrounding rock mass of the roadway was built under plane strain condition. Using COMSOL multiphysics code, the stress field and seepage field surrounding the roadway were obtained, which can take into account the influence of orientation of discontinuities. Furthermore, the in- fluences of principal direction of rock mass properties on stress, seepage and damage zone were discussed. The results show that the

  5. A DYNAMIC MIXED MODEL WITH NITROGEN LEACHING LOSSES FROM THE PONDED PADDY RICE FIELD UNDER SITUATION OF BURIED PIPE DRAINAGE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to study the law of nitrogen leaching losses from the paddy field under the condition of drainage, based on the theories of potential energy and solute transport, a water-nitrogen dynamic mixed model by combining the flow net with dynamic method was established. In the computation of buried pipe drainage, the superposition principle was used to simplify the complex solving of the two-dimensional problem about water-nitrogen transportation in Soil-Plant-Air-Continuous (SPAC) system into several one-dimensional problems. The presented method is simple and practical. Some field experiments were carried out to demonstrate the validity of the model.

  6. Variation on the magnetic field profiles of transmission lines for various surrounding conditions calculated by the finite element method; Variacion de los perfiles de campo magnetico en lineas de transmision en diversas condiciones del entorno calculadas mediante el metodo de elementos finitos

    Energy Technology Data Exchange (ETDEWEB)

    Ponta, Fernando; Ferreira, Fabiana

    2001-07-01

    This paper applies the finite element method for the calculation of line magnetic field transversal profile using own routine calculation. Using a real case, simulations were performed under various conditions gathering distortion elements, obtaining the field profile. By analysing these results conclusions are drawing related to the changes produced by the distortions on the magnetic field configuration and evaluations of the surrounding elements influence are evaluated.

  7. Effects of Tillage Mode and Straw Return on Soil Organic Carbon and Rice Yield in Direct Seeding Rice Field%耕作方式和秸秆还田对直播稻田土壤有机碳及水稻产量的影响

    Institute of Scientific and Technical Information of China (English)

    段华平; 牛永志; 卞新民

    2012-01-01

    Effects of tillage modes and straw return on soil organic carbon(SOC) and rice yield were studied in direct seeding rice field.Results showed that straw return significantly increased SOC contents,and soil tillage modes had significant effects on the vertical distribtion of SOC.There was a significant positive correlation between SOC content and rice yield(R2=0.712 9**,n=6),and significant positive correlation between SOC and TSN(R2=0.860 9**,n=43).These evidenced that straw return promoted SOC content,stabilized crop productivity in direct rice field,and achieved the win-win effect of grain safety and environmental safety.%研究了直播稻田在不同耕作方式和秸秆还田下土壤有机碳(SOC)和水稻产量的变化。结果表明,秸秆还田能够显著增加SOC含量,耕作方式可显著影响土壤有机碳的垂直分布。SOC含量与水稻籽粒产量存在显著的正相关关系(R2=0.712 9**,n=6),SOC含量与土壤全氮(TSN)之间有显著的正相关性(R2=0.860 9**,n=43)。秸秆还田能够促进土壤有机碳的增加,稳定直播稻田系统的生产力,实现粮食安全和生态环境安全的双赢。

  8. Soil tillage, rice straw and flooded irrigated rice yield

    Directory of Open Access Journals (Sweden)

    Amauri Nelson Beutler

    2014-06-01

    Full Text Available The objective of this study was evaluate the effect of management systems and straw in flooded irrigated rice yield. The experimental design was a completely randomized with three experiments and, 10 replications in experiment 1 and 2 and, 6 replications in experiment 3. The experiments were: E1 – no-till system (E1PD and conventional system with two harrowings at 0.0–0.07 m layer and leveling with remaplam (E1PC, after three years of sowing rice, after fallow of rice tillage, with sowing of rye grass in winter and grazing; E2 – no-till system (E2PD and conventional system after native field (E2PC; E3 – no-till without straw on soil surface (E30P, current straw on soil surface of 3,726 kg ha-1 (E31P, two times current straw of 7,452 kg ha-1 (E32P and three times current straw of 11,178 kg ha-1 (E33P. In soil, were evaluated the average geometric diameter of aggregates, soil bulk density, soil porosity, macro and microporosity, in 0.0-0.05 and 0.05-0.10 m layer. In harvest were evaluated the panicles number in 0,25 m2 area, number of filled, empty an total grains in 10 panicles, mass of one thousand seeds and rice grains yield in 2 m2. The conventional system presented greater macroporosity and total porosity, compared with no-till system, however, does not result in differences in production components and rice grains yield. Soil tillage in no-till, with rice straw on soil surface up to 11,178 kg ha-1, before sowing, not reduces flooded irrigated rice grains yield.

  9. Elemental composition of Malawian rice.

    Science.gov (United States)

    Joy, Edward J M; Louise Ander, E; Broadley, Martin R; Young, Scott D; Chilimba, Allan D C; Hamilton, Elliott M; Watts, Michael J

    2016-07-20

    Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice (Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers' fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg(-1), dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied greatly, and this was likely due to contamination of rice samples with soil. Risk of As, Cd or Pb toxicity due to rice consumption in Malawi appears to be minimal.

  10. Taste of Super-Dwarf Rice Cultured in Space

    Science.gov (United States)

    Hirai, Hiroaki; Kitaya, Yoshiaki

    2016-07-01

    The interest of food production for lunar base and manned Mars mission has increased recently. So far, plants cultured long duration in space were leafy vegetables, arabidopsis, wheat, barley and so on. Although rice is a staple food for most of the world, research on rice cultivation in space has not been done much. Rice grains are nutrient-rich with carbohydrate, protein and dietary fiber. Moreover, rice is a high yield crop and harvested grains have a long shelf life. Rice symbolizes the rice-eating culture of Japan, is extremely useful as a specific cultured plant candidate of Japan in space. In the previous report, 'Kozo-no-sumika' found from seedlings in raising of seedling was introduced as a super-dwarf rice to culture in space. Considering this rice as food in space, we investigate the taste characteristics of this rice. At present, waxy 'Kozo-no-sumika' and nonwaxy 'Hosetsu dwarf' of super-dwarf rice and 'Nipponbare' of previous standard rice for sensory test are cultured in paddy field. Hereafter, we will harvest rice, investigate yield, evaluate taste.

  11. Effects of implementing organic rice-duck integrated farming on reducing agricultural diffuse pollution around Dianshan Lake in the western suburbs of Shanghai

    Science.gov (United States)

    Hu, Xue-Feng; Teng, Qing

    2017-04-01

    Located in the western suburbs of Shanghai, Dianshan Lake is a major source of Huangpu River, a mother river flowing through the metropolitan area. To protect the drinking water source areas, the development of any industries and livestock breeding is forbidden around the lake since the early time. However, the lake is still under a eutrophic state throughout the year. In 2013, for example, total N and total P in the lake water were 2.98 mg L-1 and 0.17 mg L-1 on average, respectively. It is believed that 72.2% of N and 73.1% of P in the lake come from agricultural diffuse pollution. The areas surrounding the lake include six towns and are all low-lying in landform. There are 5975 ha paddy fields at the six towns, making up 33.1% of total farming land in the areas. According to our questionnaires to local farmers at Jinze Town, one of the six towns, for the consecutive five years, the amounts of N and P2O5 applied within the rice growing season under the conventional rice farming are 336.6 kg ha-1 and 76.9 kg ha-1 on average, respectively, and those lost through leaching and runoff are 15.42 kg ha-1 and 3.55 kg ha-1 on average, respectively. Further study estimated that the total amounts of N and P2O5 applied around the lake within the rice growing season are 2.01×106 kg year-1 and 4.59×105 kg year-1, respectively; those lost through leaching and runoff are 0.99×105 kg year-1 and 0.23×105 kg year-1, respectively; those discharged from the fields into the lake are 0.99×104 kg year-1 and 0.23×104 kg year-1, respectively. Our study also indicated that the amount of pesticides and herbicides discharged from the paddy fields at the six towns into the lake is approximately 1.67×104 kg year-1. Appreciately, the agricultural diffuse pollution from the paddy fields surrounding the lake have posed severe threat to the lake. The field experiments indicated that raising ducks in the paddy fields within the rice growing season can not only highly reduce weed hazards and

  12. Removal of Sulfide in the Rice Field Using Microbial Fuel Cells%微生物燃料电池对去除稻田硫离子的影响

    Institute of Scientific and Technical Information of China (English)

    张海芹; 殷瑶; 吴江; 薛诚; 欧阳涛; 蔡兰坤; 张乐华

    2013-01-01

    在模拟水稻田中构建微生物燃料电池(Microbial fuel cells,MFCs)并设置对照组,研究MFCs运行对水稻田的水和土壤中S2-浓度、pH、ORP(Oxidation-reduction potential,氧化还原电位)以及水稻生长情况的影响.结果表明,水稻种植期间,稻田MFCs的水和土壤(深2.5 mm和5.0 mm)中S2-浓度分别为(4.70±1.51)mg·L-1、(6.97±1.36)mg·L-1和(8.33±1.76)mg·L-1,在对照组相应各层中S2-浓度为(7.77±1.99)mg·L-1、(12.9±3.06)mg·L-1和(16.5±4.63)mg·L-1.稻田MFCs的水和土壤(深2.5 mm和5.0 mm)中的ORP值分别为(106±7.7)mV、(-142±30)mV和(-209±9)mV,在对照组相应各层中的ORP分别为(119±11.5)mV、(-209±9)mV和(-386±2)mV.稻田MFCs和对照组中水稻干重分别为(0.548±0.005)g和(0.442±0.003)g.在水稻田中构建MFCs可以降低水和各土壤层中S2-浓度,增高各土壤层中ORP值,且能明显促进水稻的生长.%We develop the rice microbial fuel cells(MFCs) in a lab-scale rice field and control reactors to evaluate the effect of MFCs on the sulfide concentration,pH,oxidation-reduction potential(ORP) in water and soil as well as the growth of rice.During the rice growing period the sulfide concentrations in water,2.5 mm soil layer,5.0 mm soil layer in the rice field with MFCs are(4.70± 1.51)mg· L-1,(6.97± 1.36)mg· L-1 and (8.33± 1.76) mg· L-1 respectively,the sulfide concentrations in control reactors are (7.77± 1.99)mg· L-1,(12.9±3.06)mg·L-1 and (16.5±4.63)mg·L-1 respectively.The ORP values in water,2.5 mm soil layer,5.0 mm soil layer in the rice field with MFCs are (106±7.7)mV,(-142±30)mV and (-209±9)mV.The ORP values in control reactors are (119± 11.5)mV,(-209 ±9)mV and (-386±2)mV respectively.The dry weights of rice in MFCs and control reactors are (0.548±0.005)g and(0.442±0.003)g respectively.The results show that the sulfide concentrations are lower and the ORP values are higher in the water and soil of the rice MFCs than that of the control reactors

  13. Estimating rice yield related traits and quantitative trait loci analysis under different nitrogen treatments using a simple tower-based field phenotyping system with modified single-lens reflex cameras

    Science.gov (United States)

    Naito, Hiroki; Ogawa, Satoshi; Valencia, Milton Orlando; Mohri, Hiroki; Urano, Yutaka; Hosoi, Fumiki; Shimizu, Yo; Chavez, Alba Lucia; Ishitani, Manabu; Selvaraj, Michael Gomez; Omasa, Kenji

    2017-03-01

    Application of field based high-throughput phenotyping (FB-HTP) methods for monitoring plant performance in real field conditions has a high potential to accelerate the breeding process. In this paper, we discuss the use of a simple tower based remote sensing platform using modified single-lens reflex cameras for phenotyping yield traits in rice under different nitrogen (N) treatments over three years. This tower based phenotyping platform has the advantages of simplicity, ease and stability in terms of introduction, maintenance and continual operation under field conditions. Out of six phenological stages of rice analyzed, the flowering stage was the most useful in the estimation of yield performance under field conditions. We found a high correlation between several vegetation indices (simple ratio (SR), normalized difference vegetation index (NDVI), transformed vegetation index (TVI), corrected transformed vegetation index (CTVI), soil-adjusted vegetation index (SAVI) and modified soil-adjusted vegetation index (MSAVI)) and multiple yield traits (panicle number, grain weight and shoot biomass) across a three trials. Among all of the indices studied, SR exhibited the best performance in regards to the estimation of grain weight (R2 = 0.80). Under our tower-based field phenotyping system (TBFPS), we identified quantitative trait loci (QTL) for yield related traits using a mapping population of chromosome segment substitution lines (CSSLs) and a single nucleotide polymorphism data set. Our findings suggest the TBFPS can be useful for the estimation of yield performance during early crop development. This can be a major opportunity for rice breeders whom desire high throughput phenotypic selection for yield performance traits.

  14. Rice methylmercury exposure and mitigation: a comprehensive review

    Science.gov (United States)

    Rothenberg, Sarah E.; Windham-Myers, Lisamarie; Creswell, Joel E.

    2014-01-01

    Rice cultivation practices from field preparation to post-harvest transform rice paddies into hot spots for microbial mercury methylation, converting less-toxic inorganic mercury to more-toxic methylmercury, which is likely translocated to rice grain. This review includes 51 studies reporting rice total mercury and/or methylmercury concentrations, based on rice (Orzya sativa) cultivated or purchased in 15 countries. Not surprisingly, both rice total mercury and methylmercury levels were significantly higher in polluted sites compared to non-polluted sites (Wilcoxon rank sum, price percent methylmercury (of total mercury) did not differ statistically between polluted and non-polluted sites (Wilcoxon rank sum, p=0.35), suggesting comparable mercury methylation rates in paddy soil across these sites and/or similar accumulation of mercury species for these rice cultivars. Studies characterizing the effects of rice cultivation under more aerobic conditions were reviewed to determine the mitigation potential of this practice. Rice management practices utilizing alternating wetting and drying (instead of continuous flooding) caused soil methylmercury levels to spike, resulting in a strong methylmercury pulse after fields were dried and reflooded; however, it is uncertain whether this led to increased translocation of methylmercury from paddy soil to rice grain. Due to the potential health risks, it is advisable to investigate this issue further, and to develop separate water management strategies for mercury polluted and non-polluted sites, in order to minimize methylmercury exposure through rice ingestion.

  15. Special rice in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Xianggu Rice: The rice originated from Jiangyong County, Hunan Province. Its characteristics were: even in grain shape, white in color, special fragrant in taste, and sticky in quality. Handongzao: It was from Wannian County, Jiangxi Province. The rice had big, fertile, and white grain, which was soft with fragrant smell, and it had high head rice rate. So, the local peasants liked to plant it. It was one of the "Tribute rice " in old time. Shizhu "Imperial Rice": The rice was also called "Fragrant Rice", was from Siyuan Village, Yuelai Town, Shizhu County, Sichuan Province. It was the treasure among the rices. The grain was bright in color. When it was cooked, the smell was fragrant. It was said that the rice was from "Han Dynasty", and has become the "Tribute Rice " since then. Blood Glutinous Rice: Originated from Changshu City, Jiangsu Province, the rice has been cultivated more than one hundred years. It had high nutrition value. Among the people, the Blood Glutinous Rice was often used as health food for lying-in women and patients. Qufu Fragrant Rice: Its characteristics were: clean, bright, and translucent in grain color, sticky in quality. It was suitable for cooking gruel and was also called "Fragrant Rice" in the local due to its strong fragrance. It was one of the "Tribute Rice" in old time. Taihu Lake Fragrant Japonica: The rice was from the Region