WorldWideScience

Sample records for ground cover soil

  1. Ground cover influence on evaporation and stable water isotopes in soil water

    Science.gov (United States)

    Magdalena Warter, Maria; Jiménez-Rodríguez, Cesar D.; Coenders-Gerrits, Miriam; Teuling, Adriaan J. Ryan

    2017-04-01

    Forest ecosystems are characterized by complex structures which influence hydrological processes such as evaporation. The vertical stratification of the forest modifies the effect of the evaporation process due to the composition and local distribution of species within the forest. The evaluation of it will improve the understanding of evaporation in forest ecosystems. To determine the influence of forest understory on the fractionation front, four ground cover types were selected from the Speulderbos forest in the Netherlands. The native species of Thamariskmoss (Thuidium thamariscinum), Rough Stalked Feathermoss (Brachythecium rutabulum), and Haircapmoss (Polytrichum commune) as well as one type of litter made up of Douglas-Fir needles (Pseudotsuga menziesii) were used to analyse the rate of evaporation and changes on the isotopic concentration of the soil water on an in-situ basis in a controlled environment. Over a period of 4 weeks soil water content and atmospheric conditions were continuously measured, while the rainfall simulations were performed with different amounts and timings. The reference water added to the boxes keeps a stable composition along the trial period with a δ ^2H value of -42.59±1.15 \\permil} and δ 18O of -6.01±0.21 \\permil}. The evaporation front in the four ground covers is located between 5 and 10 cm depth and deuterium excess values are bigger than 5 \\permil. The litter layer of Douglas-Fir needles is the cover with higher fractionation in respect to the added water at 10 cm depth (δ ^2H: -29.79 \\permil), while the Haircapmoss keeps the lower fractionation rate at 5 cm and 10 cm (δ ^2H: -33.62 and δ ^2H: -35.34 \\permil). The differences showed by the soil water beneath the different ground covers depict the influence of ground cover on fractionation rates of the soil water, underlining the importance of the spatial heterogeneity of the evaporation front in the first 15 cm of soil.

  2. Ground cover rice production system facilitates soil carbon and nitrogen stocks at regional scale

    Directory of Open Access Journals (Sweden)

    M. Liu

    2015-02-01

    Full Text Available Rice production is increasingly challenged by irrigation water scarcity, however covering paddy rice soils with films (ground cover rice production system: GCRPS can significantly reduce water demand as well as overcome temperature limitations at the beginning of the vegetation period resulting in increased grain yields in colder regions of rice production with seasonal water shortages. It has been speculated that the increased soil aeration and temperature under GCRPS may result in losses of soil organic carbon and nitrogen stocks. Here we report on a regional scale experiment, conducted by sampling paired adjacent Paddy and GCRPS fields at 49 representative sites in the Shiyan region, which is typical for many mountainous areas across China. Parameters evaluated included soil C and N stocks, soil physical and chemical properties, potential carbon mineralization rates, fractions of soil organic carbon and stable carbon isotopic composition of plant leaves. Furthermore, root biomass was quantified at maximum tillering stage at one of our paired sites. Against expectations the study showed that: (1 GCRPS significantly increased soil organic C and N stocks 5–20 years following conversion of production systems, (2 there were no differences between GCRPS and Paddy in soil physical and chemical properties for the various soil depths with the exception of soil bulk density, (3 GCRPS had lower mineralization potential for soil organic C compared with Paddy over the incubation period, (4 GCRPS showed lower δ15N in the soils and plant leafs indicating less NH3 volatilization in GCRPS than in Paddy; and (5 GCRPS increased yields and root biomass in all soil layers down to 40 cm depth. Our results suggest that GCRPS is an innovative rice production technique that not only increases yields using less irrigation water, but that it also is environmentally beneficial due to increased soil C and N stocks at regional scale.

  3. Mapping wind erosion hazard in Australia using MODIS-derived ground cover, soil moisture and climate data

    Science.gov (United States)

    Yang, X.; Leys, J.

    2014-03-01

    This paper describes spatial modeling methods to identify wind erosion hazard (WEH) areas across Australia using the recently available time-series products of satellite-derived ground cover, soil moisture and wind speed. We implemented the approach and data sets in a geographic information system to produce WEH maps for Australia at 500 m ground resolution on a monthly basis for the recent thirteen year period (2000-2012). These maps reveal the significant wind erosion hazard areas and their dynamic tendencies at paddock and regional scales. Dust measurements from the DustWatch network were used to validate the model and interpret the dust source areas. The modeled hazard areas and changes were compared with results from a rule-set approach and the Computational Environmental Management System (CEMSYS) model. The study demonstrates that the time series products of ground cover, soil moisture and wind speed can be jointly used to identify landscape erodibility and to map seasonal changes of wind erosion hazard across Australia. The time series wind erosion hazard maps provide detailed and useful information to assist in better targeting areas for investments and continuous monitoring, evaluation and reporting that will lead to reduced wind erosion and improved soil condition.

  4. Temporal monitoring of the soil freeze-thaw cycles over snow-cover land by using off-ground GPR

    KAUST Repository

    Jadoon, Khan

    2013-07-01

    We performed off-ground ground-penetrating radar (GPR) measurements over a bare agricultural field to monitor the freeze-thaw cycles over snow-cover. The GPR system consisted of a vector network analyzer combined with an off-ground monostatic horn antenna, thereby setting up an ultra-wideband stepped-frequency continuous-wave radar. Measurements were performed during nine days and the surface of the bare soil was exposed to snow fall, evaporation and precipitation as the GPR antenna was mounted 110 cm above the ground. Soil surface dielectric permittivity was retrieved using an inversion of time-domain GPR data focused on the surface reflection. The GPR forward model used combines a full-waveform solution of Maxwell\\'s equations for three-dimensional wave propagation in planar layered media together with global reflection and transmission functions to account for the antenna and its interactions with the medium. Temperature and permittivity sensors were installed at six depths to monitor the soil dynamics in the top 8 cm depth. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and permittivity data and in particular freeze and thaw events were clearly visible. A good agreement of the trend was observed between the temperature, permittivity and GPR time-lapse data with respect to five freeze-thaw cycles. The GPR-derived permittivity was in good agreement with sensor observations. The proposed method appears to be promising for the real-time mapping and monitoring of the frozen layer at the field scale. © 2013 IEEE.

  5. Effects of post-fire salvage logging and a skid trail treatment on ground cover, soils, and sediment production in the interior western United States

    Science.gov (United States)

    Joseph W. Wagenbrenner; Lee H. MacDonald; Robert N. Coats; Peter R. Robichaud; Robert E. Brown

    2015-01-01

    Post-fire salvage logging adds another set of environmental effects to recently burned areas, and previous studies have reported varying impacts on vegetation, soil disturbance, and sediment production with limited data on the underlying processes. Our objectives were to determine how: (1) ground-based post-fire logging affects surface cover, soil water repellency,...

  6. Unmasking the soil cover's disruption by use of a dynamic model of measurement aerospace parameters of ground vegetation

    Directory of Open Access Journals (Sweden)

    E. V. Vysotskaya

    2016-03-01

    Full Text Available The "Introduction" describes topicality and importance of revealing the soil cover's disruption for a wide range of fields. It was shown that spectral brightness and colorimetric parameters of ground vegetation can be used for this task. However, a traditional scheme of data processing for remote sensing requires a long-term observations and can not always be applied, if quick decision-making is necessary or there is lack of information. Such cases require the use of special methods, one of which is a dynamic model developed with authors' participation based on the following basic relationships: (+,- (-, - (+, 0, (-, 0 (0,0. The section "Brief description of a dynamic model" describes the basic principles of dynamic systems used to solve the problem. Using above-mentioned relationships, the dynamics of a system consisting of several components is constructed and its main properties are listed. The main feature of this model is that the identification of structure and parameters of the dynamic system does not required sequential order of observations (as for models based on time series. This feature of the model enables for identifying the system's parameters of dynamics of the natural system to use information from a single picture taken from the spacecraft rather than long-term observations. The section "Materials and Methods" describes specific colorimetric parameters used to analyze the vegetation cover. The section "Obtained results" contains an example of the model's application to a satellite image for detecting the differences in two sites of a field with vegetation. One site is a recultivated area near the liquidated gas-oil well, another site is non-recultivated area at a considerable distance from the well (500-1000 m. The simulation results are described by eight signed graphs (4 graphs for each sites, whose structure allows to identify the system differences between the two cases. The section "Conclusions" summarizes the results of

  7. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    KAUST Repository

    Jadoon, Khan

    2015-09-18

    We tested an off-ground ground-penetrating radar (GPR) system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  8. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Khan Zaib Jadoon

    2015-09-01

    Full Text Available We tested an off-ground ground-penetrating radar (GPR system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  9. Soil bulk electrical resistivity and forage ground cover: nonlinear models in an alfalfa (Medicago sativa L. case study

    Directory of Open Access Journals (Sweden)

    Roberta Rossi

    2015-12-01

    Full Text Available Alfalfa is a highly productive and fertility-building forage crop; its performance, can be highly variable as influenced by within-field soil spatial variability. Characterising the relations between soil and forage- variation is important for optimal management. The aim of this work was to model the relationship between soil electrical resistivity (ER and plant productivity in an alfalfa (Medicago sativa L. field in Southern Italy. ER mapping was accomplished by a multi-depth automatic resistivity profiler. Plant productivity was assessed through normalised difference vegetation index (NDVI at 2 dates. A non-linear relationship between NDVI and deep soil ER was modelled within the framework of generalised additive models. The best model explained 70% of the total variability. Soil profiles at six locations selected along a gradient of ER showed differences related to texture (ranging from clay to sandy-clay loam, gravel content (0 to 55% and to the presence of a petrocalcic horizon. Our results prove that multi-depth ER can be used to localise permanent soil features that drive plant productivity.

  10. Engineered soil covers for management of salt impacted sites

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, D.A. [SEACOR Environmental Inc., Vancouver, BC (Canada); Tratch, D.J. [Watermark Consulting Ltd., Regina, SK (Canada)

    2005-07-01

    The use of engineered soil cover systems to mitigate environmental impacts from tailings and waste rock piles is becoming an accepted practice. This paper presented design concepts for soil covers related to reclamation practices in the mining industry as an effective risk management practice at salt impacted sites. Research and field programs have demonstrated that a layered engineered soil cover can reduce or eliminate infiltration. Key components of the system included re-establishing surface vegetation to balance precipitation fluxes with evapotranspiration potential, and design of a capillary break below the rooting zone to minimize deeper seated infiltration. It was anticipated that the incorporation of a vegetation cover and a capillary break would minimize infiltration into the waste rock or tailing pile and reduce the generation of acid rock drainage (ARD). Design of a layered soil cover requires the incorporation of meteorological data, moisture retention characteristics of the impacted soils, and proposed engineered cover materials. Performance of the soil cover was predicted using a finite element model combined with meteorological data from the site area, unsaturated soil properties of the parent sub-surface soils and potential covered materials. The soil cover design consisted of re-vegetation and a loose clay cover overlying a compacted till layer. The design was conducted for an off site release of salt impacted pasture land adjacent to a former highway maintenance yard. The model predicted minimal infiltration during high precipitation events and no infiltration during low precipitation events. Results indicated that the proposed soil cover would enable re-establishment of a productive agricultural ground cover, as well as minimizing the potential for additional salt migration. It was concluded that further research and development is needed to ensure that the cover system is an acceptable method for long-term risk management. 17 refs., 5 figs.

  11. Development of a ground hydrology model suitable for global climate modeling using soil morphology and vegetation cover, and an evaluation of remotely sensed information

    Science.gov (United States)

    Zobler, L.; Lewis, R.

    1988-01-01

    The long-term purpose was to contribute to scientific understanding of the role of the planet's land surfaces in modulating the flows of energy and matter which influence the climate, and to quantify and monitor human-induced changes to the land environment that may affect global climate. Highlights of the effort include the following: production of geo-coded, digitized World Soil Data file for use with the Goddard Institute for Space Studies (GISS) climate model; contribution to the development of a numerical physically-based model of ground hydrology; and assessment of the utility of remote sensing for providing data on hydrologically significant land surface variables.

  12. Cover crops to improve soil health and pollinator habitat in nut orchards

    Science.gov (United States)

    Jerry. Van Sambeek

    2017-01-01

    Recently several national programs have been initiated calling for improving soil health and creating pollinator habitat using cover crops. Opportunities exist for nut growers to do both with the use of cover crops in our nut orchards. Because we can include perennial ground covers as cover crops, we have even more choices than landowners managing cover crops during...

  13. Snow cover and soil moisture in mountains

    Science.gov (United States)

    Wever, N.; Lehning, M.

    2012-04-01

    Soil moisture is an important parameter of the climate system. It constrains evapotranspiration of plants and it functions as a storage of water, giving it an economic value, e.g. for agriculture. Furthermore, soil moisture is an important factor for predicting flood risk. In mountainous areas with a seasonal snow cover, the spatial distribution of snow depth is strongly influencing the spatial variation of soil moisture. To assess potential flooding situations during snow melt and rain on snow events in particular but for any heavy precipitation event in the mountains, it is important to understand the influence of the snow cover on soil status with respect to liquid and solid water. Only if this is known, the reaction of the soil i.e. amount of runoff, storage or melt, on additional water input can be assessed. For an operational assessment of the soil moisture state in the Swiss Alps at 140 measurement sites for snow and avalanche forecasting (IMIS network), the SNOWPACK model has been extended with a soil module, solving the Richards equation for the matrix flow. The modelling is validated with vertical profile measurements of soil moisture at meteorological stations in an Alpine catchment near Davos, Switzerland. It was found that the combination of a physical based snowpack model with a Richards equation solver seems to provide an adequate description of soil moisture fluctuations, especially in near surface layers. Soil moisture fluctuations, both measured and modelled, are strongly reduced when a snow cover is present. The measurements also revealed a strong increase in soil moisture, accompanied by a daily cycle in soil moisture during snow melt, extending down to 120cm depth. When soil properties from literature were assumed for the soil type in the vertical profile, the daily cycle in the model during snow melt was restricted mainly to the top layers, while observations show also a reaction in deeper layers. These observations are consistent with the

  14. Regulatory guidance on soil cover systems

    Energy Technology Data Exchange (ETDEWEB)

    Kane, J.D. [Nuclear Regulatory Commission, Washington, DC (United States)

    1991-12-31

    The US Nuclear Regulatory Commission (NRC) in September 1991, completed revisions to 14 sections of the Standard Review Plan (SRP) for the Review of a License Application for a Low-Level Radioactive Waste Disposal Facility. The major purposes of the SRP are to ensure the quality and uniformity of the NRC staff`s safety reviews, and to present a well-defined base from which to evaluate the acceptability of information and data provided in the Safety Analysis Report (SAR) portion of the license application. SRP 3.2, entitled, Design Considerations for Normal and Abnormal/Accident Conditions, was one of the sections that was revised by the NRC staff. This revision was completed to provide additional regulatory guidance on the important considerations that need to be addressed for the proper design and construction of soil cover systems that are to be placed over the LLW. The cover system over the waste is acknowledged to be one of the most important engineered barriers for the long-term stable performance of the disposal facility. The guidance in revised SRP 3.2 summarizes the previous efforts and recommendations of the US Army Corps of Engineers (COE), and a peer review panel on the placement of soil cover systems. NRC published these efforts in NUREG/CR-5432. The discussions in this paper highlight selected recommendations on soil cover issues that the NRC staff considers important for ensuring the safe, long-term performance of the soil cover systems. The development phases to be discussed include: (1) cover design; (2) cover material selection; (3) laboratory and field testing; (4) field placement control and acceptance; and (5) penetrations through the constructed covers.

  15. Cover Crops Effects on Soil Chemical Properties and Onion Yield

    Directory of Open Access Journals (Sweden)

    Rodolfo Assis de Oliveira

    2016-01-01

    Full Text Available ABSTRACT Cover crops contribute to nutrient cycling and may improve soil chemical properties and, consequently, increase crop yield. The aim of this study was to evaluate cover crop residue decomposition and nutrient release, and the effects of these plants on soil chemical properties and on onion (Allium cepa L. yield in a no-tillage system. The experiment was carried out in an Inceptisol in southern Brazil, where cover crops were sown in April 2012 and 2013. In July 2013, shoots of weeds (WD, black oats (BO, rye (RY, oilseed radish (RD, oilseed radish + black oats (RD + BO, and oilseed radish + rye (RD + RY were cut at ground level and part of these material from each treatment was placed in litter bags. The litter bags were distributed on the soil surface and were collected at 0, 30, 45, 60, 75, and 90 days after distribution (DAD. The residues in the litter bags were dried, weighed, and ground, and then analyzed to quantify lignin, cellulose, non-structural biomass, total organic carbon (TOC, N, P, K, Ca, and Mg. In November 2012 and 2013, onion crops were harvested to quantify yield, and bulbs were classified according to diameter, and the number of rotted and flowering bulbs was determined. Soil in the 0.00-0.10 m layer was collected for chemical analysis before transplanting and after harvesting onion in December 2012 and 2013. The rye plant residues presented the highest half-life and they released less nutrients until 90 DAD. The great permanence of rye residue was considered a protection to soil surface, the opposite was observed with spontaneous vegetation. The cultivation and addition of dry residue of cover crops increased the onion yield at 2.5 Mg ha-1.

  16. Acoustic Characterization of Grass-cover Ground

    Science.gov (United States)

    2014-11-20

    for noise and rever- beration control. Examples of porous media are cements, ceramics, rocks, building insulation , foams and soil. Characterizing the... air is consid- ered as lossless fluid and Eqs. 2.1 and 2.2 can be applied without approximations. However, when acoustic waves travel in narrow...3.1) In Eq. 3.1, P1 and P2 are the acoustic pressures measured at each respective microphone, Pi is the incident pressure, k0 is wave number in air , ω

  17. Modeling increasing effect of soil temperature through plastic film mulch in ground cover rice production system using CERES-Rice%基于CERES-Rice模型的覆膜旱作稻田增温效应模拟

    Institute of Scientific and Technical Information of China (English)

    马雯雯; 金欣欣; 石建初; 宁松瑞; 李森; 陶玥玥; 张亚男; 左强

    2015-01-01

    水稻覆膜旱作技术具有显著的节水、增温、防污和减排效应,是节水稻作技术体系的重要措施之一,将CERES-Rice模型用于覆膜旱作条件时,必须首先解决覆膜增温效应的准确模拟问题。该文拟应用热量传输理论及目前旱地作物生产系统中采用的覆膜增温效应模拟方法,来模拟水稻覆膜旱作生产体系中的增温效应,从而为完善 CERES-Rice 模型并使其能用于覆膜旱作水稻的生长模拟奠定基础。参数调校与模型检验验证通过2013、2014年在湖北房县开展的2 a水稻覆膜旱作田间试验来进行,共涉及淹水(对照)、覆膜湿润栽培和覆膜旱作共3个水分处理,分别对2个生长季、2个覆膜处理地表5 cm及地下10、20 cm处温度的变化过程进行了模拟,结果表明:经过参数调校后,所建立的覆膜增温模型可较好地模拟覆膜稻田地表和剖面上土壤温度的变化规律,地表5 cm处土壤温度模拟值与实测值的均方根差、相对均方根差分别低于1.8℃和10%,相关系数在0.89以上(P<0.01);尽管地下10、20 cm处的模拟误差稍大,也基本可满足要求,相应的均方根误差<3.2℃,相对均方根差<15%,相关系数>0.65(P<0.01)。%As one of the most promising water-saving rice production technologies, the ground cover rice production system (GCRPS) has been found to save water application, increase soil temperature, and reduce nitrogen pollution and methane emission. However, the feasibility of CERES-Rice, a software package widely and successfully applied in the traditional paddy rice production system (TPRPS), for simulating the rice growth in the GCRPS still remains unknown and needs further research. Undoubtedly, it should be based on accurately quantifying the effect of soil temperature enhancement caused by the ground cover material (chosen as the plastic film in this study). Therefore, the objective of

  18. Interrelationships between soil cover and plant cover depending on land use

    Directory of Open Access Journals (Sweden)

    Tiina Köster

    2013-05-01

    Full Text Available Interrelationships between soil cover and plant cover of normally developed (or postlithogenic mineral soils are analysed on the basis of four sampling soil groups. The four-link pedo-ecological sequence of analysed soils, rendzinas → brown soils → pseudopodzolic soils → gley-podzols, forms a representative cross section in relation to the normal mineral soils of Estonia. All groups differ substantially from each other in terms of soil properties (calcareousness, acidity, nutrition conditions, profile fabric and humus cover. The primary tasks of the research were (1 to elucidate the main pedo-ecological characteristics of the four soil groups and their suitability for plant cover, (2 to evaluate comparatively soils in terms of productivity, sustainability, biodiversity and environmental protection ability and (3 to analyse possibilities for ecologically sound matching of soil cover with suitable plant cover. On the basis of the same material, the influence of land-use change on humus cover (epipedon fabric, properties of the entire soil cover and soil–plant interrelationship were also analysed. An ecosystem approach enables us to observe particularities caused by specific properties of a soil type (species, variety in biological turnover and in the formation of biodiversity.

  19. Effects of ground cover from branches of arboreal species on weed growth and maize yield

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima e Silva

    Full Text Available ABSTRACTCultivating maize under systems of alley cropping results in improvements to the soil, a reduction in weeds and an increase in yield. Studies using ground cover from tree shoots produce similar results. The aim of this study was to evaluate the effects on weed growth and maize yield of ground cover made up of 30 t ha-1 (fresh matter of branches from the tree species: neem (Azadirachta indica A. Juss, gliricidia [Gliricidia sepium(Jacq. Kunth ex Walp.], leucaena [Leucaena leucocephala (Lam. de Wit.] and sabiá (Mimosa caesalpiniifolia Benth.. Two treatment groups (cultivars and weed control were evaluated. The cultivars AG 1041 and AL Bandeirantes were subjected to the following treatments: no hoeing, double hoeing, and ground a cover of branches of the above species when sowing the maize. A randomised block design was used with split lots (cultivars in the lots and ten replications. The cultivars did not differ for green ear or grain yield. Double hoeing was more effective than ground cover at reducing the growth of weeds. However, both weeding and ground cover resulted in similar yields for green ears and grain, which were greater than those obtained with the unweeded maize.

  20. About soil cover heterogeneity of agricultural research stations' experimental fields

    Science.gov (United States)

    Rannik, Kaire; Kõlli, Raimo; Kukk, Liia

    2013-04-01

    Depending on local pedo-ecological conditions (topography, (geo) diversity of soil parent material, meteorological conditions) the patterns of soil cover and plant cover determined by soils are very diverse. Formed in the course of soil-plant mutual relationship, the natural ecosystems are always influenced to certain extent by the other local soil forming conditions or they are site specific. The agricultural land use or the formation of agro-ecosystems depends foremost on the suitability of soils for the cultivation of feed and food crops. As a rule, the most fertile or the best soils of the area, which do not present any or present as little as possible constraints for agricultural land use, are selected for this purpose. Compared with conventional field soils, the requirements for the experimental fields' soil cover quality are much higher. Experimental area soils and soil cover composition should correspond to local pedo-ecological conditions and, in addition to that, represent the soil types dominating in the region, whereas the fields should be as homogeneous as possible. The soil cover heterogeneity of seven arable land blocks of three research stations (Jõgeva, Kuusiku and Olustvere) was studied 1) by examining the large scale (1:10 000) digital soil map (available via the internet), and 2) by field researches using the transect method. The stages of soils litho-genetic and moisture heterogeneities were estimated by using the Estonian normal soils matrix, however, the heterogeneity of top- and subsoil texture by using the soil texture matrix. The quality and variability of experimental fields' soils humus status, was studied more thoroughly from the aspect of humus concentration (g kg-1), humus cover thickness (cm) and humus stocks (Mg ha-1). The soil cover of Jõgeva experimental area, which presents an accumulative drumlin landscape (formed during the last glacial period), consist from loamy Luvisols and associated to this Cambisols. In Kuusiku area

  1. Estimation of Soil Erosion Rates in Oil Palm Plantation with Different Land Cover

    Science.gov (United States)

    Sahat, S.; Yusop, Z.; Askari, M.; Ziegler, A. D.

    2016-07-01

    Soil losses from hill slopes in oil palm plantation in Sedenak Estate, Johor were measured using runoff plot and rainfall simulator. The plot was designed to be removable but the size was fixed at 8 x 3.75m. Four types of surface covers were investigated for the plots, i.e. half bare soil and half grass cover (HGC), half bare soil and half dry frond (HDF), fully grass cover (FG), and fully bare soil (BS). The influence of initial soil moisture, saturated hydraulics conductivity, Ks, bulk density and slope on rates of soil loss were also evaluated. The rainfall simulator produced rainfall intensities between 90 and 160 mm/hr with durations from 45 to 60 min per run. BS plot exhibited the highest Ks value among all plots but the percentage of initial soil moisture on this surface was low. BS plot recorded the highest runoff coefficient (C) and soil loss values of 73.6 ± 4 percent and 5.26 ± 3.2 t/ha respectively, while the lowest was from plot FG with 41.7 ± 5.7 percent and soil loss of 2.85 ± 2.1 t/ha. Meanwhile, the results suggested that the ground cover had the ability to reduce soil loss by 67% and 17%, respectively for plots BS-HGC and BS-HDF. Overall, soil erosion control such as surface is effective measures in reducing level of runoff and soil erosion.

  2. Rational design approach for landfill liner protective soil cover

    Energy Technology Data Exchange (ETDEWEB)

    Ruetten, M.G. [STS Consultants Ltd., Green Bay, WI (United States); Bandi, S.R. [Rust Environment & Infrastructure, Livonia, MI (United States); Reddy, K.R. [Univ. of Illinois, Chicago, IL (United States)

    1995-12-31

    This paper presents a rational approach for designing protective soil cover for landfill geomembrane liners in order to prevent damage to the liners. The present practice involves using a combination of geotextile and soil layer as protective cover. The geotextile is placed directly over the geomembrane and then a protective soil is placed on the geotextile. The protective soil layer generally consists of a free-draining granular soil which also serves as a drainage layer for the leachate collection and removal system. The degree of protection offered to the geomembrane depends on the type of geotextile, and the composition and thickness of the protective soil used.

  3. Airborne particulate soiling of terrestrial photovoltaic modules and cover materials

    Science.gov (United States)

    Hoffman, A. R.; Maag, C. R.

    1980-01-01

    Results are presented for the first phase of a photovoltaic-module soiling study that was carried out with NASA participation to investigate the problem of the electrical performance degradation of flat-plate photovoltaic modules exposed at outdoor sites that is due to the accumulation of airborne particulates on sensitive optical surfaces. The results were obtained in both field and laboratory soiling experiments, as well as in materials field experiments using candidate encapsulants and top covers. It is concluded that: (1) the electrical performance degradation shows a significant time and site dependence, ranging from 2% to 60% power loss; (2) the rate of particulate accumulation appears to be largely material independent when natural removal processes do not dominate; (3) the effectiveness of natural removal processes, especially rain, is strongly material dependent; (4) top-cover materials of glass and plexiglass retain fewer particles than silicone rubber; and (5) high module voltages relative to ground do not appear to affect the rate of dirt accumulation on modules.

  4. Soil moisture characterization of the Valencia anchor station. Ground, aircraft measurements and simulations

    DEFF Research Database (Denmark)

    Lopez-Baeza, E; Antolin, M C; Balling, Jan E.

    2009-01-01

    , soil type, lithology, geology, elevation, slope and vegetation cover conditions. Complementary to the ground measurements, flight operations were performed over this control area using the Helsinki University of Technology TKK Short Skyvan research aircraft which contained onboard a payload constituted...

  5. The potential of cover crops for improving soil function

    Science.gov (United States)

    Stoate, Chris; Crotty, Felicity

    2017-04-01

    Cover crops can be grown over the autumn and winter ensuring green cover throughout the year. They have been described as improving soil structure, reducing soil erosion and potentially even a form of grass weed control. These crops retain nutrients within the plant, potentially making them available for future crops, as well as increasing soil organic matter. Over the last three years, we have investigated how different cover crop regimes affect soil quality. Three separate experiments over each autumn/winter period have investigated how different cover crops affect soil biology, physics and chemistry, with each experiment building on the previous one. There have been significant effects of cover crops on soil structure, as well as significantly lower weed biomass and increased yields in the following crop - in comparison to bare stubble. For example, the effect of drilling the cover crops on soil structure in comparison to a bare stubble control that had not been driven on by machinery was quantified, and over the winter period the soil structure of the cover crop treatments changed, with compaction reduced in the cover crop treatments, whilst the bare stubble control remained unchanged. Weeds were found in significantly lower biomass in the cover crop mixes in comparison to the bare stubble control, and significantly lower weed biomass continued to be found in the following spring oat crop where the cover crops had been, indicating a weed suppressive effect that has a continued legacy in the following crop. The following spring oats have shown similar results in the last two years, with higher yields in the previous cover crop areas compared to the bare stubble controls. Overall, these results are indicating that cover crops have the potential to provide improvements to soil quality, reduce weeds and improve yields. We discuss the economic implications.

  6. Tillage System and Cover Crop Effects on Soil Quality

    DEFF Research Database (Denmark)

    Abdollahi, Lotfollah; Munkholm, Lars Juhl

    2014-01-01

    Information about the quantitative effect of conservation tillage combined with a cover crop on soil structure is still limited. This study examined the effect of these management practices on soil pore characteristics of a sandy loam soil in a long-term field trial. The tillage treatments (main...

  7. Evolution of the soil cover of soccer fields

    Science.gov (United States)

    Belobrov, V. P.; Zamotaev, I. V.

    2014-04-01

    A soccer field can be considered a soil-like technogenic formation (STF). According to the theory of soil cover patterns, the artificially constructed (anthropogenic) soil cover of a soccer field is an analogue of a relatively homogeneous elementary soil area. However, the spatial homogeneity of the upper part (50-80 cm) of the STF of soccer fields is unstable and is subjected to gradual transformation under the impact of pedogenetic processes, agrotechnical loads, and mechanical loads during the games. This transformation is favored by the initial heterogeneity of the deep (buried) parts of the STF profile. The technogenic factors and elementary pedogenetic processes specify the dynamic functioning regime of the STF. In 50-75 years, the upper part of the STF is transformed into soil-like bodies with properties close to those in zonal soils. Certain micro- and nanopatterns of the soil cover are developed within the field creating its spatial heterogeneity.

  8. Enhanced Cover Assessment Project:Soil Manipulation and Revegetation Tests

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W. Joseph [Navarro Research and Engineering, Inc.; Albright, Dr. Bill [Desert Research Inst. (DRI), Reno, NV (United States); Benson, Dr. Craig [University of Wisconsin-Madison

    2014-02-01

    The U.S. Department of Energy Office of Legacy Management is evaluating methods to enhance natural changes that are essentially converting conventional disposal cell covers for uranium mill tailings into water balance covers. Conventional covers rely on a layer of compacted clayey soil to limit exhalation of radon gas and percolation of rainwater. Water balance covers rely on a less compacted soil “sponge” to store rainwater, and on soil evaporation and plant transpiration (evapotranspiration) to remove stored water and thereby limit percolation. Over time, natural soil-forming and ecological processes are changing conventional covers by increasing hydraulic conductivity, loosening compaction, and increasing evapotranspiration. The rock armor on conventional covers creates a favorable habitat for vegetation by slowing soil evaporation, increasing soil water storage, and trapping dust and organic matter, thereby providing the water and nutrients needed for plant germination, survival, and sustainable transpiration. Goals and Objectives Our overall goal is to determine if allowing or enhancing these natural changes could improve cover performance and reduce maintenance costs over the long term. This test pad study focuses on cover soil hydrology and ecology. Companion studies are evaluating effects of natural and enhanced changes in covers on radon attenuation, erosion, and biointrusion. We constructed a test cover at the Grand Junction disposal site to evaluate soil manipulation and revegetation methods. The engineering design, construction, and properties of the test cover match the upper three layers of the nearby disposal cell cover: a 1-foot armoring of rock riprap, a 6-inch bedding layer of coarse sand and gravel, and a 2-foot protection layer of compacted fine soil. The test cover does not have a radon barrier—cover enhancement tests leave the radon barrier intact. We tested furrowing and ripping as means for creating depressions parallel to the slope

  9. Soil covering in organic cultivation of onion cultivars

    OpenAIRE

    Leonardo Barreto Tavella; Regina Lúcia Felix Ferreira; Sebastião Elviro de Araújo Neto; Antônio Jussie da Silva Solino; Eliana Mara Napoli Corrêa de Paula da Silva; Maísa Pinto Bravin

    2015-01-01

    The soil preparation in horticulture, including organic, is characterized by intense soil tillage, which increases energy costs and unbalanced the environment. The organic system in onion cultivation has shown satisfactory results, however the soil covering use tends to improve the cultivation environment and may result in higher yields. The objective of this work was to evaluate the performance of onion cultivars in organic cultivation under different soil coverages. The experiment was co...

  10. Impact of the variability of the seasonal snow cover on the ground surface regimes in Hurd Peninsula (Livingston Island, Antarctic)

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2014-05-01

    Seasonally snow cover has a great impact on the thermal regime of the active layer and permafrost. Ground temperatures over a year are strongly affected by the timing, duration, thickness, structure and physical and thermal properties of snow cover. The purpose of this communication is to characterize the shallow ground thermal regimes, with special reference to the understanding of the influence snow cover in permafrost spatial distribution, in the ice-free areas of the north western part of Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". We have analyzed and ground temperatures as well as snow thickness data in four sites distributed along an altitudinal transect in Hurd Peninsula from 2007 to 2013: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). At each study site, data loggers were installed for the monitoring of air temperatures (at 1.5 m high), ground temperatures (5, 20 and 40 cm depth) and for snow depth (2, 5, 10, 20, 40, 80 and 160 cm) at 4-hour intervals. The winter data suggests the existence of three types of seasonal stages regarding the ground surface thermal regime and the thickness of snow cover: (a) shallow snow cover with intense ground temperatures oscillations; (b) thick snow cover and low variations of soil temperatures; and (c) stability of ground temperatures. Ground thermal conditions are also conditioned by a strong variability. Winter data indicates that Nuevo Incinerador site experiences more often thicker snow cover with higher ground temperatures and absence of ground temperatures oscillations. Collado Ramos and Ohridski show frequent variations of snow cover thickness, alternating between shallow snow cover with high ground temperature fluctuation and thick snow cover and low ground temperature fluctuation. Reina Sofia in all the years has thick snow cover with little variations in soil

  11. Thresholds for soil cover and weathering in mountainous landscapes

    Science.gov (United States)

    Dixon, Jean; Benjaram, Sarah

    2017-04-01

    The patterns of soil formation, weathering, and erosion shape terrestrial landscapes, forming the foundation on which ecosystems and human civilizations are built. Several fundamental questions remain regarding how soils evolve, especially in mountainous landscapes where tectonics and climate exert complex forcings on erosion and weathering. In these systems, quantifying weathering is made difficult by the fact that soil cover is discontinuous and heterogeneous. Therefore, studies that attempt to measure soil weathering in such systems face a difficult bias in measurements towards more weathered portions of the landscape. Here, we explore current understanding of erosion-weathering feedbacks, and present new data from mountain systems in Western Montana. Using field mapping, analysis of LiDAR and remotely sensed land-cover data, and soil chemical analyses, we measure soil cover and surface weathering intensity across multiple spatial scales, from the individual soil profile to a landscape perspective. Our data suggest that local emergence of bedrock cover at the surface marks a landscape transition from supply to kinetic weathering regimes in these systems, and highlights the importance of characterizing complex critical zone architecture in mountain landscapes. This work provides new insight into how landscape morphology and erosion may drive important thresholds for soil cover and weathering.

  12. Assessing post-fire ground cover in Mediterranean shrublands with field spectrometry and digital photography

    Science.gov (United States)

    Montorio Llovería, Raquel; Pérez-Cabello, Fernando; García-Martín, Alberto

    2016-09-01

    Fire severity can be assessed by identifying and quantifying the fractional abundance of post-fire ground cover types, an approach with great capacity to predict ecosystem response. Focused on shrubland formations of Mediterranean-type ecosystems, three burned areas (Ibieca and Zuera wildfires and Peñaflor experimental fire) were sampled in the summers of 2006 and 2007. Two different ground measurements were made for each of the 356 plots: (i) 3-band high spatial resolution photography (HSRP) and (ii) the hemispherical-conical reflectance factor (HCRF) in the visible to near-infrared spectral range (VNIR, 400-900 nm). Stepwise multiple lineal regression (SMLR) models were fitted to spectral variables (HCRF, first derivative spectra or FDS, and four absorption indices) to estimate the fractional cover of seven post-fire ground cover types (vegetation and soil - unburned and charred components - and ash - char and ash, individually and as a combined category). Models were developed and validated at the Peñaflor site (training, n = 217; validation, n = 88) and applied to the samples from the Ibieca and Zuera sites (n = 51). The best results were observed for the abundance estimations of green vegetation (Radj.20.70-0.90), unburned soil (Radj.20.40-0.75), and the combination of ashes (Radj.20.65-0.80). In comparison of spectral data, FDS outperforms reflectance or absorption data because of its higher accuracy levels and, importantly, its greater capacity to yield generalizable models. Future efforts should be made to improve the estimation of intermediate severity levels and upscaling the developed models. In the context of fire severity assessment, our study demonstrates the potential of hyperspectral data to estimate in a quick and objective manner post-fire ground cover fractions and thus provide valuable information to guide management responses.

  13. Tillage System and Cover Crop Effects on Soil Quality

    DEFF Research Database (Denmark)

    Abdollahi, Lotfollah; Munkholm, Lars Juhl

    2014-01-01

    Optimal use of management systems including tillage and winter cover crops is recommended to improve soil quality and sustain agricultural production. The effects on soil properties of three tillage systems (as main plot) including direct drilling (D), harrowing to a depth of 8 to 10 cm (H......), and moldboard plowing (MP) with and without a cover crop were evaluated in a long-term experiment on a sandy loam soil in Denmark. Chemical, physical, and biological soil properties were measured in the spring of 2012. The field measurements included mean weight diameter (MWD) after the drop-shatter test......, penetration resistance, and visual evaluation of soil structure (VESS). In the laboratory, aggregate strength, water-stable aggregates (WSA), and clay dispersibility were measured. The analyzed chemical and biological properties included soil organic C (SOC), total N, microbial biomass C, labile P and K...

  14. The contribution of vegetation cover and bare soil to pixel reflectance in an arid ecosystem

    Science.gov (United States)

    Steele, C. M.; Smith, A.; Campanella, A.; Rango, A.

    2008-12-01

    The heterogeneity of vegetation and soils in arid and semi-arid environments complicates the analysis of medium spatial resolution remotely sensed imagery. A single pixel may contain several different types of vegetation, as well as a sizeable proportion of bare soil. We have used linear mixture modeling to explore the contribution of vegetation cover and bare soil to pixel reflectance. In October, 2006, aerial imagery (0.25 m spatial resolution) was acquired for our study sites in the Jornada Experimental Range, southern New Mexico. Imagery was also acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for June and November, 2006. These data corresponded with pre- and post monsoon conditions. Object-based feature extraction was used to classify the aerial imagery to shrub, grass and bare ground cover classes. Percent cover was then calculated for each cover class. Visible-near-infrared and shortwave infrared ASTER reflectance data from both dates were combined into a single 18-band dataset (30 m spatial resolution). A vector overlay from the classification results of the aerial imagery was used to define pure endmember pixels in the ASTER imagery. Estimates of the proportions of shrub, grass and bare ground cover from the linear mixture modeling approach were compared with cover calculated using feature extraction from the aerial imagery. The results indicate that reflectance in ASTER pixels is likely to be a linear combination of the cover proportions of the three main cover types (shrubs, grass, bare ground). However, noticeable outliers in the relationship between cover calculated from each method, indicate there may be other variables that affect the accuracy with which we can estimate cover using linear mixture modeling.

  15. Estimating ground water recharge from topography, hydrogeology, and land cover.

    Science.gov (United States)

    Cherkauer, Douglas S; Ansari, Sajjad A

    2005-01-01

    Proper management of ground water resources requires knowledge of the rates and spatial distribution of recharge to aquifers. This information is needed at scales ranging from that of individual communities to regional. This paper presents a methodology to calculate recharge from readily available ground surface information without long-term monitoring. The method is viewed as providing a reasonable, but conservative, first approximation of recharge, which can then be fine-tuned with other methods as time permits. Stream baseflow was measured as a surrogate for recharge in small watersheds in southeastern Wisconsin. It is equated to recharge (R) and then normalized to observed annual precipitation (P). Regression analysis was constrained by requiring that the independent and dependent variables be dimensionally consistent. It shows that R/P is controlled by three dimensionless ratios: (1) infiltrating to overland water flux, (2) vertical to lateral distance water must travel, and (3) percentage of land cover in the natural state. The individual watershed properties that comprise these ratios are now commonly available in GIS data bases. The empirical relationship for predicting R/P developed for the study watersheds is shown to be statistically viable and is then tested outside the study area and against other methods of calculating recharge. The method produces values that agree with baseflow separation from streamflow hydrographs (to within 15% to 20%), ground water budget analysis (4%), well hydrograph analysis (12%), and a distributed-parameter watershed model calibrated to total streamflow (18%). It has also reproduced the temporal variation over 5 yr observed at a well site with an average error < 12%.

  16. Soil covering in organic cultivation of onion cultivars

    Directory of Open Access Journals (Sweden)

    Leonardo Barreto Tavella

    2015-03-01

    Full Text Available The soil preparation in horticulture, including organic, is characterized by intense soil tillage, which increases energy costs and unbalanced the environment. The organic system in onion cultivation has shown satisfactory results, however the soil covering use tends to improve the cultivation environment and may result in higher yields. The objective of this work was to evaluate the performance of onion cultivars in organic cultivation under different soil coverages. The experiment was conducted in the period of April to October of 2009, under protected cropping, in the experimental area of the horticulture sector of the Universidade Federal do Acre (UFAC, in Rio Branco, Acre, Brazil. A randomized block design was adopted, in a split-plot arrangement, the plots being comprised of soil coverings: coffee bean husks, grass straw (Brachiaria decumbens; dessicated bamboo leaves (Bambusa spp. and uncovered soil (control treatment, and the subplots comprised of three onion cultivars (IPA 10, IPA 11 and IPA 12, with four repetitions. The variables analyzed were total bulb yield (t ha-1, marketable bulb yield (t ha-1, fresh mass of the bulb (g bulb-1, classification of the bulbs and loss of mass as a function of storage time. There was no interaction effect between the soil coverings and the cultivars. Cultivars IPA 10 and IPA 11 showed greater agronomic performance of the studied variables. The soil coverings did not affect the yield and average mass of the bulbs under organic cultivation. The three cultivars presented more than approximately 70% of the bulbs in class 2 and a maximum of 5% of unmarketable bulbs. The loss of mass after 49 days of storage was 10% independent of the cultivar or soil covering.

  17. Cover stones on liquefiable soil bed under waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Hatipoglu, Figen; Fredsøe, Jørgen

    2010-01-01

    of stone layers (including the effect of an intermediate filter layer) were investigated. Pore pressure was measured across the soil depth. The experiments show that the soil liquefaction depended mainly on two parameters: the packing density of stones, and the number of stone layers. When the liquefaction...... occurs, stones sink in the soil. Mechanisms of liquefaction and sinking are described, and practical guidelines are recommended.......The paper describes the results of an experimental study on the behavior of cover stones on a liquefiable soil bed exposed to a progressive wave. The soil was silt with d50=0.098mm. Stones, the size of 4cm, were used as cover material. The effect of packing density of stones, and that of number...

  18. Residue cover effects on soil erosion and the infiltration in black soil under simulated rainfall experiments

    Science.gov (United States)

    Xin, Yan; Xie, Yun; Liu, Yuxin; Liu, Hongyuan; Ren, Xiaoyu

    2016-12-01

    Residue cover is widely used in the Northeastern China Black Soil Region for soil erosion control due to the large annual production of crop residues. Quantitative evaluations of the residue cover effects on preventing soil loss and on the cumulative infiltration amount are thus desirable. Herein, rainfall simulation experiments were conducted using simulators and soil flumes to study the effects of residue cover on soil erosion and infiltration under various rainfall events. Laboratory experiments were designed utilizing five levels of residue cover (bare, 15%, 35%, 55% and 75%), four rainfall intensities (30 mm/h, 60 mm/h, 90 mm/h and 120 mm/h), two soil moistures (dry and wet run) and a fixed slope of 7%. The results indicated that residue cover strongly affects runoff, soil loss and infiltration. Equations for predicting the soil loss ratio and infiltration ratio (the ratio of residue cover soil to bare soil) are herein proposed based on nonlinear curve regression. An empirical approach presented as the infiltration ratios multiplied Philip's equation derived from bare soil was established for estimating the cumulative infiltration amounts under various residue covers. The equation was demonstrated to be suitable for infiltration prediction for black soil by the root mean square error value and 1:1 line method. In addition, the relationship between the residue cover and biomass of corn residues was provided in order to enable accurate measurement of the residue coverage. These derived equations could be used for soil erosion and infiltration prediction under no-till and residue cover management conditions in the black soil region.

  19. Relic components within the soil cover of Mexico: regional variability

    Science.gov (United States)

    Solleiro Rebolledo, Elizabeth; Sedov, Sergey

    2015-04-01

    The case of paleosols persisting on the land surface (non-buried paleosols or relict soils) besides paleoecological interest has specific implications for studies of soil geography, ecology and management. In fact these soil bodies form part of the modern soil mantle and provide ecological services for the current (agro)ecosystems but are neither formed nor re-produced by these ecosystems, conforming locally extinct soils (although similar profiles can develop at present under other bioclimatic conditions). In consequence, they are a heritage of past climatic and biotic conditions now extinct, thus presenting a non-restorable component of the present landscape. Mexico has so abundant and diverse paleosols, both surface and buried, that really could be considered to be a "paleopedological paradise". Two groups of factors promote generation of this abundance: Major part of territory of Mexico is occupied by mountainous landscapes with high intensity of tectonic, volcanic and geomorphic processes. These processes create a complex mosaic of geological materials and landforms of different age (like alluvial and lake terraces, eroded slopes, and volcanic deposits of various eruptions). Meanwhile younger landsurfaces are occupied by the recently developed soils, the older ones could bear the relict soil bodies. The same processes produce sedimentary strata (alluvial, colluvial, pyroclastic, etc.) which frequently cover the pre-existing landsurfaces and soils, producing series of buried paleosols. In this work we present three study cases of relict paleosols that are integrated to the modern soil cover of Mexico: the case of reddish-brown soils in the arid landscapes of Sonora (in the north); the pedosediments (tepetates) in central Mexico; and the red soils developed under humid conditions in Yucatan (in the south).

  20. Database for estimating tree responses of walnut and other hardwoods to ground cover management practices

    Science.gov (United States)

    J.W. Van Sambeek

    2010-01-01

    The ground cover in plantings of walnut and other hardwoods can substantially affect tree growth and seed production. The number of alternative ground covers that have been suggested for establishment in tree plantings far exceeds the number that have already been tested with walnut and other temperate hardwoods. Knowing how other hardwood species respond to ground...

  1. Large Scale Evaluation of AMSR-E Soil Moisture Products Based on Ground Soil Moisture Network Measurements

    Science.gov (United States)

    Gruhier, C.; de Rosnay, P.; Richaume, P.; Kerr, Y.; Rudiger, C.; Boulet, G.; Walker, J. P.; Mougin, E.; Ceschia, E.; Calvet, J.

    2007-05-01

    This paper presents an evaluation of AMSR-E (Advanced Microwave Scanning Radiometer for EOS) soil moisture products, based on a comparison with three ground soil moisture networks. The selected ground sites are representative of various climatic, hydrologic and environmental conditions in temperate and semi-arid areas. They are located in the south-west of France, south-east of Australia and the Gourma region of the Sahel. These sites were respectively implemented in the framework of the projects SMOSREX (Surface Monitoring Of Soil Reservoir Experiment), SASMAS/GoREx (Scaling and Assimilation of Soil Moisture and Streamflow in the Goulburn River Experimental catchment) and AMMA (African Monsoon Multidisciplinary Analysis). In all cases, the arrangement of the soil moisture measuring sites was specifically designed to address the validation of remotely sensed soil moisture in the context of the preparation of the SMOS (Soil Moisture and Ocean Salinity) project. For the purpose of this study, 25km AMSR-E products were used, including brightness temperatures at 6.9 and 10.7 GHz, and derived soil moisture. The study is focused on the year 2005. It is based on ground soil moisture network measurements from 4 stations for SMOSREX extended to the SUDOUEST project of CESBIO, 12 stations for GoRex, and 4 stations for AMMA. Temporal and spatial features of soil moisture variability and stability is a critical issue to be addressed for remotely sensed soil moisture validation. While ground measurements provide information on soil moisture dynamics at local scale and high temporal resolution (hourly), satellite measurements are sparser in time (up to several days), but cover a larger region (25km x 25km for AMSR-E). First, a statistical analysis, including mean relative difference and Spearman rank, is conducted for the three soil moisture networks. This method is mainly based on the approach proposed by Cosh et al. (2004) for the purpose of the use of ground networks for

  2. Soil microbial biomass under different management and tillage systems of permanent intercropped cover species in an orange orchard

    Directory of Open Access Journals (Sweden)

    Elcio Liborio Balota

    2011-12-01

    Full Text Available To mitigate soil erosion and enhance soil fertility in orange plantations, the permanent protection of the inter-rows by cover species has been suggested. The objective of this study was to evaluate alterations in the microbial biomass, due to different soil tillage systems and intercropped cover species between rows of orange trees. The soil of the experimental area previously used as pasture (Brachiaria humidicola was an Ultisol (Typic Paleudult originating from Caiuá sandstone in the northwestern part of the State of Paraná, Brazil. Two soil tillage systems were evaluated: conventional tillage (CT in the entire area and strip tillage (ST (strip width 2 m, in combination with different ground cover management systems. The citrus cultivar 'Pera' orange (Citrus sinensis grafted onto 'Rangpur' lime rootstock was used. Soil samples were collected after five years of treatment from a depth of 0-15 cm, under the tree canopy and in the inter-row, in the following treatments: (1 CT and an annual cover crop with the leguminous species Calopogonium mucunoides; (2 CT and a perennial cover crop with the leguminous peanut Arachis pintoi; (3 CT and an evergreen cover crop with Bahiagrass Paspalum notatum; (4 CT and a cover crop with spontaneous Brachiaria humidicola grass vegetation; and (5 ST and maintenance of the remaining grass (pasture of Brachiaria humidicola. Soil tillage and the different cover species influenced the microbial biomass, both under the tree canopy and in the inter-row. The cultivation of brachiaria increased C and N in the microbial biomass, while bahiagrass increased P in the microbial biomass. The soil microbial biomass was enriched in N and P by the presence of ground cover species and according to the soil P content. The grass species increased C, N and P in the soil microbial biomass from the inter-row more than leguminous species.

  3. COMPARATIVE ANALYSIS OF GROUNDING RESISTANCE VALUE IN SOIL AND SEPTICTANK

    Directory of Open Access Journals (Sweden)

    Abdul Syakur

    2012-02-01

    Full Text Available The aim of grounding system to protect of electrical equipment and instrumentation system and peopletogether. The lightning stroke near the strucutre of building can damage of equipment and instrumentationsystem. Therefore, it is very important to protect theese electrical and electronic equipment from lightningstrike uses lightning protection system and grounding system.This paper presents kind of grounding system at type of soil and place. The measurement of groundingresistance in soil and septictank have done. Types of soil for grounding resistance measuring aremarshland, clay and rockland.The measurement results of grounding resistance show that value of grounding resistance depend ondeepness of electrode and kind of soil and septictank. Grounding resistance value in septictank is morelower than soil.

  4. [Culturable psychrotolerant methanotrophic bacteria in landfill cover soil].

    Science.gov (United States)

    Kallistova, A Iu; Montonen, L; Jurgens, G; Munster, U; Kevbrina, M V; Nozhevnikova, A N

    2014-01-01

    Methanotrophs closely related to psychrotolerant members of the genera Methylobacter and Methylocella were identified in cultures enriched at 10@C from landfill cover soil samples collected in the period from April to November. Mesophilic methanotrophs of the genera Methylobacter and Methylosinus were found in cultures enriched at 20 degrees C from the same cover soil samples. A thermotolerant methanotroph related to Methylocaldum gracile was identified in the culture enriched at 40 degrees C from a sample collected in May (the temperature of the cover soil was 11.5-12.5 degrees C). In addition to methanotrophs, methylobacteria of the genera Methylotenera and Methylovorus and members of the genera Verrucomicrobium, Pseudomonas, Pseudoxanthomonas, Dokdonella, Candidatus Protochlamydia, and Thiorhodospira were also identified in the enrichment cultures. A methanotroph closely related to the psychrotolerant species Methylobacter tundripaludum (98% sequence identity of 16S r-RNA genes with the type strain SV96(T)) was isolated in pure culture. The introduction of a mixture of the methanotrophic enrichments, grown at 15 degrees C, into the landfill cover soil resulted in a decrease in methane emission from the landfill surface in autumn (October, November). The inoculum used was demonstrated to contain methanotrophs closely related to Methylobacter tundripaludum SV96.

  5. Spatial and temporal variability of grass cover in two olive grove catchments on contrasting soil types

    Science.gov (United States)

    Aguilera, Laura; Taguas, Encarnación V.; Gimeno, Enrique; Gómez, José A.

    2013-04-01

    Mediterranean climate conditions -characterized by the concentration of the precipitation in the seasons of autumn and spring, the low temperatures in winter and extremely warm and dry summers- determine that ground cover by adventitious (or cover crop) vegetation shows significant seasonal and annual variability. In addition, its spatial variability associates also, partially, to water availability among the landscape. This is especially relevant in olive orchards, an agricultural system under high erosion risk in the region where the establishment of herbaceous cover has proved to improve soil protection reducing erosion risk, as well as the improvement of soil properties (Gómez et al., 2009). All these benefits are based on small scale studies where full ground cover by the cover crop is relatively easy to obtain. However, few information is available about the actual ground cover achieved at farm scale, although preliminary observations suggests that this might be extremely variable (Gómez and Giráldez, 2009). This study presents the preliminary results evaluating the spatial and temporal evolution of ground cover by adventitious vegetation (the preferred option by farmers to achieve a cover crop) in two commercial olive farms during 2 hydrological years (2011-2012). The study was conducted in two farms located in the province of Cordoba, Southern Spain. Both were olive orchards grown under deficit irrigation systems and present a gauge station where rainfall, runoff and sediment loads have been measured from the year 2005. The soil management in "La Conchuela" farm was based in the use of herbicide in the line of olive trees to keep the bare soil all year round, and the application of selective herbicide in the lane between the olive trees to promote the grown of graminaceae grasses . In addition, the grass is mechanically killed in June. In the another farm, "Arroyo Blanco", the grass spontaneous cover is allowed until mid-spring in which is also

  6. [Diversity and stability of arthropod community in peach orchard under effects of ground cover vegetation].

    Science.gov (United States)

    Jiang, Jie-xian; Wan, Nian-feng; Ji, Xiang-yun; Dan, Jia-gui

    2011-09-01

    A comparative study was conducted on the arthropod community in peach orchards with and without ground cover vegetation. In the orchard with ground cover vegetation, the individuals of beneficial, neutral, and phytophagous arthropods were 1.48, 1.84 and 0.64 times of those in the orchard without ground cover vegetation, respectively, but the total number of arthropods had no significant difference with that in the orchard without ground cover vegetation. The species richness, Shannon's diversity, and Pielou's evenness index of the arthropods in the orchard with ground cover vegetation were 83.733 +/- 4.932, 4.966 +/- 0.110, and 0.795 +/- 0.014, respectively, being significantly higher than those in the orchard without ground cover vegetation, whereas the Berger-Parker's dominance index was 0.135 +/- 0.012, being significantly lower than that (0.184 +/- 0.018) in the orchard without ground cover vegetation. There were no significant differences in the stability indices S/N and Sd/Sp between the two orchards, but the Nn/Np, Nd/Np, and Sn/Sp in the orchard with ground cover vegetation were 0.883 +/- 0.123. 1714 +/- 0.683, and 0.781 +/- 0.040, respectively, being significantly higher than those in the orchard without ground cover vegetation. Pearson's correlation analysis indicated that in the orchard with ground cover vegetation, the Shannon's diversity index was significantly negatively correlated with Nd/Np, Sd/Sp, and S/N but had no significant correlations with Nn/Np and Sn/Sp, whereas in the orchard without ground cover vegetation, the diversity index was significantly positively correlated with Nn/Np and Nd/Np and had no significant correlations with Sd/Sp, Sn/Sp, and S/N.

  7. Comparison of algorithms and parameterisations for infiltration into organic-covered permafrost soils

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2010-05-01

    Full Text Available Infiltration into frozen and unfrozen soils is critical in hydrology, controlling active layer soil water dynamics and influencing runoff. Few Land Surface Models (LSMs and Hydrological Models (HMs have been developed, adapted or tested for frozen conditions and permafrost soils. Considering the vast geographical area influenced by freeze/thaw processes and permafrost, and the rapid environmental change observed worldwide in these regions, a need exists to improve models to better represent their hydrology.

    In this study, various infiltration algorithms and parameterisation methods, which are commonly employed in current LSMs and HMs were tested against detailed measurements at three sites in Canada's discontinuous permafrost region with organic soil depths ranging from 0.02 to 3 m. Field data from two consecutive years were used to calibrate and evaluate the infiltration algorithms and parameterisations. Important conclusions include: (1 the single most important factor that controls the infiltration at permafrost sites is ground thaw depth, (2 differences among the simulated infiltration by different algorithms and parameterisations were only found when the ground was frozen or during the initial fast thawing stages, but not after ground thaw reaches a critical depth of 15 to 30 cm, (3 despite similarities in simulated total infiltration after ground thaw reaches the critical depth, the choice of algorithm influenced the distribution of water among the soil layers, and (4 the ice impedance factor for hydraulic conductivity, which is commonly used in LSMs and HMs, may not be necessary once the water potential driven frozen soil parameterisation is employed. Results from this work provide guidelines that can be directly implemented in LSMs and HMs to improve their application in organic covered permafrost soils.

  8. Comparison of algorithms and parameterisations for infiltration into organic-covered permafrost soils

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2009-09-01

    Full Text Available Infiltration into frozen and unfrozen soils is critical in hydrology, controlling active layer soil water dynamics and influencing runoff. Few Land Surface Models (LSMs and Hydrological Models (HMs have been developed, adapted or tested for frozen conditions and permafrost soils. Considering the vast geographical area influenced by freeze/thaw processes and permafrost, and the rapid environmental change observed worldwide in these regions, a need exists to improve models to better represent their hydrology.

    In this study, various infiltration algorithms and parameterisation methods, which are commonly employed in current LSMs and HMs were tested against detailed measurements at three sites in Canada's discontinuous permafrost region with organic soil depths ranging from 0.02 to 3 m. Field data from two consecutive years were used to calibrate and evaluate the infiltration algorithms and parameterisations. Important conclusions include: (1 the single most important factor that controls the infiltration at permafrost sites is ground thaw depth, (2 differences among the simulated infiltration by different algorithms and parameterisations were only found when the ground was frozen or during the initial fast thawing stages, but not after ground thaw reaches a critical depth of 15–30 cm, (3 despite similarities in simulated total infiltration after ground thaw reaches the critical depth, the choice of algorithm influenced the distribution of water among the soil layers, and (4 the ice impedance factor for hydraulic conductivity, which is commonly used in LSMs and HMs, may not be necessary once the water potential driven frozen soil parameterisation is employed. Results from this work provide guidelines and can be directly implemented in LSMs and HMs to improve their application in organic covered permafrost soils.

  9. Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

    Directory of Open Access Journals (Sweden)

    Michele Freppaz

    2011-02-01

    Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

  10. Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

    Directory of Open Access Journals (Sweden)

    Ermanno Zanini

    Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

  11. Legume ground covers alter defoliation response of black walnut saplings to drought and anthracnose

    Science.gov (United States)

    J. W. Van Sambeek

    2003-01-01

    Growth and premature defoliation of black walnut saplings underplanted 5 or 6 years earlier with six different ground covers were quantified in response to a summer drought or anthracnose. Walnut saplings growing with ground covers of hairy vetch, crownvetch, and to a lesser extent sericea lespedeza continued to have more rapid height and diameter growth than saplings...

  12. Spatiotemporal patterns of soil CO2 efflux in drylands are modulated by the type of cover: The role of biocrusts

    Science.gov (United States)

    Chamizo, Sonia; Sánchez-Cañete, Enrique P.; Cantón, Yolanda; Rodríguez-Caballero, Emilio; Oyonarte, Cecilio; Domingo, Francisco

    2015-04-01

    χc in all cover types but marked differences were found among them: soil under plant reached the highest values, while in the interplant soil, soils covered by biocrusts showed up to 2 times greater soil χc than bare soils. Soil χc also varied depending on the type of biocrust, with higher values under lichen than cyanobacteria biocrusts, attributed to higher organic matter content and higher abundance and diversity of microfauna under more developed than less developed biocrusts. At daily scale, there was a positive relationship between soil χc and soil temperature. Positive values of Fs (CO2 emissions) were frequently found after rain. Fs was higher in soil under plant (up to 2 µmol m-2 s-1), followed by soil covered by lichens and the lowest in soils covered by cyanobacteria and bare soils (~0.5 µmol m-2 s-1). Our results demonstrate the high spatial variability in CO2 efflux in arid and semiarid areas and the need to consider the contributions of the different representative ground covers to improve C quantification and to make more accurate predictions of the effects of climate change in arid and semiarid regions.

  13. The role of snow cover in ground thermal conditions in three sites with contrasted topography in Sierra Nevada (Spain)

    Science.gov (United States)

    Oliva, Marc; Salvador, Ferran; Gómez Ortiz, Antonio; Salvà, Montserrat

    2014-05-01

    Snow cover has a high capacity to insulate the soil from the external thermal influences. In regions of high snowfall, such as the summit areas of the highest Iberian mountain ranges, the presence of a thick snow cover may condition the existence or inexistence of permafrost conditions. In order to analyze the impact of the thickness, duration and interannual variability of snow cover on the ground thermal regime in the massif of Sierra Nevada, we have analyzed soil temperatures at a depth of 2 cm for the period 2006-2012 in three sites of contrasting topography as well as air temperatures for the same period: (a) Corral del Veleta (3100 m) in a rock glacier located in the northern Veleta cirque, with high and persistent snow cover. (b) Collado de los Machos (3300 m), in a summit area with relict stone circles, with little snow accumulation due to wind effect. (c) Río Seco (3000 m), in a solifluction lobe located in this southern glacial cirque with moderate snowfall. Considering the air and 2 cm depth soil temperature records, the freezing degree-days were calculated for each year from November to May in order to characterize the role of snow as a thermal insulator of the ground during the cold season (Frauenfeld et al., 2007). In all cases, the highest values of freezing degree-days correspond to years with little snowfall (2006-2007, 2007-2008, 2011-2012), while in years with a thicker snow cover (2008-2009, 2009-2010, 2010-2011) the total freezing degree-days were significantly lower. The accumulation of freezing degree-days is maximum at the wind-exposed site of Collado de los Machos, where the wind redistributes snow and favours the penetration of cold into the ground. The opposite pattern occurs in the Veleta cirque, where most persistent snow cover conditions determine lower accumulated freezing degree-days than in Collado de los Machos and Rio Seco.

  14. Consequences of artic ground squirrels on soil carbon loss from Siberian tundra

    Science.gov (United States)

    Golden, N. A.; Natali, S.; Zimov, N.

    2014-12-01

    A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years. Much of this C has been frozen in permafrost and unavailable for microbial decomposition. As the climate warms and permafrost thaws, the fate of this large C pool will be driven not only by climatic conditions, but also by ecosystem changes brought about by arctic animal populations. In this project we studied arctic ground squirrels (Spermophilus parryii), which are widely-distributed throughout the Arctic. These social mammals create subterranean burrows that mix soil layers, increase aeration, alter soil moisture and temperature, and redistribute soil nutrients, all of which may impact microbial decomposition. We examined the effects of arctic ground squirrel activity on soil C mineralization in dry heath tundra underlain by continuous permafrost in the Kolyma River watershed in northeast Siberia, Russia. Vegetation cover was greatly reduced on the ground squirrel burrows (80% of ground un-vegetated), compared to undisturbed sites (35% of ground un-vegetated). Soils from ground squirrel burrows were also significantly dryer and warmer. To examine effects of ground squirrel activity on microbial respiration, we conducted an 8-day incubation of soil fromburrows and from adjacent undisturbed tundra. In addition, we assessed the impact of nutrient addition by including treatments with low and high levels of nitrogen addition. Microbial respiration (per gram soil) was three-fold higher in incubated soils from the undisturbed sites compared to soils collected from the burrows. The lower rates of respiration from the disturbed soils may have been a result of lower carbon quality or low soil moisture. High nitrogen addition significantly increased respiration in the undisturbed soils, but not in the disturbed burrow soils, which suggests that microbial respiration in the burrow soils was not primarily limited by nitrogen. These results demonstrate the importance of wildlife

  15. Soil and soil cover changes in spruce forests after final logging

    Directory of Open Access Journals (Sweden)

    E. M. Lapteva

    2015-10-01

    Full Text Available Soil cover transformation and changes of morphological and chemical properties of Albeluvisols in clear-cuttings of middle taiga spruce forests were studied. The observed changes in structure and properties of podzolic texturally-differentiated soils at cuttings of spruce forests in the middle taiga subzone do not cause their transition to any other soil type. Soil cover of secondary deciduous-coniferous forests which replace cut forests are characterized with a varied soil contour and a combination of the main type of podzolic soils under undisturbed spruce forests. The increased surface hydromorphism in cut areas causes formation of complicated sub-types of podzolic texturally differentiated soils (podzolic surface-gley soils with microprofile of podzol and enlarges their ratio (up to 35–38 % in soil cover structure. Temporary soil over-wetting at the initial (5–10 years stage of after-cutting self-restoring vegetation succession provides for soil gleyzation, improves yield and segregation of iron compounds, increases the migratory activity of humic substances. Low content and resources of total nitrogen in forest litters mark anthropogenic transformation processes of podzolic soils at this stage. Later (in 30–40 years after logging, soils in cut areas still retain signs of hydromorphism. Forest litters are denser, less acidic and thick with a low weight ratio of organic carbon as compared with Albeluvisols of undisturbed spruce forest. The upper mineral soil horizons under secondary deciduous-coniferous forests contain larger amounts of total iron, its mobile (oxalate-dissolvable components, and Fe-Mn-concretions.

  16. Estimation of Soil Moisture Under Vegetation Cover at Multiple Frequencies

    Science.gov (United States)

    Jadghuber, Thomas; Hajnsek, Irena; Weiß, Thomas; Papathanassiou, Konstantinos P.

    2015-04-01

    Soil moisture under vegetation cover was estimated by a polarimetric, iterative, generalized, hybrid decomposition and inversion approach at multiple frequencies (X-, C- and L-band). Therefore the algorithm, originally designed for longer wavelength (L-band), was adapted to deal with the short wavelength scattering scenarios of X- and C-band. The Integral Equation Method (IEM) was incorporated together with a pedo-transfer function of Dobson et al. to account for the peculiarities of short wavelength scattering at X- and C-band. DLR's F-SAR system acquired fully polarimetric SAR data in X-, C- and L-band over the Wallerfing test site in Lower Bavaria, Germany in 2014. Simultaneously, soil and vegetation measurements were conducted on different agricultural test fields. The results indicate a spatially continuous inversion of soil moisture in all three frequencies (inversion rates >92%), mainly due to the careful adaption of the vegetation volume removal including a physical constraining of the decomposition algorithm. However, for X- and C-band the inversion results reveal moisture pattern inconsistencies and in some cases an incorrectly high inversion of soil moisture at X-band. The validation with in situ measurements states a stable performance of 2.1- 7.6vol.% at L-band for the entire growing period. At C- and X-band a reliable performance of 3.7-13.4vol.% in RMSE can only be achieved after distinct filtering (X- band) leading to a loss of almost 60% in spatial inversion rate. Hence, a robust inversion for soil moisture estimation under vegetation cover can only be conducted at L-band due to a constant availability of the soil signal in contrast to higher frequencies (X- and C-band).

  17. Soil carbon sequestration via cover crops- A meta-analysis

    Science.gov (United States)

    Poeplau, Christopher; Don, Axel

    2014-05-01

    Agricultural soils are depleted in soil organic carbon (SOC) and have thus a huge potential to sequester SOC. This can primarily be achieved by increasing carbon inputs into the soil. Replacing winter fallows by cover crop cultivation for green manure has many benefits for the soil and forms an additional carbon input. An increase in carbon concentration has been reported in several studies worldwide. However, the effect on SOC stocks, as well as the influence of environmental parameters and management on SOC dynamics is not known. We therefore conducted a meta-analysis to investigate those issues. A total of 33 studies, comprising 47 sites and 147 plots were compiled. A pedotransfer function was used to estimate bulk densities and calculate SOC stocks. SOC stock change was found to be a linear function of time since introduction, with an annual sequestration rate of 0.32 Mg C ha-1 yr-1. Since no saturation was visible in the observations, we used the model RothC to estimate a new steady state level and the resulting total SOC stock change for an artificial "average cropland". The total average SOC stock change with an annual input of 1.87 Mg C ha-1 yr-1 was 16.76 Mg C ha-1 for the average soil depth of 22 cm. We estimated a potential global SOC sequestration of 0.12±0.03 Pg C yr-1, which would compensate for 8 % of the direct annual greenhouse gas emissions from agriculture.

  18. Water consumption and water-saving characteristics of a ground cover rice production system

    Science.gov (United States)

    Jin, Xinxin; Zuo, Qiang; Ma, Wenwen; Li, Sen; Shi, Jianchu; Tao, Yueyue; Zhang, Yanan; Liu, Yang; Liu, Xiaofei; Lin, Shan; Ben-Gal, Alon

    2016-09-01

    The ground cover rice production system (GCRPS) offers a potentially water-saving alternative to the traditional paddy rice production system (TPRPS) by furrow irrigating mulched soil beds and maintaining soils under predominately unsaturated conditions. The guiding hypothesis of this study was that a GCRPS would decrease both physiological and non-physiological water consumption of rice compared to a TPRPS while either maintaining or enhancing production. This was tested in a two-year field experiment with three treatments (TPRPS, GCRPSsat keeping root zone average soil water content near saturated, and GCRPS80% keeping root zone average soil water content as 80-100% of field water capacity) and a greenhouse experiment with four treatments (TPRPS, GCRPSsat, GCRPSfwc keeping root zone average soil water content close to field water capacity, and GCRPS80%). The water-saving characteristics of GCRPS were analyzed as a function of the measured soil water conditions, plant parameters regarding growth and production, and water input and consumption. In the field experiment, significant reduction in both physiological and non-physiological water consumption under GCRPS lead to savings in irrigation water of ∼61-84% and reduction in total input water of ∼35-47%. Compared to TPRPS, deep drainage was reduced ∼72-88%, evaporation was lessened ∼83-89% and transpiration was limited ∼6-10% under GCRPS. In addition to saving water, plant growth and grain yield were enhanced under GCRPS due to increased soil temperature in the root zone. Therefore, water use efficiencies (WUEs), based on transpiration, irrigation and total input water, were respectively improved as much as 27%, 609% and 110% under GCRPS. Increased yield attributed to up to ∼19%, decreased deep drainage accounted for ∼75%, decreased evaporation accounted for ∼14% and reduced transpiration for ∼5% of the enhancement in WUE of input water under GCRPS, while increased runoff and water storage had

  19. Land cover changes and greenhouse gas emissions in two different soil covers in the Brazilian Caatinga.

    Science.gov (United States)

    Ribeiro, Kelly; Sousa-Neto, Eráclito Rodrigues de; Carvalho, João Andrade de; Sousa Lima, José Romualdo de; Menezes, Rômulo Simões Cezar; Duarte-Neto, Paulo José; da Silva Guerra, Glauce; Ometto, Jean Pierre Henry Baulbaud

    2016-11-15

    The Caatinga biome covers an area of 844,453km(2) and has enormous endemic biodiversity, with unique characteristics that make it an exclusive Brazilian biome. It falls within the earth's tropical zone and is one of the several important ecoregions of Brazil. This biome undergoes natural lengthy periods of drought that cause losses in crop and livestock productivity, having a severe impact on the population. Due to the vulnerability of this ecosystem to climate change, livestock has emerged as the main livelihood of the rural population, being the precursor of the replacement of native vegetation by grazing areas. This study aimed to measure GHG emissions from two different soil covers: native forest (Caatinga) and pasture in the municipality of São João, Pernambuco State, in the years 2013 and 2014. GHG measurements were taken by using static chamber techniques in both soil covers. According to a previous search, so far, this is the first study measuring GHG emissions using the static chamber in the Caatinga biome. N2O emissions ranged from -1.0 to 4.2mgm(-2)d(-1) and -1.22 to 3.4mgm(-2)d(-1) in the pasture and Caatinga, respectively, and they did not significantly differ from each other. Emissions were significantly higher during dry seasons. Carbon dioxide ranged from -1.1 to 14.1 and 1.2 to 15.8gm(-2)d(-1) in the pasture and Caatinga, respectively. CO2 emissions were higher in the Caatinga in 2013, and they were significantly influenced by soil temperature, showing an inverse relation. Methane emission ranged from 6.6 to 6.8 and -6.0 to 4.8mgm(-2)d(-1) in the pasture and Caatinga, respectively, and was significantly higher only in the Caatinga in the rainy season of 2014. Soil gas fluxes seemed to be influenced by climatic and edaphic conditions as well as by soil cover in the Caatinga biome. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Soil phosphorus forms as quality indicators of soils under different vegetation covers.

    Science.gov (United States)

    Turrión, María-Belén; López, Olga; Lafuente, Francisco; Mulas, Rafael; Ruipérez, César; Puyo, Alberto

    2007-05-25

    The type of vegetation cover determines the physicochemical and biological properties of the soil over which they are developing. The objective of this study was to determine the effect of different vegetation covers on the forms of soil phosphorus, in order to know which of these forms can be used as a soil quality indicator. The experimental area was located on the acidic plateau at the North of Palencia (North Spain), where an area was selected vegetation covers very close to each other: pine (Pinus sylvestris), oak (Quercus pyrenaica), and three different shrub species (Arctostaphylos uva-ursi, Erica australis and Halimium alyssoides). The Ah horizon was sampled and pH, total organic C (C(org)), total N (N), cationic exchange capacity (CEC), sum of bases (S) and P forms by a sequential fractionation were analysed. Results showed that oak and A. uva-ursi improve the considered soil parameters (pH, C(org)/N ratio, CEC, and S) and provide soils of better quality. Inorganic soil P forms were influenced in greater extent by the vegetation cover than were P organic forms. Labile inorganic P forms could be used as indicators of soil quality. The organic P forms were less sensitive than inorganic ones to the indicated improvements.

  1. Grau de cobertura do solo e dinâmica da vegetação em olivais de sequeiro com a introdução de herbicidas Ground cover and dynamic of weeds after the introduction of herbicides as soil management system in a rainfed olive orchard

    Directory of Open Access Journals (Sweden)

    Manuel Ângelo Rodrigues

    2009-12-01

    herbicides as soil management strategies in a rainfed olive orchard. The field experiment was carried out in Mirandela, NE Portugal. The soil management treatments included: conventional tillage; post-emergence herbicide (glyphosate; and post-emergence plus residual herbicide (diuron+glyphosate+terb utilazine. The ground cover percentage and the botanical composition of vegetation were monitored since 2002 to 2007 from the point-quadrat method. Both the herbicide formulations killed efficiently the vegetation in a single annual application. The ground cover percentages in conventional tillage, prior to the first tillage event, varied between 50 to 80 % beneath the trees and between 30 to 60 % in the open space. The ground cover percentages in April, in the treatment of glyphosate, were in the range of 60 to 90 % and 40 to 50 % beneath the trees and between rows, respectively. In the residual herbicide plot the ground cover percentages were always very low. The soil of the glyphosate plot was covered with vegetation over all the year. In au-tumn/spring the soil was covered with green weeds and in the summer with a mulching of the dead material. In the glyphosate plot the dynamic of species was high. One year after the first application of herbicide, Ornithopus compressus appeared as the most abundant species. Thereafter, acquired relevance species with short growing cycles which seeds mature before April (e.g. Mibora minima, Logfia gallica and other that produce a high number of seeds easily spread by wind (e.g. Hypochaeris radicata, Conyza canadensis and which seeds proceeded from surrounding untilled fields and rural-tracks or from individual plants that escaped to the herbicide control.

  2. Law school design blends functionalism, energy conservation. [Earth-covered with ground-cover growing on roof

    Energy Technology Data Exchange (ETDEWEB)

    1976-08-01

    Construction is under way on a new University of Minnesota Law School Building, whose distinctive features include a stepped design on its southern elevation and an earth-covered roof to promote energy conservation. The design is described with emphasis on the library facilities. Energy conservation was a major design factor. The portion of the earth-covered roof will be 15 inches thick planted with low ground-cover vegetation. Overall ..mu.. value of the building envelope will be 0.11. (MCW)

  3. Transient Soil Moisture Characteristics Below Different Land Cover Types: Implications for Quantifying Groundwater Recharge

    Science.gov (United States)

    Jayawickreme, D. H.; van Dam, R. L.; Hyndman, D. W.

    2006-12-01

    Statistical analysis of temporal water budgets in Michigan watersheds shows a significant link between land covers and streamflow characteristics. The observed differences in water budgets between the investigated watersheds are largely attributed to spatial heterogeneity and temporal variability of vegetation characteristics. Our findings suggest that management of regional groundwater resources should consider the effects of spatial and temporal vegetation changes. However, due to inadequate information, vegetation dynamics are not considered in most hydrologic models. By instrumenting suitable field sites in Michigan with different land cover types to monitor spatial and temporal variations in subsurface soil moisture , we investigate the interdependence of land cover, climate, soil moisture, and groundwater recharge in regional watersheds. Our approach involves resistivity and ground penetrating radar surveys, in-situ continuous moisture/temperature monitoring at field sites, and computer modeling of evapotranspiration and groundwater recharge. The results of this research are expected to improve our understanding of the impact of vegetation on soil moisture and groundwater recharge from site to regional scales and demonstrate the importance of incorporating land cover types and vegetation dynamics in regional groundwater resource assessment models.

  4. Plant uptake of radiocaesium from artificially contaminated soil monoliths covering major European soil types

    Energy Technology Data Exchange (ETDEWEB)

    Waegeneers, Nadia [Laboratory for Soil and Water Management, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee (Belgium)], E-mail: nadia.waegeneers@agr.kuleuven.ac.be; Sauras-Yera, Teresa [Departament de Biologia Vegetal, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona (Spain); Thiry, Yves [SCK.CEN, Radioecology Laboratory, Boeretang 200, B-2400 Mol (Belgium); Vallejo, V. Ramon [Departament de Biologia Vegetal, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona (Spain); CEAM, Parque Tecnologico, Charles Darwin 14, 46980 Parterna (Spain); Smolders, Erik [Laboratory for Soil and Water Management, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee (Belgium); Madoz-Escande, Chantal; Brechignac, Francois [SERLAB, ISPN, Department for Environmental Protection, CE-Cadarache Batiment 159, Saint-Paul-lez-Durance Cedex 13108 (France)

    2009-06-15

    Uptake of {sup 137}Cs was measured in different agricultural plant species (beans, lettuce, barley and ryegrass) grown in 5 undisturbed soil monoliths covering major European soil types. The first cultivation was made three years after soil contamination and plants were grown during 3 successive years. The plant-soil {sup 137}Cs transfer factors varied maximally 12-fold among soils and 35-fold among species when grown on the same soil. Single correlations between transfer factors and soil properties were found, but they varied widely with plant type and can hardly be used as a predictive tool because of the few soils used. The variation of {sup 137}Cs concentrations in plants among soils was related to differences in soil solution {sup 137}Cs and K concentrations, consistent with previous observations in hydroponics and pot trials. Absolute values of transfer factors could not be predicted based on a model validated for pot trials. The {sup 137}Cs activity concentration in soil solution decreased significantly (11- to 250-fold) for most soils in the 1997-1999 period and is partly explained by decreasing K in soil solution. Transfer factors of lettuce showed both increasing and decreasing trends between 2 consecutive years depending on soil type. The trends could be explained by the variation in {sup 137}Cs and K concentrations in soil solution. It is concluded that differences in {sup 137}Cs transfer factors among soils and trends in transfer factors as a function of time can be explained from soil solution composition, as shown previously for pot trials, although absolute values of transfer factors could not be predicted.

  5. Plant uptake of radiocaesium from artificially contaminated soil monoliths covering major European soil types.

    Science.gov (United States)

    Waegeneers, Nadia; Sauras-Yera, Teresa; Thiry, Yves; Vallejo, V Ramón; Smolders, Erik; Madoz-Escande, Chantal; Bréchignac, François

    2009-06-01

    Uptake of (137)Cs was measured in different agricultural plant species (beans, lettuce, barley and ryegrass) grown in 5 undisturbed soil monoliths covering major European soil types. The first cultivation was made three years after soil contamination and plants were grown during 3 successive years. The plant-soil (137)Cs transfer factors varied maximally 12-fold among soils and 35-fold among species when grown on the same soil. Single correlations between transfer factors and soil properties were found, but they varied widely with plant type and can hardly be used as a predictive tool because of the few soils used. The variation of (137)Cs concentrations in plants among soils was related to differences in soil solution (137)Cs and K concentrations, consistent with previous observations in hydroponics and pot trials. Absolute values of transfer factors could not be predicted based on a model validated for pot trials. The (137)Cs activity concentration in soil solution decreased significantly (11- to 250-fold) for most soils in the 1997-1999 period and is partly explained by decreasing K in soil solution. Transfer factors of lettuce showed both increasing and decreasing trends between 2 consecutive years depending on soil type. The trends could be explained by the variation in (137)Cs and K concentrations in soil solution. It is concluded that differences in (137)Cs transfer factors among soils and trends in transfer factors as a function of time can be explained from soil solution composition, as shown previously for pot trials, although absolute values of transfer factors could not be predicted.

  6. Lightning electromagnetic field generated by grounding electrode considering soil ionization

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong; HE Jinliang; ZHANG Bo; GAO Yanqing

    2006-01-01

    A circuit model with lumped time-variable parameter is proposed to calculate the transient characteristic of grounding electrode under lightning current, which takes into consideration the dynamic and nonlinear effect of soil ionization around the grounding electrode. The ionization phenomena in the soil are simulated by means of time-variable parameters under appropriate conditions. The generated electromagnetic field in the air is analyzed by using electrical dipole theory and image theory when the lightning current flows into the grounding electrode. The influence of soil ionization on the electromagnetic field is investigated.

  7. Interannual changes in snow cover and its impact on ground surface temperatures in Livingston Island (Antarctica)

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2015-04-01

    In permafrost areas the seasonal snow cover is an important factor on the ground thermal regime. Snow depth and timing are important in ground insulation from the atmosphere, creating different snow patterns and resulting in spatially variable ground temperatures. The aim of this work is to characterize the interactions between ground thermal regimes and snow cover and the influence on permafrost spatial distribution. The study area is the ice-free terrains of northwestern Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". Air and ground temperatures and snow thickness data where analysed from 4 sites along an altitudinal transect in Hurd Peninsula from 2007 to 2012: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). The data covers 6 cold seasons showing different conditions: i) very cold with thin snow cover; ii) cold with a gradual increase of snow cover; iii) warm with thick snow cover. The data shows three types of periods regarding the ground surface thermal regime and the thickness of snow cover: a) thin snow cover and short-term fluctuation of ground temperatures; b) thick snow cover and stable ground temperatures; c) very thick snow cover and ground temperatures nearly constant at 0°C. a) Thin snow cover periods: Collado Ramos and Ohridski sites show frequent temperature variations, alternating between short-term fluctuations and stable ground temperatures. Nuevo Incinerador displays during most of the winter stable ground temperatures; b) Cold winters with a gradual increase of the snow cover: Nuevo Incinerador, Collado Ramos and Ohridski sites show similar behavior, with a long period of stable ground temperatures; c) Thick snow cover periods: Collado Ramos and Ohridski show long periods of stable ground, while Nuevo Incinerador shows temperatures close to 0°C since the beginning of the winter, due to early snow cover

  8. Effects of bryophyte and lichen cover on permafrost soil temperature at large scale

    Science.gov (United States)

    Porada, Philipp; Ekici, Altug; Beer, Christian

    2016-09-01

    Bryophyte and lichen cover on the forest floor at high latitudes exerts an insulating effect on the ground. In this way, the cover decreases mean annual soil temperature and can protect permafrost soil. Climate change, however, may change bryophyte and lichen cover, with effects on the permafrost state and related carbon balance. It is, therefore, crucial to predict how the bryophyte and lichen cover will react to environmental change at the global scale. To date, current global land surface models contain only empirical representations of the bryophyte and lichen cover, which makes it impractical to predict the future state and function of bryophytes and lichens. For this reason, we integrate a process-based model of bryophyte and lichen growth into the global land surface model JSBACH (Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg). The model simulates bryophyte and lichen cover on upland sites. Wetlands are not included. We take into account the dynamic nature of the thermal properties of the bryophyte and lichen cover and their relation to environmental factors. Subsequently, we compare simulations with and without bryophyte and lichen cover to quantify the insulating effect of the organisms on the soil. We find an average cooling effect of the bryophyte and lichen cover of 2.7 K on temperature in the topsoil for the region north of 50° N under the current climate. Locally, a cooling of up to 5.7 K may be reached. Moreover, we show that using a simple, empirical representation of the bryophyte and lichen cover without dynamic properties only results in an average cooling of around 0.5 K. This suggests that (a) bryophytes and lichens have a significant impact on soil temperature in high-latitude ecosystems and (b) a process-based description of their thermal properties is necessary for a realistic representation of the cooling effect. The advanced land surface scheme, including a dynamic bryophyte and lichen model, will be the basis for an improved

  9. Soil carbon vulnerability to land-cover change and implications for the global carbon cycle

    Science.gov (United States)

    Georgiou, K.; Abramoff, R. Z.; Koven, C.; Riley, W. J.; Torn, M. S.

    2015-12-01

    Soil is a major reservoir of carbon (C) that contains more than three times the C in vegetation. While the terrestrial biosphere acts as a sink for approximately 2.5 petagrams C per year (PgC/yr) - equivalent to about 25% of fossil fuel emissions - anthropogenic land-use change reduces the global net land C sink by approximately 1 PgC/yr. Although most assessments of land-use focus on changes in aboveground biomass C, changes to 'live C' (above- and below-ground plant biomass) drive lagged, yet substantial, changes to 'dead C' (soil, dead wood, and litter) storage, with important implications for the overall land C balance. Here we provide an observation- and model-based assessment of the impacts of land-cover change on total C stocks (live and dead C) over the last decade and the potential for long-term soil C storage or loss. We find that afforestation in northern latitudes counteracts deforestation in the tropics, due in part to the greater soil C content of boreal and temperate forests. Deriving geospatial estimates of the steady-state ratio of dead to live C and the turnover time of dead C, we demonstrate that, although many recent studies have focused on forests, non-forest ecosystems (particularly shrublands and savannahs) may be responsible for larger changes in total C stocks in response to changes in C input rates due to their high soil C content. Furthermore, we disaggregate our geospatial predictions by biome and explore the depth-resolved vulnerability of soil C globally, with particular focus on the covariation of soil C sensitivity with soil properties and climate. Our findings suggest that the response of soil to changes in plant inputs significantly contributes to regional and global C budgets.

  10. Influence of understory cover on soil water and evaporation fluxes: a trial

    Science.gov (United States)

    Jiménez-Rodríguez, César; Magdalena Warter, Maria; Coenders-Gerrits, Miriam

    2017-04-01

    Within a forest ecosystem the litter layer is an important hydrological component and contributes towards the water and energy exchange between the sub-canopy and the soil. Evaporation within a forest is made up of different fractions coming from the dry soil, vegetation and litter layers. The quantification and partitioning of each fraction remains difficult as there is hard to estimate correctly the amount of water moved by evaporation or percolation at ecosystem level. With the aim to determine the influence of forest understory on the evaporation fluxes, four ground cover types were selected from the Speulderbos forest in the Netherlands. The mosses species of "Thamariskmoss" (Thuidium thamariscinum), "Rough Stalked Feathermoss" (Brachythecium rutabulum), and "Haircapmoss" (Polytrichum commune) were compared with a litter layer made up of Douglas-Fir needles (Pseudotsuga menziesii). Four PVC basins with 40cm x 60cm were filled with forest soil and sheltered with the selected ground covers. Each box was equipped with a soil moisture sensor, and a set Temperature and Relative Humidity sensors to determine the VPD during the study period. The study period lasts 4 weeks, while the percolation rates were measured in a daily basis. The rainfall events were simulated in the lab, applying the same rain event to each box at the same time. A total amount of 43.12 mm of rain were added to the boxes during the 4 weeks of the experiment, and distributed in 11 rain events which differ in amount and timing between events. The percolation in all the boxes was more than the 50% of the rain events due to the sandy condition of the soil, while the evaporation rates were affected not only by the room atmospheric conditions, but for the cover type present in each box. Except for the Polytrichum moss, a moss known for its water conducting abilities, all cover types showed a decline before and increase after a rain event. This species showed a steady increase in soil water content

  11. Estonian soil classification as a tool for recording information on soil cover and its matching with local site types, plant covers and humus forms classifications

    Science.gov (United States)

    Kõlli, Raimo; Tõnutare, Tõnu; Rannik, Kaire; Krebstein, Kadri

    2015-04-01

    Estonian soil classification (ESC) has been used successfully during more than half of century in soil survey, teaching of soil science, generalization of soil databases, arrangement of soils sustainable management and others. The Estonian normally developed (postlithogenic) mineral soils (form 72.4% from total area) are characterized by mean of genetic-functional schema, where the pedo-ecological position of soils (ie. location among other soils) is given by means of three scalars: (i) 8 stage lithic-genetic scalar (from rendzina to podzols) separates soils each from other by parent material, lithic properties, calcareousness, character of soil processes and others, (ii) 6 stage moisture and aeration conditions scalar (from aridic or well aerated to permanently wet or reductic conditions), and (iii) 2-3 stage soil development scalar, which characterizes the intensity of soil forming processes (accumulation of humus, podzolization). The organic soils pedo-ecological schema, which links with histic postlithogenic soils, is elaborated for characterizing of peatlands superficial mantle (form 23.7% from whole soil cover). The position each peat soil species among others on this organic (peat) soil matrix schema is determined by mean of 3 scalars: (i) peat thickness, (ii) type of paludification or peat forming peculiarities, and (iii) stage of peat decomposition or peat type. On the matrix of abnormally developed (synlithogenic) soils (all together 3.9%) the soil species are positioned (i) by proceeding in actual time geological processes as erosion, fluvial processes (at vicinity of rivers, lakes or sea) or transforming by anthropogenic and technological processes, and (ii) by 7 stage moisture conditions (from aridic to subaqual) of soils. The most important functions of soil cover are: (i) being a suitable environment for plant productivity; (ii) forming adequate conditions for decomposition, transformation and conversion of falling litter (characterized by humus

  12. Diseases of Ornamental and Shade Trees, Shrubs, Vines, and Ground Covers.

    Science.gov (United States)

    Nichols, Lester P.

    This agriculture extension service publication from Pennsylvania State University covers the identification and control of common ornamental trees, shrubs, and ground cover diseases. The publication is divided into sections. The first section discusses the diseases of ornamental and shade trees, including general diseases and diseases of specific…

  13. Microbial mitigation of greenhouse gas emissions from landfill cover soils

    Science.gov (United States)

    Lee, Sung-Woo

    Landfills are one of the major sources of methane (CH4), a potent greenhouse gas with a global warming potential (GWP) ˜23 times higher than that of carbon dioxide (CO2). Although some effective strategies have been formulated to prevent methane emissions from large landfills, many landfills allow methane to be freely emitted to the atmosphere. In such situations, it is often proposed to stimulate methanotrophs, a group of bacteria that consume methane, in the cover soil to prevent fugitive methane emissions. Several factors, however, must be addressed to make such a biogenic removal mechanism effective. First, methanotrophic activity can be inhibited by nonmethane organic compounds (NMOCs) that are commonly found in landfill soil gas. Second, although methanotrophs can be easily stimulated with the addition of nitrogenous fertilizers, biogenic production of nitrous oxide with a GWP ˜296 times higher than that of carbon dioxide, is also stimulated. To consider these issues, two general areas of research were performed. First, a dimensionless number was developed based on Michaelis-Menten kinetics that describes the effects of the presence of multiple NMOCs on methanotrophic growth and survival. This model was validated via experimental measurements of methanotrophic growth in the presence of varying amounts of NMOCs. Second, the effects of nutrient amendments on methane oxidation and nitrous oxide production were examined by constructing soil microcosms using landfill cover soils. Here, it was shown that the addition of ammonium in the presence of phenylacetylene stimulated methane oxidation but inhibited nitrous oxide production. Furthermore, to understand the methanotrophic community structure and activity in response to these amendments, DNA microarray and transcript analyses were performed. The results indicated the predominance of Type II methanotrophs but that Type I methanotrophs responded more significantly to these amendments. Also, substantial activity

  14. Peculiarities of changes in the soil cover of landscapes adjacent to a megalopolis

    Science.gov (United States)

    Lazareva, Margarita; Aparin, Boris; Sukhacheva, Elena

    2017-04-01

    The progressive growth of cities has a significant impact on the soil cover of territories adjacent to the same. Megalopolises are centers of anthropogenic impact on the soils. Generally, forms and intensity of the urban impact on the soil cover weaken with increasing distance from the city's boundaries. In this respect, ample opportunities for the analysis of urban impact on the adjacent territories are provided by the study of the soil cover in the Leningrad Region (the LR). Saint Petersburg is a major European megalopolis, which is the administrative center of the LR. The time period of Saint Petersburg's impact on the environment does not exceed 300 years, which allows us to identify very clearly the character and areas of its impact on the soil cover. Over the past decades, there have been significant changes in the soils and the soil cover of the LR. In a large territory, there appeared new anthropogenic soils and soil cover organization forms, having no natural analogues, with a dramatic increase in the surface area of degraded soils. To access the current state of soil cover, to identify the role of anthropogenic factors of changes in this state; to carry out land reclamation, remediation and rehabilitation measures; to perform land cadastral valuation etc., we need an information resource containing data on the current state of soils and soil cover in the LR, the key element of which should be a map. We carried out mapping and created a 1:200 000 digital soil map (DSM) for the LR's territories. Diagnostics of soil contours were performed using traditionally drawn-up (paper) maps of soils and soil-formation factors; satellite images (Google, Yandex); data of remote sensing (Spot 5, Landsat 7,8); digital maps of main soil-formation factors (topographical ones, etc.). The digital soil map of the LR has been created in the geographic information system - QGIS. The map clarifies the contours of natural soils and soil combinations, and shows, for the first time

  15. Land Cover Differences in Soil Carbon and Nitrogen at Fort Benning, Georgia

    Energy Technology Data Exchange (ETDEWEB)

    Garten Jr., C.T.

    2004-02-09

    Land cover characterization might help land managers assess the impacts of management practices and land cover change on attributes linked to the maintenance and/or recovery of soil quality. However, connections between land cover and measures of soil quality are not well established. The objective of this limited investigation was to examine differences in soil carbon and nitrogen among various land cover types at Fort Benning, Georgia. Forty-one sampling sites were classified into five major land cover types: deciduous forest, mixed forest, evergreen forest or plantation, transitional herbaceous vegetation, and barren land. Key measures of soil quality (including mineral soil density, nitrogen availability, soil carbon and nitrogen stocks, as well as properties and chemistry of the O-horizon) were significantly different among the five land covers. In general, barren land had the poorest soil quality. Barren land, created through disturbance by tracked vehicles and/or erosion, had significantly greater soil density and a substantial loss of carbon and nitrogen relative to soils at less disturbed sites. We estimate that recovery of soil carbon under barren land at Fort Benning to current day levels under transitional vegetation or forests would require about 60 years following reestablishment of vegetation. Maps of soil carbon and nitrogen were produced for Fort Benning based on a 1999 land cover map and field measurements of soil carbon and nitrogen stocks under different land cover categories.

  16. COVER CROPS ENHANCE SOIL ORGANIC MATTER, CARBON DYNAMICS AND MICROBIOLOGICAL FUNCTION IN A MEDITERRANEAN VINEYARD AGROECOSYSTEM

    Science.gov (United States)

    Impacts of soil tillage and cover crops on soil carbon (C) dynamics and microbiological function were investigated in a vineyard grown in California’s Mediterranean climate. We 1) compared soil organic matter (SOM), C dynamics and microbiological activity of two cover crops [Trios 102 (Triticale x T...

  17. Soil quality assessment for peat-mineral mix cover soil used in oil sands reclamation.

    Science.gov (United States)

    Ojekanmi, A A; Chang, S X

    2014-09-01

    A soil quality (SQ) assessment and rating framework that is quantitative, iterative, and adaptable, with justifiable weighting for quality scores, is required for evaluating site-specific SQ at land reclamation sites. Such a framework needs to identify the minimum dataset that reflects the current knowledge regarding relationships between SQ indicators and relevant measures of ecosystem performance. Our objective was to develop nonlinear scoring functions for assessing the impact on SQ of peat-mineral mix (PMM) used as a cover soil at land reclamation sites. Soil functional indicators affected by PMM were extracted from existing databases and correlated with soil organic carbon (SOC). Based on defined objectives for SQ assessment, indicators with significant correlation ( soil nitrogen, and cation exchange capacity of PMM using SOC as input parameter. Application of the SQFs to an independent dataset produced ratings with mean differences similar to the treatment effects of mixing three levels of peat and mineral soil. These results show that derived ratings and weighing factors using SOC reflect the relationship between PMM treatment and other SQ indicators. Applying the developed SQFs to a long-term soil monitoring dataset shows that an increase or decrease in SOC from 10 to 20 g kg causes a significant change in SQ. This identifies the need for further nutrient and moisture management of PMM to support long-term SQ development in land reclamation.

  18. A review on soil cover in Waste and contaminant containment: design, monitoring, and modeling

    Institute of Scientific and Technical Information of China (English)

    Sheng PENG; Huilian JIANG

    2009-01-01

    Soil cover is a widely-used but relatively new method for solid waste containment. Standard while site-specific procedures for cover design, monitoring, and evluation are needed to insure reliable cover performance. This paper presents a review of soil cover types, design principles and procedures, cover monitoring, and long-term performance modeling. Cover types and cover design are introduced with the general concepts and discussed on their specific applicabilities in different circumstances. Detailed discussion is given on unsaturated flow system properties and their field measurements, including meth-ods, apparatuses/equipments and their advantages and disadvantages. Several unsaturated flow simulators are discussed and compared with regards to their simulation capacities for critical parameters closely related to soil cover performance such as runoff, infiltration and evaporation. Finally, research subjects are suggested for future work for better soil cover monitoring and modeling.

  19. Minimum depth of soil cover above long-span soil-steel railway bridges

    Science.gov (United States)

    Esmaeili, Morteza; Zakeri, Jabbar Ali; Abdulrazagh, Parisa Haji

    2013-12-01

    Recently, soil-steel bridges have become more commonly used as railway-highway crossings because of their economical advantages and short construction period compared with traditional bridges. The currently developed formula for determining the minimum depth of covers by existing codes is typically based on vehicle loads and non-stiffened panels and takes into consideration the geometrical shape of the metal structure to avoid the failure of soil cover above a soil-steel bridge. The effects of spans larger than 8 m or more stiffened panels due to railway loads that maintain a safe railway track have not been accounted for in the minimum cover formulas and are the subject of this paper. For this study, two-dimensional finite element (FE) analyses of four low-profile arches and four box culverts with spans larger than 8 m were performed to develop new patterns for the minimum depth of soil cover by considering the serviceability criterion of the railway track. Using the least-squares method, new formulas were then developed for low-profile arches and box culverts and were compared with Canadian Highway Bridge Design Code formulas. Finally, a series of three-dimensional (3D) finite element FE analyses were carried out to control the out-of-plane buckling in the steel plates due to the 3D pattern of train loads. The results show that the out-of-plane bending does not control the buckling behavior of the steel plates, so the proposed equations for minimum depth of cover can be appropriately used for practical purposes.

  20. BOREAS HYD-6 Ground Gravimetric Soil Moisture Data

    Science.gov (United States)

    Carroll, Thomas; Knapp, David E. (Editor); Hall, Forrest G. (Editor); Peck, Eugene L.; Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-6 team collected several data sets related to the moisture content of soil and overlying humus layers. This data set contains percent soil moisture ground measurements. These data were collected on the ground along the various flight lines flown in the Southern Study Area (SSA) and Northern Study Area (NSA) during 1994 by the gamma ray instrument. The data are available in tabular ASCII files. The HYD-06 ground gravimetric soil moisture data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  1. Fungal growth and biomass development is boosted by plants in snow-covered soil.

    Science.gov (United States)

    Kuhnert, Regina; Oberkofler, Irmgard; Peintner, Ursula

    2012-07-01

    Soil microbial communities follow distinct seasonal cycles which result in drastic changes in processes involving soil nutrient availability. The biomass of fungi has been reported to be highest during winter, but is fungal growth really occurring in frozen soil? And what is the effect of plant cover on biomass formation and on the composition of fungal communities? To answer these questions, we monitored microbial biomass N, ergosterol, and the amount of fungal hyphae during summer and winter in vegetated and unvegetated soils of an alpine primary successional habitat. The winter fungal communities were identified by rDNA ITS clone libraries. Winter soil temperatures ranged between -0.6°C and -0.1°C in snow-covered soil. We found distinct seasonal patterns for all biomass parameters, with highest biomass concentrations during winter in snow-covered soil. The presence of plant cover had a significant positive effect on the amount of biomass in the soil, but the type of plant cover (plant species) was not a significant factor. A mean hyphal ingrowth of 5.6 m g(-1) soil was detected in snow-covered soil during winter, thus clearly proving fungal growth during winter in snow-covered soil. Winter fungal communities had a typical species composition: saprobial fungi were dominating, among them many basidiomycete yeasts. Plant cover had no influence on the composition of winter fungal communities.

  2. Potential feedbacks between snow cover, soil moisture and surface energy fluxes in Southern Norway

    Science.gov (United States)

    Brox Nilsen, Irene; Tallaksen, Lena M.; Stordal, Frode

    2017-04-01

    At high latitudes, the snow season has become shorter during the past decades because snowmelt is highly sensitive to a warmer climate. Snowmelt influences the energy balance by changing the albedo and the partitioning between latent and sensible heat fluxes. It further influences the water balance by changing the runoff and soil moisture. In a previous study, we identified southern Norway as a region where significant temperature changes in summer could potentially be explained by land-atmosphere interactions. In this study we hypothesise that changes in snow cover would influence the summer surface fluxes in the succeeding weeks or months. The exceptionally warm summer of 2014 was chosen as a test bed. In Norway, evapotranspiration is not soil moisture limited, but energy limited, under normal conditions. During warm summers, however, such as in 2014, evapotranspiration can be restricted by the available soil moisture. Using the Weather Research and Forecasting (WRF) model we replace the initial ground conditions for 2014 with conditions representative of a snow-poor spring and a snow-rich spring. WRF was coupled to Noah-MP at 3 km horizontal resolution in the inner domain, and the simulations covered mid-May through September 2014. Boundary conditions used to force WRF were taken from the Era-Interim reanalysis. Snow, runoff, soil moisture and soil temperature observational data were provided by the Norwegian Water Resources and Energy Directorate for validation. The validation shows generally good agreement with observations. Preliminary results show that the reduced snowpack, hereafter "sim1" increased the air temperature by up to 5 K and the surface temperature by up to 10 K in areas affected by snow changes. The increased snowpack, hereafter "sim2", decreased the air and surface temperature by the same amount. These are weekly mean values for the first eight simulation weeks from mid May. Because of the higher net energy available ( 100 Wm-2) in sim 1, both

  3. Phytomass and soil organic carbon inventories related to land cover classification and periglacial features in Taimyr Peninsula,Siberia

    Science.gov (United States)

    Ramage, J. L.; Hugelius, G.; Kuhry, P.; Palmtag, J.; Lashchinskiy, N.

    2012-12-01

    The predicted increase in atmospheric temperatures is expected to affect the turnover of soil organic carbon in permafrost soils through modifications of the soil thermal regime. However, the tundra biome is formed of a mosaic of diverse landscape types with differing patterns of soil organic carbon storage and partitioning. Among these, differences in e.g. vegetation diversity and soil movements due to freeze-thaw processes are of main importance for assessing potential C remobilization under a changing climate. In this study, we described the storage of soil organic carbon (SOC) and the aboveground phytomass carbon in relation to geomorphology and periglacial features for two areas on Taymir Peninsula (Arctic Russia). An average of 29.5 kg C m2, calculated by upscaling with a land cover classification, is stored in the upper soil meter at these two study sites. The mean C phytomass storage amounts to ca.0.406 Kg C m2, or only 1.38 % of the total SOC storage. The topography, at different scales, plays an important role in the carbon partitioning. High amounts of soil organic carbon are found in highland areas and within the patterned ground features found in peatlands. The highest amounts of aboveground phytomass carbon are found in deciduous shrubs and moss layers. The large variability in carbon distribution within land cover types among the sites reveals the challenge of upscaling the carbon storage values over the Arctic and thus highlights the necessity to carry out detailed field inventories in this region.

  4. Studies on deposition, adhesion and resuspension of radioactive substances on the ground surface and ground cover

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Susumu; Kurihara, Kazuo [Meteorological Research Inst., Tsukuba, Ibaraki (Japan)

    1999-03-01

    After the Chernobyl` nuclear power plant accident, resuspension of radioactive nuclei into the atmosphere is recognized as the one of the important processes that must be considered in the estimation of inhalation doses to humans. In this study, resuspensions of particles from soil and grass have been studied. The resuspension of particles from bare soil was modelized by using Shao`s method. The resuspension of particles from grass was studied by a wind tunnel and a field experiment. Dependencies of the resuspension rate on time and on friction velocity were obtained clearly. And it was also found that the other meteorological parameters, such as temperature, relative humidity, solar radiation and condensation, affected the resuspension rate in the field. (author)

  5. Summer cover crops and soil amendments to improve growth and nutrient uptake of okra

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q.R.; Li, Y.C.; Klassen, W. [University of Florida, Homestead, FL (United States). Center for Tropical Research & Education

    2006-04-15

    A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on 'Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudan-grass (Sorghum bicolor x S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash), coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. The results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.

  6. The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards

    Science.gov (United States)

    Madzaric, Suzana; Aly, Adel; Ladisa, Gaetano; Calabrese, Generosa

    2014-05-01

    The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards Madzaric S., Aly A., Ladisa G. and Calabrese G. The loss of natural plant cover due to the inappropriate soil cover management is often a decisive factor for soil degradation in Mediterranean area. This accompanied with typical climate, characterized by cool, wet winters and hot and dry summers leads to soil erosion and loss of productivity. Due to simplification of agricultural practice and to the attempt to decrease cost of production, keeping soil bare is a widespread agricultural practice in Mediterranean ancient olive orchards (AOOs). The consequences of this are degradation of soil quality and reduction of plant biodiversity. In last year's some alternative practices are proposed in order to protect soil and biodiversity. One of these practices is the "grassing" i.e. covering the soil by selected autochthonous plant species. Objectives of our study are: (1) to evaluate impact of different soil cover management practices on soil properties and plant biodiversity in AOOs and (2) to define a minimum indicators' set (Minimum Data Set - MDS) to evaluate the effectiveness of different agricultural practices in environmental performance of AOOs. A comparison was carried on considering two management systems (conventional vs. organic) and three agricultural practices: conventional with bare soil (CON), organic with soil covered by selected autochthonous species (MIX) and organic left to the native vegetation (NAT). In general a clear positive influence of organic management system was recognized. Some soil quality indicators (physical, chemical and biological) showed responsiveness in describing the effects of management system and agricultural practices on soil properties. The both approaches with vegetation cover on the soil surface (either sowing of mixture or soil left to the natural plant cover) performed better than

  7. The role of snow cover and soil freeze/thaw cycles affecting boreal-arctic soil carbon dynamics

    Directory of Open Access Journals (Sweden)

    Y. Yi

    2015-07-01

    Full Text Available Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (∼ 0.8–1.3 days decade−1 in the mean annual snow cover extent and frozen season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to changes in snow cover and soil freeze/thaw processes in the Pan-Arctic region over the past three decades (1982–2010. Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 ± 12.0 (SD cm, corresponding with widespread warming and lengthening non-frozen season. Warming promotes vegetation growth and soil heterotrophic respiration, particularly within surface soil layers (≤ 0.2 m. The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥ 0.5 m soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤ 0.2 m soil layers, especially in colder climate zones (mean annual T ≤ −10 °C. Our results demonstrate the important control of snow cover in affecting northern soil freeze/thaw and soil carbon decomposition processes, and the necessity of considering both warming, and changing precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  8. The role of snow cover and soil freeze/thaw cycles affecting boreal-arctic soil carbon dynamics

    Science.gov (United States)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-07-01

    Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (∼ 0.8-1.3 days decade-1) in the mean annual snow cover extent and frozen season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to changes in snow cover and soil freeze/thaw processes in the Pan-Arctic region over the past three decades (1982-2010). Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 ± 12.0 (SD) cm, corresponding with widespread warming and lengthening non-frozen season. Warming promotes vegetation growth and soil heterotrophic respiration, particularly within surface soil layers (≤ 0.2 m). The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥ 0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤ 0.2 m) soil layers, especially in colder climate zones (mean annual T ≤ -10 °C). Our results demonstrate the important control of snow cover in affecting northern soil freeze/thaw and soil carbon decomposition processes, and the necessity of considering both warming, and changing precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  9. Soil Stabilisation Using Ground Granulated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Pathak

    2014-05-01

    Full Text Available Stabilisation is a broad sense for the various methods employed and modifying the properties of a soil to improve its engineering performance and used for a variety of engineering works. In today‟s day soil stabilisation is the major problem for civil engineers, either for construction of road and also for increasing the strength or stability of soil and reduces the construction cost. In this thesis the soil are stabilised by ground granulated blast furnace slag (GGBS and this material is obtained from the blast furnace of cement plant, which is the byproduct of iron (from ACC plant, sindri. It is generally obtained in three shaped one is air cooled, foamed shaped and another is in granulated shaped. The use of by-product materials for stabilisation has environmental and economic benefits. Ground granulated blast furnace slag (GGBS material is used in the current work to stabilise soil (clay. The main objectives of this research were to investigate the effect of GGBS on the engineering property (optimum moisture content and maximum dry density, plastic limit, liquid limit, compaction, unconfined compressive strength, triaxial and California bearing ratio test of the soil and determine the engineering properties of the stabilised.

  10. The repair of ground cover of Bolivia-Brazil gas pipeline near Paraguay River crossing, in a swamp soft soil region, using geo synthetics reinforced backfilling; Reparo da cobertura do gasoduto Bolivia-Brasil junto ao Rio Paraguai, em trecho com solo mole, utilizando aterro reforcado com geosinteticos

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Cesar Augusto; Jorge, Kemal Vieira; Bechuate Filho, Pedro [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Campo Grande, MS (Brazil). Gerencia Regional Centro Oeste (CRGO); Teixeira, Sidnei H.C. [Geohydrotech Engenharia S.C. Ltda., Braganca Paulista, SP (Brazil)

    2005-07-01

    TBG - Transportadora Gasoduto Bolivia-Brasil S.A, executes routine maintenance works at the Gas Pipeline Right of Way, seeking its integrity. In the wetlands of Pantanal, near the Paraguay river crossing, the organic-alluvial soil was submitted to the process of subsidence. This process, associated with the river water flow erosion, shrank the soil volume and diminished or extinguished the pipeline land cover. The pipeline was exposed to the environment, and submitted to tension stresses and the risk of low cycle fatigue during the floods. The cathodic protection system also had to be evaluated, specially in the drought. To mitigate the problem, the embankment technique was adopted using sandy soil, reinforced with polyester geo-webs and with woven polipropene geo-textiles. The solution also used geo-webs with soil-cement as protection elements against the degradation of the geo-textiles blankets. Some monitoring works are associated with those interventions: monitoring of cathodic protection; topographical verification of horizontal and vertical displacements of the pipeline; levels of land covering, and rainfalls and flood measurement. The base of the embankment was built with hydraulic transported soil, and at the end consistently supported the gas pipeline. (author)

  11. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    Science.gov (United States)

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

  12. Cover crop effects on soil carbon and nitrogen under bioenergy sorghum crops

    Science.gov (United States)

    Cover crops can increase soil C and N storage and reduce the potential for N leaching under agronomic crops, but information on their benefits under bioenergy crops is scanty due to the removal of aboveground biomass. The objective of the study was to evaluate the effect of cover crops on soil organ...

  13. Soil management system in hazelnut groves (Corylus sp. versus the presence of ground beetles (Coleoptera: Carabidae

    Directory of Open Access Journals (Sweden)

    Nietupski Mariusz

    2015-01-01

    Full Text Available Sustaining biodiversity as well as taking advantage of the natural environment’s resistance are the key elements which should be considered when designing integrated plans for the protection of hazelnut groves. An effort has been made in this study to analyse the impact of different soil cultivation methods in hazelnut groves, on the species composition and number of individuals in carabid assemblages (Coleoptera: Carabidae. Another aim was to determine which method of inter-row soil management had the least negative effect on assemblages of these beetles. Because of the type of habitat, the xerothermic species characteristic for southeastern Europe, i.e. Calathus ambiguus, Poecilus lepidus, Harpalus calceatus, and H. griseus, were the most numerous. The qualitative and quantitative analysis of the captured individuals implied that the optimal soil tillage system in young hazelnut groves is when soil is kept fallow with machines or chemicals, or when soil is covered with manure. The least favourable practice for the appearance of ground beetles of the Carabidae family is the use of polypropylene fabric, bark or sawdust, to cover soil

  14. Land cover change and soil fertility decline in tropical regions

    NARCIS (Netherlands)

    Hartemink, A.E.; Veldkamp, A.; Bai, Zhanguo

    2008-01-01

    Land cover changes influence the biogeochemistry, hydrology, and climate of the earth. Studies that assessed land cover changes at the global scale mostly focused on: deforestation, cropland expansion, dry land degradation, urbanisation, pasture expansion, and agricultural intensification. For the a

  15. The role of snow cover affecting boreal-arctic soil freeze-thaw and carbon dynamics

    Science.gov (United States)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-10-01

    Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (~ 0.8-1.3 days decade-1) in the mean annual snow cover extent and frozen-season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with a detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to climate warming and changes in snow cover conditions in the pan-Arctic region over the past 3 decades (1982-2010). Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 ± 12.0 (SD) cm, corresponding to widespread warming. Warming promotes vegetation growth and soil heterotrophic respiration particularly within surface soil layers (≤ 0.2 m). The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥ 0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤ 0.2 m) soil layers, especially in colder climate zones (mean annual T ≤ -10 °C). Our results demonstrate the important control of snow cover on northern soil freeze-thaw and soil carbon decomposition processes and the necessity of considering both warming and a change in precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  16. Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern China

    Institute of Scientific and Technical Information of China (English)

    LI Xin-Hu; ZHANG Zhan-Yu; YANG Jie; ZHANG Guo-Hua; WANG Bin

    2011-01-01

    Rainfall, runoff (surface runoff, interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover, mulch and bare ground) on sloping red soil in southern China. Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains. In contrast, the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield. There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots. The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C. Effects of Bahia grass cover were excellent, indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.

  17. Estimation of snow cover distribution in Beas basin, Indian Himalaya using satellite data and ground measurements

    Indian Academy of Sciences (India)

    H S Negi; A V Kulkarni; B S Semwal

    2009-10-01

    In the present paper,a methodology has been developed for the mapping of snow cover in Beas basin,Indian Himalaya using AWiFS (IRS-P6)satellite data.The complexities in the mapping of snow cover in the study area are snow under vegetation,contaminated snow and patchy snow. To overcome these problems,field measurements using spectroradiometer were carried out and reflectance/snow indices trend were studied.By evaluation and validation of different topographic correction models,it was observed that,the normalized difference snow index (NDSI)values remain constant with the variations in slope and aspect and thus NDSI can take care of topography effects.Different snow cover mapping methods using snow indices are compared to find the suitable mapping technique.The proposed methodology for snow cover mapping uses the NDSI (estimated using planetary re flectance),NIR band reflectance and forest/vegetation cover information.The satellite estimated snow or non-snow pixel information using proposed methodology was validated with the snow cover information collected at three observatory locations and it was found that the algorithm classify all the sample points correctly,once that pixel is cloud free.The snow cover distribution was estimated using one year (2004 –05)cloud free satellite data and good correlation was observed between increase/decrease areal extent of seasonal snow cover and ground observed fresh snowfall and standing snow data.

  18. Effects of Ground Conditions on Microbial Cementation in Soils

    Directory of Open Access Journals (Sweden)

    Daehyeon Kim

    2013-12-01

    Full Text Available The purpose of this study is to understand the effect of ground conditions on microbial cementation in cohesionless soils. Since the method of microbial cementation is still at the experimental stage, for its practical use in the field, a number of laboratory experiments are required for the quantification of microbial cementation under various ground conditions, such as relative densities, relative compactions and particle size distributions. In this study, in order to evaluate the effectiveness of microbial cementation in treated sands and silts, an experiment was performed for different relative densities of silica sands, for different relative compactions of silts and for different particle size distributions of weathered soils sampled from the field. Scanning electron microscope (SEM, X-ray diffraction (XRD, energy dispersive X-ray (EDX spectroscopy and mapping analyses were implemented for the quantification of the levels of microbial cementations for sand, silt and weathered soil specimens. Based on the test results, a considerable microbial cementation was estimated depending on the soil conditions; therefore, an implementation of this new type of bio-grouting on a weak foundation may be possible to increase the strength and stiffness of weak ground.

  19. Fractional Vegetation Cover of East African Wetlands Observed on Ground and from Space

    Science.gov (United States)

    Schmidt, M.; Amler, E.; Guerschmann, J. P.; Scarth, P.; Behn, K.; Thonfeld, F.

    2016-08-01

    Wetlands are important ecosystems providing numerous ecosystem services. They are of particular importance to communities in East Africa where agriculture is the most important economic sector and where food availability to households critical. During an intensive field campaign in the dry season of 2013 were Fractional Vegetation Cover (FVC) measurements, botanical vegetation cover and vegetation structure estimates acquired in three wetland test sites within the East African region. FVC cover data were collated in three strata: ground layer, midstorey and overstorey (woody vegetation greater than 2 m). Fractional cover estimates for the green and no-green vegetative fraction were calculated for Landsat MODIS imagery. These FVC data products were evaluated a) with FVC field data and b) relative to each other for their usability in the East African region. First results show some promise for further studies.

  20. Effect of Covers and Rainfall on Soil and Water Conservation Using a Tilting Flume Model

    Directory of Open Access Journals (Sweden)

    S. Compliew

    2007-01-01

    Full Text Available The effect of stone and vegetative covers was evaluated for soil and water conservation in a waterway on salty soils in the Northeast of Thailand. Experiments were conducted on a hydraulic tilting flume under simulated unit flow (120 and 45 cm2s-1, rainfall (120 mm/hr and slope (0, 1.2,1.4,1.6,1.8,2.0, 2.2, 2.4, 2.6, 2.8 and 3.0% conditions. The depth of soil was maintained at 0.20 m. over a perforated bed to facilitate deep drainage. A comparative study of bare soil, stone cover (50% and vegetative cover (50% is made to evaluate soil loss, deep drainage, Manning’s roughness coefficient. The study has revealed that stone cover is more effective than vegetative cover at lower discharge in reducing the flow velocity and thereby soil erosion. Deep drainage has been reduced from lower discharge to higher discharge for all the slopes with cover measures, including bare soil. It is also found that cover measures are necessary beyond 2.6% bed slope in order to prevent rill erosion in salty soils.

  1. [Recovery of three tropical forest covers from mid-elevation sites in Costa Rica: oligochaetes, litter and soil analysis].

    Science.gov (United States)

    Pérez-Molina, Junior Pastor; Cordero Solórzano, Roberto A

    2012-12-01

    In Costa Rica, the region of Rio Macho is a highly fragmented landscape with imminent risk of landslides. This area, which provides important environmental services, has been partially recovered to its original forest through intentional reforestation with exotic species or natural regeneration after abandonment. The aim of this study was to evaluate the bioindicator potential of oligochaete presence as well as some litter and soil characteristics. The ecosystem recovery of the two common restoration modes was measured within three different forest covers. For this, some substrate characteristics were analyzed and compared in a-50 years old secondary forest, a 13 years tacotal, and a 35 years cypress (Cupressus lusitanica) plantation. The three sites studied differed in density, biomass and average mass of oligochaetes, and in some litter (depth, nitrogen, phosphorus and C/N ratio of litter), and soil variables (soil water content (CA), pH, phosphorus, cation exchange capacity, and magnesium). The forest registered the lowest density of earthworms and soil pH, and the highest soil CA and phosphorus. CA was inversely related to the oligochaete density across sites. Besides, there were positive correlations between C/N and C/P ratios from the litter and soil pH, and inverse correlations of litter depth, litter N and P concentrations with soil P. Discriminant Analysis (AD) performed with all soil and litter variables, produced a sharp classification of the three forest cover types. AD suggests that site differences were mostly determined by soil CA and litter nitrogen concentration. Considering all the evaluated parameters, our results suggest in the first place, that oligochaetes are sensitive to changes in some soil and litter characteristics. Secondly, aside from the striking oligochaete differences between the old secondary forest and the other two sites, some soil and litter traits resulted good indicators of the present recovery of the three forest covers. In

  2. Influence of Land Cover and Climate on CO2 and CH4 fluxes from Urban Soils

    Science.gov (United States)

    Smith, R. M.; Groffman, P. M.; Kaushal, S.; Gold, A.; Cole, J. N.

    2015-12-01

    Soils are important sinks for greenhouse gases globally. Urbanization influences biogeochemical processes and gas fluxes through increased nitrogen deposition, heat island effects, and vegetation management. Previous work at the Baltimore Ecosystem Study LTER site has reported elevated CO2 fluxes and reduced CH4 consumption in urban soils. Differences among soils (urban forest, rural forest, lawns) have been linked to nitrogen cycling and may also be driven by temperature differences between land cover types. A combination of site-specific changes (land cover, nitrogen availability) and climatological (temperature, soil moisture) factors are likely to influence long-term patterns in gas fluxes and therefore carbon storage in growing urban regions. We utilized 15 years of measured gas fluxes and continuous temperature and soil moisture data to model CO2 emissions and CH4 consumption under different vegetation classes. We scaled these fluxes to the metropolitan region using high-resolution spatial, and found that regional CH4 consumption and CO2 fluxes are sensitive to changes in temperature and land cover. For instance, in 2007 land cover in Baltimore City had 21% lawn and 22% forest cover. If all of the lawn area in the city were converted to urban forest, CH4 consumption by urban soils would increase by 70% and CO2 emissions would decrease by 20%. In suburban Baltimore County, lawns and urban forests comprised 35 and 50% of land cover respectively. If all lawns in the county were converted to urban forest, soil CH4 consumption would increase by 55% and soil CO2 flux would decrease by 20%. Soil CO2 fluxes also increase by approximately 0.1g C m-2 d-1 for every 1° C increase across all land cover classes. CH4 consumption increases with temperature in urban and rural forest soils. Our results highlight the interacting effects of land cover change and climate on carbon fluxes from urban soils.

  3. The effect of covering and mulching on the soil temperature, growth and yield of tomato

    Directory of Open Access Journals (Sweden)

    Kosterna Edyta

    2014-12-01

    Full Text Available By improving the thermal and moisture conditions in the immediate vicinity of plants, plastic covers influenced the growth and development and increased the yield of vegetables. Soil mulching with organic material is one method of soil water protection and also helps maintain a constant soil temperature within the root system of crops. This study investigated the effect of plant covering and the type of straw applied to soil mulching (rye, corn, rape or buckwheat on the soil temperature, development of the plant and the yield of ‘Polfast’ F1 tomato. The effect of the straw was compared to a control plot without mulch. Soil temperature at a depth of 10 cm was higher in covered plots than in the plot without covers. The increase in soil temperature as a result of covering amounted to 1.3°C at 8:00 a.m. and 1.7°C at 2:00 p.m. Both in the morning and in the afternoon, the soil temperature in the plots without straw and without covers and under polypropylene fibre was higher than in the plots with straw. The application of covers resulted in higher aboveground parts of plants and higher leaf area compared to cultivation without covers. Irrespective of whether a covering was used, all of the types of straw investigated in the experiment caused the acceleration of growth and development of tomato plants. Simultaneous plant covering and soil mulching increased the total yield of fruits but did not have an influence on the share of marketable yield of the total yield.

  4. [Effects of ground cover and water-retaining agent on winter wheat growth and precipitation utilization].

    Science.gov (United States)

    Wu, Ji-Cheng; Guan, Xiu-Juan; Yang, Yong-Hui

    2011-01-01

    An investigation was made at a hilly upland in western Henan Province to understand the effects of water-retaining agent (0, 45, and 60 kg x hm(-2)), straw mulching (3000 and 6000 kg x hm(-2)), and plastic mulching (thickness straw- or plastic mulching was combined with the use of water-retaining agent. Comparing with the control, all the measures increased the soil moisture content at different growth stages by 0.1%-6.5%. Plastic film mulching had the best water-retention effect before jointing stage, whereas water-retaining agent showed its best effect after jointing stage. Soil moisture content was the lowest at flowering and grain-filling stages. Land cover increased the grain yield by 2.6%-20.1%. The yield increment was the greatest (14.2%-20.1%) by the combined use of straw mulching and water-retaining agent, followed by plastic mulching combined with water-retaining agent (11.9% on average). Land cover also improved the precipitation use efficiency (0.4-3.2 kg x mm(-1) x hm(-2)) in a similar trend as the grain yield. This study showed that land cover and water-retaining agent improved soil moisture and nutrition conditions and precipitation utilization, which in turn, promoted the tillering of winter wheat, and increased the grain number per ear and the 1000-grain mass.

  5. Analysis of soil moisture variation by forest cover structure in lower western Himalayas, India

    Institute of Scientific and Technical Information of China (English)

    J.v.Tyagi; Nuzhat Qazi; S.P.Rai; M.P.Singh

    2013-01-01

    Soil moisture affects various hydrological processes,including evapotranspiration,infiltration,and runoff.Forested areas in the lower western Himalaya in India constitute the headwater catchments for many hill streams and have experienced degradation in forest cover due to grazing,deforestation and other human activities.This change in forest cover is likely to alter the soil moisture regime and,consequently,flow regimes in streams.The effect of change in forest cover on soil moisture regimes of this dry region has not been studied through long term field observations.We monitored soil matric potentials in two small watersheds in the lower western Himalaya of India.The watersheds consisted of homogeneous land covers of moderately dense oak forest and moderately degraded mixed oak forest.Observations were recorded at three sites at three depths in each watershed at fortnightly intervals for a period of three years.The soil moisture contents derived from soil potential measurements were analyzed to understand the spatial,temporal and profile variations under the two structures of forest cover.The analysis revealed large variations in soil moisture storage at different sites and depths and also during different seasons in each watershed.Mean soil moisture storage during monsoon,winter and summer seasons was higher under dense forest than under degraded forest.Highest soil moisture content occurred at shallow soil profiles,decreasing with depth in both watersheds.A high positive correlation was found between tree density and soil moisture content.Mean soil moisture content over the entire study period was higher under dense forest than under degraded forest.This indicated a potential for soil water storage under well managed oak forest.Because soil water storage is vital for sustenance of low flows,attention is needed on the management of oak forests in the Himalayan region.

  6. Land cover for Ukraine: the harmonization of remote sensing and ground-based data

    Science.gov (United States)

    Lesiv, M.; Shchepashchenko, D.; Shvidenko, A.; See, L. M.; Bun, R.

    2012-12-01

    This study focuses on the development of a land cover map of the Ukraine through harmonization of remote sensing and ground-based data. At present there is no land cover map of the Ukraine available that is of sufficient accuracy for use in environmental modeling. The existing remote sensing data are not enough accurate. In this study we compare the territory of the Ukraine from three global remote sensing products (GlobCover 2009, MODIS Land Cover and GLC-2000) using a fuzzy logic methodology in order to capture the uncertainty in the classification of land cover. The results for the Ukraine show that GlobCover 2009, MODIS Land Cover and GLC-2000 have a fuzzy agreement of 65%. We developed a weighted algorithm for the creation of a land cover map based on an integration of a number of global land cover and remote sensing products including the GLC-2000, GlobCover 2009, MODIS Land Cover, the Vegetation Continuous Fields product, digital map of administrative units and forest account data at the local level. This weighted algorithm is based on the results of comparing these products and an analysis of a dataset of validation points for different land cover types in the Ukraine. We applied this algorithm to generate a forest land cover type map. This raster map contains a forest expectation index that was calculated for each pixel. Forest land was then allocated based on forest statistics at the local level. Areas with a higher forest expectation index were allocated with forest first until the results matched the forest statistics. The result is the first digital map of forest (with a spatial resolution of 300m) for the Ukraine, which consistent with forest and land accounts, remote sensing datasets and GIS products. The forest land was well defined in forest rich areas (i.e. in the northern part of the Ukraine, the Carpathians and the Crimea); well less accurate areas were identified in the steppe due to heterogeneous land cover. Acknowledgements. This research was

  7. A Comprehensive Laboratory Study to Improve Ground Truth Calibration of Remotely Sensed Near-Surface Soil Moisture

    Science.gov (United States)

    Babaeian, E.; Tuller, M.; Sadeghi, M.; Sheng, W.; Jones, S. B.

    2016-12-01

    Optical satellite and airborne remote sensing (RS) have been widely applied for characterization of large-scale surface soil moisture distributions. However, despite the excellent spatial resolution of RS data, the electromagnetic radiation within the optical bands (400-2500 nm) penetrates the soil profile only to a depth of a few millimeters; hence obtained moisture estimates are limited to the soil surface region. Furthermore, moisture sensor networks employed for ground truth calibration of RS observations commonly exhibit very limited spatial resolution, which consequently leads to significant discrepancies between RS and ground truth observations. To better understand the relationship between surface and near-surface soil moisture, we employed a benchtop hyperspectral line-scan imaging system to generate high resolution surface reflectance maps during evaporation from soil columns filled with source soils covering a wide textural range and instrumented with a novel time domain reflectometry (TDR) sensor array that allows monitoring of near surface moisture at 0.5-cm resolution. A recently developed physical model for surface soil moisture predictions from shortwave infrared reflectance was applied to estimate surface soil moisture from surface reflectance and to explore the relationship between surface and near-surface moisture distributions during soil drying. Preliminary results are very promising and their applicability for ground truth calibration of RS observations will be discussed.

  8. Accurate Quantification of Grassland Cover Density in an Alpine Meadow Soil Based on Remote Sensing and GPS

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-Sui; HU Ye-Cui; PENG Liu-Ying

    2005-01-01

    The principles of remotely estimating grassland cover density in an alpine meadow soil from space lie in the synchronous collection of in situ samples with the satellite pass and statistically linking these cover densities to their image properties according to their geographic coordinates. The principles and procedures for quantifying grassland cover density from satellite image data were presented with an example from Qinghai Lake, China demonstrating how quantification could be made more accurate through the integrated use of remote sensing and global positioning systems (GPS). An empirical model was applied to an entire satellite image to convert pixel values into ground cover density. Satellite data based on 68 field samples was used to produce a map of ten cover densities. After calibration a strong linear regression relationship (r2 = 0.745) between pixel values on the satellite image and in situ measured grassland cover density was established with an 89% accuracy level. However, to minimize positional uncertainty of field samples, integrated use of hyperspatial satellite data and GPS could be utilized. This integration could reduce disparity in ground and space sampling intervals,and improve future quantification accuracy even more.

  9. Electromagnetic wave scattering from vegetation (Potato) and vegetation covered soil moisture for remote sensing

    Science.gov (United States)

    Singh, Keshev

    In the country with limited resources, where the nutrition level of the population has to be maintained under inhospitable situation, the potato has a special value as food. Therefore efforts should be made for improvement and spreading the cultivation of this important crop. It demands an effective program that may provide information about potato growing areas and the growth conditions. Remote sensing has been acknowledged to be a valuable source of spatially comprehensive and temporally repeatable information of crop covered soil moisture, crop growth climatic information etc, which is useful and necessary for agriculture purposes. For this purpose, microwave remote sensing has evolved as an important tool. Since microwave are able to penetrate more deeply into vegetation and underneath ground surface. It is also preferred to the optical frequency band because microwave can work in all type of weather and have a wide signal dynamic range compared optical wavelengths. However interpretation of microwave scattering from agricultural crops requires an understanding the interaction among microwave, vegetative material and the soil. In order to develop useful forward and inverse models for retrieving the vegetation characteristic, it is necessary to know in detail the dielectric properties and plant structure of the vegetation over the range of expected growing conditions. In this paper, a theoretical model based on microwave interaction with potato crop along with examination of biomass of potato crop with the varying underlying soil moisture is studied. For this purpose, X-band (9.5GHz) scatterometer is used for studying the interaction of microwave with potato crop biomass and underlying soil moisture at various sensor parameters (i.e. angular variation and polarization, HH- and VV-). Although there may be a lot of crop parameters (i.e. crop height, leaf area index, etc) which also gives their effect on microwave. All this parameters are interlinked in the crop

  10. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Directory of Open Access Journals (Sweden)

    Daniel Paredes

    Full Text Available Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history, the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard, or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae in 2,528 olive groves in Andalusia (Spain from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  11. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Science.gov (United States)

    Paredes, Daniel; Cayuela, Luis; Gurr, Geoff M; Campos, Mercedes

    2015-01-01

    Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history), the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard), or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae) in 2,528 olive groves in Andalusia (Spain) from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  12. [Advance in researches on vegetation cover and management factor in the soil erosion prediction model].

    Science.gov (United States)

    Zhang, Yan; Yuan, Jianping; Liu, Baoyuan

    2002-08-01

    Vegetation cover and land management are the main limiting factors of soil erosion, and quantitative evaluation on the effect of different vegetation on soil erosion is essential to land use and soil conservation planning. The vegetation cover and management factor (C) in the universal soil loss equation (USLE) is an index to evaluate this effect, which has been studied deeply and used widely. However, the C factor study is insufficient in China. In order to strengthen the research of C factor, this paper reviewed the developing progress of C factor, and compared the methods of estimating C value in different USLE versions. The relative studies in China were also summarized from the aspects of vegetation canopy coverage, soil surface cover, and root density. Three problems in C factor study were pointed out. The authors suggested that cropland C factor research should be furthered, and its methodology should be unified in China to represent reliable C values for soil loss prediction and conservation planning.

  13. Covering of heating load of object by using ground heat as a renewable energy source

    Directory of Open Access Journals (Sweden)

    Čenejac Aleksandra R.

    2012-01-01

    Full Text Available Rational use of energy, improving energy performance of buildings and use of renewable energy sources are the most important measures for reducing consumption of non-renewable primary energy (solid, liquid, and gaseous fuels, environmental protection and for the future sustainable development of mankind. In the total primary energy consumption great part is related to building industry, for heating spaces in which people stay and live. Renewable energy sources (RES present natural resources and they are one of the alternatives that allow obtaining heat for heating buildings, and by that they provide a significant contribution to the energy balance of a country. This paper analyzes the participation of ground source as RES, when the vertical (the probe in the ground and horizontal (registry in the ground heat exchangers are used for covering heating load of the building.

  14. Changes in Soil Organic Carbon Fractions in Response to Cover Crops in an Orange Orchard

    Directory of Open Access Journals (Sweden)

    Francisco Éder Rodrigues de Oliveira

    2016-01-01

    Full Text Available ABSTRACT The cultivation of cover crops intercropped with fruit trees is an alternative to maintain mulch cover between plant rows and increase soil organic carbon (C stocks. The objective of this study was to evaluate changes in soil total organic C content and labile organic matter fractions in response to cover crop cultivation in an orange orchard. The experiment was performed in the state of Bahia, in a citrus orchard with cultivar ‘Pera’ orange (Citrus sinensis at a spacing of 6 × 4 m. A randomized complete block design with three replications was used. The following species were used as cover crops: Brachiaria (Brachiaria decumbes – BRAQ, pearl millet (Pennisetum glaucum – MIL, jack bean (Canavalia ensiformis – JB, blend (50 % each of jack bean + millet (JB/MIL, and spontaneous vegetation (SPV. The cover crops were broadcast-seeded between the rows of orange trees and mechanically mowed after flowering. Soil sampling at depths of 0.00-0.10, 0.10-0.20, and 0.20-0.40 m was performed in small soil trenches. The total soil organic C (SOC content, light fraction (LF, and the particulate organic C (POC, and oxidizable organic C fractions were estimated. Total soil organic C content was not significantly changed by the cover crops, indicating low sensitivity in reacting to recent changes in soil organic matter due to management practices. Grasses enabled a greater accumulation of SOC stocks in 0.00-0.40 m compared to all other treatments. Jack bean cultivation increased LF and the most labile oxidizable organic C fraction (F1 in the soil surface and the deepest layer tested. Cover crop cultivation increased labile C in the 0.00-0.10 m layer, which can enhance soil microbial activity and nutrient absorption by the citrus trees. The fractions LF and F1 may be suitable indicators for monitoring changes in soil organic matter content due to changes in soil management practices.

  15. Utilisation of chemically stabilized arsenic-contaminated soil in a landfill cover.

    Science.gov (United States)

    Kumpiene, Jurate; Desogus, Paolo; Schulenburg, Sven; Arenella, Mariarita; Renella, Giancarlo; Brännvall, Evelina; Lagerkvist, Anders; Andreas, Lale; Sjöblom, Rolf

    2013-12-01

    The aim of the study was to determine if an As-contaminated soil, stabilized using zerovalent iron (Fe(0)) and its combination with gypsum waste, coal fly ash, peat, or sewage sludge, could be used as a construction material at the top layer of the landfill cover. A reproduction of 2 m thick protection/vegetation layer of a landfill cover using a column setup was used to determine the ability of the amendments to reduce As solubility and stimulate soil functionality along the soil profile. Soil amendment with Fe(0) was highly efficient in reducing As in soil porewater reaching 99 % reduction, but only at the soil surface. In the deeper soil layers (below 0.5 m), the Fe treatment had a reverse effect, As solubility increased dramatically exceeding that of the untreated soil or any other treatment by one to two orders of magnitude. A slight bioluminescence inhibition of Vibrio fischeri was detected in the Fe(0) treatment. Soil amendment with iron and peat showed no toxicity to bacteria and was the most efficient in reducing dissolved As in soil porewater throughout the 2 m soil profile followed by iron and gypsum treatment, most likely resulting from a low soil density and a good air diffusion to the soil. The least suitable combination of soil amendments for As immobilization was a mixture of iron with coal fly ash. An increase in all measured enzyme activities was observed in all treatments, particularly those receiving organic matter. For As to be stable in soil, a combination of amendments that can keep the soil porous and ensure the air diffusion through the entire soil layer of the landfill cover is required.

  16. Cover crops and crop residue management under no-till systems improve soils and environmental quality

    Science.gov (United States)

    Kumar, Sandeep; Wegner, Brianna; Vahyala, Ibrahim; Osborne, Shannon; Schumacher, Thomas; Lehman, Michael

    2015-04-01

    Crop residue harvest is a common practice in the Midwestern USA for the ethanol production. However, excessive removal of crop residues from the soil surface contributes to the degradation of important soil quality indicators such as soil organic carbon (SOC). Addition of a cover crop may help to mitigate these negative effects. The present study was set up to assess the impacts of corn (Zea mays L.) residue removal and cover crops on various soil quality indicators and surface greenhouse gas (GHG) fluxes. The study was being conducted on plots located at the North Central Agricultural Research Laboratory (NCARL) in Brookings, South Dakota, USA. Three plots of a corn and soybean (Glycine max (L.) Merr.) rotation under a no-till (NT) system are being monitored for soils and surface gas fluxes. Each plot has three residue removal (high residue removal, HRR; medium residue removal, MRR; and low residue removal, LRR) treatments and two cover crops (cover crops and no cover crops) treatments. Both corn and soybean are represented every year. Gas flux measurements were taken weekly using a closed static chamber method. Data show that residue removal significantly impacted soil quality indicators while more time was needed for an affect from cover crop treatments to be noticed. The LRR treatment resulted in higher SOC concentrations, increased aggregate stability, and increased microbial activity. The LRR treatment also increased soil organic matter (SOM) and particulate organic matter (POM) concentrations. Cover crops used in HRR (high corn residue removal) improved SOC (27 g kg-1) by 6% compared to that without cover crops (25.4 g kg-1). Cover crops significantly impacted POM concentration directly after the residue removal treatments were applied in 2012. CO2 fluxes were observed to increase as temperature increased, while N2O fluxes increased as soil moisture increased. CH4 fluxes were responsive to both increases in temperature and moisture. On average, soils under

  17. Study of seasonal snow cover influencing the ground thermal regime on western flank of Da Xing'anling Mountains, northeastern China

    Institute of Scientific and Technical Information of China (English)

    XiaoLi Chang; HuiJun Jin; YanLin Zhang; HaiBin Sun

    2015-01-01

    Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of the soils in permafrost regions in the mid-latitudes and boreal regions, such as that on the western flank of the Da Xing'anling (Hinggan) Mountains, northeastern China. This paper gives a detailed analysis on meteorological data series from 2001 to 2010 provided by the Gen'he Weather Station, which is located in a talik of discontinuous permafrost zone and with sparse meadow on the observation field. It is inferred that snow cover is important for the ground thermal regime in the middle Da Xing'anling Mountains. Snow cover of 10-cm in thickness and five to six months in duration (generally November to next March) can reduce the heat loss from the ground to the atmosphere by 28%, and by 71% if the snow depth increases to 36 cm. Moreover, the occurrence of snow cover resulted in mean annual ground surface temperatures 4.7–8.2°C higher than the mean annual air temperatures recorded at the Gen'he Weather Station. The beginning date for stable snow cover establishment (SE date) and the initial snow depth (SDi) also had a great influences on the ground freezing process. Heavy snowfall before ground surface freeze-up could postpone and retard the freezing process in Gen'he. As a result, the duration of ground freezing was shortened by at least 20 days and the maximum depth of frost penetration was as much as 90 cm shallower.

  18. Soil Water Improvements with the Long Term Use of a Winter Rye Cover Crop

    Science.gov (United States)

    Basche, A.; Kaspar, T.; Archontoulis, S.; Jaynes, D. B.; Sauer, T. J.; Parkin, T.; Miguez, F.

    2015-12-01

    The Midwestern United States, a region that produces one-third of maize and one-quarter of soybeans globally, is projected to experience increasing rainfall variability with future climate change. One approach to mitigate climate impacts is to utilize crop and soil management practices that enhance soil water storage, reducing the risks of flooding and runoff as well as drought-induced crop water stress. While some research indicates that a winter cover crop in a maize-soybean rotation increases soil water, producers continue to be concerned that water use by cover crops will reduce water for a following cash crop. We analyzed continuous in-field soil moisture measurements over from 2008-2014 at a Central Iowa research site that has included a winter rye cover crop in a maize-soybean rotation for thirteen years. This period of study included years in the top third of wettest years on record (2008, 2010, 2014) as well as years in the bottom third of driest years (2012, 2013). We found the cover crop treatment to have significantly higher soil water storage from 2012-2014 when compared to the no cover crop treatment and in most years greater soil water content later in the growing season when a cover crop was present. We further found that the winter rye cover crop significantly increased the field capacity water content and plant available water compared to the no cover crop treatment. Finally, in 2012 and 2013, we measured maize and soybean biomass every 2-3 weeks and did not see treatment differences in crop growth, leaf area or nitrogen uptake. Final crop yields were not statistically different between the cover and no cover crop treatment in any of the years of this analysis. This research indicates that the long-term use of a winter rye cover crop can improve soil water dynamics without sacrificing cash crop growth.

  19. Soil acidification and its impact on ground vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Falkengren-Grerup, U.

    1989-01-01

    Forest soils in southern Sweden have become more acid during the last decades, partly due to deposition of acidifying substances. The top soil pH has decreased by up to 1.5 units over a period of 35 years (average decrease 0.8). The decrease ocurred not only in the root zone but throughout the whole soil profile, and were particularly marked in the originally less acid soils. The pH decrease has been accompanied by considerable losses of exchangeable Na, K, Mg and Ca, as well as of Zn and Mn ions. The species diversity of the vascular plants in the field layer increased over a 15-35-year period in spite of the acidification of the forest soils. Among species that increased were the nitrophiles, e.g. Rubus idaeus, Aegopodium podagraria and Chamaenerion angustifolium, probably an effect of the increased N-deposition. A few species decreased on a majority of sites, Polygonatum multiflorum, Pulmonaria officinalis, Dentaria bulbifera, while Mercurialis perennis, Lamium galeobdolon, Galium odoratum and Oxalis acetocella decreased at the lower pH levels. The greater abundance of several species is probably caused by the increased nitrogen deposition. The most common species appeared to respond very clearly to the acid properties of the humus layer. Acidification gradients, caused by large stemflow volumes from beech trees, showed that the species cover was closely related to the variation in soil pH. The cover curves of species growing in the narrow stemflow gradients were congruent with those of beech stands with different acidity, spread over a geographical area. (author) (With 36 refs.).

  20. Modeling of methane oxidation in landfill cover soil using an artificial neural network.

    Science.gov (United States)

    Abushammala, Mohammed F M; Basri, Noor Ezlin Ahmad; Elfithri, Rahmah; Younes, Mohammad K; Irwan, Dani

    2014-02-01

    Knowing the fraction of methane (CH4) oxidized in landfill cover soils is an important step in estimating the total CH4 emissions from any landfill. Predicting CH4 oxidation in landfill cover soils is a difficult task because it is controlled by a number of biological and environmental factors. This study proposes an artificial neural network (ANN) approach using feedforward backpropagation to predict CH4 oxidation in landfill cover soil in relation to air temperature, soil moisture content, oxygen (O2) concentration at a depth of 10 cm in cover soil, and CH4 concentration at the bottom of cover soil. The optimum ANN model giving the lowest mean square error (MSE) was configured from three layers, with 12 and 9 neurons at the first and the second hidden layers, respectively, log-sigmoid (logsig) transfer function at the hidden and output layers, and the Levenberg-Marquardt training algorithm. This study revealed that the ANN oxidation model can predict CH4 oxidation with a MSE of 0.0082, a coefficient of determination (R2) between the measured and predicted outputs of up to 0.937, and a model efficiency (E) of 0.8978. To conclude, further developments of the proposed ANN model are required to generalize and apply the model to other landfills with different cover soil properties.

  1. Expression of allelopathy in the soil environment: Soil concentration and activity of benzoxazinoid compounds released by rye cover crop residue

    Science.gov (United States)

    The activity of allelopathic compounds is often reduced in the soil environment where processes involving release from donor plant material, soil adsorption and degradation, and uptake by receptor plants naturally result in complex interactions. Rye (Secale cereale L.) cover crops are known to supp...

  2. Field evaluation of the effectiveness of engineered soil covers for reactive tailings

    Energy Technology Data Exchange (ETDEWEB)

    Yanful, E.K.; Woyshner, M.R.; Aube, B.C.

    1993-10-01

    The purpose is to design, construct, and evaluate the effectiveness of soil covers and a geomembrane, or plastic cover, to reduce acid generation in reactive mine tailings. The evaluation involves performance monitoring of field test plots at the decommissioned Waite Amulet tailings site and laboratory experiments. Gaseous oxygen concentrations, water content, suction, temperature, and pore water quality at various depths were measured at plots set up to test two soil covers, the geomembrane cover, and as a control. The results from the four tests are reported and evaluated. 43 refs., 98 figs., 27 tabs.

  3. Intensity of Ground Cover Crop Arachis pintoi, Rhizobium Inoculation and Phosphorus Application and Their Effects on Field Growth and Nutrient Status of Cocoa Plants

    Directory of Open Access Journals (Sweden)

    John Bako Baon

    2006-08-01

    Full Text Available Arachis pintoiis potentially as a cover crop for cocoa (Theobroma cacaoL. farm, however information regarding its effect on the growth of cocoa plants in the field is very limited. The objective of this experiment is to investigate the combined influence of ground cover crop A. pintoi, rhizobial bacterial inoculation and phosphorus (P fertilizer on the growth of cocoa in the field and nutrient status. This experiment laid out in split-split plot design consisted of three levels of cover crop (without, A. pintoiand Calopogonium caeruleum, two levels of rhizobium inoculation (not inoculated and inoculated and two levels of phosphorus application (no P added and P added. The results showed that in field condition the presence of A. pintoias cover crop did not affect the growth of cocoa. On the other hand, C. caeruleumas cover crop tended to restrict cocoa growth compared to A. pintoi. Application of P increased leaf number of cocoa plant. Biomass production of A. pintoiwas 40% higher than C. caeruleum. Soil organic carbon and nitrogen contents were not affected by ground cover crops, though higher value (0.235% N and 1.63% organic C was obtained from combined treatments of inoculation and P addition or neither inoculation nor P addition. In the case of no rhizobium inoculation, soil N content in cocoa farm with A. pintoicover crop was lower than that of without cover crop or with C. caeruleum. Cover crop increased plant N content when there was no inoculation, on the other hand rhizobium inoculation decreased N content of cocoa tissue. Tissue P content of cocoa plant was not influenced by A. Pintoicover crop or by rhizobium inoculation, except that the P tissue content of cocoa was 28% higher when the cover crop was C. caeruleumand inoculated. Key words : Arachis pintoi, Theobroma cacao, Calopogonium caeruleum, rhizobium, nitrogen, phosphorus.

  4. Soil physical properties and grape yield influenced by cover crops and management systems

    Directory of Open Access Journals (Sweden)

    Jaqueline Dalla Rosa

    2013-10-01

    Full Text Available The use of cover crops in vineyards is a conservation practice with the purpose of reducing soil erosion and improving the soil physical quality. The objective of this study was to evaluate cover crop species and management systems on soil physical properties and grape yield. The experiment was carried out in Bento Gonçalves, RS, Southern Brazil, on a Haplic Cambisol, in a vineyard established in 1989, using White and Rose Niagara grape (Vitis labrusca L. in a horizontal, overhead trellis system. The treatments were established in 2002, consisting of three cover crops: spontaneous species (SS, black oat (Avena strigosa Schreb (BO, and a mixture of white clover (Trifolium repens L., red clover (Trifolium pratense L. and annual rye-grass (Lolium multiflorum L. (MC. Two management systems were applied: desiccation with herbicide (D and mechanical mowing (M. Soil under a native forest (NF area was collected as a reference. The experimental design consisted of completely randomized blocks, with three replications. The soil physical properties in the vine rows were not influenced by cover crops and were similar to the native forest, with good quality of the soil structure. In the inter-rows, however, there was a reduction in biopores, macroporosity, total porosity and an increase in soil density, related to the compaction of the surface soil layer. The M system increased soil aggregate stability compared to the D system. The treatments affected grapevine yield only in years with excess or irregular rainfall.

  5. Effects of methane on the microbial populations and oxidation rates in different landfill cover soil columns.

    Science.gov (United States)

    He, Ruo; Ruan, Aidong; Shen, Dong-Sheng

    2007-05-01

    A considerable fraction of methane produced in landfills is oxidized by landfill cover soils. In this work, microbial populations and oxidation rates developed in response to the presence of methane were studied in three soil columns simulated landfill cover soil environments. The population of aerobic heterotrophic bacteria was highest in the waste soil, middle in the clay soil, and lowest in the red soil. After exposure to methane-rich environments, the populations of methanotrophic bacteria showed increases in the waste and clay soils. The population of methanotrophic bacteria increased from 30.77x10(4) to 141.77x10(4) cfu g d.w.-1 in the middle layer of the waste soil column as a function of exposure to methane for 120 days. The populations of methanotrophic bacteria were correlated with the potential methane oxidation rates in the waste and clay soils, respectively. The topsoil was observed to be dried in the three soil columns. Most of methane oxidation occurred at the depth of between 10 and 20 cm in the waste soil column, while it took place mainly at the depth of between 20 and 30 cm in the clay soil column.

  6. Soil Organic Carbon Response to Cover Crop and Nitrogen Fertilization under Bioenergy Sorghum

    Science.gov (United States)

    Sainju, U. M.; Singh, H. P.; Singh, B. P.

    2015-12-01

    Removal of aboveground biomass for bioenergy/feedstock in bioenergy cropping systems may reduce soil C storage. Cover crop and N fertilization may provide additional crop residue C and sustain soil C storage compared with no cover crop and N fertilization. We evaluated the effect of four winter cover crops (control or no cover crop, cereal rye, hairy vetch, and hairy vetch/cereal rye mixture) and two N fertilization rates (0 and 90 kg N ha-1) on soil organic C (SOC) at 0-5, 5-15, and 15-30 cm depths under forage and sweet sorghums from 2010 to 2013 in Fort Valley, GA. Cover crop biomass yield and C content were greater with vetch/rye mixture than vetch or rye alone and the control, regardless of sorghum species. Soil organic C was greater with vetch/rye than rye at 0-5 and 15-30 cm in 2011 and 2013 and greater with vetch than rye at 5-15 cm in 2011 under forage sorghum. Under sweet sorghum, SOC was greater with cover crops than the control at 0-5 cm, but greater with vetch and the control than vetch/rye at 15-30 cm. The SOC increased at the rates of 0.30 Mg C ha-1 yr-1 at 0-5 cm for rye and the control to 1.44 Mg C ha-1 yr-1 at 15-30 cm for vetch/rye and the control from 2010 to 2013 under forage sorghum. Under sweet sorghum, SOC also increased linearly at all depths from 2010 to 2013, regardless of cover crops. Nitrogen fertilization had little effect on SOC. Cover crops increased soil C storage compared with no cover crop due to greater crop residue C returned to the soil under forage and sweet sorghum and hairy vetch/cereal rye mixture had greater C storage than other cover crops under forage sorghum.

  7. The effect of different tillage and cover crops on soil quality

    DEFF Research Database (Denmark)

    Abdollahi, Lotfollah; Munkholm, Lars Juhl

    This paper examines the effect of different tillage treatments and cover crop on soil physical, chemical and biological properties of a sandy loam soil in a long-term field trial set up in 2007 at Foulum, Denmark. The experimental design is a split plot design with different tillage practices...

  8. Multiple microbial activity-based measures reflect effects of cover cropping and tillage on soils

    Science.gov (United States)

    Agricultural producers, conservation professionals, and policy makers are eager to learn of soil analytical techniques and data that document improvement in soil health by agricultural practices such as no-till and incorporation of cover crops. However, there is considerable uncertainty within the r...

  9. Soil carbon and nitrogen affected by perennial grass, cover crop, and nitrogen fertilization

    Science.gov (United States)

    Soil C and N sequestration and the potential for N leaching can be influenced by the type of perennial grass, cover crop, and N fertilization due to differences in crop yields and the amount of residue returned to the soil. We evaluated the effects of the combinations of perennial grasses (energy ca...

  10. Erosion control in orchards and vineyards by a new soil and cover crop management method

    Science.gov (United States)

    Hartl, Wilfried; Guettler, Hans; Auer, Karl; Erhart, Eva

    2016-04-01

    Cover crops are the basis for an erosion-free soil management in orchards and vineyards. The soil cover provided by the foliage and the intensive root formation counteract erosion. Cover crops provide the soil microfauna with fresh organic matter which improves soil structure and porosity. The water demand of cover crops, however, may pose problems for the water supply of the trees and vines in dry seasons. Therefore it is necessary to adjust the growth of the cover crops to the actual water conditions. In years with ample precipitation cover crops may be allowed lush vegetative growth till flowering and formation of seeds. In dry years, the growth of the cover crop must be restricted to stop the competition for water, sometimes even by cutting off the cover crop roots. The course of the weather is incalculable and rainfall may be very variable during the year, so it is sometimes necessary to adust the cover crop management several times a year. A new special equipment, which can perform all the tasks necessary for the flexible cover crop management has been developed together with the agricultural machinery manufacturers Bodenwerkstatt Ertl-Auer GmbH and Güttler GmbH. The GreenManager® device consists of three modules, namely a specific type of cultivator, a harrow and a prismatic roller with seeding equipment, which can be used separately or in combination. The GreenManager® can reduce cover crops by flattening the plants in the whole row middle, by bringing down the cover crops with the harrow, or by horizontally cutting the cover crop roots a few centimetres beneath the soil surface in the central part of the row middle or in the whole row middle. These measures reduce the water competition by cover crops without generating further losses of soil moisture through intensive soil cultivation. At the same time the risk of soil erosion is kept to a minimum, because the soil remains covered by dead plant biomass. In one passage the GreenManager® can direct

  11. Changes in soil properties and soil cover structure due to intensive erosion and accumulation processes in loess soils

    Science.gov (United States)

    Zadorova, Tereza; Penizek, Vit; Jaksik, Ondrej; Kodesova, Radka; Jirku, Veronika; Fer, Miroslav

    2010-05-01

    Intensive water and tillage erosion and consequent accumulation are the most important processes affecting the agroecosystems in loess regions and changing soil properties, e.g. organic carbon content, carbonate content or structure stability, and general distribution of soil units in the landscape. South Moravian loess belt, formerly covered mostly by Haplic Chernozem, is now formed by a highly diversified soil mosaic. At a morphologically heterogenous study plot (6 ha), a study on relationship between soil properties and terrain characteristics was held. DTM analysis, detailed terrain survey and laboratory analysis were the main methods adopted in the study. Three main soil units were identified: Haplic Chernozem, calcareous Regosol and Colluvial soil. The distribution of each soil unit correlates with different terrain attributes. Regosols are significatly connected to the steep slope, while their correlation with the curvature or hydrological indexes is lower. On the contrary, the Colluvial soils distribution depends mainly on values of curvature and topographical wetness index and is independent on the slope. Chernozem is related to a specific terrain position more than to any of the terrain attributes. Soil depth and humus horizon thickness vary extremelly - from 0.2 m at the erosionally exposed slopes to more than 2.5 m at the concave parts and the toeslope. Soil depth is significantly correlated with all of the tested terrain attributes except of the slope - the strongest correlation was proved in case of mean curvature, topographical wetness index and catchment area. Different degree of changes in particular soil properties results from the specificity of both erosion process and parent material character. Organic carbon content in the topsoil varies significantly. Humus is practically absent in the steepest parts of the slope where the loess is exposed. High amounts of Corg were identified in the undisturbed A horizons of the Chernozem unit. In the

  12. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    Science.gov (United States)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the coarser (content. Further, compaction effort was much significant

  13. Mechanizing Weakly Ground Termination Proving of Term Rewriting Systems by Structural and Cover-Set Inductions

    Institute of Scientific and Technical Information of China (English)

    Su Feng

    2005-01-01

    The paper presents three formal proving methods for generalized weakly ground terminating property, i.e.,weakly terminating property in a restricted domain of a term rewriting system, one with structural induction, one with cover-set induction, and the third without induction, and describes their mechanization based on a meta-computation model for term rewriting systems-dynamic term rewriting calculus. The methods can be applied to non-terminating, nonconfluent and/or non-left-linear term rewriting systems. They can do "forward proving" by applying propositions in the proof, as well as "backward proving" by discovering lemmas during the proof.

  14. Monitoring of Ecological and Geochemical State of the Soil Cover in the City of Voronezh

    Directory of Open Access Journals (Sweden)

    Sereda Lyudmila Olegovna

    2015-09-01

    Full Text Available Soil cover in the city of Voronezh accumulates a lot of pollutants and indicates the centers of technological pollution. The high rates of housing construction, functioning and development of urban infrastructure cause infringement to the soil cover. The paper contains main results of an ecological and geochemical research of the soil cover in Voronezh, its characteristics, properties of the horizons of the different types of soils. During spring and summer of 2014 75 samples of soil were collected in special points of monitoring (according to GOST 17.4.3.01-83 and GOST 17.4.4.02-84. During the research the following methods were applied – volt-ampermetric method was used for detecting the concentration of heavy metals, the method of cholophorm-hexan extraction – for petrochemicals, the method of I.V. Tyurin – for humus concentration, potentiometric method and biotesting methods (analysis of seedlings of the following indicating plants – Lepidium sativum, Avena sativa, as well as defining the phytotoxic effect – for actual acidity detection. The obtained results are used for creating an overview soil map of Voronezh. Urbanozems are dominating in the soil cover of Voronezh. There era large areas of them in the majority of the city districts. A smaller part of a total urban area is presented by soils, which are slightly touched by human economic activity. Urban soils of industrial and transport city zones have disadvantageous properties – low rate of humus and alkali reaction of soil environment, high rate of pollution by petrochemicals and heavy metals. The least rate of pollution of a soil cover by heavy metals is detected in residential areas, situated far from industrial objects and highways. We have detected dependence between accumulation of polluting substances in soil cover and functional and planning peculiarities of the city. For example, accumulation of zinc takes place in soils with alkali reaction of soil and low

  15. Grass cover crop and tillage method on watermelon production on porous soils

    Science.gov (United States)

    Watermelon [Citrullus lanatus (Thunb.) Cogn.] production in the Southern Plains is often on well-drained soil, which makes conservation of water difficult. Established cover crops can conserve moisture, but it needs to be determined what cover and tillage method provides the most benefit to watermel...

  16. Snow cover manipulation effects on microbial community structure and soil chemistry in a mountain bog

    NARCIS (Netherlands)

    Robroek, B.J.M.; Heijboer, A.; Jassey, V.E.J.; Hefting, M.M.; Rouwenhorst, T.G.; Buttler, A.; Bragazza, L.

    2013-01-01

    Background and Aims Alterations in snow cover driven by climate change may impact ecosystem functioning, including biogeochemistry and soil (microbial) processes. We elucidated the effects of snow cover manipulation (SCM) on above-and belowground processes in a temperate peatland. Methods In a Swiss

  17. Snow cover manipulation effects on microbial community structure and soil chemistry in a mountain bog

    NARCIS (Netherlands)

    Robroek, B.J.M.; Heijboer, A.; Jassey, V.E.J.; Hefting, M.M.; Rouwenhorst, T.G.; Buttler, A.; Bragazza, L.

    2013-01-01

    Background and Aims Alterations in snow cover driven by climate change may impact ecosystem functioning, including biogeochemistry and soil (microbial) processes. We elucidated the effects of snow cover manipulation (SCM) on above-and belowground processes in a temperate peatland. Methods In a Swiss

  18. Estimating photosynthetic vegetation, non-photosynthetic vegetation and bare soil fractions using Landsat and MODIS data: Effects of site heterogeneity, soil properties and land cover

    Science.gov (United States)

    Guerschman, J. P.; Scarth, P.; McVicar, T.; Malthus, T. J.; Stewart, J.; Rickards, J.; Trevithick, R.; Renzullo, L. J.

    2013-12-01

    Vegetation fractional cover is a key indicator for land management monitoring, both in pastoral and agricultural settings. Maintaining adequate vegetation cover protects the soil from the effects of water and wind erosion and also ensures that carbon is returned to soil through decomposition. Monitoring vegetation fractional cover across large areas and continuously in time needs good remote sensing techniques underpinned by high quality ground data to calibrate and validate algorithms. In this study we used Landsat and MODIS reflectance data together with field measurements from 1476 observations across Australia to produce estimates of vegetation fractional cover using a linear unmixing technique. Specifically, we aimed at separating fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (B). We used Landsat reflectance averaged over a 3x3 pixel window representing the area actually measured on the ground and also a 'degraded' Landsat reflectance 40x40 pixel window to simulate the effect of a coarser sensor. Using these two Landsat reflectances we quantified the heterogeneity of each site. We used data from two MODIS-derived reflectance products: the Nadir BRDF-Adjusted surface Reflectance product (MCD43A4) and the MODIS 8-day surface reflectance (MOD09A1). We derived endmembers from the data and estimated fractional cover using a linear unmixing technique. Log transforms and band interaction terms were added to account for non-linearities in the spectral mixing. For each reflectance source we investigated if the residuals were correlated with site heterogeneity, soil colour, soil moisture and land cover type. As expected, the best model was obtained when Landsat data for a small region around each site was used. We obtained root mean square error (RMSE) values of 0.134, 0.175 and 0.153 for PV, NPV and B respectively. When we degraded the Landsat data to an area of ~1 km2 around each site the model performance decreased to

  19. Soil Physical and Environmental Conditions Controlling Patterned-Ground Variability at a Continuous Permafrost Site, Svalbard

    DEFF Research Database (Denmark)

    Watanabe, Tatsuya; Matsuoka, Norikazu; Christiansen, Hanne Hvidtfeldt

    2017-01-01

    This study examines soil physical and environmental conditions controlling patterned-ground variability on an alluvial fan in a continuous permafrost landscape, at Adventdalen, Svalbard. On-site monitoring of ground temperature, soil moisture and snow depth, laboratory analyses of soil physical...

  20. Effect of leguminous cover crops on soil biological activity in pots of Citrus unshiu Marcovitch

    Directory of Open Access Journals (Sweden)

    Cristina Abbate

    2011-02-01

    Full Text Available Little is known about the effects of cover crops on soil properties in citrus orchards. To fill this gap, this work was aimed to determine the effects of leguminous cover crops on the chemical and biological properties of the soil and on the structure of the microbial community in pots of Citrus unshiu (Marcovitch. After amendment with cover crops, an increase in total organic C (TOC, total extractable C (TEC, and total N (TN contents were observed irrespective of the type of soil. Substrate induced respiration (SIR, and potentially mineralisable nitrogen (PMN, tested three times in one year, were higher in soils with leguminous cover crops while no significant differences were observed in protease and deaminase activity. The effect on the chemical and biochemical properties of the soil was more evident in plots containing Trifolium subterraneum. No changes were observed in the microbial communities studied (_-proteobacteria, _-proteobacteria, nitrogen-fixing, and ammonia oxidizers irrespective of the kind of cover crop or type of soil, neither were variations noted during the trial.

  1. Cover crops to improve soil health and pollinator habitat in nut orchards: Part II

    Science.gov (United States)

    Jerry. Van Sambeek

    2017-01-01

    Integrating cover crops into a nut orchard can have some unique benefits and problems not found when used cover crops during the fallow period between cash crops. Studies show ground covers can reduce hardwood tree growth anywhere from a few percent to more than 70 percent in the case of tall fescue. This means if it takes 3 years to put on one inch of diameter growth...

  2. Impact of vetch cover crop on runoff, soil loss, soil chemical properties and yield of chickpea in North Gondar, Ethiopia

    Science.gov (United States)

    Demelash, Nigus; Klik, Andreas; Holzmann, Hubert; Ziadat, Feras; Strohmeier, Stefan; Bayu, Wondimu; Zucca, Claudio; Abera, Atikilt

    2016-04-01

    Cover crops improve the sustainability and quality of both natural system and agro ecosystem. In Gumara-Maksegnit watershed which is located in Lake Tana basin, farmers usually use fallow during the rainy season for the preceding chickpea production system. The fallowing period can lead to soil erosion and nutrient losses. A field experiment was conducted during growing seasons 2014 and 2015 to evaluate the effect of cover crops on runoff, soil loss, soil chemical properties and yield of chickpea in North Gondar, Ethiopia. The plot experiment contained four treatments arranged in Randomized Complete Block Design with three replications: 1) Control plot (Farmers' practice: fallowing- without cover crop), 2) Chickpea planted with Di-ammonium phosphate (DAP) fertilizer with 46 k ha-1 P2O5 and 23 k ha-1 nitrogen after harvesting vetch cover crop, 3) Chick pea planted with vetch cover crop incorporated with the soil as green manure without fertilizer, 4) Chick pea planted with vetch cover crop and incorporated with the soil as green manure and with 23 k ha-1 P2O5 and 12.5 k ha-1 nitrogen. Each plot with an area of 36 m² was equipped with a runoff monitoring system. Vetch (Vicia sativa L.) was planted as cover crop at the onset of the rain in June and used as green manure. The results of the experiment showed statistically significant (P 0.05) on average plant height, average number of branches and hundred seed weight. Similarly, the results indicated that cover crop has a clear impact on runoff volume and sediment loss. Plots with vetch cover crop reduce the average runoff by 65% and the average soil loss decreased from 15.7 in the bare land plot to 8.6 t ha-1 with plots covered by vetch. In general, this result reveales that the cover crops, especially vetch, can be used to improve chickpea grain yield in addition to reduce soil erosion in the watershed.

  3. Effect of land use land cover change on soil erosion potential in an agricultural watershed.

    Science.gov (United States)

    Sharma, Arabinda; Tiwari, Kamlesh N; Bhadoria, P B S

    2011-02-01

    Universal soil loss equation (USLE) was used in conjunction with a geographic information system to determine the influence of land use and land cover change (LUCC) on soil erosion potential of a reservoir catchment during the period 1989 to 2004. Results showed that the mean soil erosion potential of the watershed was increased slightly from 12.11 t ha(-1) year(-1) in the year 1989 to 13.21 t ha(-1) year(-1) in the year 2004. Spatial analysis revealed that the disappearance of forest patches from relatively flat areas, increased in wasteland in steep slope, and intensification of cultivation practice in relatively more erosion-prone soil were the main factors contributing toward the increased soil erosion potential of the watershed during the study period. Results indicated that transition of other land use land cover (LUC) categories to cropland was the most detrimental to watershed in terms of soil loss while forest acted as the most effective barrier to soil loss. A p value of 0.5503 obtained for two-tailed paired t test between the mean erosion potential of microwatersheds in 1989 and 2004 also indicated towards a moderate change in soil erosion potential of the watershed over the studied period. This study revealed that the spatial location of LUC parcels with respect to terrain and associated soil properties should be an important consideration in soil erosion assessment process.

  4. Evidence of wintertime CO2 emission from snow-covered grounds in high latitudes

    Institute of Scientific and Technical Information of China (English)

    方精云; 唐艳鸿KOIZUMI; Hiroshi(Division; of; Plant; Ecology; National; Institute; of; Agro-Environmental; Sciences; Tsukuba; 305; Japan)BEKKU; Yukiko(National; Polar; Institute; Tokyo; 192; Japan)

    1999-01-01

    In order to measure CO2 flux in wintertime arctic ecosystems, CO2 gas was sampled from various snow-covered grounds by using a closed chamber method during the First China Arctic Scientific Expedition from March to May in 1995. The CO2 gas samples were measured by using an infra-red analyzer (IRGA). The results showed that (ⅰ) CO2 emission was detected from all kinds of the snow-covered grounds, which provides direct evidence that the arctic tundra is functioning as a source of atmospheric CO2; (ⅱ) CO2 release was also detected from the permanent ice profile and icecap, and (ⅲ) CO2 evolution from terrestrial ecosystems in higher latitudes increased with an increase of surface temperature in accordance with the exponential function. This indicates a close coincidence with that under normal temperature conditions, and provides a useful method for predicting change in CO2 flux in the arctic ecosystems with the global climate change.

  5. Structure of bacterial communities in soil following cover crop and organic fertilizer incorporation.

    Science.gov (United States)

    Fernandez, Adria L; Sheaffer, Craig C; Wyse, Donald L; Staley, Christopher; Gould, Trevor J; Sadowsky, Michael J

    2016-11-01

    Incorporation of organic material into soils is an important element of organic farming practices that can affect the composition of the soil bacterial communities that carry out nutrient cycling and other functions crucial to crop health and growth. We conducted a field experiment to determine the effects of cover crops and fertilizers on bacterial community structure in agricultural soils under long-term organic management. Illumina sequencing of 16S rDNA revealed diverse communities comprising 45 bacterial phyla in corn rhizosphere and bulk field soil. Community structure was most affected by location and by the rhizosphere effect, followed by sampling time and amendment treatment. These effects were associated with soil physicochemical properties, including pH, moisture, organic matter, and nutrient levels. Treatment differences were apparent in bulk and rhizosphere soils at the time of peak corn growth in the season following cover crop and fertilizer application. Cover crop and fertilizer treatments tended to lower alpha diversity in early season samples. However, winter rye, oilseed radish, and buckwheat cover crop treatments increased alpha diversity in some later season samples compared to a no-amendment control. Fertilizer treatments and some cover crops decreased relative abundance of members of the ammonia-oxidizing family Nitrosomonadaceae. Pelleted poultry manure and Sustane® (a commercial fertilizer) decreased the relative abundance of Rhizobiales. Our data point to a need for future research exploring how (1) cover crops influence bacterial community structure and functions, (2) these effects differ with biomass composition and quantity, and (3) existing soil conditions and microbial community composition influence how soil microbial populations respond to agricultural management practices.

  6. Capability of Spaceborne Hyperspectral EnMAP Mission for Mapping Fractional Cover for Soil Erosion Modeling

    Directory of Open Access Journals (Sweden)

    Sarah Malec

    2015-09-01

    Full Text Available Soil erosion can be linked to relative fractional cover of photosynthetic-active vegetation (PV, non-photosynthetic-active vegetation (NPV and bare soil (BS, which can be integrated into erosion models as the cover-management C-factor. This study investigates the capability of EnMAP imagery to map fractional cover in a region near San Jose, Costa Rica, characterized by spatially extensive coffee plantations and grazing in a mountainous terrain. Simulated EnMAP imagery is based on airborne hyperspectral HyMap data. Fractional cover estimates are derived in an automated fashion by extracting image endmembers to be used with a Multiple End-member Spectral Mixture Analysis approach. The C-factor is calculated based on the fractional cover estimates determined independently for EnMAP and HyMap. Results demonstrate that with EnMAP imagery it is possible to extract quality endmember classes with important spectral features related to PV, NPV and soil, and be able to estimate relative cover fractions. This spectral information is critical to separate BS and NPV which greatly can impact the C-factor derivation. From a regional perspective, we can use EnMAP to provide good fractional cover estimates that can be integrated into soil erosion modeling.

  7. Structure of Living Soil Cover of the White Sea

    Directory of Open Access Journals (Sweden)

    Moseev Dmitriy Sergeevich

    2016-12-01

    Full Text Available The living soil of the Dry Sea gulf's coast in the South-East part of the White Sea's Dvina Bay is practically a blind spot. The bay is a unique water body in respect of plant communities. The majority of halophytes typical for the White Sea coast grows here. There are differences between plant communities of the East and West shores of the Dry Sea gulf. The East coast has developed communities with domination of Phragmites australis, the West coast is occupied by communities of psammophytonis levees with a predominance of Leymus arenarius. For the first time ever, the article provides a classification of halophytic vegetation of the gulf's marshes, which highlighted the prodromus containing ten associations, consisting of seven formations of the type grass vegetation, many of which are rare. The research results can be used to develop environmental protection measures during the construction of a deep sea port in the Dry Sea gulf.

  8. SOIL CHEMICAL ATTRIBUTES AND LEAF NUTRIENTS OF ‘PACOVAN’ BANANA UNDER TWO COVER CROPS

    Directory of Open Access Journals (Sweden)

    JOSÉ EGÍDIO FLORI

    2016-01-01

    Full Text Available Banana is one of the most consumed fruits in the world, which is grown in most tropical countries. The objective of this work was to evaluate the main attributes of soil fertility in a banana crop under two cover crops and two root development locations. The work was conducted in Curaçá, BA, Brazil, between October 2011 and May 2013, using a randomized block design in split plot with five repetitions. Two cover crops were assessed in the plots, the cover 1 consisting of Pueraria phaseoloides, and the cover 2 consisting of a crop mix with Sorghum bicolor, Ricinus communis L., Canavalia ensiformis, Mucuna aterrima and Zea mays, and two soil sampling locations in the subplots, between plants in the banana rows (location 1 and between the banana rows (location 2. There were significant and independent effects for the cover crop and sampling location factors for the variables organic matter, Ca and P, and significant effects for the interaction between cover crops and sampling locations for the variables potassium, magnesium and total exchangeable bases. The cover crop mix and the between-row location presented the highest organic matter content. Potassium was the nutrient with the highest negative variation from the initial content and its leaf content was below the reference value, however not reducing the crop yield. The banana crop associated with crop cover using the crop mix provided greater availability of nutrients in the soil compared to the coverage with tropical kudzu.

  9. Vegetative cover and PAHs accumulation in soils of urban green space.

    Science.gov (United States)

    Peng, Chi; Ouyang, Zhiyun; Wang, Meie; Chen, Weiping; Jiao, Wentao

    2012-02-01

    We investigated how urban land uses influence soil accumulation of polycyclic aromatic hydrocarbons (PAHs) in the urban green spaces composed of different vegetative cover. How did soil properties, urbanization history, and population density affect the outcomes were also considered. Soils examined were obtained at 97 green spaces inside the Beijing metropolis. PAH contents of the soils were influenced most significantly by their proximity to point source of industries such as the coal combustion installations. Beyond the influence circle of industrial emissions, land use classifications had no significant effect on the extent of PAH accumulation in soils. Instead, the nature of vegetative covers affected PAH contents of the soils. Tree-shrub-herb and woodland settings trapped more airborne PAH and soils under these vegetative patterns accumulated more PAHs than those of the grassland. Urbanization history, population density and soil properties had no apparent impact on PAHs accumulations in soils of urban green space. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  10. Hydrodynamic behaviour and pedological differentiation of a hydromorphic loamy soil cover from the Parisian Basin.

    Science.gov (United States)

    Nicole, J.; Vachier, P.; Coquet, Y.; Michelin, J.

    2003-04-01

    The geological stratification of the plateau of Alluets-le-Roi (Yvelines) is typical of the Parisian Basin. A 2-m layer of loam covers a buhrstone clay bed called "Argiles à Meulières" that crowns the sands and sandstones of the "Sables de Fontainebleau" formation. The clay bed constitutes a discontinuous aquitard on whitch a temporary perched water table may be formed. The purpose of the study was to characterise the hydrodynamic behaviour of this vadose zone and its linkage to the pedogenetic evolution of the original carbonated loam. The dynamics of the temporary perched water table was monitored by 13 piezometers spread on a 80-m long, 10-m large, 2-m deep area of a cropped field. Piezometric domes appeared straight under local topographic depressions (about 40 cm) identified by a detailed DEM of the area. Field observations showed runoff concentration and preferential infiltration in these depressions. The temporary perched water table flows out laterally to draining windows or channels located within the clay bed, and recharges the underlying sand aquifer. The lateral extension between the refill and discharge zones is around 40-m. Around topographic domes, Luvisols (FAO 1976) can be observed in which temporary hydromorphy leaves redox reddish-brown mottles and iron-manganic concretions. Under the topographic depressions, pedogenetic evolution is more intence with a glossic Podzoluvisol (FAO 1976). On a 40-m transect, the lateral differentiation of the soil cover could be related to preferential water infiltration zones. A quasi-continuous 2D-distribution of the ground resistivity was obtained by a geoelectrical exploration (Standard Wenner) along the transect. The apparent resistivity map correlated well with the pedological differentiations observed within the transect. The limit between the eluviated "E" horizon and the illuviated "Bt" horizon which is deeper in glossic Podzoluvisol could be matched with a strong resistivity contrast.

  11. Soil moisture and evapotranspiration of different land cover types in the Loess Plateau, China

    Directory of Open Access Journals (Sweden)

    S. Wang

    2012-08-01

    Full Text Available We studied the impacts of re-vegetation on soil moisture dynamics and evapotranspiration (ET of five land cover types in the Loess Plateau in northern China. Soil moisture and temperature variations under grass (Andropogon, subshrub (Artemisia scoparia, shrub (Spiraea pubescens, plantation forest (Robinia pseudoacacia, and crop (Zea mays vegetation were continuously monitored during the growing season of 2011. There were more than 10 soil moisture pulses during the period of data collection. Surface soil moisture of all of the land cover types showed an increasing trend in the rainy season. Soil moisture under the corn crop was consistently higher than the other surfaces. Grass and subshrubs showed an intermediate moisture level. Grass had slightly higher readings than those of subshrub most of the time. Shrubs and plantation forests were characterized by lower soil moisture readings, with the shrub levels consistently being slightly higher than those of the forests. Despite the greater post-rainfall loss of moisture under subshrub and grass vegetation than forests and shrubs, subshrub and grass sites exhibit a higher soil moisture content due to their greater soil retention capacity in the dry period. The daily ET trends of the forests and shrub sites were similar and were more stable than those of the other types. Soils under subshrubs acquired and retained soil moisture resources more efficiently than the other cover types, with a competitive advantage in the long term, representing an adaptive vegetation type in the study watershed. The interactions between vegetation and soil moisture dynamics contribute to structure and function of the ecosystems studied.

  12. Using high-resolution radar images to determine vegetation cover for soil erosion assessments.

    Science.gov (United States)

    Bargiel, D; Herrmann, S; Jadczyszyn, J

    2013-07-30

    Healthy soils are crucial for human well-being. Because soils are threatened worldwide, politicians recognize the need for soil protection. For example, the European Commission has launched the Thematic Strategy for Soil Protection, which requests the European member states to identify high risk areas for soil degradation. Most states use the Universal Soil Loss Equation (USLE) to assess soil erosion risk at the national scale. The USLE includes different factors, one of them is the vegetation cover and management factor (C factor). Modern satellite-based radar sensors now provide highly accurate vegetation cover data, enabling opportunities to improve the accuracy of the C factor. The presented study proves the suitability for C factor determination based on a multi-temporal classification of high-resolution radar images. Further USLE factors were derived from existing data sources (meteorological data, soil maps, digital elevation model) to conduct an USLE-based soil erosion assessment. The resulting map illustrates a qualitative assessment for soil erosion risk within a plot of about 7*12 km in an agricultural region in Poland that is very susceptible to soil erosion processes. A high erosion risk of more than 10 tonnes per ha and year was assessed to occur on 13.6% (646 ha) of the agricultural areas within the investigated plot. Further 7.8% (372 ha) of agricultural land is threaten by a medium risk of 5-10 tonnes per ha and year. Such a spatial information about areas of high or medium soil erosion risk are crucial for the development of strategies for the protection of soils.

  13. Impact assessment of intermediate soil cover on landfill stabilization by characterizing landfilled municipal solid waste.

    Science.gov (United States)

    Qi, Guangxia; Yue, Dongbei; Liu, Jianguo; Li, Rui; Shi, Xiaochong; He, Liang; Guo, Jingting; Miao, Haomei; Nie, Yongfeng

    2013-10-15

    Waste samples at different depths of a covered municipal solid waste (MSW) landfill in Beijing, China, were excavated and characterized to investigate the impact of intermediate soil cover on waste stabilization. A comparatively high amount of unstable organic matter with 83.3 g kg(-1) dry weight (dw) total organic carbon was detected in the 6-year-old MSW, where toxic inorganic elements containing As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn of 10.1, 0.98, 85.49, 259.7, 530.4, 30.5, 84.0, and 981.7 mg kg(-1) dw, respectively, largely accumulated because of the barrier effect of intermediate soil cover. This accumulation resulted in decreased microbial activities. The intermediate soil cover also caused significant reduction in moisture in MSW under the soil layer, which was as low as 25.9%, and led to inefficient biodegradation of 8- and 10-year-old MSW. Therefore, intermediate soil cover with low permeability seems to act as a barrier that divides a landfill into two landfill cells with different degradation processes by restraining water flow and hazardous matter.

  14. Soil macrofauna communities under plant cover in a no-till system in Thailand

    Directory of Open Access Journals (Sweden)

    Phakphoom Tantachasatid

    2017-02-01

    Full Text Available The impact of no-till cropping systems with plant cover on soil macrofauna communities was assessed according to their abundance and biomass. The study was carried out in northeastern Thailand under a conventional cropping system (plow-based tillage, no-till cropping systems with plant cover (Brachiaria ruziziensis, Stylosanthes guianensis, S. guianensis associated with B. ruziziensis, rice straw and under a natural dipterocarp forest. Soil macrofauna populations were sampled in 2007 (June and October during the rainy season and at a beginning of the dry season, respectively. The results revealed that in the short term, the biological compartment responded quickly to the presence of plant cover, as shown by a significant increase in soil macrofauna abundance and total biomass. The highest mean total abundance (MTA of 4224 individuals/m2 at the end of planting period (October 2007 was observed under S. guianensis cover and also the highest mean total soil macrofauna biomass (MTB of 14.63 g/m2 was observed in the forest system in the same period. However, in the system of cultivation, the highest MTB of 11.33 g/m2 was observed under S. guianensis cover. Moreover, the change rate of soil macrofauna MTA was the highest under S. guianensis cover (+751.61% and the change rate of soil macrofauna MTB revealed that this change rate was highest in forest (+430.07%. However, in the other systems of cultivation, the highest change rate of MTB was under S. guianensis cover (+12.96%.

  15. Effects of over-winter green cover on soil solution nitrate concentrations beneath tillage land.

    Science.gov (United States)

    Premrov, Alina; Coxon, Catherine E; Hackett, Richard; Kirwan, Laura; Richards, Karl G

    2014-02-01

    There is a growing need to reduce nitrogen losses from agricultural systems to increase food production while reducing negative environmental impacts. The efficacy of vegetation cover for reducing nitrate leaching in tillage systems during fallow periods has been widely investigated. Nitrate leaching reductions by natural regeneration (i.e. growth of weeds and crop volunteers) have been investigated to a lesser extent than reductions by planted cover crops. This study compares the efficacy of natural regeneration and a sown cover crop (mustard) relative to no vegetative cover under both a reduced tillage system and conventional plough-based system as potential mitigation measures for reducing over-winter soil solution nitrate concentrations. The study was conducted over three winter fallow seasons on well drained soil, highly susceptible to leaching, under temperate maritime climatic conditions. Mustard cover crop under both reduced tillage and conventional ploughing was observed to be an effective measure for significantly reducing nitrate concentrations. Natural regeneration under reduced tillage was found to significantly reduce the soil solution nitrate concentrations. This was not the case for the natural regeneration under conventional ploughing. The improved efficacy of natural regeneration under reduced tillage could be a consequence of potential stimulation of seedling germination by the autumn reduced tillage practices and improved over-winter plant growth. There was no significant effect of tillage practices on nitrate concentrations. This study shows that over winter covers of mustard and natural regeneration, under reduced tillage, are effective measures for reducing nitrate concentrations in free draining temperate soils.

  16. Environmental factors regulating winter CO2 flux in snow-covered boreal forest soil, interior Alaska

    Science.gov (United States)

    Kim, Y.; Kodama, Y.

    2012-01-01

    Winter CO2 flux is an important element to assess when estimating the annual carbon budget on regional and global scales. However, winter observation frequency is limited due to the extreme cold weather in sub-Arctic and Arctic ecosystems. In this study, the continuous monitoring of winter CO2 flux in black spruce forest soil of interior Alaska was performed using NDIR CO2 sensors at 10, 20, and 30 cm above the soil surface during the snow-covered period (DOY 357 to 466) of 2006/2007. The atmospheric pressure was divided into four phases: >1000 hPa (HP: high pressure); 985emission represents 20 % of the annual CO2 emissions in this boreal black spruce forest soil. Atmospheric temperature, pressure, and soil temperature correlate at levels of 56, 25, and 31 % to winter CO2 flux, respectively, during the snow-covered period of 2006/2007, when snow depth experienced one of its lowest totals of the past 80 years. Atmospheric temperature and soil temperature at 5 cm depth, modulated by atmospheric pressure, were found to be significant factors in determining winter CO2 emission and fluctuation in snowpack. Regional/global process-based carbon cycle models should be reassessed to account for the effect of winter CO2 emissions, regulated by temperature and soil latent-heat flux, in the snow-covered soils of Arctic and sub-Arctic terrestrial ecosystems of the Northern Hemisphere.

  17. The 'Soil Cover App' - a new tool for fast determination of dead and living biomass on soil

    Science.gov (United States)

    Bauer, Thomas; Strauss, Peter; Riegler-Nurscher, Peter; Prankl, Johann; Prankl, Heinrich

    2017-04-01

    Worldwide many agricultural practices aim on soil protection strategies using living or dead biomass as soil cover. Especially for the case when management practices are focusing on soil erosion mitigation the effectiveness of these practices is directly driven by the amount of soil coverleft on the soil surface. Hence there is a need for quick and reliable methods of soil cover estimation not only for living biomass but particularly for dead biomass (mulch). Available methods for the soil cover measurement are either subjective, depending on an educated guess or time consuming, e.g., if the image is analysed manually at grid points. We therefore developed a mobile application using an algorithm based on entangled forest classification. The final output of the algorithm gives classified labels for each pixel of the input image as well as the percentage of each class which are living biomass, dead biomass, stones and soil. Our training dataset consisted of more than 250 different images and their annotated class information. Images have been taken in a set of different environmental conditions such as light, soil coverages from between 0% to 100%, different materials such as living plants, residues, straw material and stones. We compared the results provided by our mobile application with a data set of 180 images that had been manually annotated A comparison between both methods revealed a regression slope of 0.964 with a coefficient of determination R2 = 0.92, corresponding to an average error of about 4%. While average error of living plant classification was about 3%, dead residue classification resulted in an 8% error. Thus the new mobile application tool offers a fast and easy way to obtain information on the protective potential of a particular agricultural management site.

  18. Effects of bryophyte and lichen cover on permafrost soil temperature at large scale

    Science.gov (United States)

    Porada, Philipp; Ekici, Altug; Beer, Christian

    2017-04-01

    Bryophytes and lichens covering the soil surface at high latitudes act as an insulating layer, which has a net cooling effect on the soil and thereby protects permafrost. Climate change, however, may lead to changes in the average surface coverage of bryophytes and lichens. This can result in thawing of permafrost and an associated release of soil carbon to the atmosphere, which may cause a positive feedback on atmospheric CO2 concentration. Hence, it is crucial to predict the future large-scale response of bryophyte and lichen cover to climatic change at high latitudes. Current global land surface models, however, contain mostly empirical approaches to represent the surface cover of bryophytes and lichens, which makes it difficult to quantify its future extent and dynamics. Therefore, we integrate a process-based model of bryophyte and lichen growth into the global land surface model JSBACH (Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg). Thereby, we explicitly simulate dynamic thermal properties of the bryophyte and lichen cover and their relation to environmental factors. To quantify the insulating effect of the cover on the soil, we compare simulations with and without simulated bryophyte and lichen cover. We estimate that the bryophyte and lichen cover exerts an average cooling effect of 2.7 K on temperature in the topsoil for the region north of 50o N under current climatic conditions. Locally, a cooling of up to 5.7 K may be reached. Furthermore, we show that using a simple, empirical representation of the bryophyte and lichen cover instead of a dynamic one results only in an average cooling of around 0.5 K. We conclude that bryophytes and lichens have a significant impact on soil temperature in high-latitude ecosystems and that dynamic thermal properties are necessary for a realistic representation of the cooling effect.

  19. MICROORGANISMS OF PEDOSPHERE AND PECULIARITIES OF THE SOIL COVER OF AGRICULTURAL LANDSCAPES

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    Belyuchenko I. S.

    2016-09-01

    Full Text Available The soil by it physical and chemical properties is a poly-dispersed heterogeneous multicomponent unique environment for development of most microorganisms. The soil is the richest natural substrate according to microbial gene fund. Presence of plants and animals in soil maintains it heterogeneous as environment of soil microorganisms, which are main regulators of natural gas composition of atmosphere of Earth, including its macro- and micro-components (including the main "greenhouse" gases - methane, carbon dioxide, nitrous oxide. Recently, the elucidation of these singularities of vital activity of soil organisms has resulted in general conclusion - due to them soil cover serves as a global bio-geo-chemical membrane, through which the exchange of matter and energy between pedosphere, lithosphere, atmosphere, hydrosphere and main living inhabitants of Earth does its work

  20. Variability in soil CO2 efflux across distinct urban land cover types

    Science.gov (United States)

    Weissert, Lena F.; Salmond, Jennifer A.; Schwendenmann, Luitgard

    2015-04-01

    As a main source of greenhouse gases urban areas play an important role in the global carbon cycle. To assess the potential role of urban vegetation in mitigating carbon emissions we need information on the magnitude of biogenic CO2 emissions and its driving factors. We examined how urban land use types (urban forest, parklands, sportsfields) vary in their soil CO2 efflux. We measured soil CO2 efflux and its isotopic signature, soil temperature and soil moisture over a complete growing season in Auckland, New Zealand. Soil physical and chemical properties and vegetation characteristics were also measured. Mean soil CO2 efflux ranged from 4.15 to 12 μmol m-2 s-1. We did not find significant differences in soil CO2 efflux among land cover types due to high spatial variability in soil CO2 efflux among plots. Soil (soil carbon and nitrogen density, texture, soil carbon:nitrogen ratio) and vegetation characteristics (basal area, litter carbon density, grass biomass) were not significantly correlated with soil CO2 efflux. We found a distinct seasonal pattern with significantly higher soil CO2 efflux in autumn (Apr/May) and spring (Oct). In urban forests and sportsfields over 80% of the temporal variation was explained by soil temperature and soil water content. The δ13C signature of CO2 respired from parklands and sportsfields (-20 permil - -25 permil) were more positive compared to forest plots (-29 permil) indicating that parkland and sportsfields had a considerable proportion of C4 grasses. Despite the large intra-urban variability, our results compare to values reported from other, often climatically different cities, supporting the hypothesis of homogenization across urban areas as a result of human management practices.

  1. Effects of winter cover crop, soil amendment, and variety on organic rice production and greenhouse gas emissions

    Science.gov (United States)

    Nitrogen supply and disease are two main challenges in organic rice production. Cover crop and soil amendment can be options to increase soil N while keeps rice health. The objective of this study was to test the effects of cover crop and soil amendment on the production of organic rice. Three popul...

  2. Adsorption and transport of methane in landfill cover soil amended with waste-wood biochars.

    Science.gov (United States)

    Sadasivam, Bala Yamini; Reddy, Krishna R

    2015-08-01

    The natural presence of methane oxidizing bacteria (MOB) in landfill soils can stimulate the bio-chemical oxidation of CH4 to CO2 and H2O under suitable environmental conditions. This mechanism can be enhanced by amending the landfill cover soil with organic materials such as biochars that are recalcitrant to biological degradation and are capable of adsorbing CH4 while facilitating the growth and activity of MOB within their porous structure. Several series of batch and small-scale column tests were conducted to quantify the CH4 sorption and transport properties of landfill cover soil amended with four types of waste hardwood biochars under different levels of amendment percentages (2, 5 and 10% by weight), exposed CH4 concentrations (0-1 kPa), moisture content (dry, 25% and 75% water holding capacity), and temperature (25, 35 and 45 °C). The linear forms of the pseudo second-order kinetic model and the Langmuir isotherm model were used to determine the kinetics and the maximum CH4 adsorption capacity of cover materials. The maximum CH4 sorption capacity of dry biochar-amended soils ranged from 1.03 × 10(-2) to 7.97 × 10(-2) mol kg(-1) and exhibited a ten-fold increase compared to that of soil with 1.9 × 10(-3) mol kg(-1). The isosteric heat of adsorption for soil was negative and ranged from -30 to -118 kJ/mol, while that of the biochar-amended soils was positive and ranged from 24 to 440 kJ/mol. The CH4 dispersion coefficients for biochar-amended soils obtained through predictive transport modeling indicated that amending the soil with biochar enhanced the methane transport rates by two orders of magnitude, thereby increasing their potential for enhanced exchange of gases within the cover system. Overall, the use of hardwood biochars as a cover soil amendment to reduce methane emissions from landfills appears to be a promising alternative to conventional soil covers.

  3. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    Science.gov (United States)

    Ladoni, Moslem; Kravchenko, Alexandra N; Robertson, G Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row

  4. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    Directory of Open Access Journals (Sweden)

    Moslem Ladoni

    Full Text Available Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover and non-leguminous (winter rye cover crops on potentially mineralizable N (PMN and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management

  5. Colored polyethylene soil covers and grafting effects on cucumber flowering and yield

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    Fonseca Inês Cristina de Batista

    2003-01-01

    Full Text Available Cucumber (Cucumis sativus L. is one of the most cultivated vegetable crops in plastic greenhouses in Brazil because of the short cycle and its high economic value in off-season harvests. To better understand this management technique the effect of different colored polyethylene soil covers was evaluated in relation to flowering and yield of the hybrid cucumber 'Yoshinari' grafted or not on the hybrid squash 'Ikky'. The polyethylene cover colors were black, white on black and green plus a control without cover. Covered but not grafted crops had a more uniform flowering distribution. The number of flowers was greater for the white/black grafted treatment. All the polyethylene covers favored flowering for the non grafted plants. Grafting reduced flowering for the black or green polyethylene covers treatments. The fruit set increased with the use of polyethylene cover but was not influenced by grafting. The uniform distribution of flowering remained during fruiting only for grafted plants and soil covered with black or green polyethylene. Both polyethylene cover and grafting favored early harvesting. The 'Yoshinari'/'Ikky' graft caused taller plants but fruit were thicker and smaller and did not meet the commercial standard. The best quality fruit and highest yields were obtained in the black and white/black treatments, without grafting.

  6. Morphostructural characterization of soil conventionally tilled with mechanized and animal traction with and without cover crop

    Directory of Open Access Journals (Sweden)

    Ricardo Ralisch

    2010-12-01

    Full Text Available The structural stability and restructuring ability of a soil are related to the methods of crop management and soil preparation. A recommended strategy to reduce the effects of soil preparation is to use crop rotation and cover crops that help conserve and restore the soil structure. The aim of this study was to evaluate and quantify the homogeneous morphological units in soil under conventional mechanized tillage and animal traction, as well as to assess the effect on the soil structure of intercropping with jack bean (Canavalia ensiformis L.. Profiles were analyzed in April of 2006, in five counties in the Southern-Central region of Paraná State (Brazil, on family farms producing maize (Zea mays L., sometimes intercropped with jack bean. The current structures in the crop profile were analyzed using Geographic Information Systems (GIS and subsequently principal component analysis (PCA to generate statistics. Morphostructural soil analysis showed a predominance of compact units in areas of high-intensity cultivation under mechanized traction. The cover crop did not improve the structure of the soil with low porosity and compact units that hamper the root system growth. In areas exposed to animal traction, a predominance of cracked units was observed, where roots grew around the clods and along the gaps between them.

  7. Impacts of changes in vegetation cover on soil water heat coupling in an alpine meadow of the Qinghai-Tibet Plateau, China

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    W. Genxu

    2009-03-01

    Full Text Available Alpine meadow is one of the most widespread grassland types in the permafrost regions of the Qinghai-Tibet Plateau, and the transmission of coupled soil water heat is one of the most crucial processes influencing cyclic variations in the hydrology of frozen soil regions, especially under different vegetation covers. The present study assesses the impact of changes in vegetation cover on the coupling of soil water and heat in a permafrost region. Soil moisture (θv, soil temperature (Ts, soil heat content, and differences in θvTs coupling were monitored on a seasonal and daily basis under three different vegetation covers (30, 65, and 93% on both thawed and frozen soils. Regression analysis of θv vs. Ts plots under different levels of vegetation cover indicates that soil freeze-thaw processes were significantly affected by the changes in vegetation cover. The decrease in vegetation cover of an alpine meadow reduced the difference between air temperature and ground temperature (ΔTa−s, and it also resulted in a decrease in Ts at which soil froze, and an increase in the temperature at which it thawed. This was reflected in a greater response of soil temperature to changes in air temperature (Ta. For ΔTa−s outside the range of −0.1 to 1.0°C, root zone soil-water temperatures showed a significant increase with increasing ΔTa−s; however, the magnitude of this relationship was dampened with increasing vegetation cover. At the time of maximum water content in the thawing season, the soil temperature decreased with increasing vegetation. Changes in vegetation cover also led to variations in θvTs coupling. With the increase in vegetation cover, the surface heat flux decreased. Soil heat storage at 20 cm in

  8. Experimental evaluation of ALS point cloud ground extraction over different land cover in the Malopolska Province

    Science.gov (United States)

    Korzeniowska, Karolina; Mandlburger, Gottfried; Klimczyk, Agata

    2013-04-01

    The paper presents an evaluation of different terrain point extraction algorithms for Airborne Laser Scanning (ALS) point clouds. The research area covers eight test sites in the Małopolska Province (Poland) with varying point density between 3-15points/m² and surface as well as land cover characteristics. In this paper the existing implementations of algorithms were considered. Approaches based on mathematical morphology, progressive densification, robust surface interpolation and segmentation were compared. From the group of morphological filters, the Progressive Morphological Filter (PMF) proposed by Zhang K. et al. (2003) in LIS software was evaluated. From the progressive densification filter methods developed by Axelsson P. (2000) the Martin Isenburg's implementation in LAStools software (LAStools, 2012) was chosen. The third group of methods are surface-based filters. In this study, we used the hierarchic robust interpolation approach by Kraus K., Pfeifer N. (1998) as implemented in SCOP++ (Trimble, 2012). The fourth group of methods works on segmentation. From this filtering concept the segmentation algorithm available in LIS was tested (Wichmann V., 2012). The main aim in executing the automatic classification for ground extraction was operating in default mode or with default parameters which were selected by the developers of the algorithms. It was assumed that the default settings were equivalent to the parameters on which the best results can be achieved. In case it was not possible to apply an algorithm in default mode, a combination of the available and most crucial parameters for ground extraction were selected. As a result of these analyses, several output LAS files with different ground classification were achieved. The results were described on the basis of qualitative and quantitative analyses, both being in a formal description. The classification differences were verified on point cloud data. Qualitative verification of ground extraction was

  9. Combining climatic and soil properties better predicts covers of Brazilian biomes

    Science.gov (United States)

    Arruda, Daniel M.; Fernandes-Filho, Elpídio I.; Solar, Ricardo R. C.; Schaefer, Carlos E. G. R.

    2017-04-01

    Several techniques have been used to model the area covered by biomes or species. However, most models allow little freedom of choice of response variables and are conditioned to the use of climate predictors. This major restriction of the models has generated distributions of low accuracy or inconsistent with the actual cover. Our objective was to characterize the environmental space of the most representative biomes of Brazil and predict their cover, using climate and soil-related predictors. As sample units, we used 500 cells of 100 km2 for ten biomes, derived from the official vegetation map of Brazil (IBGE 2004). With a total of 38 (climatic and soil-related) predictors, an a priori model was run with the random forest classifier. Each biome was calibrated with 75% of the samples. The final model was based on four climate and six soil-related predictors, the most important variables for the a priori model, without collinearity. The model reached a kappa value of 0.82, generating a highly consistent prediction with the actual cover of the country. We showed here that the richness of biomes should not be underestimated, and that in spite of the complex relationship, highly accurate modeling based on climatic and soil-related predictors is possible. These predictors are complementary, for covering different parts of the multidimensional niche. Thus, a single biome can cover a wide range of climatic space, versus a narrow range of soil types, so that its prediction is best adjusted by soil-related variables, or vice versa.

  10. AN ASSESSMENT OF CITIZEN CONTRIBUTED GROUND REFERENCE DATA FOR LAND COVER MAP ACCURACY ASSESSMENT

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    G. M. Foody

    2015-08-01

    Full Text Available It is now widely accepted that an accuracy assessment should be part of a thematic mapping programme. Authoritative good or best practices for accuracy assessment have been defined but are often impractical to implement. Key reasons for this situation are linked to the ground reference data used in the accuracy assessment. Typically, it is a challenge to acquire a large sample of high quality reference cases in accordance to desired sampling designs specified as conforming to good practice and the data collected are normally to some degree imperfect limiting their value to an accuracy assessment which implicitly assumes the use of a gold standard reference. Citizen sensors have great potential to aid aspects of accuracy assessment. In particular, they may be able to act as a source of ground reference data that may, for example, reduce sample size problems but concerns with data quality remain. The relative strengths and limitations of citizen contributed data for accuracy assessment are reviewed in the context of the authoritative good practices defined for studies of land cover by remote sensing. The article will highlight some of the ways that citizen contributed data have been used in accuracy assessment as well as some of the problems that require further attention, and indicate some of the potential ways forward in the future.

  11. Influence of green top cover for soil protection ins Spanish olives trees. Root tensile strength

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Casanova, C.; Solar, C.; Sobrino, E.; Delgado, M.; Miralles, H. R.; Martin, S. J.

    2009-07-01

    Natural development of certain top living covers is the best way for soil protection under arid climate conditions. a number of certain gramineas was experimental field trial for 5 years looking for soil cover protection and adaptability under the olives tree rows. Olives trees are a fully expanded crop in spain occupying 2.5 million of hectares. Is very interesting crop because one ha of pre-treated olive tree pruned residues will produce 0.3 t of ethanol (Cara, C. et al. 2007). (Author)

  12. Trait-based characterisation of soil exploitation strategies of banana, weeds and cover plant species

    Science.gov (United States)

    Tardy, Florence; Damour, Gaëlle; Dorel, Marc; Moreau, Delphine

    2017-01-01

    Cover plants can be introduced in cropping systems to provide agroecosystem services, including weed control via competition for resources. There is currently no consensus on how to identify the best cover plant species, while trait-based approaches are promising for screening plant species due to their agroecosystem service provision potential. This study was carried out to characterize soil exploitation strategies of cover plant species in banana agroecosystems using a trait-based approach, and in turn identify cover plant species with a high weed control potential via competition for soil resources in banana cropping systems. A field experiment was conducted on 17 cover plant species, two weed species and two banana cultivars grown individually. Four functional traits were measured. Two of them (i.e., the size of the zone explored by roots and the root impact density) were used to characterize root system soil exploration patterns. Two other traits (i.e., specific root length and root diameter) were used to characterize resource acquisition within the soil zone explored by the roots. All studied traits exhibited marked variations among species. The findings suggested a trade-off between the abilities of species to develop a limited number of large diameter roots exploring a large soil zone versus many thin roots exploring a smaller soil zone. Three soil-resource exploitation strategies were identified among species: (i) with large diameter roots that explore a large soil zone; (ii) with small diameter roots and a high specific length that explore a smaller soil zone; and (iii) with a high total root-impact density and an intermediate specific root length that explore the uppermost soil layers. Interestingly, in our panel of species, no correlations with regard to belowground and aboveground strategies were noted: species with an acquisitive belowground strategy could display an acquisitive or a conservative aboveground strategy. The findings of this study

  13. Trait-based characterisation of soil exploitation strategies of banana, weeds and cover plant species.

    Science.gov (United States)

    Tardy, Florence; Damour, Gaëlle; Dorel, Marc; Moreau, Delphine

    2017-01-01

    Cover plants can be introduced in cropping systems to provide agroecosystem services, including weed control via competition for resources. There is currently no consensus on how to identify the best cover plant species, while trait-based approaches are promising for screening plant species due to their agroecosystem service provision potential. This study was carried out to characterize soil exploitation strategies of cover plant species in banana agroecosystems using a trait-based approach, and in turn identify cover plant species with a high weed control potential via competition for soil resources in banana cropping systems. A field experiment was conducted on 17 cover plant species, two weed species and two banana cultivars grown individually. Four functional traits were measured. Two of them (i.e., the size of the zone explored by roots and the root impact density) were used to characterize root system soil exploration patterns. Two other traits (i.e., specific root length and root diameter) were used to characterize resource acquisition within the soil zone explored by the roots. All studied traits exhibited marked variations among species. The findings suggested a trade-off between the abilities of species to develop a limited number of large diameter roots exploring a large soil zone versus many thin roots exploring a smaller soil zone. Three soil-resource exploitation strategies were identified among species: (i) with large diameter roots that explore a large soil zone; (ii) with small diameter roots and a high specific length that explore a smaller soil zone; and (iii) with a high total root-impact density and an intermediate specific root length that explore the uppermost soil layers. Interestingly, in our panel of species, no correlations with regard to belowground and aboveground strategies were noted: species with an acquisitive belowground strategy could display an acquisitive or a conservative aboveground strategy. The findings of this study

  14. Ground penetrating radar detection of subsnow liquid overflow on ice-covered lakes in interior Alaska

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    A. Gusmeroli

    2012-07-01

    Full Text Available Lakes are abundant throughout the pan-Arctic region. For many of these lakes ice cover lasts for up to two thirds of the year. This frozen cover allows human access to these lakes, which are therefore used for many subsistence and recreational activities, including water harvesting, fishing, and skiing. Safe access to these lakes may be compromised, however, when, after significant snowfall, the weight of the snow acts on the ice and causes liquid water to spill through weak spots and overflow at the snow-ice interface. Since visual detection of subsnow liquid overflow (SLO is almost impossible our understanding on SLO processes is still very limited and geophysical methods that allow SLO detection are desirable. In this study we demonstrate that a commercially available, lightweight 1GHz, ground penetrating radar system can detect and map extent and intensity of SLO. Radar returns from wet snow-ice interfaces are at least twice as much in strength than returns from dry snow-ice interface. The presence of SLO also affects the quality of radar returns from the base of the lake ice. During dry conditions we were able to profile ice thickness of up to 1 m, conversely, we did not retrieve any ice-water returns in areas affected by SLO.

  15. Comparison of seasonal soil microbial process in snow-covered temperate ecosystems of northern China.

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    Xinyue Zhang

    Full Text Available More than half of the earth's terrestrial surface currently experiences seasonal snow cover and soil frost. Winter compositional and functional investigations in soil microbial community are frequently conducted in alpine tundra and boreal forest ecosystems. However, little information on winter microbial biogeochemistry is known from seasonally snow-covered temperate ecosystems. As decomposer microbes may differ in their ability/strategy to efficiently use soil organic carbon (SOC within different phases of the year, understanding seasonal microbial process will increase our knowledge of biogeochemical cycling from the aspect of decomposition rates and corresponding nutrient dynamics. In this study, we measured soil microbial biomass, community composition and potential SOC mineralization rates in winter and summer, from six temperate ecosystems in northern China. Our results showed a clear pattern of increased microbial biomass C to nitrogen (N ratio in most winter soils. Concurrently, a shift in soil microbial community composition occurred with higher fungal to bacterial biomass ratio and gram negative (G- to gram positive (G+ bacterial biomass ratio in winter than in summer. Furthermore, potential SOC mineralization rate was higher in winter than in summer. Our study demonstrated a distinct transition of microbial community structure and function from winter to summer in temperate snow-covered ecosystems. Microbial N immobilization in winter may not be the major contributor for plant growth in the following spring.

  16. Organic farming and cover crops as an alternative to mineral fertilizers to improve soil physical properties

    Science.gov (United States)

    Sánchez de Cima, Diego; Luik, Anne; Reintam, Endla

    2015-10-01

    For testing how cover crops and different fertilization managements affect the soil physical properties in a plough based tillage system, a five-year crop rotation experiment (field pea, white potato, common barley undersown with red clover, red clover, and winter wheat) was set. The rotation was managed under four different farming systems: two conventional: with and without mineral fertilizers and two organic, both with winter cover crops (later ploughed and used as green manure) and one where cattle manure was added yearly. The measurements conducted were penetration resistance, soil water content, porosity, water permeability, and organic carbon. Yearly variations were linked to the number of tillage operations, and a cumulative effect of soil organic carbon in the soil as a result of the different fertilization amendments, organic or mineral. All the systems showed similar tendencies along the three years of study and differences were only found between the control and the other systems. Mineral fertilizers enhanced the overall physical soil conditions due to the higher yield in the system. In the organic systems, cover crops and cattle manure did not have a significant effect on soil physical properties in comparison with the conventional ones, which were kept bare during the winter period. The extra organic matter boosted the positive effect of crop rotation, but the higher number of tillage operations in both organic systems counteracted this effect to a greater or lesser extent.

  17. Assessment of soil organic carbon stocks under future climate and land cover changes in Europe.

    Science.gov (United States)

    Yigini, Yusuf; Panagos, Panos

    2016-07-01

    Soil organic carbon plays an important role in the carbon cycling of terrestrial ecosystems, variations in soil organic carbon stocks are very important for the ecosystem. In this study, a geostatistical model was used for predicting current and future soil organic carbon (SOC) stocks in Europe. The first phase of the study predicts current soil organic carbon content by using stepwise multiple linear regression and ordinary kriging and the second phase of the study projects the soil organic carbon to the near future (2050) by using a set of environmental predictors. We demonstrate here an approach to predict present and future soil organic carbon stocks by using climate, land cover, terrain and soil data and their projections. The covariates were selected for their role in the carbon cycle and their availability for the future model. The regression-kriging as a base model is predicting current SOC stocks in Europe by using a set of covariates and dense SOC measurements coming from LUCAS Soil Database. The base model delivers coefficients for each of the covariates to the future model. The overall model produced soil organic carbon maps which reflect the present and the future predictions (2050) based on climate and land cover projections. The data of the present climate conditions (long-term average (1950-2000)) and the future projections for 2050 were obtained from WorldClim data portal. The future climate projections are the recent climate projections mentioned in the Fifth Assessment IPCC report. These projections were extracted from the global climate models (GCMs) for four representative concentration pathways (RCPs). The results suggest an overall increase in SOC stocks by 2050 in Europe (EU26) under all climate and land cover scenarios, but the extent of the increase varies between the climate model and emissions scenarios.

  18. Delineation of ground-water contamination using soil-gas analyses near Jackson, Tennessee

    Science.gov (United States)

    Lee, R.W.

    1991-01-01

    An investigation of the ground-water resources near Jackson, West Tennessee, was conducted during 1988-89. The study included determination of the occurrence of contaminants in the shallow aquifer using soil-gas analyses in the unsaturated zone. Between 1980 and 1988, an underground fuel-storage tank leaked about 3,000 gallons of unleaded fuel to the water table about 4 feet below land surface. A survey of soil gas using a gas chromatograph equipped with a photoionization detector showed concentrations of volatile organic compounds greater than IO, 000 parts per million near the leak These compounds were detected in an area about 240 feet long and 110 feet wide extending west from the point source. The chromatograms provided two distinct 'fingerprints' of volatile organic compounds. The first revealed the presence of benzene, toluene, andxylenes, which are constituents of unleaded fuel, in addition to other volatile compounds, in soil gas in the area near the leak The second did not reveal any detectable benzene, toluene, or xylenes in the soil-gas samples, but showed the presence of other unidentified volatile organic compounds in soil gas north of the storage tank. The distribution of total concentrations of volatile organic compounds in the unsaturated zone indicated that a second plume about 200 feet long and 90 feet wide was present about 100 feet north of the storage tank The second plume could have been the result of previous activities at this site during the 1950's or earlier. Activities at the site are believed to have included storage of solvents used at the nearby railyard and flushing of tanks containing tar onto a gravel-covered parking area. The delineation of these plumes has shown that soil-gas analyses can be a useful technique for identifying areas of contamination with volatile organic compounds in shallow water-table aquifers and may have broad applications in similar situations where the water table is relatively close to the surface.

  19. Modeling Transient Root-zone Soil Moisture Dichotomies in Landscapes with Intermixed Land Covers

    Science.gov (United States)

    Patrignani, A.; Ochsner, T. E.

    2015-12-01

    Although large-scale in situ soil moisture monitoring networks are becoming increasingly valuable research tools, deficiencies of many existing networks include the small spatial support of each station, the low spatial density of stations, and the almost exclusive deployment of stations in grassland vegetation. These grassland soil moisture observations may not adequately represent the real soil moisture patterns in landscapes with intermixed land cover types. The objectives of this study were i) to compare root-zone soil moisture dynamics of two dominant vegetation types across Oklahoma, grassland (observed) and winter wheat cropland (simulated); ii) to relate the soil moisture dynamics of grassland and cropland vegetation using an artificial neural network (ANN) as a transfer function; and iii) to use the resulting ANN to estimate the soil moisture spatial patterns for a landscape of intermixed grassland and wheat cropland. Root-zone soil moisture was represented by plant available water (PAW) in the top 0.8 m of the soil profile. PAW under grassland was calculated from 18 years of soil moisture observations at 78 stations of the Oklahoma Mesonet, whereas PAW under winter wheat was simulated for the same 78 locations using a soil water balance model. Then, we trained an ANN to reproduce the simulated PAW under winter wheat using only seven inputs: day of the year, latitude and longitude, measured PAW under grassland, and percent sand, silt, and clay. The resulting ANN was used, along with grassland soil moisture observations, to estimate the detailed soil moisture pattern for a 9x9 km2 Soil Moisture Active Passive (SMAP) grid cell. The seasonal dynamics of root-zone PAW for grassland and winter wheat were strongly asynchronous, so grassland soil moisture observations rarely reflect cropland soil moisture conditions in the region. The simple ANN approach facilitated efficient and accurate prediction of the simulated PAW under winter wheat, RMSE = 24 mm, using

  20. Soil erosion control, plant diversity, and arthropod communities under heterogeneous cover crops in an olive orchard.

    Science.gov (United States)

    Gómez, José Alfonso; Campos, Mercedes; Guzmán, Gema; Castillo-Llanque, Franco; Vanwalleghem, Tom; Lora, Ángel; Giráldez, Juan V

    2017-01-30

    A 3-year experiment compared in an olive orchard the effect of different cover crops' composition on runoff, water erosion, diversity of annual plants, and arthropod communities which could provide an alternative to conventional management based on tillage (CT). The cover crops evaluated were a seeded homogeneous grass (GC), a seeded mix of ten different species (MCseeded), and a non-seeded cover by vegetation naturally present at the farm after 20 years of mowing (MCnatural). The results suggest that heterogeneous cover crops can provide a viable alternative to homogeneous ones in olives, providing similar benefits in reducing runoff and soil losses compared to management based on bare soil. The reduction in soil loss was particularly large: 46.7 in CT to 6.5 and 7.9 t ha(-1) year(-1) in GC and MCseeded, respectively. The heterogeneous cover crops resulted in greater diversity of plant species and a modification of the arthropod communities with an increased number of predators for pests. The reduction of the cost of implanting heterogeneous cover crops, improvement of the seeding techniques, and selection of species included in the mixes require additional research to promote the use of this practice which can deliver enhanced environmental benefits.

  1. Calculation set for design and optimization of vegetative soil covers Sandia National Laboratories, Albuquerque, New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Peace, Gerald L.; Goering, Timothy James (GRAM, Inc., Albuquerque, NM)

    2005-02-01

    This study demonstrates that containment of municipal and hazardous waste in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers combining layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem will meet the technical equivalency criteria prescribed by the U. S. Environmental Protection Agency. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards. equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 3-foot (ft) cover in arid and semiarid environments is the minimum design thickness necessary to meet the U. S. Environmental Protection Agency-prescribed technical equivalency criteria of 31.5 millimeters/year and 1 x 10{sup -7} centimeters/second for net annual percolation and average flux, respectively. Increasing cover thickness to 4 or 5 ft results in limited additional improvement in cover performance.

  2. Physical properties of soil cultivated with Jatropha curcas and associated green vegetation covers

    Directory of Open Access Journals (Sweden)

    Willian José Ferreira

    2013-12-01

    Full Text Available The cultivation of physic nut (Jatropha curcas L. is a sustainable option for biodiesel production due to its adaptation to different agro-ecological conditions and its high content of non-edible oil grains. The possibility of its cultivation in degraded low fertility soils makes the physic nut attractive to the Paraíba do Sul Valley region. This study evaluated physical attributes and water processes of an Oxisol which had been previously used for livestock and later converted to experimental farming. The soil was intercropped with perennial herbaceous legumes (Arachis pintoi and Calopogonio muconoides in place of the original cover of Brachiaria brizantha, largely cultivated in the region. We determined the soil texture, the levels of saturation and water retention, soil resistance to root penetration and the basic infiltration rate of water into the soil (VIB. The soil resistance to root penetration in B. brizantha ranged from high to moderate at 30 cm depth, while the addition of perennial herbaceous legumes as cover crops intercropped with Jatropha reduced this resistance and increased the average soil VIB from 4 mm h-1 (B. brizantha to 33 mm h-1. We conclude that the association of herbaceous legumes with Jatropha contributed to the improvement of the soil’s physical properties.

  3. Forest Cover Change and Soil Erosion in Toledo's Rio Grande Watershed

    Science.gov (United States)

    Chicas, S.; Omine, K.

    2015-04-01

    Toledo, the southernmost district, is the hub of Belize's Mayan population, descendants of the ancient Mayan civilization. The Toledo District is primarily inhibited by Kekchi and Mopan Mayans whose subsistence needs are met by the Milpa slash-and-burn agricultural system and the extraction of forest resources. The poverty assessment in the country indicates that Toledo is the district with the highest percentage of household an individual indigence of 37.5 % and 49.7 % respectively. Forest cover change in the area can be attributed to rapid population growth among the Maya, together with increase in immigration from neighboring countries, logging, oil exploration and improvement and construction of roads. The forest cover change analysis show that from 2001 to 2011 there was a decrease of Lowland broad-leaved wet forest of 7.53 km sq, Shrubland of 4.66 km sq, and Wetland of 0.08 km sq. Forest cover change has resulted in soil erosion which is causing the deterioration of soils. The land cover types that are contributing the most to total erosion in the Rio Grande watershed are no-forest, lowland broad-leaved wet forest and submontane broad-leaved wet forest. In this study the Revised Universal Soil Loss Equation (RUSLE) was employed in a GIS platform to quantify and assess forest cover change and soil erosion. Soil erosion vulnerability maps in Toledo's Rio Grande watershed were also created. This study provides scientifically sound information in order to understand and respond effectively to the impacts of soil erosion in the study site.

  4. Linkages between land Cover, enzymes, and soil organic matter chemistry following encroachment of leguminous woody plant into grasslands

    Science.gov (United States)

    Filley, T. R.; Stott, D. E.; Boutton, T. W.; Creamer, C. A.; Olk, D.

    2009-12-01

    only weak trends with age when normalized to carbon content. Although, PPO was nearly invariant across the chronosequence, lignin content rose dramatically, normalized both to soil mass and to organic carbon content, indicating oxidase activity was not matched to input and lignin was selectively accruing in the below ground carbon pools. We propose that the dramatic increase in available N in the leguminous system suppressed microbial oxidase production allowing lignin to selectively accrue while microbial activity for the other plant biopolymers has nearly kept pace with input-consistent with recent findings in other temperate deciduous systems. These results have important implications for the modeling of woodland-grassland conversion and the dynamics of biogeochemical cycles in this globally significant land cover change.

  5. Tillage and cover cropping effects on soil properties and crop production in Illinois

    Science.gov (United States)

    Cover crops (CCs) have been heralded for their potential to improve soil properties, retain nutrients in the field, and increase subsequent crop yields yet support for these claims within the state of Illinois remains limited. We assessed the effects of integrating five sets of CCs into a corn-soybe...

  6. Cover Crop and Liquid Manure Effects on Soil Quality Indicators in a Corn Silage System.

    Science.gov (United States)

    Due to a lack of surface residue and organic matter inputs, continuous corn (Zea mays L.) silage production is one of the most demanding cropping systems imposed on our soil resources. In this study, our objective was to determine if using cover/companion crops and/or applying low-solids liquid dair...

  7. MULTITEMPORAL ANALYSIS OF THE SOIL COVER IN THE INFLUENCE AREA OF THE PCH –

    Directory of Open Access Journals (Sweden)

    Kmila Gomes da Silva

    2011-10-01

    Full Text Available The objective proposed by the study was to map and analyze the spatial changes of the soil cover of the influence area of the Small Central Hydroelectric power plant (Pequena Central Hidrelétrica - PHC – São Simão, Alegre ES. The images were processed with the support of SPRING 5.1.6 and classified by using the algorithm Bhattacharya, from its two images of high suborbital definition (Ortofoto /2007 and orbital (Geoeye/ 2009 which retracted the periods that come before and after the referred Substation construction. Six thematic classes were defined. The Supervised Classification Battacharya, demonstrated being a good instrument to evaluate the alterations of the soil cover. Comparison of the data, we can see that there was a significant increase in pasture class with 17.38%, followed by the class water corps with 3.54% and 3.46 with rocky material. Had significant reduction class remnants of natural vegetation with 22.30%, followed by non-road - paved with 1.30% and 0.78% with exposed soil. The use and occupation of the soil on the places nearby the area of study, remains being covered by pasture (69.55% in 2009, and a good part of the vegetation cover was reduced to pasture. The construction of the PCH- São Simão favored for increasing rural exodus in neighboring community to the enterprise.

  8. Soil microbial communities under cacao agroforestry and cover crop systems in Peru

    Science.gov (United States)

    Cacao (Theobroma cacao) trees are grown in tropical regions worldwide for chocolate production. We studied the effects of agroforestry management systems and cover cropping on soil microbial communities under cacao in two different replicated field experiments in Peru. Two agroforestry systems, Imp...

  9. Cover crops for enriching soil carbon and nitrogen under bioenergy sorghum

    Science.gov (United States)

    Soil carbon (C) and nitrogen (N) can be enriched with cover crops under agronomic crops, but little is known about their enrichment under bioenergy crops. Legume (hairy vetch [Vicia villosa Roth]), nonlegume (rye [Secaele cereale L.]), a mixture of legume and nonlegume (hairy vetch and rye) and a co...

  10. Areal variability of the mineral soil cover in a reclaimed soda waste dumping site

    Directory of Open Access Journals (Sweden)

    Klatka Sławomir

    2017-03-01

    Full Text Available Areal variability of the mineral soil cover in a reclaimed soda waste dumping site. This paper provides an analysis of the areal variability of the thickness and selected physical and chemical properties of the mineral cover formed in the process of settling ponds reclamation at the former Krakow Soda Plant “Solvay”. The topsoil is intended to provide a substrate for plants, therefore, its quality is the main determinant of the development for herbaceous and woody vegetation. Areal variability of the topsoil parameters was determined by kriging. In the context of the envisaged direction of management of the settling ponds, the analysis showed that electrical conductivity, thickness of the soil cover and the sand fraction content have potentially the highest impact on the diversification of vegetation. Understanding the spatial variability of the soil cover parameters, that are essential for vegetation, may contribute to increasing the efficiency of biological reclamation and also to cost reduction. Precise selection of the areas unsuitable for plant growth makes it possible to improve soil parameters on limited areas similarly as in the precision agriculture.

  11. Rhizosphere microorganisms affected by soil solarization and cover cropping in Capsicum annuum and Phaseolus lunatus agroecosystems

    Science.gov (United States)

    Field experiments were conducted to evaluate the effects of soil solarization or cover cropping on bell pepper (Capsicum annuum) and lima bean (Phaseolus lunatus, L.) rhizosphere microorganisms. In Experiment I, flat surface solarization (FSS), raised bed solarization (RBS), cowpea (Vigna unguiculat...

  12. Empirical gas emission and oxidation measurement at cover soil of dumping site: example from Malaysia.

    Science.gov (United States)

    Abushammala, Mohammed F M; Basri, Noor Ezlin Ahmad; Basri, Hassan; Kadhum, Abdul Amir H; El-Shafie, Ahmed Hussein

    2013-06-01

    Methane (CH₄) is one of the most relevant greenhouse gases and it has a global warming potential 25 times greater than that of carbon dioxide (CO₂), risking human health and the environment. Microbial CH₄ oxidation in landfill cover soils may constitute a means of controlling CH₄ emissions. The study was intended to quantify CH₄ and CO₂ emissions rates at the Sungai Sedu open dumping landfill during the dry season, characterize their spatial and temporal variations, and measure the CH₄ oxidation associated with the landfill cover soil using a homemade static flux chamber. Concentrations of the gases were analyzed by a Micro-GC CP-4900. Two methods, kriging values and inverse distance weighting (IDW), were found almost identical. The findings of the proposed method show that the ratio of CH₄ to CO₂ emissions was 25.4 %, indicating higher CO₂ emissions than CH₄ emissions. Also, the average CH₄ oxidation in the landfill cover soil was 52.5 %. The CH₄ and CO₂ emissions did not show fixed-pattern temporal variation based on daytime measurements. Statistically, a negative relationship was found between CH₄ emissions and oxidation (R(2) = 0.46). It can be concluded that the variation in the CH₄ oxidation was mainly attributed to the properties of the landfill cover soil.

  13. Long-term effects of compost and cover crops on soil phosphorus in two California agroecosystems

    Science.gov (United States)

    Inefficient P use in agriculture results in soil P accumulation and losses to surrounding ecosystems, highlighting the need to reduce external inputs and use them more efficiently. Composts reduce the need for mineral fertilizers by recycling P from wastes at the regional scale, whereas cover crops ...

  14. Impact of Vegetative Cover on Runoff and Soil Erosion at Hillslope Scale in Lanjaron, Spain

    NARCIS (Netherlands)

    Duran Zuazo, V.H.; Francia-Martinez, J.R.; Martinez-Raya, A.

    2004-01-01

    Soil loss and surface runoff patterns over a four-year period (1997¿2000) were studied in erosion plots from three hillslopes under different vegetative covers (Rosmarinus officinalis, Triticum aestivum and natural-spontaneous vegetation) in Lanjaron (Alpujarras) on the south flank of the Sierra Nev

  15. Effects of covering highland banana stumps with soil on banana weevil Cosmopolites sordidus (Coleoptera: Curculionidae) oviposition

    NARCIS (Netherlands)

    Masanza, M.; Gold, C.S.; Huis, van A.; Ragama, P.E.

    2005-01-01

    The effect of covering post-harvest banana stumps with soil on banana weevil Cosmopolites sordidus (Germar) oviposition levels was investigated at three locations, Sendusu, Kawanda Agricultural Research Institute (KARI) and Ntungamo district of southwestern Uganda. In the first experiment ovipositio

  16. Fate of glyphosate and degradates in cover crop residues and underlying soil: A laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Cassigneul, A. [Université de Toulouse — École d' ingénieurs de Purpan, UMR 1248 AGIR — 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3 (France); INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon (France); Benoit, P.; Bergheaud, V.; Dumeny, V.; Etiévant, V. [INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon (France); Goubard, Y. [AgroParisTech, UMR 1402 ECOSYS, 78850 Thiverval-Grignon (France); Maylin, A. [Université de Toulouse — École d' ingénieurs de Purpan, UMR 1248 AGIR — 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3 (France); Justes, E. [INRA, UMR 1248 AGIR Auzeville — BP 52 627, 31 326, Castanet-Tolosan cedex (France); Alletto, L. [Université de Toulouse — École d' ingénieurs de Purpan, UMR 1248 AGIR — 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3 (France)

    2016-03-01

    The increasing use of cover crops (CC) may lead to an increase in glyphosate application for their destruction. Sorption and degradation of {sup 14}C-glyphosate on and within 4 decaying CC-amended soils were compared to its fate in a bare soil. {sup 14}C-Glyphosate and its metabolites distribution between mineralized, water-soluble, NH{sub 4}OH-soluble and non-extractable fractions was determined at 5 dates during a 20 °C/84-d period. The presence of CC extends {sup 14}C-glyphosate degradation half-life from 7 to 28 days depending on the CC. {sup 14}C-Glyphosate dissipation occurred mainly through mineralization in soils and through mineralization and bound residue formation in decaying CC. Differences in sorption and degradation levels were attributed to differences in composition and availability to microorganisms. CC- and soil-specific dissipation patterns were established with the help of explicit relationships between extractability and microbial activity. - Highlights: • Glyphosate sorption on cover crop residues increases with their decomposition degree. • Glyphosate degradation and mineralization are lower in mulch than in soil. • Nonextractable residue formation is one of the main dissipation pathways of glyphosate in cover crop mulch.

  17. Soft Soil Site Characterization on the Coast of Yantai and Its Effect on Ground Motion Parameters

    Institute of Scientific and Technical Information of China (English)

    Lü Yuejun; Tang Rongyu; Peng Yanju

    2005-01-01

    According to the Chinese GB50011-2001 code and the recommended provisions of FEMANEHRP and EUROCODE 8, by using shear wave velocity and borehole data, the site classification is evaluated for a typical soft soil site on the Yantai seacoast. The site seismic ground motion effect is analyzed and the influence of the coastal soil on design ground motion parameters is discussed. The results show that the brief site classification can not represent the real conditions of a soft soil site; the soft soil on the coast has a remarkable impact on the magnitude and spectrum of ground motion acceleration. The magnification on peak acceleration is bigger, however, due to the nonlinear deformation of the soil. The magnification is reduced nonlinearly with the increase of input ground motion; the spectrum is broadened and the characteristic period elongated on the soft soil site.

  18. The role of rock fragment cover on soil erosion in conventional vineyards in Eastern Spain

    Science.gov (United States)

    Rodrigo Comino, Jesús; Jordán, Antonio; García-Díaz, Andrés; Brevik, Eric C.; Pereira, Paulo; Keesstra, Saskia; Novara, Agata; Cerdà, Artemi

    2017-04-01

    Soil erosion results in soil degradation and losses in crop production, specifically, in vineyards are active sources of sediments and water (Martínez-Casasnovas et al., 2005; Rodrigo Comino et al., 2016). Several studies confirm that the main causes of this degradation include lack of vegetative cover, widespread use of herbicides and sprays, and compaction by heavy machinery and trampling effect, suggesting the use of organic amendments and management of mulch covers as solutions (Prosdocimi et al., 2016). Local, inexpensive materials are easier to manage, less costly to apply, and more sustainable if already in the soil, such as the rock fragments. Rock fragments can improve soil quality by conserving the temperature such as the slates in German vineyards (Rodrigo Comino et al., 2015) or contributing to the forestation of degraded ecosystems (Jiménez et al., 2016), but no information exists from tilled vineyards. Therefore, the main goal of this research was to determine the impact of soil cover and soil properties (slope, soil organic carbon, vegetation cover, soil water content, and rock fragments) on soil erosion in tilled vineyards. To achieve this goal, simulated rainfall experiments were carried out to avoid the spatial variability of natural rainfall (Cerdà, 1999, 1997). After performing the rainfall simulations and assessing the statistical analysis, our interest was focused on the impact of one concrete parameter: the rock fragment cover. The main reason was because experimental results showed significant correlations with runoff (positive) and sediment yield (negative). The results of our study show that the rock fragments at the pedon scale can act as mulch in Mediterranean vineyards, but a pavement of embedded rock fragments will trigger high runoff rates. Acknowledgments This research was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant no. 603498 (RECARE Project). References Cerdà, A., 1999. Parent Material

  19. Oat cover cropping and soil insecticides in an integrated sugarbeet root maggot (Diptera: Otitidae) management program.

    Science.gov (United States)

    Dregseth, Robert J; Boetel, Mark A; Schroeder, Allen J; Carlson, Robert B; Armstrong, J S

    2003-10-01

    Sugarbeet, Beta vulgaris L., producers occasionally establish cereal cover crops to minimize early-season soil erosion, wind abrasion, and mechanical injury of seedlings. We evaluated the use of living oat, Avena sativa L., cover cropping as a cultural tactic to minimize feeding injury from sugarbeet root maggot, Tetanops myopaeformis (Röder), larvae at five field sites during 1996, 1998, and 1999. Sweep-net sampling yielded 4.8-, 11.2-, and 7.2-fold more flies from oat cover-cropped chlorpyrifos, terbufos, and untreated control plots, respectively, than in noncover counterparts. However, larval feeding injury in terbufos-treated plots was reduced when cover-cropped (383 seeds/m2) at St. Thomas in all years. A reduced oat seeding rate (224 seeds/m2) also enhanced root protection in terbufos-treated plots at St. Thomas in 1999. Less root injury was sustained in cover-cropped chlorpyrifos plots than in noncover counterparts at St. Thomas in 2 study yr. Oat cover cropping also frequently resulted in reduced T. myopaeformis feeding injury in the absence of a soil insecticide. Although trends toward increased yields were often evident, significant yield benefits were limited to a 6.8% root yield increase in oat cover plots when compared with noncover treatments overall at St. Thomas in 1996 and an 18.4% sucrose yield increase in terbufos-treated plots at St. Thomas in 1999. These findings suggest that beneficial interactions between planting-time soil insecticides and cereal cover crops are achievable in areas infested by T. myopaeformis. Demonstrated reductions in root feeding injury, combined with additional agronomic benefits, may warrant use of this production practice as part of an integrated management program for this key insect pest of sugarbeet.

  20. [Effects of soil covering on solar greenhouse pepper water use efficiency and soil nitrate N and available phosphorus contents].

    Science.gov (United States)

    Zhou, Mao-juan; Liang, Yin-li; Chen, Jia-rui; Xiong, Ya-mei; Wei, Ze-xiu

    2007-06-01

    A greenhouse study on the effects of soil covering on pepper (Capsicum anmuum L.) water use efficiency and soil nitrate and available phosphorus contents showed that straw mulch + plastic film mulch could get the highest pepper yield water use efficiency (33.04 kg . m(-3)) and economic water use efficiency (50.22 yuan . m(-3)), followed by plastic film mulch, with the two parameters being 18.81 kg . m(-3) and 28.57 yuan . m(-3), respectively. Significant differences of nitrate N content in 0-20 cm soil layer were observed among different treatments. The control had the highest nitrate N content (50.33 mg . kg(-1)), followed by straw mulch (31.98 mg . kg(-1)) and straw + plastic film mulch (31.96 mg . kg(-1)), and plastic film mulch and applying water preserving agent. Compared with the control, soil covering could increase the nitrate N use efficiency of pepper, and decrease the accumulation of nitrate N in plough layer. In 0-20 cm soil layer, treatment plastic film mulch had the lowest available phosphorus content (0.72 mg . kg(-3)), and the second (0. 92 mg . kg(-1)) was the treatment straw + plastic film mulch. Treatments straw + plastic film mulch and plastic film mulch could increase pepper fruit yield and fertilizer use efficiency, and decrease fertilizer loss.

  1. Modeled Impacts of Cover Crops and Vegetative Barriers on Corn Stover Availability and Soil Quality

    Energy Technology Data Exchange (ETDEWEB)

    Ian J. Bonner; David J. Muth Jr.; Joshua B. Koch; Douglas L. Karlen

    2014-06-01

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable lignocellulosic biofuel industry. Our objective was to demonstrate a landscape planning process that can ensure adequate supplies of corn (Zea mays L.) stover feedstock while protecting and improving soil quality. The Landscape Environmental Assessment Framework (LEAF) was used to develop land use strategies that were then scaled up for five U.S. Corn Belt states (Nebraska, Iowa, Illinois, Indiana, and Minnesota) to illustrate the impact that could be achieved. Our results show an annual sustainable stover supply of 194 million Mg without exceeding soil erosion T values or depleting soil organic carbon [i.e., soil conditioning index (SCI)?>?0] when no-till, winter cover crop, and vegetative barriers were incorporated into the landscape. A second, more rigorous conservation target was set to enhance soil quality while sustainably harvesting stover. By requiring erosion to be <1/2 T and the SCI-organic matter (OM) subfactor to be >?0, the annual sustainable quantity of harvestable stover dropped to148 million Mg. Examining removal rates by state and soil resource showed that soil capability class and slope generally determined the effectiveness of the three conservation practices and the resulting sustainable harvest rate. This emphasizes that sustainable biomass harvest must be based on subfield management decisions to ensure soil resources are conserved or enhanced, while providing sufficient biomass feedstock to support the economic growth of bioenergy enterprises.

  2. Structure and function of methanotrophic communities in a landfill-cover soil.

    Science.gov (United States)

    Henneberger, Ruth; Lüke, Claudia; Mosberger, Lona; Schroth, Martin H

    2012-07-01

    In landfill-cover soils, aerobic methane-oxidizing bacteria (MOB) convert CH(4) to CO(2), mitigating emissions of the greenhouse gas CH(4) to the atmosphere. We investigated overall MOB community structure and assessed spatial differences in MOB diversity, abundance and activity in a Swiss landfill-cover soil. Molecular cloning, terminal restriction-fragment length polymorphism (T-RFLP) and quantitative PCR of pmoA genes were applied to soil collected from 16 locations at three different depths to study MOB community structure, diversity and abundance; MOB activity was measured in the field using gas push-pull tests. The MOB community was highly diverse but dominated by Type Ia MOB, with novel pmoA sequences present. Type II MOB were detected mainly in deeper soil with lower nutrient and higher CH(4) concentrations. Substantial differences in MOB community structure were observed between one high- and one low-activity location. MOB abundance was highly variable across the site [4.0 × 10(4) to 1.1 × 10(7) (g soil dry weight)(-1)]. Potential CH(4) oxidation rates were high [1.8-58.2 mmol CH(4) (L soil air)(-1) day(-1) ] but showed significant lateral variation and were positively correlated with mean CH(4) concentrations (P structure are driving factors in CH(4) oxidation at this landfill.

  3. Comparison of buried soil sensors, surface chambers and above ground measurements of carbon dioxide fluxes

    Science.gov (United States)

    Soil carbon dioxide (CO2) flux is an important component of the terrestrial carbon cycle. Accurate measurements of soil CO2 flux aids determinations of carbon budgets. In this study, we investigated soil CO2 fluxes with time and depth and above ground CO2 fluxes in a bare field. CO2 concentrations w...

  4. SPATIAL-TEMPORAL VARIATION OF HEAVY METAL ELEMENTS CONTENT IN COVERING SOIL OF RECLAMATION AREA IN FUSHUN COAL MINE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Grid method is employed for sampling covering soil at the test field, which is reclamation area filled bycoal mining wastes for cropland in the Fushun coal mine, Liaoning Province, the Northeast China. The soil samples aretaken at different locations, including three kinds of covering soil, three different depths of soil layers and four differentcovering ages of covering soil. The spatial-temporal variation of heavy metal element content in reclamation soil is studied. The results indicate that the content of heavy metal elements is decreasing year after year; the determinant reasonwhy the content of heavy metal elements at 60cm depth layer is higher than that at 30em depth layer and surface is fertilizer and manure apphcation; the metal elements mainly come from external environment; there is no metal pollution comingfrom mother material (coal mining wastes) in plough layer of covering soil.

  5. Restoring the biological crust cover of soils across biomes in arid North America

    Science.gov (United States)

    Garcia-Pichel, Ferran; Antoninka, Anita; Bowker, Matthew; Giraldo Silva, Ana; Nelson, Corey; Velasco Ayuso, Sergio; Barger, Nichole; Belnap, Jayne; Reed, Sasha; Duniway, Michael

    2015-04-01

    Biological soil crust communities provide important ecosystem services to arid lands, particularly regarding soil fertility and stability against erosion. In North America, and in many other areas of the globe, increasingly intense human activities, ranging from cattle grazing to military training, have resulted in the significant deterioration of biological soil surface cover of soils. With the intent of attaining sustainable land use practices, we are conducting a 5-year, multi-institutional research effort to develop feasible soil crusts restoration strategies for US military lands. We are including field sites of varying climatic regions (warm and cold deserts, in the Chihuahuan Desert and in the Great Basin, respectively) and varying edaphic characteristics (sandy and silty soils in each). We have multiple aims. First, we aim to establishing effective "biocrust nurseries" that produce viable and pedigreed inoculum, as a supply center for biocrust restoration and for research and development. Second, we aim to develop optimal field application methods of biocrust inoculum in a series of field trials. Currently in our second year of research, we will be reporting on significant advances made on optimizing methodologies for the large-scale supply of inoculum based on a) pedigreed laboratory cultures that match the microbial community structure of the original sites, and b) "in soil" biomass enhancement, whereby small amounts of local crusts are nursed under greenhouse conditions to yield hundred-fold increases in biomass without altering significantly community structure. We will also report on field trials for methodologies in field application, which included shading, watering, application of chemical polymers, and soil surface roughening. In a soon-to-be-initiated effort we also aim to evaluate soil and plant responses to biocrust restoration with respect to plant community structure, soil fertility, and soil stability, in multi-factorial field experiments. An

  6. Evaluation of Soil Manipulation to Prepare Engineered Earthen Waste Covers for Revegetation.

    Science.gov (United States)

    Waugh, W Joseph; Benson, Craig H; Albright, William H; Smith, Gregory M; Bush, Richard P

    2015-11-01

    Seven ripping treatments designed to improve soil physical conditions for revegetation were compared on a test pad simulating an earthen cover for a waste disposal cell. The field test was part of study of methods to convert compacted-soil waste covers into evapotranspiration covers. The test pad consisted of a compacted layer of fine-textured soil simulating a barrier protection layer overlain by a gravelly sand bedding layer and a cobble armor layer. Treatments included combinations of soil-ripping implements (conventional shank [CS], wing-tipped shank [WTS], and parabolic oscillating shank with wings [POS]), ripping depths, and number of passes. Dimensions, dry density, moisture content, and particle size distribution of disturbance zones were determined in two trenches excavated across rip rows. The goal was to create a root-zone dry density between 1.2 and 1.6 Mg m and a seedbed soil texture ranging from clay loam to sandy loam with low rock content. All treatments created V-shaped disturbance zones as measured on trench faces. Disturbance zone size was most influenced by ripping depth. Winged implements created larger disturbance zones. All treatments lifted fines into the bedding layer, moved gravel and cobble down into the fine-textured protection layer, and thereby disrupted the capillary barrier at the interface. Changes in dry density within disturbance zones were comparable for the CS and WTS treatments but were highly variable among POS treatments. Water content increased in the bedding layer and decreased in the protection layer after ripping. The POS at 1.2-m depth and two passes created the largest zone with a low dry density (1.24 Mg m) and the most favorable seedbed soil texture (gravely silt loam). However, ripping also created large soil aggregates and voids in the protection layer that may produce preferential flow paths and reduce water storage capacity.

  7. Evaluation of the behavior of water in soil under eucalipto and native forest covers

    Directory of Open Access Journals (Sweden)

    Geberson Ricardo de Paula

    2013-12-01

    Full Text Available Areas occupied by grasslands have been replaced by eucalyptus plantations, which modifies the landscape, the regional economy, and water dynamics in soils. Thus, this study aimed to evaluate the behavior of water in Oxisol in two vegetation land covers, a six years old eucalyptus plantation, and a native forest in regeneration process for twenty years. The study was developed in the Una River Basin from June 2009 to April 2011. Ninety six moisture sensors were installed (Watermark™ at depths of 20, 60, and 120 cm. It was observed that, upon the occurrence of rainfall, the superficial and intermediate layers had increased humidity, which did not occur in the deepest layer. It was found that there were differences in soil moisture measured in the areas of eucalyptus and native forest and throughout the study period humidity was maintained between field capacity and permanent wilting point, with no water restriction. Canopy temperature of the eucalyptus plantation remained lower, indicating that its evapotranspiration was higher than in the forest area. The differences in moisture can be explained by the difference between the physical properties of soils in the study areas, because although they have the same slope, receive the same insolation and are close to each other, soil covered by eucalyptus presented a water storage capacity 63% above the area with native forest. It was also observed that all rainfall reaching the soil surface infiltrated and there was no runoff in the two areas studied. It was concluded that the results of this research provide important insights about differences in the behavior of water in the soil when covered by eucalyptus or native forest. For this reason, we suggest further studies with greater geographic reach in paired areas with different slopes, aspects and soil types.

  8. Grass Cover Influences Hydrophysical Parameters and Heterogeneity of Water Flow in a Sandy Soil

    Institute of Scientific and Technical Information of China (English)

    L. LICHNER; D. J. ELDRIDGE; K. SCHACHT; N. ZHUKOVA; L. HOLKO; M. (S)(I)R; J. PECHO

    2011-01-01

    Vegetation cover has a major effect on water flow in soils.Two sites,separated by distance of about 50 m,were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot,dry period.A control soil (pure sand) with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area,and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses.The persistence of water repellency was measured using the water drop penetration time test,sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer,and saturated hydraulic conductivity using a double-ring infiltrometer.Dye tracer experiments were used to assess the heterogeneity of water flow,and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles.Most hydrophysical parameters were substantially different between the two surfaces.The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand.Water and ethanol sorptivities in the grassland soil were 7% and 43%,respectively,of those of the pure sand.Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16% of those of the pure sand,respectively.Dye tracer experiments revealed a stable flow with "air-draining" condition in pure sand and well-developed preferential flow in grassland soil,corresponding to individual grass tussocks and small micro-depressions.The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand.The results of this study reinforce our view that the consequences of any change in climate

  9. Pile-soil stress ratio in bidirectionally reinforced composite ground by considering soil arching effect

    Institute of Scientific and Technical Information of China (English)

    邹新军; 杨眉; 赵明华; 杨小礼

    2008-01-01

    To discuss the soil arching effect on the load transferring model and sharing ratios by the piles and inter-pile subsoil in the bidirectionally reinforced composite ground, the forming mechanism, mechanical behavior and its effect factors were discussed in detail. Then, the unified strength theory was introduced to set up the elastoplastic equilibrium differential equation of the subsoil under the limit equilibrium state. And from the equation, the solutions were derived with the corresponding formulas presented to calculate the earth pressure over and beneath the horizontal reinforced cushion or pillow, the stress of inter-pile subsoil and the pile-soil stress ratio. Based on the obtained solutions and measured data from an engineering project, the influence rules by the soil property parameters (i.e., the cohesion c and internal friction angle φ) and pile spacing on the pile-soil stress ratio n were discussed respectively. The results show that to improve the load sharing ratio by the piles, the more effective means for filling materials with a larger value of φ is to increase the ratio of pile cap size to spacing, while to reduce the pile spacing properly and increase the value of cohesion c is advisable for those filling materials with a smaller value of φ.

  10. Pattern and dynamics of the ground vegetation in south Swedish Carpinus betulus forests. Importance of soil chemistry and management

    Energy Technology Data Exchange (ETDEWEB)

    Brunet, J. [Swedish Univ. of Agricultural Sciences, Dept. of Conservation Biology, Uppsala (Sweden); Falkengren-Grerup, U.; Tyler, G. [Plant Ecology, Dept. of Ecology, Lund (Sweden)

    1997-10-01

    The vegetation and environmental conditions of south Swedish horn-beam Carpinus betulus forests are described with data from 35 permanent sample plots. The main floristic gradient of the ground vegetation is closely related to acid-base properties of the top soil: Base saturation, pH and organic matter content. Other floristic differences are related to tree canopy cover and the distance of the sample plots to the Baltic coast. Species richness of herbaceous plants typical of forests increases with soil pH. The number of other herbaceous species, occurring in both forests and open habitats, and of woody species is not related to pH. Comparisons of vegetation data from 1983 and 1993 show relatively small compositional differences of the herbaceous forest flora. The number of other herbaceous species increased considerably in those plots where canopy trees had been cut after 1983. The number of new species in managed plots increases with soil pH. Species losses and gains of the herbaceous forest flora between 1983 and 1993 are generally lower as compared with other herbaceous species and woody species. However, the ground cover of herbaceous forest species, especially of Oxalis acetosella and Lamium galeobdolon, was considerably lower in 1993 as compared to 1983 in both unmanaged and managed plots. Possible explanations for this decrease are current soil acidification and drought during the growing season. (au) 32 refs.

  11. Crop Ground Cover Fraction and Canopy Chlorophyll Content Mapping using RapidEye imagery

    Science.gov (United States)

    Zillmann, E.; Schonert, M.; Lilienthal, H.; Siegmann, B.; Jarmer, T.; Rosso, P.; Weichelt, T.

    2015-04-01

    Remote sensing is a suitable tool for estimating the spatial variability of crop canopy characteristics, such as canopy chlorophyll content (CCC) and green ground cover (GGC%), which are often used for crop productivity analysis and site-specific crop management. Empirical relationships exist between different vegetation indices (VI) and CCC and GGC% that allow spatial estimation of canopy characteristics from remote sensing imagery. However, the use of VIs is not suitable for an operational production of CCC and GGC% maps due to the limited transferability of derived empirical relationships to other regions. Thus, the operational value of crop status maps derived from remotely sensed data would be much higher if there was no need for reparametrization of the approach for different situations. This paper reports on the suitability of high-resolution RapidEye data for estimating crop development status of winter wheat over the growing season, and demonstrates two different approaches for mapping CCC and GGC%, which do not rely on empirical relationships. The final CCC map represents relative differences in CCC, which can be quickly calibrated to field specific conditions using SPAD chlorophyll meter readings at a few points. The prediction model is capable of predicting SPAD readings with an average accuracy of 77%. The GGC% map provides absolute values at any point in the field. A high R2 value of 80% was obtained for the relationship between estimated and observed GGC%. The mean absolute error for each of the two acquisition dates was 5.3% and 8.7%, respectively.

  12. Fate of glyphosate and degradates in cover crop residues and underlying soil: A laboratory study.

    Science.gov (United States)

    Cassigneul, A; Benoit, P; Bergheaud, V; Dumeny, V; Etiévant, V; Goubard, Y; Maylin, A; Justes, E; Alletto, L

    2016-03-01

    The increasing use of cover crops (CC) may lead to an increase in glyphosate application for their destruction. Sorption and degradation of (14)C-glyphosate on and within 4 decaying CC-amended soils were compared to its fate in a bare soil. (14)C-Glyphosate and its metabolites distribution between mineralized, water-soluble, NH4OH-soluble and non-extractable fractions was determined at 5 dates during a 20 °C/84-d period. The presence of CC extends (14)C-glyphosate degradation half-life from 7 to 28 days depending on the CC. (14)C-Glyphosate dissipation occurred mainly through mineralization in soils and through mineralization and bound residue formation in decaying CC. Differences in sorption and degradation levels were attributed to differences in composition and availability to microorganisms. CC- and soil-specific dissipation patterns were established with the help of explicit relationships between extractability and microbial activity.

  13. The influence of cover crops and tillage on actual and potential soil erosion in an olive grove

    Science.gov (United States)

    Sastre, Blanca; Bienes, Ramón; García-Díaz, Andrés; Panagopoulos, Thomas; José Marqués, Maria

    2014-05-01

    The study was carried out in an olive grove in central Spain (South of Madrid; Tagus River Basin). In this semi-arid zone, the annual mean temperature is 13.8 ºC and the annual precipitation is 395 mm. Olive groves are planted in an erosion prone area due to steep slopes up to 15%. Soil is classified as Typic Haploxerept with clay loam texture. The land studied was formerly a vineyard, but it was replaced by the studied olive grove in 2004. It covers approximately 3 ha and olive trees are planted every 6 x 7 metres. They were usually managed by tillage to decrease weed competition. This conventional practice results in a wide surface of bare soil prone to erosion processes. In the long term soil degradation may lead to increase the desertification risk in the area. Storms have important consequences in this shallow and vulnerable soil, as more than 90 Mg ha-1 have been measured after one day with 40 mm of rainfall. In order to avoid this situation, cover crops between the olive trees were planted three years ago: sainfoin (Onobrychis viciifolia), barley (Hordeum vulgare), and purple false brome (Brachypodium distachyon), and they were compared with annual spontaneous vegetation after a minimum tillage treatment (ASV). The results regarding erosion control were positive. We observed (Oct. 2012/Sept. 2013) annual soil loss up to 11 Mg ha-1 in ASV, but this figure was reduced in the sown covers, being 8 Mg ha-1 in sainfoin treatment, 3,7 Mg ha-1 in barley treatment, and only 1,5 Mg ha-1 in false brome treatment. Those results are used to predict the risk of erosion in long term. Moreover, soil organic carbon (SOC) increased with treatments, this is significant as it reduces soil erodibility. The increases were found both in topsoil (up to 5 cm) and more in depth, in the root zone (from 5 to 10 cm depth). From higher to lower SOC values we found the false brome (1.05%), barley (0.92%), ASV (0.79%) and sainfoin (0.71%) regarding topsoil. In the root zone (5-10 cm depth

  14. Response of soil heat-water processes to vegetation cover on the typical permafrost and seasonally frozen soil in the headwaters of the Yangtze and Yellow Rivers

    Institute of Scientific and Technical Information of China (English)

    HU HongChang; WANG GenXu; WANG YiBo; LIU GuangSheng; LI TaiBing; REN DongXing

    2009-01-01

    The response of soil temperature and moisture to vegetative cover in the active layer of permafrost and seasonally frozen soil were assessed and compared. Soil temperature and moisture, under a range of vegetation covers (92%, 65% and 30%) in the permafrost and vegetation covers (95%, 70%-80%, 40%-50% and 10%) in the seasonally frozen soil, were measured on a daily basis. A decline in vege-tation cover led to e decrease in the integral of freezing depth of active permafrost layer, but an in-crease in seasonally frozen soil. The maximum invasion depth and duration of the negative isotherm during the frozen period and of the positive isotherm during the non-frozen period clearly increased when vegetation cover declined. With a reduction of vegetation cover, the soil moisture in the active layer of the permafrost decreased for depths of 0.20-0.60 m, but increased for depths of 0.60-0.80 m, while for seasonally frozen soil, soil moisture of the entire profile (0.10-1.20 m) increased. Variation in vegetation cover alters soil heat-water processes, but the response to it is different between permafrost and seasonally frozen soil.

  15. Contamination of ground water, surface water, and soil, and evaluation of selected ground-water pumping alternatives in the Canal Creek area of Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Lorah, Michelle M.; Clark, Jeffrey S.

    1996-01-01

    Chemical manufacturing, munitions filling, and other military-support activities have resulted in the contamination of ground water, surface water, and soil in the Canal Creek area of Aberdeen Proving Ground, Maryland. Chlorinated volatile organic compounds, including 1,1,2,2-tetrachloroethane and trichloroethylene, are widespread ground-water contaminants in two aquifers that are composed of unconsolidated sand and gravel. Distribution and fate of chlorinated organic compounds in the ground water has been affected by the movement and dissolution of solvents in their dense immiscible phase and by microbial degradation under anaerobic conditions. Detection of volatile organic contaminants in adjacent surface water indicates that shallow contaminated ground water discharges to surface water. Semivolatile organic compounds, especially polycyclic aromatic hydrocarbons, are the most prevalent organic contaminants in soils. Various trace elements, such as arsenic, cadmium, lead, and zinc, were found in elevated concentrations in ground water, surface water, and soil. Simulations with a ground-water-flow model and particle tracker postprocessor show that, without remedial pumpage, the contaminants will eventually migrate to Canal Creek and Gunpowder River. Simulations indicate that remedial pumpage of 2.0 million gallons per day from existing wells is needed to capture all particles originating in the contaminant plumes. Simulated pumpage from offsite wells screened in a lower confined aquifer does not affect the flow of contaminated ground water in the Canal Creek area.

  16. Interaction effects of climate and land use/land cover change on soil organic carbon sequestration.

    Science.gov (United States)

    Xiong, Xiong; Grunwald, Sabine; Myers, D Brenton; Ross, C Wade; Harris, Willie G; Comerford, Nicolas B

    2014-09-15

    Historically, Florida soils stored the largest amount of soil organic carbon (SOC) among the conterminous U.S. states (2.26 Pg). This region experienced rapid land use/land cover (LULC) shifts and climate change in the past decades. The effects of these changes on SOC sequestration are unknown. The objectives of this study were to 1) investigate the change in SOC stocks in Florida to determine if soils have acted as a net sink or net source for carbon (C) over the past four decades and 2) identify the concomitant effects of LULC, LULC change, and climate on the SOC change. A total of 1080 sites were sampled in the topsoil (0-20 cm) between 2008 and 2009 representing the current SOC stocks, 194 of which were selected to collocate with historical sites (n = 1251) from the Florida Soil Characterization Database (1965-1996) for direct comparison. Results show that SOC stocks significantly differed among LULC classes--sugarcane and wetland contained the highest SOC, followed by improved pasture, urban, mesic upland forest, rangeland, and pineland while crop, citrus and xeric upland forest remained the lowest. The surface 20 cm soils acted as a net sink for C with the median SOC significantly increasing from 2.69 to 3.40 kg m(-2) over the past decades. The SOC sequestration rate was LULC dependent and controlled by climate factors interacting with LULC. Higher temperature tended to accelerate SOC accumulation, while higher precipitation reduced the SOC sequestration rate. Land use/land cover change observed over the past four decades also favored the C sequestration in soils due to the increase in the C-rich wetland area by ~140% and decrease in the C-poor agricultural area by ~20%. Soils are likely to provide a substantial soil C sink considering the climate and LULC projections for this region.

  17. Ionic conductivity anomaly in soil cover——Exploration of blind mineralization beneath regolith cover

    Institute of Scientific and Technical Information of China (English)

    KEELING; John; L.

    2010-01-01

    This paper briefly describes the formation of ionic conductivity anomalies in soil cover, and the characteristics of ionic composition that forms conductivity anomalies, based on the theory of geoelectrochemical halo. Based on some practical results of soluble ions in soil cover and soil conductivity derived from a number of mining areas of both China and overseas, here we present the correlation of a conductivity anomaly with the ionic composition and establish a model for the formation of conductivity anomalies in soil cover. The results indicate that the formation of a conductivity anomaly is not a simple transformation of a secondary geochemical anomaly. A conductivity anomaly is formed as the result of electrochemical and chemical processes, by transformation of orebody into various ionic haloes through four physicochemical processes: 1) dissolution of the orebody, 2) migration of dissolved matter, 3) conversion of matter near the surface, and 4) the formation of ionic conductivity anomalies. The conductivity anomaly, as a physical parameter, essentially represents the integration of various geochemical compositions and is controlled by a set of particular ionic groups.

  18. Water Balance Components in Covered and Uncovered Soil Growing Irrigated Muskmelon

    Directory of Open Access Journals (Sweden)

    Paulo Leonel Libardi

    2015-10-01

    Full Text Available ABSTRACT Knowledge of the terms (or processes of the soil water balance equation or simply the components of the soil water balance over the cycle of an agricultural crop is essential for soil and water management. Thus, the aim of this study was to analyze these components in a Cambissolo Háplico (Haplocambids growing muskmelon (Cucumis melo L. under drip irrigation, with covered and uncovered soil, in the municipality of Baraúna, State of Rio Grande do Norte, Brazil (05º 04’ 48” S, 37º 37’ 00” W. Muskmelon, variety AF-646, was cultivated in a flat experimental area (20 × 50 m. The crop was spaced at 2.00 m between rows and 0.35 m between plants, in a total of ten 50-m-long plant rows. At points corresponding to ⅓ and ⅔ of each plant row, four tensiometers (at a distance of 0.1 m from each other were set up at the depths of 0.1, 0.2, 0.3, and 0.4 m, adjacent to the irrigation line (0.1 m from the plant row, between two selected plants. Five random plant rows were mulched using dry leaves of banana (Musa sp. along the drip line, forming a 0.5-m-wide strip, which covered an area of 25 m2 per of plant row with covered soil. In the other five rows, there was no covering. Thus, the experiment consisted of two treatments, with 10 replicates, in four phenological stages: initial (7-22 DAS - days after sowing, growing (22-40 DAS, fruiting (40-58 DAS and maturation (58-70 DAS. Rainfall was measured with a rain gauge and water storage was estimated by the trapezoidal method, based on tensiometer readings and soil water retention curves. For soil water flux densities at 0.3 m, the tensiometers at the depths of 0.2, 0.3, and 0.4 m were considered; the tensiometer at 0.3 m was used to estimate soil water content from the soil water retention curve at this depth, and the other two to calculate the total potential gradient. Flux densities were calculated through use of the Darcy-Buckingham equation, with hydraulic conductivity determined by

  19. Land agroecological quality assessment in conditions of high spatial soil cover variability at the Pereslavskoye Opolye.

    Science.gov (United States)

    Morev, Dmitriy; Vasenev, Ivan

    2015-04-01

    The essential spatial variability is mutual feature for most natural and man-changed soils at the Central region of European territory of Russia. The original spatial heterogeneity of forest soils has been further complicated by a specific land-use history and human impacts. For demand-driven land-use planning and decision making the quantitative analysis and agroecological interpretation of representative soil cover spatial variability is an important and challenging task that receives increasing attention from private companies, governmental and environmental bodies. Pereslavskoye Opolye is traditionally actively used in agriculture due to dominated high-quality cultivated soddy-podzoluvisols which are relatively reached in organic matter (especially for conditions of the North part at the European territory of Russia). However, the soil cover patterns are often very complicated even within the field that significantly influences on crop yield variability and have to be considered in farming system development and land agroecological quality evaluation. The detailed investigations of soil regimes and mapping of the winter rye yield have been carried in conditions of two representative fields with slopes sharply contrasted both in aspects and degrees. Rye biological productivity and weed infestation have been measured in elementary plots of 0.25 m2 with the following analysis the quality of the yield. In the same plot soil temperature and moisture have been measured by portable devices. Soil sampling was provided from three upper layers by drilling. The results of ray yield detailed mapping shown high differences both in average values and within-field variability on different slopes. In case of low-gradient slope (field 1) there is variability of ray yield from 39.4 to 44.8 dt/ha. In case of expressed slope (field 2) the same species of winter rye grown with the same technology has essentially lower yield and within-field variability from 20 to 29.6 dt/ha. The

  20. Microbial diversity in alpine tundra soils correlates with snow cover dynamics.

    Science.gov (United States)

    Zinger, Lucie; Shahnavaz, Bahar; Baptist, Florence; Geremia, Roberto A; Choler, Philippe

    2009-07-01

    The temporal and spatial snow cover dynamics is the primary factor controlling the plant communities' composition and biogeochemical cycles in arctic and alpine tundra. However, the relationships between the distribution of snow and the diversity of soil microbial communities remain largely unexplored. Over a period of 2 years, we monitored soil microbial communities at three sites, including contiguous alpine meadows of late and early snowmelt locations (LSM and ESM, respectively). Bacterial and fungal communities were characterized by using molecular fingerprinting and cloning/sequencing of microbial ribosomal DNA extracted from the soil. Herein, we show that the spatial and temporal distribution of snow strongly correlates with microbial community composition. High seasonal contrast in ESM is associated with marked seasonal shifts for bacterial communities; whereas less contrasted seasons because of long-lasting snowpack in LSM is associated with increased fungal diversity. Finally, our results indicate that, similar to plant communities, microbial communities exhibit important shifts in composition at two extremes of the snow cover gradient. However, winter conditions lead to the convergence of microbial communities independently of snow cover presence. This study provides new insights into the distribution of microbial communities in alpine tundra in relation to snow cover dynamics, and may be helpful in predicting the future of microbial communities and biogeochemical cycles in arctic and alpine tundra in the context of a warmer climate.

  1. Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

    Science.gov (United States)

    Rivera, Desirée; Mejías, Violeta; Jáuregui, Berta M; Costa-Tenorio, Marga; López-Archilla, Ana Isabel; Peco, Begoña

    2014-01-01

    The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm) on two surrogates of microbial activity (β-glucosidase and phosphatase enzymes activity and soil respiration), and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%), nitrogen (44%), assimilable phosphorous (50%) and silt content (54%) than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased β-glucosidase activity (45%), phosphatase activity (57%) and soil respiration (60%). Depth seemed to affect soil respiration, β-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to the

  2. Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

    Directory of Open Access Journals (Sweden)

    Desirée Rivera

    Full Text Available The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm on two surrogates of microbial activity (β-glucosidase and phosphatase enzymes activity and soil respiration, and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%, nitrogen (44%, assimilable phosphorous (50% and silt content (54% than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased β-glucosidase activity (45%, phosphatase activity (57% and soil respiration (60%. Depth seemed to affect soil respiration, β-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to

  3. Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

    Energy Technology Data Exchange (ETDEWEB)

    Song Qing, E-mail: qsong3@uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada); Yanful, Ernest K., E-mail: eyanful@eng.uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada)

    2011-05-15

    Research Highlights: > A channelled cover with preferential flow can still mitigate ARD to some extent. > Oxygen ingress was more sensitive to the location of the channel than to K{sub s}. > The channel in the barrier layer was a major passage for O{sub 2} ingress. > Actual flushing was an important factor when estimating O{sub 2} decay coefficient. - Abstract: An ideal engineered soil cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O{sub 2} ingress into an underlying waste rock pile. However, the barrier layer in the soil cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O{sub 2} transport in the soil cover and decrease performance in the long run. The present study employed a 10-cm-wide sand-filled channel installed in a soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the cover. The soil cover had a slope of 20%. Oxygen transport through the soil cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without soil cover). Moreover, gaseous O{sub 2} transport in the soil cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the soil cover with channel had a lower oxidation rate than the waste rock without cover because of reduced O{sub 2} ingress and water flushing in the soil cover with channel, which meant a partial soil cover might still be effective to some extent in reducing ARD generation. Gaseous O{sub 2} ingress into the covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy

  4. Inoculum production of arbuscular mycorrhizal fungi native to soils under different forest covers

    Directory of Open Access Journals (Sweden)

    Renata Soares dos Santos

    Full Text Available ABSTRACT The low natural fertility of Brazilian soils requires the use of inoculants that facilitate the absorption of nutrients by plants. Arbuscular mycorrhizal fungi such as obligatory biotrophics of active roots perform this function, but access to this resource is limited by the difficulty in producing inoculants. The objective of this study was to investigate the production of AMF inoculants native of soils under different forest covers in Vitória da Conquista, BA, by means of spore quantification, colonization rate and species identification. For this purpose, soils were collected from sites under Mata Nativa (native forest and plantations of Madeira Nova (Pterogyne nitens and Eucalyptus, placed into separate 500 mL disposable cups with seeds of Brachiaria sp. and cultivated for five months. Spores were quantified and the AMF species identified in the control soil (without brachiaria and in the cups cultivated with brachiaria at each month. From the first month, the colonization rate of brachiaria roots was evaluated. The inoculants produced showed differences in the number of spores and species, in the AMF species identified, and in the root colonization rate as a function of the forest cover. Thus, considering the increase in the number of spores, species and colonization over time, the inoculant produced from the soil under native forest was more promising for utilization.

  5. Chemical composition of overland flow produced on soils covered with vegetative ash

    Directory of Open Access Journals (Sweden)

    M.B. Bodí

    2013-05-01

    Full Text Available The objective of this study was to ascertain the differences between the soluble elements of ash obtained under laboratory conditions and the dissolved in overland flow from soils covered with a layer of ash. The overland flow was obtained during series of rainfall simulations over soils covered with two different types of ash. This study indicates that the soluble elements released from ash can modify water quality increasing its pH, electrical conductivity and especially cation content. The nutrients solubilised are not necessarily the same as the elemental composition of ash itself. Runoff composition depends on the volume of water produced, on the solubility of the ash components and on the chemical interactions with water from rainfall and soil. After the first intense rain event, most of the elements are solubilised and lixiviated or washed out, however, some of them may increase in the runoff or soil water some weeks later due to chemical interactions with water from rainfall and soil nutrients.

  6. Frequent fire promotes diversity and cover of biological soil crusts in a derived temperate grassland.

    Science.gov (United States)

    O'Bryan, Katharine E; Prober, Suzanne Mary; Lunt, Ian D; Eldridge, David J

    2009-04-01

    The intermediate disturbance hypothesis (IDH) predicts that species diversity is maximized at moderate disturbance levels. This model is often applied to grassy ecosystems, where disturbance can be important for maintaining vascular plant composition and diversity. However, effects of disturbance type and frequency on cover and diversity of non-vascular plants comprising biological soil crusts are poorly known, despite their potentially important role in ecosystem function. We established replicated disturbance regimes of different type (fire vs. mowing) and frequency (2, 4, 8 yearly and unburnt) in a high-quality, representative Themeda australis-Poa sieberiana derived grassland in south-eastern Australia. Effects on soil crust bryophytes and lichens (hereafter cryptogams) were measured after 12 years. Consistent with expectations under IDH, cryptogam richness and abundance declined under no disturbance, likely due to competitive exclusion by vascular plants as well as high soil turnover by soil invertebrates beneath thick grass. Disturbance type was also significant, with burning enhancing richness and abundance more than mowing. Contrary to expectations, however, cryptogam richness increased most dramatically under our most frequent and recent (2 year) burning regime, even when changes in abundance were accounted for by rarefaction analysis. Thus, from the perspective of cryptogams, 2-year burning was not an adequately severe disturbance regime to reduce diversity, highlighting the difficulty associated with expression of disturbance gradients in the application of IDH. Indeed, significant correlations with grassland structure suggest that cryptogam abundance and diversity in this relatively mesic (600 mm annual rainfall) grassland is maximised by frequent fires that reduce vegetation and litter cover, providing light, open areas and stable soil surfaces for colonisation. This contrasts with detrimental effects of 2-year burning on native perennial grasses

  7. Minimum depth of soil cover above long-span soil-steel railway bridges

    National Research Council Canada - National Science Library

    Esmaeili, Morteza; Zakeri, Jabbar Ali; Abdulrazagh, Parisa Haji

    2013-01-01

    .... The currently developed formula for determining the minimum depth of covers by existing codes is typically based on vehicle loads and non-stiffened panels and takes into consideration the geometrical...

  8. Effect of soil roughness on the inversion of off-ground monostatic GPR signal for noninvasive quantification of soil properties

    NARCIS (Netherlands)

    Lambot, S.; Antoine, M.; Vanclooster, M.; Slob, E.C.

    2006-01-01

    We report on a laboratory experiment that investigates the effect of soil surface roughness on the identification of the soil electromagnetic properties from full-wave inversion of ground-penetrating radar (GPR) data in the frequency domain. The GPR system consists of an ultrawide band stepped-frequ

  9. The effect of surface cover and soil devastation on infiltration rate in steep forest plantations

    Science.gov (United States)

    Onda, Y.; Hiraoka, M.; Kato, H.; Gomi, T.; Miyata, S.; Mizugaki, S.

    2008-12-01

    The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore there is a concern for overlandflow and sediment yield due to infiltration rate lowering. We developed a light-weight rainfall simulator based on the design of Meyer and Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fan sweeps across the targeting 1 m x 1 m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can simulate the high raindrop kinetic energy of natural throughfall. A targeted rainfall rate is 180 mm/h. About 30 sprinkling experiments have been conducted on 35-degree hillslopes with varying surface cover in 5 locations in Japan. We obtained the minimum infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the increasing total surface cover, and generally higher regression coefficient was found for the case of the total surface cover. In some cases, high infiltration rates were obtained where surface cover is low. Two possible explanations can be made; 1) surface soil (especially fine particles) has been washed away, where soil is mostly composed of gravel and the percentage of fine fraction is low, or 2) because of long-term soil loss by raindrop detachment, remaining soil looks like "ghanging"h between exposed fine root networks of Japanese cypress, where soil bulk density is significantly lower than other site. Therefore the infiltration rate in the devastated Japanese cypress plantations is not only controlled by loss of surface vegetation by low light condition, but soil

  10. Changes in Soil Spectral Reflectance Curves by Varying Percentages of Vegetative Cover

    Science.gov (United States)

    1981-02-27

    plant species used in this study were marigold (Targetes sp.) and silver lace dusty miller (Cineraria sp.), that were green (Munsell color 7.5GY4/4...collection, pots containing the marigolds were placed in a test plot in the 12 x 12 pot matrix to form the 100% vegetative cover condition. Soil was carefully...placed around each pot, so only sunlit and shadowed plants and soil formed the target in the field-of- view (FOV). The potted marigolds were removed

  11. Characterization of H2S removal and microbial community in landfill cover soils.

    Science.gov (United States)

    Xia, Fang-Fang; Zhang, Hong-Tao; Wei, Xiao-Meng; Su, Yao; He, Ruo

    2015-12-01

    H2S is a source of odors at landfills and poses a threat to the surrounding environment and public health. In this work, compared with a usual landfill cover soil (LCS), H2S removal and biotransformation were characterized in waste biocover soil (WBS), an alternative landfill cover material. With the input of landfill gas (LFG), the gas concentrations of CH4, CO2, O2, and H2S, microbial community and activity in landfill covers changed with time. Compared with LCS, lower CH4 and H2S concentrations were detected in the WBS. The potential sulfur-oxidizing rate and sulfate-reducing rate as well as the contents of acid-volatile sulfide, SO4(2-), and total sulfur in the WBS and LCS were all increased with the input of LFG. After exposure to LFG for 35 days, the sulfur-oxidizing rate of the bottom layer of the WBS reached 82.5 μmol g dry weight (d.w.)(-1) day(-1), which was 4.3-5.4 times of that of LCS. H2S-S was mainly deposited in the soil covers, while it escaped from landfills to the atmosphere. The adsorption, absorption, and biotransformation of H2S could lead to the decrease in the pH values of landfill covers; especially, in the LCS with low pH buffer capacity, the pH value of the bottom layer dropped to below 4. Pyrosequencing of 16S ribosomal RNA (rRNA) gene showed that the known sulfur-metabolizing bacteria Ochrobactrum, Paracoccus, Comamonas, Pseudomonas, and Acinetobacter dominated in the WBS and LCS. Among them, Comamonas and Acinetobacter might play an important role in the metabolism of H2S in the WBS. These findings are helpful to understand sulfur bioconversion process in landfill covers and to develop techniques for controlling odor pollution at landfills.

  12. Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

    Science.gov (United States)

    Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

    2017-03-06

    Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  13. Sustainable Production of Japanese Eggplants in a Piedmont Soil in Rotation with Winter Cover Crops

    Directory of Open Access Journals (Sweden)

    Ahmed Elobeid

    2013-03-01

    Full Text Available Eggplant is a popular vegetable consumed all over the world. Cover cropping is an efficient way of recycling nutrients and reducing inorganic fertilizer requirements to maintain the sustainability of the soil without affecting productivity and profitability. Eggplants (Solanum melongena (Japanese varieties Hansel and Kamo were grown in a Piedmont soil with two main treatments, cover crop (CC and no cover crop (NC, and four sub-fertilizer treatments (T1: 0-0-0, T2: 56-28-112, T3: 84-56-168, and T4: 168-112-224 N-P-K kg/ha, using four replications. The Hansel variety eggplant yield was significantly higher than the Kamo variety. Eggplant yields from CC treatments for both varieties were significantly higher (p < 0.001 than the yields from NC treatments. No significant difference was observed in the yields between T1 and T2 treatments, but the yields from T3 were significantly higher than T1 and T2 and yields from T4 were significantly higher than T3 yields. N released through mineralization of cover crop mixture ranged from 13.33 g/kg at the beginning of the growing season and increased to 18.32 g/kg at the end of the growing season. These results suggest that Japanese eggplants can be successfully grown in the Piedmont area of North Carolina in rotation with cover crops for higher yields.

  14. Upland rice under no-tillage preceded by crops for soil cover and nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Edemar Moro

    2013-12-01

    Full Text Available The grain yield of upland rice under no-tillage has been unsatisfactory and one reason could be the nitrate/ammonium balance in the soil. Cover crops and nitrogen fertilization can be used to change the nitrate/ammonium relation in the soil and improve conditions for the development of upland rice in the no-tillage (NT system. The aim was to study the effect of cover crops and nitrogen sources on grain yield of upland rice under no tillage. The study was carried out on the Fazenda Experimental Lageado, in Botucatu, State of São Paulo, Brazil, in an Oxisol area under no-tillage for six years. The experiment was arranged in a randomized block split-plot design with four replications. The plots consisted of six cover crop species (Brachiaria brizantha, B. decumbens, B. humidicola, B. ruziziensis, Pennisetum americanum, and Crotalaria spectabilis and the split-plots of seven forms of N fertilizer management. Millet is the best cover crop to precede upland rice under NT. The best form of N application, as nitrate, is in split rates or total rate at topdressing or an ammonium source with or without a nitrification inhibitor, in split doses. When the cover crops C. spectabilis, B. brizantha, B. decumbens, B. humidicola, and B. ruziziensis preceded rice, they induced the highest grain yield when rice was fertilized with N as ammonium sulfate source + nitrification inhibitor in split rates or total dose at topdressing.

  15. Citizen science land cover classification based on ground and satellite imagery: Case study Day River in Vietnam

    Science.gov (United States)

    Nguyen, Son Tung; Minkman, Ellen; Rutten, Martine

    2016-04-01

    Citizen science is being increasingly used in the context of environmental research, thus there are needs to evaluate cognitive ability of humans in classifying environmental features. With the focus on land cover, this study explores the extent to which citizen science can be applied in sensing and measuring the environment that contribute to the creation and validation of land cover data. The Day Basin in Vietnam was selected to be the study area. Different methods to examine humans' ability to classify land cover were implemented using different information sources: ground based photos - satellite images - field observation and investigation. Most of the participants were solicited from local people and/or volunteers. Results show that across methods and sources of information, there are similar patterns of agreement and disagreement on land cover classes among participants. Understanding these patterns is critical to create a solid basis for implementing human sensors in earth observation. Keywords: Land cover, classification, citizen science, Landsat 8

  16. Estimating Cotton Nitrogen Nutrition Status Using Leaf Greenness and Ground Cover Information

    Directory of Open Access Journals (Sweden)

    Farrah Melissa Muharam

    2015-05-01

    Full Text Available Assessing nitrogen (N status is important from economic and environmental standpoints. To date, many spectral indices to estimate cotton chlorophyll or N content have been purely developed using statistical analysis approach where they are often subject to site-specific problems. This study describes and tests a novel method of utilizing physical characteristics of N-fertilized cotton and combining field spectral measurements made at different spatial scales as an approach to estimate in-season chlorophyll or leaf N content of field-grown cotton. In this study, leaf greenness estimated from spectral measurements made at the individual leaf, canopy and scene levels was combined with percent ground cover to produce three different indices, named TCCLeaf, TCCCanopy, and TCCScene. These indices worked best for estimating leaf N at early flowering, but not for chlorophyll content. Of the three indices, TCCLeaf showed the best ability to estimate leaf N (R2 = 0.89. These results suggest that the use of green and red-edge wavelengths derived at the leaf scale is best for estimating leaf greenness. TCCCanopy had a slightly lower R2 value than TCCLeaf (0.76, suggesting that the utilization of yellow and red-edge wavelengths obtained at the canopy level could be used as an alternative to estimate leaf N in the absence of leaf spectral information. The relationship between TCCScene and leaf N was the lowest (R2 = 0.50, indicating that the estimation of canopy greenness from scene measurements needs improvement. Results from this study confirmed the potential of these indices as efficient methods for estimating in-season leaf N status of cotton.

  17. Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River

    NARCIS (Netherlands)

    Ouyang, W.; Hao, F.; Skidmore, A.K.; Toxopeus, A.G.

    2010-01-01

    Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and

  18. Applications of remote sensing and GIS in surface hydrology: Snow cover, soil moisture and precipitation

    Science.gov (United States)

    Wang, Xianwei

    Studies on surface hydrology can generally be classified into two categories, observation for different components of surface water, and modeling their dynamic movements. This study only focuses on observation part of surface water components: snow cover, soil moisture, and precipitation. Moreover, instead of discussion on the detailed algorithm and instrument technique behind each component, this dissertation pours efforts on analysis of the standard remotely sensed products and their applications under different settings. First in Chapter 2, validation of MODIS Terra 8-day maximum snow cover composite (MOD10A2) in the Northern Xinjiang, China, from 2000-2006, shows that the 8-day MODIS/Terra product has high agreements with in situ measurements as the in situ snow depth is larger or equal to 4 cm, while the agreement is low for the patchy snow as the in situ snow depth less than 4 cm. According to the in situ observation, this chapter develops an empirical algorithm to separate the cloud-covered pixels into snow and no snow. Continued long-term production of MODIS-type snow cover product is critical to assess water resources of the study area, as well as other larger scale global environment monitoring. Terra and Aqua satellites carry the same MODIS instrument and provide two parallel MODIS daily snow cover products at different time (local time 10:30 am and 1:30 pm, respectively). Chapter 3 develops an algorithm and automated scripts to combine the daily MODIS Terra (MOD10A1) and Aqua (MYD10A1) snow cover products, and to automatically generate multi-day Terra-Aqua snow cover image composites, with flexible starting and ending dates and a user-defined cloud cover threshold. Chapter 4 systematically compares the difference between MODIS Terra and Aqua snow cover products within a hydrologic year of 2003-2004, validates the MODIS Terra and Aqua snow cover products using in situ measurements in Northern Xinjiang, and compares the accuracy among the standard MODIS

  19. Soil microbial functionality in response to the inclusion of cover crop mixtures in agricultural systems

    Energy Technology Data Exchange (ETDEWEB)

    Chavarría, D.N.; Verdenelli, R.A.; Muñoz, M.J.; Conforto, C.; Restovich, S.B.; Andriulo, A.E.; Meriles, J.M.; Vargas-Gil, S.

    2016-11-01

    Agricultural systems where monoculture prevails are characterized by fertility losses and reduced contribution to ecosystem services. Including cover crops (CC) as part of an agricultural system is a promising choice in sustainable intensification of those demanding systems. We evaluated soil microbial functionality in cash crops in response to the inclusion of CC by analyzing soil microbial functions at two different periods of the agricultural year (cash crop harvest and CC desiccation) during 2013 and 2014. Three plant species were used as CC: oat (Avena sativa L.), vetch (Vicia sativa L.) and radish (Raphanus sativus L.) which weresown in two different mixtures of species: oat and radish mix (CC1) and oat, radish and vetch mix (CC2), with soybean monoculture and soybean/corn being the cash crops. The study of community level physiological profiles showed statistical differences in respiration of specific C sources indicating an improvement of catabolic diversity in CC treatments. Soil enzyme activities were also increased with the inclusion of CC mixtures, with values of dehydrogenase activity and fluorescein diacetate hydrolysis up to 38.1% and 35.3% higher than those of the control treatment, respectively. This research evidenced that CC inclusion promotes soil biological quality through a contribution of soil organic carbon, improving the sustainability of agrosystems. The use of a CC mixture of three plant species including the legume vetch increased soil biological processes and catabolic diversity, with no adverse effects on cash crop grain yield. (Author)

  20. Soil microbial functionality in response to the inclusion of cover crop mixtures in agricultural systems

    Directory of Open Access Journals (Sweden)

    Diego N. Chavarría

    2016-06-01

    Full Text Available Agricultural systems where monoculture prevails are characterized by fertility losses and reduced contribution to ecosystem services. Including cover crops (CC as part of an agricultural system is a promising choice in sustainable intensification of those demanding systems. We evaluated soil microbial functionality in cash crops in response to the inclusion of CC by analyzing soil microbial functions at two different periods of the agricultural year (cash crop harvest and CC desiccation during 2013 and 2014. Three plant species were used as CC: oat (Avena sativa L., vetch (Vicia sativa L. and radish (Raphanus sativus L. which were sown in two different mixtures of species: oat and radish mix (CC1 and oat, radish and vetch mix (CC2, with soybean monoculture and soybean/corn being the cash crops. The study of community level physiological profiles showed statistical differences in respiration of specific C sources indicating an improvement of catabolic diversity in CC treatments. Soil enzyme activities were also increased with the inclusion of CC mixtures, with values of dehydrogenase activity and fluorescein diacetate hydrolysis up to 38.1% and 35.3% higher than those of the control treatment, respectively. This research evidenced that CC inclusion promotes soil biological quality through a contribution of soil organic carbon, improving the sustainability of agrosystems. The use of a CC mixture of three plant species including the legume vetch increased soil biological processes and catabolic diversity, with no adverse effects on cash crop grain yield.

  1. Phosphatase activity in sandy soil influenced by mycorrhizal and non-mycorrhizal cover crops

    Directory of Open Access Journals (Sweden)

    Alceu Kunze

    2011-06-01

    Full Text Available Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat (Avena strigosa Schreb or the non-mycorrhizal species oilseed radish (Raphanus sativus L. var. oleiferus Metzg and corn spurry (Spergula arvensis L.. The control treatment consisted of resident vegetation (fallow in the winter season. In the summer, a mixture of pearl millet (Pennisetum americanum L. with sunnhemp (Crotalaria juncea L. or with soybean (Glycine max L. was sown in all plots. Soil cores (0-10 cm and root samples were collected in six growing seasons (winter and summer of each year. Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35 % higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.

  2. Effect of Winter Cover Crops on Soil Nitrogen Availability, Corn Yield, and Nitrate Leaching

    Directory of Open Access Journals (Sweden)

    S. Kuo

    2001-01-01

    Full Text Available Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3 leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L., annual ryegrass (Lolium multiflorum, and hairy vetch (Vicia villosa, and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L. yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha-1, referred to as N0, N1, N2, and N3, respectively applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N0, N2, and N3 treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency’s drinking water standard of 10 mg N l�1 even at recommended N rate for corn in this region (coastal Pacific Northwest. In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake correlated well with average NO3

  3. Effect of winter cover crops on soil nitrogen availability, corn yield, and nitrate leaching.

    Science.gov (United States)

    Kuo, S; Huang, B; Bembenek, R

    2001-10-25

    Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3 leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha(-1), referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N 0, N 2, and N 3 treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency's drinking water standard of 10 mg N l(-1) even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during

  4. Methane oxidation in a landfill cover soil reactor: Changing of kinetic parameters and microorganism community structure.

    Science.gov (United States)

    Xing, Zhi L; Zhao, Tian T; Gao, Yan H; Yang, Xu; Liu, Shuai; Peng, Xu Y

    2017-02-23

    Changing of CH4 oxidation potential and biological characteristics with CH4 concentration was studied in a landfill cover soil reactor (LCSR). The maximum rate of CH4 oxidation reached 32.40 mol d(-1) m(-2) by providing sufficient O2 in the LCSR. The kinetic parameters of methane oxidation in landfill cover soil were obtained by fitting substrate diffusion and consumption model based on the concentration profile of CH4 and O2. The values of [Formula: see text] (0.93-2.29%) and [Formula: see text] (140-524 nmol kgsoil-DW(-1)·s(-1)) increased with CH4 concentration (9.25-20.30%), while the values of [Formula: see text] (312.9-2.6%) and [Formula: see text] (1.3 × 10(-5) to 9.0 × 10(-3) nmol mL(-1) h(-1)) were just the opposite. MiSeq pyrosequencing data revealed that Methylobacter (the relative abundance was decreased with height of LCSR) and Methylococcales_unclassified (the relative abundance was increased expect in H 80) became the key players after incubation with increasing CH4 concentration. These findings provide information for assessing CH4 oxidation potential and changing of biological characteristics in landfill cover soil.

  5. Ground and canopy soil N2O fluxes from smallholder oil palm plantations following deforestation in Sumatra, Indonesia

    Science.gov (United States)

    Hassler, Evelyn; Corre, Marife D.; Kurniawan, Syahrul; Allen, Kara; Veldkamp, Edzo

    2017-04-01

    Due to an increasing global demand in cheap oils and biofuels, forest conversion to oil palm plantations is rapidly increasing in Indonesia. Although forest conversion is known to influence soil N2O fluxes, measurements from oil palm are scarce. Our study aimed to (1) quantify changes in soil N2O fluxes with forest conversion to oil palm plantations, (2) quantify the contribution of oil-palm canopy soil (lodged between the stems and leaf axils) to N2O fluxes, and (3) determine their controlling factors. In Jambi, Sumatra, we selected two landscapes that mainly differed in soil texture but both on heavily weathered soils: loam and clay Acrisol soils. Within each landscape, we investigated lowland forest, jungle rubber (rubber trees interspersed in secondary forest), both as the reference (previous) land uses, and the converted oil palm plantations by smallholders. Each land use had four replicate plots within each landscape. Each replicate plot had four permanently placed chambers, and soil N2O fluxes were measured monthly from December 2012 to December 2013 by placing vented static covers on chamber bases for 30 minutes for gas flux measurement. For oil-palm canopy soil, each replicate plot was represented by five oil palms, and each oil palm stem was delineated into three 1-m sections (low, middle, and top) in order to represent possible gradients of canopy soil conditions that influence N2O fluxes. Measurements were conducted from February 2013 to May 2014 by collecting canopy soil from each stem section and incubating it in-situ in an air-tight glass jar. Land-use conversion to smallholder plantations had no effect on soil N-oxide fluxes (P = 0.58 to 0.76) due to the inherently low soil N availability and the low N fertilization rates (commonly 48 to 88 kg N ha-1 yr-1) of smallholder oil palm plantations. Soil N2O fluxes (kg N ha-1 yr-1) were: 0.6 ± 0.1 to 1.2 ± 0.6 from the reference land uses and 1.0 ± 0.2 to 1.1 ± 0.5 from the smallholder oil palm

  6. Winter pasture and cover crops and their effects on soil and summer grain crops

    Directory of Open Access Journals (Sweden)

    Alvadi Antonio Balbinot Junior

    2011-10-01

    Full Text Available The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N fertilization (intercropping cover; the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N; the same intercropping, with grazing and without nitrogen fertilization (pasture without N; oilseed radish, without grazing and nitrogen fertilization (oilseed radish; and natural vegetation, without grazing and nitrogen fertilization (fallow. Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.

  7. The use of cover crops to increase soil organic carbon in Mediterranean vineyards

    Science.gov (United States)

    García-Díaz, Andrés; Bienes Allas, Ramón; Sastre Rodriguez, Blanca

    2016-04-01

    In Central Spain the vineyards are commonly managed with conventional tillage (CT) to remove water and nutrient competition between the spontaneous vegetation and the vine plants. The continuous tillage promotes high mineralization rates resulting in soils with low organic matter content and prone to erosion. Consequently the increase of soil organic carbon (SOC) in Mediterranean soils has been a main concern in the last years. It is necessary to carry out different soil managements to enhance soil fertility and reduce erosion through the increase of SOC. The aim of this study was to assess the capacity of cover crops (CC) to increase SOC in vineyards in Mediterranean climate. The experiment consisted in four vineyards in four different locations (different type of soil and microclimate), in the same region, to analyze the influence of CC on different conditions. A seeded CC (Brachypodium distachyon L. P. Beauv) and spontaneous vegetation were performed to compare to CT. The Brachypodium distachyon cover was seeded in December, 2012. We analyzed the organic carbon content and bulk density after three agronomy seasons. The samples were taken in the summer of 2015 at the depth of 0-5 cm. The bulk density of Brachypodium distachyon was 1.42 t•m-3, which was statistically significant comparing to both CT (1.33 t•m-3) and spontaneous vegetation (1.34 t•m-3). The SOC percentage of CT, Brachypodium distachyon and spontaneous vegetation was 0.82, 0.96 and 1.10 respectively. Only spontaneous vegetation showed statistically significant differences compared to CT. The results were highly variable depending on the vineyard. The spontaneous vegetation was the most effective CC increasing SOC with an average of 2 t•ha-1 more than CT in three agronomy seasons. These results point out the different efficiency of CC and the high influence of local conditions on SOC increase.

  8. The Role of Snow Cover in Affecting Pan-Arctic Soil Freeze/Thaw and Carbon Dynamics

    Science.gov (United States)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-12-01

    Satellite data records spanning the past 3 decades indicate widespread reductions (~0.8-1.3 days decade-1) in mean annual snow cover and frozen season duration across the pan-Arctic domain, coincident with regional climate warming. How the northern soil carbon pool responds to these changes will have a large impact on projected regional and global climate trends. The objective of this study was to assess how northern soil thermal and carbon dynamics respond to changes in surface snow cover and freeze/thaw (F/T) cycles indicated from satellite observations. We developed a coupled permafrost, hydrology and carbon model framework to investigate the sensitivity of soil organic carbon stocks and soil decomposition to recent climate variations across the pan-Arctic region from 1982 to 2010. The model simulations were also evaluated against satellite observation records on snow cover and F/T processes. Our results indicate that surface warming promotes wide-spread soil thawing and active layer deepening due to strong control of surface air temperature on upper (-5°C) and promote permafrost degradation in these areas. Our results also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤0.2 m) soil layers, especially in colder climate zones (mean annual Tair≤-10 °C). This non-linear relationship between snow cover and soil decomposition is particularly important in permafrost areas, where a large amount of soil carbon is stored in deep perennial frozen soils that are potentially vulnerable to thawing, with resulting mobilization and accelerated carbon losses from near-term climate change.

  9. Numerical Simulation of Heat Transfer Characteristics of Horizontal Ground Heat Exchanger in Frozen Soil Layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified numerical model of heat transfer characteristics of horizontal ground heat exchanger (GHE) in the frozen soil layer is presented and the steady-state distribution of temperature field is simulated. Numerical results show that the frozen depth mainly depends on the soil's moisture content and ambient temperature. The heat transfer loss of horizontal GHE tends to grow with the increase of the soil's moisture content and the decrease of ambient temperature. Backfilled materials with optimal thermal conductivity can reduce the thermal loss effectively in the frozen soil. The applicability of the Chinese national standard "Technical Code for Ground Source Heat Pump (GB 50366-2005)" is verified. For a ground source heat pump project, the feasible layout of horizontal GHE should be determined based on the integration of the soil's structure, backfilled materials,weather data, and economic analysis.

  10. Spatial Data Mining for Estimating Cover Management Factor of Universal Soil Loss Equation

    Science.gov (United States)

    Tsai, F.; Lin, T. C.; Chiang, S. H.; Chen, W. W.

    2016-12-01

    Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes long-term soil erosion processes. Among the six different soil erosion risk factors of USLE, the cover-management factor (C-factor) is related to land-cover/land-use. The value of C-factor ranges from 0.001 to 1, so it alone might cause a thousandfold difference in a soil erosion analysis using USLE. The traditional methods for the estimation of USLE C-factor include in situ experiments, soil physical parameter models, USLE look-up tables with land use maps, and regression models between vegetation indices and C-factors. However, these methods are either difficult or too expensive to implement in large areas. In addition, the values of C-factor obtained using these methods can not be updated frequently, either. To address this issue, this research developed a spatial data mining approach to estimate the values of C-factor with assorted spatial datasets for a multi-temporal (2004 to 2008) annual soil loss analysis of a reservoir watershed in northern Taiwan. The idea is to establish the relationship between the USLE C-factor and spatial data consisting of vegetation indices and texture features extracted from satellite images, soil and geology attributes, digital elevation model, road and river distribution etc. A decision tree classifier was used to rank influential conditional attributes in the preliminary data mining. Then, factor simplification and separation were considered to optimize the model and the random forest classifier was used to analyze 9 simplified factor groups. Experimental results indicate that the overall accuracy of the data mining model is about 79% with a kappa value of 0.76. The estimated soil erosion amounts in 2004-2008 according to the data mining results are about 50.39 - 74.57 ton/ha-year after applying the sediment delivery ratio and correction coefficient. Comparing with estimations calculated with C-factors from look-up tables, the soil erosion

  11. Effect of management systems and cover crops on organic matter dynamics of soil under vegetables

    Directory of Open Access Journals (Sweden)

    Rodrigo Fernandes de Souza

    2014-06-01

    Full Text Available Vegetable production in conservation tillage has increased in Brazil, with positive effects on the soil quality. Since management systems alter the quantity and quality of organic matter, this study evaluated the influence of different management systems and cover crops on the organic matter dynamics of a dystrophic Red Latosol under vegetables. The treatments consisted of the combination of three soil tillage systems: no-tillage (NT, reduced tillage (RT and conventional tillage (CT and of two cover crops: maize monoculture and maize-mucuna intercrop. Vegetables were grown in the winter and the cover crops in the summer for straw production. The experiment was arranged in a randomized block design with four replications. Soil samples were collected between the crop rows in three layers (0.0-0.05, 0.05-0.10, and 0.10-0.30 m twice: in October, before planting cover crops for straw, and in July, during vegetable cultivation. The total organic carbon (TOC, microbial biomass carbon (MBC, oxidizable fractions, and the carbon fractions fulvic acid (C FA, humic acid (C HA and humin (C HUM were determined. The main changes in these properties occurred in the upper layers (0.0-0.05 and 0.05-0.10 m where, in general, TOC levels were highest in NT with maize straw. The MBC levels were lowest in CT systems, indicating sensitivity to soil disturbance. Under mucuna, the levels of C HA were lower in RT than NT systems, while the C FA levels were lower in RT than CT. For vegetable production, the C HUM values were lowest in the 0.05-0.10 m layer under CT. With regard to the oxidizable fractions, the tillage systems differed only in the most labile C fractions, with higher levels in NT than CT in the 0.0-0.05 m layer in both summer and winter, with no differences between these systems in the other layers. The cabbage yield was not influenced by the soil management system, but benefited from the mulch production of the preceding maize-mucuna intercrop as cover

  12. Application of Ground Phosphate Rock to Diminish the Effects of Simulated Acid Rain of Soil Properties

    Institute of Scientific and Technical Information of China (English)

    DONGYUAN-YAN; LIXUE-YUAN

    1992-01-01

    The effects of simulated acid rain retained in soil on the properties of acid soil and its diminishing by application of ground phosphate rock were investigated by using the sorption method.Results show as follows:(1)For yellow brown soil,the effect of simulated acid rain on the properties of soil with a pH value of 5.9 was relatively small,except a great quantity of acid rain deposited on it.(2) for red soil,the effect of simulated acid rain on the properties of soil was significant.With the increase of the amount of acid deposition,the pH value of soil was declined,but the contents of exchangeable H+,Al3+ and Mn2+ and the amount of SO41- retention were increased.(3) Many properties of acid soils could be improved by applying ground phosphate rock.For example,pH value of soils and the amounts of available P and exchangeable Ca2+ and Mg2+ were increased,and the amounts of exchangeable H+ and Al3+ and SO42- retained was reduced.The application of ground posphate rock could effctively diminish the pollution of acid rain to soil.

  13. Effect of the different cover crops on the soil moisture in a Hungarian vineyard

    Science.gov (United States)

    Donkó, Ádám; Miglécz, Tamás; Valkó, Orsolya; Deák, Balázs; Kelemen, András; Török, Péter; Tóthmérész, Béla; Drexler, Dóra

    2017-04-01

    Since many years it is well known that the one-sided mechanical soil cultivation of vineyard inter-rows has many disadvantages. Growers can choose from alternative tillage technologies, such as the usage of green manure, or covering the inter-rows with straw mulch. Another possible technology is tto cover the inter-rows with species-rich seed mixtures. However, selection of the most suitable species is crucial; we have to take into consideration the age of the vines, and the specific characteristics of the vineyards involved. Species rich cover crop technology has many advantages: 1) it helps to prevent erosion and creates easier cultivation circumstances, 2) it has a positive effect on soil structure, soil fertility and ecosystem services, 3) we can create native mixtures from local provenance, adapted to the local climate/vine region/vineyard which enhances the nature conservation value of our site. But, they should not compete significantly with the grapevines, or negatively influence produce quality. In the year of 2012 we created, and started to study three different cover-crop mixtures in Hungarian wine regions under on-farm conditions: Biocont-Ecovin mixture, Mixture of Legumes, Mixture of Grass and Herbs. The results of the botanical surveys, yield and pruning weight were published in many papers and presentations before (e.g. Miglécz et al. 2015, Donkó et al. 2016). Besides the above measures, one key point of the effectiveness and sustainability of the living mulch vegetation is the level of soil moisture. That is why we started to investigate the soil moisture (vol %) of different treatments (Biocont-Ecovin mixture, Mixture of Legumes, Mixture of Grass and Herbs, coverage with Lolium perenne, and Control (spontaneous weed flora)) in at the Feind Winery in Balatonfőkajár (Hungary). The investigated variety is Welschriesling on loamy soil (Tihany Formation), planted in 2010. The seed mixtures were sown in the spring of 2013. We measured soil moisture

  14. Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    Science.gov (United States)

    Eagleson, Peter S.; Jasinski, Michael F.

    1988-01-01

    The estimation of the spatially variable surface moisture and heat fluxes of natural, semivegetated landscapes is difficult due to the highly random nature of the vegetation (e.g., plant species, density, and stress) and the soil (e.g., moisture content, and soil hydraulic conductivity). The solution to that problem lies, in part, in the use of satellite remotely sensed data, and in the preparation of those data in terms of the physical properties of the plant and soil. The work was focused on the development and testing of a stochastic geometric canopy-soil reflectance model, which can be applied to the physically-based interpretation of LANDSAT images. The model conceptualizes the landscape as a stochastic surface with bulk plant and soil reflective properties. The model is particularly suited for regional scale investigations where the quantification of the bulk landscape properties, such as fractional vegetation cover, is important on a pixel by pixel basis. A summary of the theoretical analysis and the preliminary testing of the model with actual aerial radiometric data is provided.

  15. Tillage systems and cover crops on soil physical properties after soybean cultivation

    Directory of Open Access Journals (Sweden)

    Rafael B. Teixeira

    Full Text Available ABSTRACT Soil management alters soil physical attributes and may affect crop yield. In order to evaluate soil physical attributes in layers from 0 to 0.40 m and soybean grain yield, in the 2012/2013 agricultural year, an essay was installed in the experimental area of the Federal University of Mato Grosso do Sul (UFMS/CPCS. Soil tillage systems were: conventional tillage (CT, minimum tillage (MT and no tillage (DS, the cover crops used were millet, sunn hemp and fallow. The experimental design was randomized blocks with split plots. For the layer of 0.20-0.30 m, millet provided the best results for soil bulk density, macro and microporosity. The resistance to penetration (RP was influenced in the layer of 0-0.10 m, and millet provided lower RP. The DS provided the lowest RP values for the layer of 0.10-0.20 m. The treatments did not influence yield or thousand-seed weight.

  16. Spatial patterns of methane oxidation and methanotrophic diversity in landfill cover soils of southern China.

    Science.gov (United States)

    Chi, Zi-Fang; Lu, Wen-Jing; Wang, Hong-Tao

    2015-04-01

    Aerobic CH4 oxidation is an important CH4 sink in landfills. To investigate the distribution and community diversity of methanotrophs and link with soil characteristics and operational parameters (e.g., concentrations of O2, CH4), cover soil samples were collected at different locations and depths from the Mengzi semi-aerobic landfill (SAL) in Yunnan Province of southern China. Specific PCR followed by denaturing gradient gel electrophoresis and realtime PCR were used to examine methanotrophs in the landfill cover soils. The results showed that different locations did harbor distinct methanotroph communities. Methanotrophs were more abundant in areas near the venting pipes because of the higher O2 concentrations. The depth of 20-25 cm, where the ratio of the CH4 to O2 was within the range from 1.3 to 8.6, was more conducive to the growth of CH4-oxidizing bacteria. Type II methanotrophs dominated in all samples compared with Type I methanotrophs, as evidenced by the high ratio of Type II to Type I methanotrophic copy numbers (from 1.76 to 11.60). The total copy numbers of methanotrophs detected were similar to other ecosystems, although the CH4 concentration was much higher in SAL cover soil. Methylobacter and Methylocystis were the most abundant Type I and Type II methanotrophs genera, respectively, in the Mengzi SAL. The results suggested that SALs could provide a special environment with both high concentrations of CH4 and O2 for methanotrophs, especially around the vertical venting pipes.

  17. Measuring soil frost depth in forest ecosystems with ground penetrating radar

    Science.gov (United States)

    John R. Butnor; John L. Campbell; James B. Shanley; Stanley. Zarnoch

    2014-01-01

    Soil frost depth in forest ecosystems can be variable and depends largely on early winter air temperatures and the amount and timing of snowfall. A thorough evaluation of ecological responses to seasonally frozen ground is hampered by our inability to adequately characterize the frequency, depth, duration and intensity of soil frost events. We evaluated the use of...

  18. Spatial distribution of caesium-137 in soil cover of background terrestrial ecosystems, Central European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation); Shamshurina, Evgenia N. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation)

    2014-07-01

    ¹³⁷Cs - the main long-living anthropogenic radionuclide - arrived in mass at Russian terrestrial ecosystems after nuclear tests in the atmosphere in 1960-yy. and after Chernobyl accident in 1986 y., but in spite of a long period since these events soil cover contamination by ¹³⁷Cs is considered as extremely resistant due to its firmly fixation by soil solid matter and a long half-life of the radionuclide. Wide-scale investigation in maximal diversity of natural, semi-natural and anthropogenic landscapes of Central European Russia (more than 400 soils samples from Vologda, Yaroslavl, Ivanovo, Tver regions which are representative for the southern taiga zone) demonstrates that modern average specific activity of ¹³⁷Cs in the upper 15-cm layer of soil is 11±3 Bq/kg (contamination density 0.05±0.01 Ci/km²), that is fully ecologically acceptable. It is important that the average concentrations of ¹³⁷Cs in the soil cover of individual regions are close to each other. The most likely these average values are approximate assessment of background radioactive contamination of soils in central European Russia outside of the immediate Chernobyl trace. At the same time approximately 3% of soils are characterized by elevated ¹³⁷Cs content - 62-98 Bq/kg (0.24-0.43 Ci/km²), that indicates the presence of low radioactive spots on the territory and may be considered as local Chernobyl fallout. All of them attribute with forest soils which are commonly characterized by considerably more high accumulation of ¹³⁷Cs (18±5 Bq/kg, 0.06±0.01 Ci/km²) due to advanced absorbing surface of trees. Agricultural lands (plagued or under meadows) and soils of industrial plots with scarce vegetation contain only 6±2 Bq/kg (0.03±0.01 Ci/km²) of ¹³⁷Cs. About 84-92% of ¹³⁷Cs are concentrated in the upper 15-cm layer of natural soils or in Ap horizon of plagued soils, thus vertical migration of radionuclide is very slow in spite of ~30 years after Chernobyl

  19. Assessing alternative measures of tree canopy cover: Photo-interpreted NAIP and ground-based estimates

    Science.gov (United States)

    Chris Toney; Greg Liknes; Andy Lister; Dacia Meneguzzo

    2012-01-01

    In preparation for the development of the National Land Cover Database (NLCD) 2011 tree canopy cover layer, a pilot project for research and method development was completed in 2010 by the USDA Forest Service Forest Inventory and Analysis (FIA) program and Remote Sensing Applications Center (RSAC).This paper explores one of several topics investigated during the NLCD...

  20. Condition of forest crops and soil cover at reclaimed dump of coal mine

    Directory of Open Access Journals (Sweden)

    V. A. Androkhanov

    2016-04-01

    Full Text Available The investigation of processes of recovery of disturbed land at the urban areas is a new, urgent problem for indus-trialized centers. Currently disturbed areas where recovery operations are conducted by various reclamation tech-nologies are within the city of Novokuznetsk area in Kuznetsk Basin. Monitoring investigations to determine their environmental condition and the level of natural ingredients recovery have not been conducted at these areas until recently. The lack of such information does not allow efficient analysis of the conducted reclamation activities and determination of the prospects for recovery and further use of such land. The paper presents the results of an inves-tigation of forest plantations and areas with natural revegetation of disturbed areas, and the complex of soil studies to determine the basic physical and agrochemical characteristics of young soils formed on the disturbed surface is conducted. Based on these studies the vegetation and soil cover were characterized and the soil-ecological condition of the reclaimed areas from the 1970’ stailings pile of «Baidaevskij» coal mine was assessed. As a result of reclama-tion activities, the sites with different plant communities are formed at the tailings pile surface. Botanic composition at the reclaimed areas represented species able to operate successfully in a technogenic landscapes. Because the grand dump territory is reclaimed by the forest approach the statement of forest is characterized by the special aspects, such as high density of planting with little crown density, high opacity and low level of stable forest recovery. The tailings pile sites reclaimed by different methods are characterized by specific soil-ecological condition, which can be used to assess the efficiency of reclamation. Soil-ecological assessment of the conducted reclamation efficiency is carried out on the basis of assessment of the soil, formed on the surface of the disturbed area. The more

  1. Fertile ground? : soil fertility management and the African smallholder

    NARCIS (Netherlands)

    Misiko, M.

    2007-01-01

    Keywords: smallholder farmers, soil fertility, experimentation, "inconvenience", realist.The focus in this thesis is to form a view of how well soil fertility research performs within the ever shifting smallholder contexts. This study examined application of agro-ecological knowled

  2. Infiltration through layered-soil trench covers: Response to an extended period of rainfall

    Science.gov (United States)

    Larson, T. H.; Keefer, D. A.; Albrecht, K. A.; Cartwright, K.

    1988-12-01

    Four experimental waste disposal trench covers were constructed to test the effectiveness of layered-soil cover designs in reducing infiltration. Three covers each consisted of a layer of gravel between an overlying wick layer of compacted fine-grained material (either silt or loam) and a compacted loam base; the fourth consisted of compactd silt over a loam base. Capillary pressures were monitored at various depths within each cover during October through December, 1985, a period of high rainfall following a dry summer. Moisture movement in response to the rainfall was rapid within the upper layers of all four test covers, but was retained within the upper layers of the three wick-system trenches, despite variations in the design thickness and composition of the wick layers. In the wick systems, moisture did not enter the gravel until a threshold level of pressure approaching saturation was established in the wick layer. Once this level was reached, moisture moved into and through the gravel. This experiment demonstrates the functionality of field-scale wick systems.

  3. Infiltration through layered-soil trench covers: Response to an extended period of rainfall

    Science.gov (United States)

    Larson, T.H.; Keefer, D.A.; Albrecht, K.A.; Cartwright, K.

    1988-01-01

    Four experimental waste disposal trench covers were constructed to test the effectiveness of layered-soil cover designs in reducing infiltration. Three covers each consisted of a layer of gravel between an overlying wick layer of compacted fine-grained material (either silt or loam) and a compacted loam base; the fourth consisted of compactd silt over a loam base. Capillary pressures were monitored at various depths within each cover during October through December, 1985, a period of high rainfall following a dry summer. Moisture movement in response to the rainfall was rapid within the upper layers of all four test covers, but was retained within the upper layers of the three wick-system trenches, despite variations in the design thickness and composition of the wick layers. In the wick systems, moisture did not enter the gravel until a threshold level of pressure approaching saturation was established in the wick layer. Once this level was reached, moisture moved into and through the gravel. This experiment demonstrates the functionality of field-scale wick systems. ?? 1988.

  4. Comparison of deep percolation rates below contrasting land covers with a joint canopy and soil model

    Science.gov (United States)

    Domínguez, C. G.; Pryet, A.; García Vera, M.; Gonzalez, A.; Chaumont, C.; Tournebize, J.; Villacis, M.; d'Ozouville, N.; Violette, S.

    2016-01-01

    A Rutter-type canopy interception model is combined with a 1-D physically-based soil water flow model to compare deep percolation rates below distinct land covers. The joint model allows the quantification of both evaporation and transpiration rates as well as deep percolation from vegetation and soil characteristics. Experimental observations are required to constitute the input and calibration datasets. An appropriate monitoring design is described which consists in meteorological monitoring together with throughfall and soil water tension measurements. The methodology is illustrated in Santa Cruz Island in the Galapagos Archipelago, which has been affected by significant land use changes. Two adjacent study plots are investigated: a secondary forest and a pasture. The results of the model reveal that evaporation of canopy interception is higher in the pasture due to the bigger canopy storage capacity, which promotes evaporation against canopy drainage. This is however compensated by higher transpiration in the secondary forest, due to the smaller surface resistance. As a consequence, total evapotranspiration is similar for the two plots and no marked difference in deep percolation can be observed. In both cases, deep percolation reaches ca. 2 m/year which corresponds to 80% of the incoming rainfall. This methodology not only allows the quantification of deep percolation, but can also be used to identify the controlling factors of deep percolation under contrasting land covers.

  5. Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils

    Energy Technology Data Exchange (ETDEWEB)

    Jeremy Semrau; Sung-Woo Lee; Jeongdae Im; Sukhwan Yoon; Michael Barcelona

    2010-09-30

    The overall objective of this project, 'Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils' was to develop effective, efficient, and economic methodologies by which microbial production of nitrous oxide can be minimized while also maximizing microbial consumption of methane in landfill cover soils. A combination of laboratory and field site experiments found that the addition of nitrogen and phenylacetylene stimulated in situ methane oxidation while minimizing nitrous oxide production. Molecular analyses also indicated that methane-oxidizing bacteria may play a significant role in not only removing methane, but in nitrous oxide production as well, although the contribution of ammonia-oxidizing archaea to nitrous oxide production can not be excluded at this time. Future efforts to control both methane and nitrous oxide emissions from landfills as well as from other environments (e.g., agricultural soils) should consider these issues. Finally, a methanotrophic biofiltration system was designed and modeled for the promotion of methanotrophic activity in local methane 'hotspots' such as landfills. Model results as well as economic analyses of these biofilters indicate that the use of methanotrophic biofilters for controlling methane emissions is technically feasible, and provided either the costs of biofilter construction and operation are reduced or the value of CO{sub 2} credits is increased, can also be economically attractive.

  6. Geochemical disturbance of soil cover in the nonferrous mining centers of the Selenga River basin.

    Science.gov (United States)

    Timofeev, Ivan V; Kosheleva, Natalia E

    2016-07-04

    The anthropogenic geochemical transformation of soil cover in large nonferrous mining centers of the Selenga River basin was assessed. The results of the geochemical survey of 2010-2012 revealed the spatial distribution patterns and abundances of 18 hazardous heavy metals and metalloids in the soils of Erdenet (Mongolia) and Zakamensk (Buryat republic, Russian Federation). In both cities, mining activities disturbed soil cover which accumulates Mo, Cu, As, Sb, W in Erdenet and Bi, W, Cd, Be, Pb, Mo, Sb in Zakamensk. Maximum accumulation of elements in Erdenet is restricted to the industrial zone. In Zakamensk, it has spread on ½ of the territory with the degree of multielemental pollution exceeding the extremely dangerous level by 16 times. The effect of mining centers on the state of the river system is local and does not spread to the Selenga River. Downstream from Erdenet, an artificial pool intercepts heavy metal and metalloid flows of the Erdenetii-Gol River. By contrast, downstream from the tailing dumps of the Dzhida tungsten-molybdenum plant the concentrations of ore elements W and Mo and their accessories Bi and Cd in the Modonkul River exceed background values by 146, 20, 57, and 21 times, respectively, decreasing by an order of magnitude 30 km downstream.

  7. A proposal for soil cover and management factor (C) for RUSLE in vineyards with different soil management across Europe

    Science.gov (United States)

    Gómez, José Alfonso; Biddoccu, Marcella; Guzman, Gema; Bauer, Thomas; Strauss, Peter; Winter, Silvia; Zaller, Johann; Cavallo, Eugenio

    2017-04-01

    The Revised Universal Soil Loss Equation RUSLE (Dabney et al., 2012) is commonly used to estimate rates of soil erosion caused by rainfall and its associated overland flow on cropland and many other disturbed and undisturbed lands. Several studies have been focused on the evaluation of erosion risk in vineyards across Europe, which has four countries, France, Italy, Spain and Portugal, among the world's top ten vine growers. Other European countries, such as Romania, Greece, Austria, Serbia and Hungary, also have significant surface devoted to vineyards (FAO, 2014). However, literature shows a wide variability among C factors from different sources (Auerswald and Schwab, 1999; Kouli et al., 2009; Novara et al., 2011; Pacheco et al., 2014; Rodrigo Comino et al., 2016) that complicates their interpretation and use outside the area where they were developed. Gómez et al. (2016) presented a simplified erosion prediction model based on RUSLE, ORUSCAL, to demonstrate the possibility to calibrate RUSLE for a broad range of management conditions in vineyards with limited datasets. This approach have already been pursued successfully in olives (Gómez et al. 2003, Vanwalleghem et al., 2011). This communication reports the results of an evaluation of the calibration strategies and model predictions of ORUSCAL using a long-term experiment dataset (Bidoccu et al., 2016) in a vineyard in Northern Italy, and its implementation to develop soil cover and management factors (C) in three different soil, climate and management conditions across Europe: Southern Spain, Northern Italy and Austria. The communication, furthermore, explores and discusses of the application of the ORUSCAL model to additional vineyards areas in France and Romania in the context of the Vinedivers project (www.vinedivers.eu). Keywords: vineyard, erosion, soil management, RUSLE, model. References Auerswald K., Schwab, S. 1999. Erosion risk (C factor) of different viticultural practices. Vitic. Enol. Sci.54

  8. Effects of rainfall intensity and intermittency on woody vegetation cover and deep soil moisture in dryland ecosystems

    Science.gov (United States)

    Zhang, Ding-Hai; Li, Xin-Rong; Zhang, Feng; Zhang, Zhi-Shan; Chen, Yong-Le

    2016-12-01

    Identifying the relationship between the stochastic daily rainfall regime and the dynamics of plants and soil moisture is fundamental for the sustainable management of dryland ecosystems in a context of global climate change. An eco-hydrological model that couples the dynamics of woody vegetation cover and deep soil moisture (typically with a depth interval of 30-150 cm) was used to investigate the effect of stochastic intensity and the intermittency of precipitation on soil moisture in this deep interval, which affects woody vegetation cover. Our results suggest that the precipitation intensity and intermittency play an important role in the dynamics of wood vegetation cover and deep soil moisture. In arid and semiarid regions, as the annual precipitation increased, the rate of woody vegetation cover increased as a power-law function, and the deep soil moisture increased exponentially. For a given annual rainfall, there were positive correlations between the rainfall intensity (or rainfall intermittency) and both the woody vegetation cover and deep soil moisture. The positive correlations between wood vegetation cover and both rainfall intensity and intermittency may decrease with increases in the precipitation intensity or precipitation intermittency. The positive correlations between deep soil moisture and both rainfall intensity and rainfall intermittency increase as the precipitation intensity or precipitation intermittency increases. Moreover, these positive correlations may increase with increases in the mean annual rainfall. Our results emphasize the importance of daily precipitation variations in controlling the responses of woody vegetation cover and deep soil moisture to climate variations in arid and semiarid regions. Our model can aid the understanding of rainfall processes and indicates that increases in rainfall intensity or rainfall intermittency may lead to an increase in woody vegetation cover and deep soil moisture given an invariable annual

  9. Land-cover effects on soil organic carbon stocks in a European city.

    Science.gov (United States)

    Edmondson, Jill L; Davies, Zoe G; McCormack, Sarah A; Gaston, Kevin J; Leake, Jonathan R

    2014-02-15

    Soil is the vital foundation of terrestrial ecosystems storing water, nutrients, and almost three-quarters of the organic carbon stocks of the Earth's biomes. Soil organic carbon (SOC) stocks vary with land-cover and land-use change, with significant losses occurring through disturbance and cultivation. Although urbanisation is a growing contributor to land-use change globally, the effects of urban land-cover types on SOC stocks have not been studied for densely built cities. Additionally, there is a need to resolve the direction and extent to which greenspace management such as tree planting impacts on SOC concentrations. Here, we analyse the effect of land-cover (herbaceous, shrub or tree cover), on SOC stocks in domestic gardens and non-domestic greenspaces across a typical mid-sized U.K. city (Leicester, 73 km(2), 56% greenspace), and map citywide distribution of this ecosystem service. SOC was measured in topsoil and compared to surrounding extra-urban agricultural land. Average SOC storage in the city's greenspace was 9.9 kg m(-2), to 21 cm depth. SOC concentrations under trees and shrubs in domestic gardens were greater than all other land-covers, with total median storage of 13.5 kg m(-2) to 21 cm depth, more than 3 kg m(-2) greater than any other land-cover class in domestic and non-domestic greenspace and 5 kg m(-2) greater than in arable land. Land-cover did not significantly affect SOC concentrations in non-domestic greenspace, but values beneath trees were higher than under both pasture and arable land, whereas concentrations under shrub and herbaceous land-covers were only higher than arable fields. We conclude that although differences in greenspace management affect SOC stocks, trees only marginally increase these stocks in non-domestic greenspaces, but may enhance them in domestic gardens, and greenspace topsoils hold substantial SOC stores that require protection from further expansion of artificial surfaces e.g. patios and driveways.

  10. Road Maintenance Experience Using Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization as Ground Rehabilitation

    Science.gov (United States)

    Fakhar, A. M. M.; Asmaniza, A.

    2016-07-01

    There are many types of ground rehabilation and improvement that can be consider and implement in engineering construction works for soil improvement in order to prevent road profile deformation in later stage. However, when comes to road maintenance especially on operated expressways, not all method can be apply directly as it must comply to opreation's working window and lane closure basis. Key factors that considering ideal proposal for ground rehabilitation are time, cost, quality and most importantly practicality. It should provide long lifespan structure in order to reduce continuous cycle of maintenance. Thus, this paper will present two approaches for ground rehabilitation, namely Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization. The first approach is an injection system which consists two-parts chemical grout of Isocynate and Polyol when mixed together within soil structure through injection will polymerized with volume expansion. The strong expansion of grouting causes significant compression and compacting of the surrounding soil and subsequently improve ground properties and uplift sunken structure. The later is a cold in-place recyclying whereby mixture process that combines in-situ soil materials, cement, white powder (alkaline) additive and water to produce hard yet flexible and durable ground layer that act as solid foundation with improved bearing capacity. The improvement of the mechanical behaviour of soil through these two systems is investigated by an extensive testing programme which includes in-situ and laboratory test in determining properties such as strength, stiffness, compressibility, bearing capacity, differential settlement and etc.

  11. Cover crops influence soil microorganisms and phytoextraction of copper from a moderately contaminated vineyard.

    Science.gov (United States)

    Mackie, K A; Schmidt, H P; Müller, T; Kandeler, E

    2014-12-01

    We investigated the ability of summer (Avena sativa [oat], Trifolium incarnatum [crimson clover], Chenopodium [goosefoot]) and winter (Vicia villosa [hairy vetch], Secale Cereale L. [Rye], Brassica napus L. partim [rape]) cover crops, including a mixed species treatment, to extract copper from an organic vineyard soil in situ and the microbial communities that may support it. Clover had the highest copper content (14.3mgCukg(-1) DM). However, it was the amount of total biomass production that determined which species was most effective at overall copper removal per hectare. The winter crop rye produced significantly higher amounts of biomass (3532kgDMha(-1)) and, therefore, removed significantly higher amounts of copper (14,920mgCuha(-1)), despite less accumulation of copper in plant shoots. The maximum annual removal rate, a summation of best performing summer and winter crops, would be 0.033kgCuha(-1)y(-1). Due to this low annual extraction efficiency, which is less than the 6kgCuha(-1)y(-1) permitted for application, phytoextraction cannot be recommended as a general method of copper extraction from vineyards. Copper concentration did not influence aboveground or belowground properties, as indicated by sampling at two distances from the grapevine row with different soil copper concentrations. Soil microorganisms may have become tolerant to the copper levels at this site. Microbial biomass and soil enzyme activities (arylsulfatase and phosphatase) were instead driven by seasonal fluxes of resource pools. Gram+ bacteria were associated with high soil moisture, while fungi seemed to be driven by extractable carbon, which was linked to high plant biomass. There was no microbial group associated with the increased phytoextraction of copper. Moreover, treatment did not influence the abundance, activity or community structure of soil microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Relationships between basic soils-engineering equations and basic ground-water flow equations

    Science.gov (United States)

    Jorgensen, Donald G.

    1980-01-01

    The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

  13. Methane oxidation and degradation of organic compounds in landfill soil covers

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Kjeldsen, Peter

    2002-01-01

    High rates of methane oxidation and degradation of the lowed halogenated methanes (TCM and DCM) and HCFCs (HCFC-21 and HCFC-22) were found in an investigation of the oxidation of methane and halogenated organic compunds (HOCs) in landfill gas affected soil. The degradation followed zero-order kin......High rates of methane oxidation and degradation of the lowed halogenated methanes (TCM and DCM) and HCFCs (HCFC-21 and HCFC-22) were found in an investigation of the oxidation of methane and halogenated organic compunds (HOCs) in landfill gas affected soil. The degradation followed zero......-order kinetics and occurred in parallel with the oxidation of methane. TeCM, CFC-11, and CFC-12 were not degradable in presence of oxygen and degradation of these compounds in the oxidative zone in landfill top covers is therefore expected to be limited. However these compounds were found degradable...... in the anaerobic zone in the lower part of soil columns permeated with artificial landfill gas. The lesser-chlorinated compounds were degraded in the upper oxic zone with overlapping gradients of methane and oxygen. Methane oxidation and degradation of HOCs in the top-soils may play a very important role...

  14. Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Municipal solid waste landfills emit nitrous oxide (N2O) gas. Assuming that the soil cover is the primary N2O source from landfills,this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites. The N2O emission rates from all test sites were considerably lower than those reported in the published reports. Specifically, the N2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil. The effects of leachate recirculation and irrigation were minimal. Properly chosen cover soils applied to the landfills reduced N2O flux.

  15. Technogenic contaminations of the soil-plant cover in the Primorsky Krai, Russia

    Science.gov (United States)

    Molchanova, Inna; Pozolotina, Vera; Mikhailovskaya, Ludmila; Antonova, Elena; Zhuravlev, Yury; Timofeeva, Yana; Burdukovsky, Maxim

    2013-04-01

    All economical development of the countries carries out monitoring as with the aim to estimate impact of the industrial enterprises and nuclear-energetic complexes as consequences of the nuclear accidents. The investigation the region of the Far East due to proximity to epicentre of accident on Fukushima-1 NPP is of a great interest. The aim of this work are radioecological investigations and estimate technogenic load on the ecosystems of tightly populated plots of the shore zone of the Vladivostok region. Eight plots were located on the investigated territory. The tree fall, forest litters and soils were sampling from the profile cuts of layer by layer, up to 20 cm. The artificial radionuclides (Sr-90 and Cs-134,137), as heavy metals and microelements (Co, Cu, Zn, Pb and Mn) content in the prepared samples was determined. The stock of Sr-90 fluctuates from 0.3 to 1.3 kBq/m2 and Cs-137 was from 0.4 to 3.0 kBq/m2 in the examined soils. On the whole, the level of the radionuclides content in the soil cover is within the limits of the background that was formed in the belt between 50° and 60° of northern latitude. The presence in investigated samples of Cs-134 indicates to contribution of accidental fallout of Fukushima-1 into contamination of the components of the natural ecosystems. In a year's time after the accident the stock of this isotope in the soils was 0.01-0.20 kBq/m^2. It is by factor of 10-100 lower than the stock of Cs-137. Taking into account that the ratio Cs-134/Cs-137 on the moment of accident was equal to unity (1:1). It can be estimated the quantity of Cs-137 entering into environment during post - accident period. This quantity was an average 0.03-0.30 kBq/m2 (with correction on radionuclides decay). The observation for the state of the soil cover includes the estimate of the level and peculiarities of distribution in the soils of heavy metals and microelements. Their content in the soils is formed from Clarke number and additional industrial

  16. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: daily, intermediate, and final California cover soils.

    Science.gov (United States)

    Bogner, Jean E; Spokas, Kurt A; Chanton, Jeffrey P

    2011-01-01

    Compared with natural ecosystems and managed agricultural systems, engineered landfills represent a highly managed soil system for which there has been no systematic quantification of emissions from coexisting daily, intermediate, and final cover materials. We quantified the seasonal variability of CH, CO, and NO emissions from fresh refuse (no cover) and daily, intermediate, and final cover materials at northern and southern California landfill sites with engineered gas extraction systems. Fresh refuse fluxes (g m d [± SD]) averaged CH 0.053 (± 0.03), CO 135 (± 117), and NO 0.063 (± 0.059). Average CH emissions across all cover types and wet/dry seasons ranged over more than four orders of magnitude (types, including both final covers, averaging 200 cm) cover materials, below which methanogenesis was well established, the variability in gaseous fluxes was attributable to cover thickness, texture, density, and seasonally variable soil moisture and temperature at suboptimal conditions for CH oxidation. Thin daily covers (30 cm local soil) and fresh refuse generally had the highest CO and NO fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently buried refuse, with rates similar to soil ecosystems and windrow composting of organic waste. This study has emphasized the need for more systematic field quantification of seasonal emissions from multiple types of engineered covers.

  17. The influence of soil type, vegetation cover and soil moisture on spin up behaviour of a land surface model in a monsoonal region

    Science.gov (United States)

    Bhattacharya, Anwesha; Mandal, Manabottam

    2015-04-01

    Model spin-up is the process through which the model is adequately equilibrated to ensure balance between the mass fields and velocity fields. In this study, an offline one dimensional Noah land surface model is integrated recursively for three years to assess its spin-up behavior at different sites over the Indian Monsoon domain. Several numerical experiments are performed to investigate the impact of soil category, vegetation cover, initial soil moisture and subsequent dry or wet condition on model spin-up. These include simulations with the dominant soil and vegetation covers of this region, different initial soil moisture content (observed soil moisture; dry soil; moderately wet soil; saturated soil), simulations initialized at different rain conditions (no rain; infrequent rain; continuous rain) and different seasons (Winter, Spring, Summer/Pre-Monsoon, Monsoon and Autumn). It is seen that the spin-up behavior of the model depends on the soil type and vegetation cover with soil characteristics having the larger influence. Over India, the model has the longest spin-up in the case of simulations with loamy soil covered with mixed-shrub. It is noted that the model has a significantly longer spin-up when initialized with very low initial soil moisture content than with higher soil moisture content. It is also seen that in general, simulations initialized just before a continuous rainfall event have the least spin-up time. This observation is reinforced by the results from the simulations initialized in different seasons. It is seen that for monsoonal region, the model spin-up time is least for simulations initialized just before the Monsoon. Model initialized during the Monsoon rain episodes has a longer spin-up than that initialized in any other season. Furthermore, it is seen that the model has a shorter spin-up if it reaches the equilibrium state predominantly via drying process and could be as low as two months under quasi-equilibrium condition depending on

  18. GEOEPIDERM – AN ECOLOGICAL CONCEPT THAT INTEGRATES SOIL COVER WITH ASSOCIATED LAND SURFACE COMPONENTS

    Directory of Open Access Journals (Sweden)

    I. Munteanu

    2008-10-01

    Full Text Available Based on the new concept of the “Epiderm of the Earth” introduced by the 2006 edition of the WRB-SR, the idea of “geoepiderm” has been developed. Besides its holistic meaning, by including both soil and non-soil materials found in the first 2 meters of the land surface, the term “geoepiderm” has a strong ecological sense, by suggesting similarity with the skin of the living organisms, as such, this concept is fully concordant with that of “Gaia” (Living Earth developed by James Lovelock. According to the main pedo-ecological characteristics of the soil and not soil coverings from the earth surface, ten kinds (classes of ‘geoepiderms” have been identified:1 – Protoderma (Entiderma– the primitive (emerging geoepiderm (mainly non-soil materials; five main subtypes: a Regoderma, b Leptoderma, c Areniderma, d Fluviderma and e Gleyoderma, were identified;2 – Cryoderma (Geliderma – geoepiderm of cold, mainly artic and subartic, regions with mean annual soil temperature <00C (often with perennial frozen subsoil - permafrost:3 – Arididerma – geoepiderm of arid regions and salt affected lands with limited or scarce available moisture; two subtypes: a Desertiderma, b Saliderma4 – Inceptiderma (or Juvenilederma – with 2 subtypes: a Cambiderma – a young (incipiently developed geoepiderm and b Andiderma, geoepiderm developed in volcanic materials;5 – Euderma – nutrient rich geoepiderm with two main subtypes: a Cherniderma (or Molliderma and b Luviderma (or Alfiderma;6 – Oligoderma – geoepiderm with low macro-nutrient and weatherable minerals content with 2 subtypes: a Podziderma (or Spodiderma and b Acriderma (or Ultiderma;7 – Ferriderma (Oxiderma or Senilederma – geoepiderm strongly weathered and with iron and aluminium hydroxides enrichment and low weatherable minerals reserve;8 – Vertiderma (Contractilederma – Contractile geoepiderm, developed from swelling clays;9 – Histoderma (Organiderma

  19. Evaluation of gravimetric ground truth soil moisture data collected for the agricultural soil moisture experiment, 1978 Colby, Kansas, aircraft mission

    Science.gov (United States)

    Arya, L. M.; Phinney, D. E. (Principal Investigator)

    1980-01-01

    Soil moisture data acquired to support the development of algorithms for estimating surface soil moisture from remotely sensed backscattering of microwaves from ground surfaces are presented. Aspects of field uniformity and variability of gravimetric soil moisture measurements are discussed. Moisture distribution patterns are illustrated by frequency distributions and contour plots. Standard deviations and coefficients of variation relative to degree of wetness and agronomic features of the fields are examined. Influence of sampling depth on observed moisture content an variability are indicated. For the various sets of measurements, soil moisture values that appear as outliers are flagged. The distribution and legal descriptions of the test fields are included along with examinations of soil types, agronomic features, and sampling plan. Bulk density data for experimental fields are appended, should analyses involving volumetric moisture content be of interest to the users of data in this report.

  20. Quantifying the impact of cloud cover on ground radiation flux measurements using hemispherical images

    NARCIS (Netherlands)

    Roupioz, L.; Colin, J.; Jia, L.; Nerry, F.; Menenti, M.

    2015-01-01

    Linking observed or estimated ground incoming solar radiation with cloud coverage is difficult since the latter is usually poorly described in standard meteorological observation protocols. To investigate the benefits of detailed observation and characterization of cloud coverage and distribution

  1. Effect of plant cover on distribution of soil organic matter pools

    Science.gov (United States)

    Gunina, Anna; Kuzyakov, Yakov; Ryzhova, Irina

    2013-04-01

    Numerous studies reported that quality and quantity of primary production and also the rate of litter decomposition determine the carbon (C) content and its distribution in soils. Our objective was to examine how the type of plant cover affects C sequestration in the following pools: unprotected, spatial inaccessible, interacting with silt and clay, and biochemically protected SOM. The large lysimeters of Moscow State University allowed quantification of C stocks under broadleaf forest (Acer platanoides and Quercus robur), coniferous forest (Picea abies) and agricultural crops (9-field rotation), while other soil forming factors affecting SOC content were identical. In 1965 the lysimeters (S=9 m2, depth=1.5 m) were filled with carbonate free clay loam taken in Moscow region, originated from the Valday glaciation, and plant communities listed above were planted. We collected soil samples from the mineral horizons, from 0-5 cm depth, in spring 2012. The soils were physically separated by combination of the particle size and density fractionations (8 fractions in total), and C and N contents were analyzed. The total C and N contents in non-fractionated soil were higher under broadleaf forest (66 and 3.1 g kg-1), than under coniferous forest (34.5 and 1.23 g kg-1) and agricultural crops (13.7 and 0.9 g kg-1). Under forests 45-50% of Ctotal and 30% of Ntotal were in the unprotected pool, in agricultural soil these percentages were in 3 times less. The greatest portions of protected C were in spatial inaccessible pool: 28, 32 and 40% of the Ctotal for broadleaf forest, coniferous forest and agricultural crops, respectively. However, the total C amount in this pool under agricultural crops was in 3 times less, than under forests. This is indicative for the loss of C-rich macroaggregates and an increase of C-depleted microaggregates in agricultural soils due to the plowing. The amounts of C, stabilized by interactions with silt and clay, were nearly the same (3-6 g kg-1

  2. Partial least-squares regression for linking land-cover patterns to soil erosion and sediment yield in watersheds

    Science.gov (United States)

    Shi, Z. H.; Ai, L.; Li, X.; Huang, X. D.; Wu, G. L.; Liao, W.

    2013-08-01

    There are strong ties between land cover patterns and soil erosion and sediment yield in watersheds. The spatial configuration of land cover has recently become an important aspect of the study of geomorphological processes related to erosion within watersheds. Many studies have used multivariate regression techniques to explore the response of soil erosion and sediment yield to land cover patterns in watersheds. However, many landscape metrics are highly correlated and may result in redundancy, which violates the assumptions of a traditional least-squares approach, thus leading to singular solutions or otherwise biased parameter estimates and confidence intervals. Here, we investigated the landscape patterns within watersheds in the Upper Du River watershed (8973 km2) in China and examined how the spatial patterns of land cover are related to the soil erosion and sediment yield of watersheds using hydrological modeling and partial least-squares regression (PLSR). The results indicate that the watershed soil erosion and sediment yield are closely associated with the land cover patterns. At the landscape level, landscape characteristics, such as Shannon’s diversity index (SHDI), aggregation index (AI), largest patch index (LPI), contagion (CONTAG), and patch cohesion index (COHESION), were identified as the primary metrics controlling the watershed soil erosion and sediment yield. The landscape characteristics in watersheds could account for as much as 65% and 74% of the variation in soil erosion and sediment yield, respectively. Greater interspersion and an increased number of patch land cover types may significantly accelerate soil erosion and increase sediment export. PLSR can be used to simply determine the relationships between land-cover patterns and watershed soil erosion and sediment yield, providing quantitative information to allow decision makers to make better choices regarding landscape planning. With readily available remote sensing data and rapid

  3. Species-diversified plant cover enhances orchard ecosystem resistance to climatic stress and soil erosion in subtropical hillsid

    Institute of Scientific and Technical Information of China (English)

    陈欣; 杨一松; 唐建军

    2004-01-01

    Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang) orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 15×8m2 and separated by 2m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positive ecological effects on citrus orchard ecosystem stability.

  4. Species-diversified plant cover enhances orchard ecosystem resistance to climatic stress and soil erosion in subtropical hillside

    Institute of Scientific and Technical Information of China (English)

    陈欣; 杨一松; 唐建军

    2004-01-01

    Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang)orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 15×8m2 and separated by 2 m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positiveecological effects on citrus orchard ecosystem stability.

  5. Water-saving ground cover rice production system reduces net greenhouse gas fluxes in an annual rice-based cropping system

    Directory of Open Access Journals (Sweden)

    Z. Yao

    2014-06-01

    Full Text Available To safeguard food security and preserve precious water resources, the technology of water-saving ground cover rice production system (GCRPS is being increasingly adopted for the rice cultivation. However, changes in soil water status and temperature under GCRPS may affect soil biogeochemical processes that control the biosphere–atmosphere exchanges of methane (CH4, nitrous oxide (N2O and carbon dioxide (CO2. The overall goal of this study is to better understand how net ecosystem greenhouse gas exchanges (NEGE and grain yields are affected by GCRPS in an annual rice-based cropping system. Our evaluation was based on measurements of the CH4 and N2O fluxes and soil heterotrophic respiration (CO2 emission over a complete year, as well as the estimated soil carbon sequestration intensity for six different fertilizer treatments for conventional paddy and GCRPS. The fertilizer treatments included urea application and no N fertilization for both conventional paddy (CUN and CNN and GCRPS (GUN and GNN, solely chicken manure (GCM and combined urea and chicken manure applications (GUM for GCRPS. Averaging across all the fertilizer treatments, GCRPS increased annual N2O emission and grain yield by 40% and 9%, respectively, and decreased annual CH4 emission by 69%, while GCRPS did not affect soil CO2 emissions relative to the conventional paddy. The annual direct emission factors of N2O were 4.01, 0.087 and 0.50% for GUN, GCM and GUM, respectively, and 1.52% for the conventional paddy (CUN. The annual soil carbon sequestration intensity under GCRPS was estimated to be an average of −1.33 Mg C ha−1 yr−1, which is approximately 44% higher than the conventional paddy. The annual NEGE were 10.80–11.02 Mg CO2-eq ha−1 yr−1 for the conventional paddy and 3.05–9.37 Mg CO2-eq ha−1 yr−1 for the GCRPS, suggesting the potential feasibility of GCRPS in reducing net greenhouse effect from rice cultivation. Using organic fertilizers for GCRPS

  6. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    Science.gov (United States)

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions.

  7. The In-Transit Vigilant Covering Tour Problem of Routing Unmanned Ground Vehicles

    Science.gov (United States)

    2012-08-01

    15 Figure 2. A classic VRP ...17 Figure 3. Solution for a VRP ........................................................................................18 Figure 4. Solution...of NP-hard problems, such as the Traveling Salesman Problem (TSP), Vehicle Routing Problem ( VRP ), and Covering Salesman Problem (CSP) etc. We will

  8. Associations between soil bacterial community structure and nutrient cycling functions in long-term organic farm soils following cover crop and organic fertilizer amendment.

    Science.gov (United States)

    Fernandez, Adria L; Sheaffer, Craig C; Wyse, Donald L; Staley, Christopher; Gould, Trevor J; Sadowsky, Michael J

    2016-10-01

    Agricultural management practices can produce changes in soil microbial populations whose functions are crucial to crop production and may be detectable using high-throughput sequencing of bacterial 16S rRNA. To apply sequencing-derived bacterial community structure data to on-farm decision-making will require a better understanding of the complex associations between soil microbial community structure and soil function. Here 16S rRNA sequencing was used to profile soil bacterial communities following application of cover crops and organic fertilizer treatments in certified organic field cropping systems. Amendment treatments were hairy vetch (Vicia villosa), winter rye (Secale cereale), oilseed radish (Raphanus sativus), buckwheat (Fagopyrum esculentum), beef manure, pelleted poultry manure, Sustane(®) 8-2-4, and a no-amendment control. Enzyme activities, net N mineralization, soil respiration, and soil physicochemical properties including nutrient levels, organic matter (OM) and pH were measured. Relationships between these functional and physicochemical parameters and soil bacterial community structure were assessed using multivariate methods including redundancy analysis, discriminant analysis, and Bayesian inference. Several cover crops and fertilizers affected soil functions including N-acetyl-β-d-glucosaminidase and β-glucosidase activity. Effects, however, were not consistent across locations and sampling timepoints. Correlations were observed among functional parameters and relative abundances of individual bacterial families and phyla. Bayesian analysis inferred no directional relationships between functional activities, bacterial families, and physicochemical parameters. Soil functional profiles were more strongly predicted by location than by treatment, and differences were largely explained by soil physicochemical parameters. Composition of soil bacterial communities was predictive of soil functional profiles. Differences in soil function were

  9. Vegetation cover and land use impacts on soil water repellency in an Urban Park located in Vilnius, Lithuania

    Science.gov (United States)

    Pereira, Paulo; Cerda, Artemi

    2015-04-01

    It is strongly recognized that vegetation cover, land use have important impacts on the degree of soil water repellency (SWR). Soil water repellency is a natural property of soils, but can be induced by natural and anthropogenic disturbances as fire and soil tillage (Doerr et al., 2000; Urbanek et al., 2007; Mataix-Solera et al., 2014). Urban parks are areas where soils have a strong human impact, with implications on their hydrological properties. The aim of this work is to study the impact of different vegetations cover and urban soils impact on SWR and the relation to other soil variables as pH, Electrical Conductivity (EC) and soil organic matter (SOM) in an urban park. The study area is located in Vilnius city (54°.68' N, 25°.25' E). It was collected 15 soil samples under different vegetation cover as Pine (Pinus Sylvestris), Birch (Alnus glutinosa), Penduculate Oak (Quercus robur), Platanus (Platanus orientalis) and other human disturbed areas as forest trails and soils collected from human planted grass. Soils were taken to the laboratory, air-dried at room temperature and sieved with the 3600 (extremely water repellent). The results showed significant differences among the different vegetation cover (Kruskal-Wallis H=20.64, pgrass were significantly higher than Platanus soil. The soils from Pine, Birch, Penduculate Oak, forest trails and planted grass were majorly severely water repellent, while Platanus soils were mostly strong water repellent. Soil water repellency of Pine soils had a significant negative correlation with pH (-0.52, ppH (-0.88, ppH, EC and SOM. Acknowledgments POSTFIRE (Soil quality, erosion control and plant cover recovery under different post-fire management scenarios, CGL2013-47862-C2-1-R), funded by the Spanish Ministry of Economy and Competitiveness; Fuegored; RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES

  10. Evaluation of two methods for measuring saturated hydraulic conductivity of soils under two vegetation covers

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, C.M.; Josa, R.; Poyatos, R.; Llorens, P.; Gallart, F.; Latron, J.; Ferrer, F.

    2009-07-01

    The main goal of this work is to determine and to evaluate the saturated hydraulic conductivity for a silt loam soil in field and laboratory conditions. the experimental area was located in the Vallcebre research catchment, in headwaters of the Llobregat River (NE Spain). Hydraulic conductivity was measured in the field using the Guelph permeameter and field saturated hydraulic conductivity (K{sub f}s) based on Elrick equation was calculated. The Guelph permeameter measures were made in two conditions (dry and wet) and in profiles below two vegetation covers (meadows and forest). To determine the saturated hydraulic conductivity at the laboratory (K{sub s}) the constant head permeameter was used. The average K{sub f}s values for the wet period was about 2 cm.h{sup -}1. During the dry period, both soil profiles presented higher values, about 7.5 cm.h{sup -}1. Under laboratory conditions, means observed K{sub s} values were between 12 and 25 cm.h{sup -}1. The relationship K{sub f}s/k{sub s} was of 0.1 cm.h{sup -}1 in wet conditions and about 0.4 cm.h{sup -}1 in dry conditions. The results indicated significant differences between both methods and between both seasons. differences can be explained by the anisotropy of soils as a consequence of vegetation root system that promotes preferential flows paths. (Author) 10 refs.

  11. Effectiveness of compacted soil liner as a gas barrier layer in the landfill final cover system.

    Science.gov (United States)

    Moon, Seheum; Nam, Kyoungphile; Kim, Jae Young; Hwan, Shim Kyu; Chung, Moonkyung

    2008-01-01

    A compacted soil liner (CSL) has been widely used as a single barrier layer or a part of composite barrier layer in the landfill final cover system to prevent water infiltration into solid wastes for its acceptable hydraulic permeability. This study was conducted to test whether the CSL was also effective in prohibiting landfill gas emissions. For this purpose, three different compaction methods (i.e., reduced, standard, and modified Proctor methods) were used to prepare the soil specimens, with nitrogen as gas, and with water and heptane as liquid permeants. Measured gas permeability ranged from 2.03 x 10(-10) to 4.96 x 10(-9) cm(2), which was a magnitude of two or three orders greater than hydraulic permeability (9.60 x 10(-13) to 1.05 x 10(-11) cm(2)). The difference between gas and hydraulic permeabilities can be explained by gas slippage, which makes gas more permeable, and by soil-water interaction, which impedes water flow and then makes water less permeable. This explanation was also supported by the result that a liquid permeability measured with heptane as a non-polar liquid was similar to the intrinsic gas permeability. The data demonstrate that hydraulic requirement for the CSL is not enough to control the gas emissions from a landfill.

  12. Comparison of revegetation techniques on mineral clay soil: analysis of quantitative response of vegetation cover

    Directory of Open Access Journals (Sweden)

    Enrico Muzzi

    2016-08-01

    Full Text Available Revegetation of mineral-clay soils is a notably complex ecological and technically challenging undertaking that depends on substrate profile and local micro-environmental conditions, factors making it a particularly long procedure as well. This study compared and assessed the medium-term effectiveness of four treatments employed to promote stable pedogenesis and herbaceous recolonisation of abandoned clay quarries in the Apennine foothills of northern Italy’s Emilia- Romagna region. The treatments included: slow-release N organic fertiliser, phosphate fertiliser, organic amendment and topsoil [the soil top layer (0-0.2 m of a local natural meadow]. The state of the vegetative cover was monitored monthly from 1994 through 2004, until problems of slope stability at the site compromised the integrity of the trial plots. Significant effects were achieved by the recycled topsoil through 8 years and by organic amendment through 6 years; the effects of slow-release nitrogen were notably limited over time and phosphorous delivered a medium-term response but of notable year-toyear swings. No interactions among factors emerged in the mediumterm. After 11 years, treatments did not induce effects statistical appreciable. Our results suggest that the tested agronomic strategies on mineral clay soil did not trigger, in the medium-term, secondary succession processes able to potentially alter the spontaneous revegetation course.

  13. BALANCE OF WATER AND ENERGY FOR EUCALYPTUS PLANTATIONS WITH PARTIAL SOIL COVER

    Directory of Open Access Journals (Sweden)

    Mariana Gonçalves dos Reis

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813329Eucalyptus plots with initial development ages presented discontinuity in soil cover, resulting in greaterexposure of the leaves to wind and solar radiation, which alters soil-plant-atmosphere interactions. Theobjective of this study was to study the components of the water and energy balances along the first yearof eucalyptus development in the Brazilian coastal plain region. The experimental site is located in anarea belonging to the company Fibria in the municipality of Aracruz, Espírito Santo state, Brazil. Thespace between the planted eucalyptus trees in the area studied was 3 x 3 m and the data of planting wason August 15th , 2004. The period of study lasted from the planting date until the plot reached an ageof 19 months. It was verified that there was a greater availability of energy during the summer and theprecipitation directly influenced the energy balance where during the period of study the energy available necessary for evapotranspiration was always greater than the fraction necessary for heating the soil-plantatmospheresystem, presenting a λE/Rn ratio of 59.57%. It was also observed that the water balance with themodeled evapotranspiration showed a good correspondence with the observed moisture content, presentinga determination coefficient of 0,94. In the majority of trees, greater indices of leaf and root system areasfavored evapotranspiration, indicating that most energy available was utilized for changing the phase ofwater

  14. Fate and Transport of Pharmaceutical Compounds Applied to Turf-Covered Soil

    Science.gov (United States)

    Young, M.; Green, R. L.; Devitt, D.; McCullough, M.; Wright, L.; Vanderford, B. J.; Snyder, S. A.

    2012-12-01

    In arid and semi-arid regions, the use of treated wastewater for landscape irrigation is becoming common practice and a significant asset to conserve potable water supplies. Public interest and lack of field-scale data are leading to a concern that compounds found in reuse water could persist in the environment and contaminate groundwater. As part of a larger study, 2-yr experiments were conducted in CA and NV, where reuse water was the primary source of non-ambient water input. A total of 13 compounds were studied, all originating in irrigation water applied to soil covered in turf or left bare. The target compounds included atenolol, atorvastatin, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, ibuprofen, meprobamate, naproxen, primidone, sulfamethoxazole, triclosan, and trimethoprim. Analytical protocols for all compounds (detection at ng/L range) were established before the study commenced. The goals of the research were to increase available data on the fate and transport of these target compounds in turfgrass/soil systems, and to use these data to assess long-term risk from using water containing these compounds. Experiments conducted at two scales are discussed here: lysimeter-scale and field-scale. At the lysimeter-scale, 24 drainage lysimeters (120 cm thick) were exposed to treated wastewater as an irrigation source. Lysimeters varied by soil type (two types), soil cover (bare- versus turf-covered) and leaching fraction (5% and 25%). Upper and lower boundary conditions were monitored throughout the study. Water samples were collected periodically after water breakthrough. After the study, soil samples were analyzed for compound mass, allowing compound mass balance and removal to be assessed. At the field-scale, passive drain gages (Decagon Devices) were installed in triplicate in fairways at four operational golf courses, one in NV and three in CA, all with histories of using treated wastewater. The gages measure water fluxes through the 60

  15. TCE REMOVAL FROM CONTAMINATED SOIL AND GROUND WATER

    Science.gov (United States)

    Widespread use of trichloroethylene (TEE) in the U.S. has resulted in its frequent detection in soil and groundwater. EE can become a health hazard after being processed in the human liver; or reductive dehalogenation in the environment may result in production of vinyl chloride,...

  16. Mechanism of H2S removal during landfill stabilization in waste biocover soil, an alterative landfill cover.

    Science.gov (United States)

    He, Ruo; Xia, Fang-Fang; Bai, Yun; Wang, Jing; Shen, Dong-Sheng

    2012-05-30

    Hydrogen sulfide (H(2)S) is one of the primary contributors to odors at landfills. The mechanism of waste biocover soil (WBS) for H(2)S removal was investigated in simulated landfill systems with the contrast experiment of a landfill cover soil (LCS). The H(2)S removal efficiency was higher than 90% regardless of the WBS or LCS covers. The input of landfill gas (LFG) could stimulate the growth of aerobic heterotrophic bacteria, actinomycete, sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) in the WBS cover, while that caused a decrease of 1-2 orders of magnitude in the populations of actinomycete and fungi in the bottom layer of the LCS cover. As H(2)S inputted, the sulfide content in the WBS cover increased and reached the maximum on day 30. In the LCS cover, the highest soil sulfide content was exhibited in the bottom layer during the whole experiment. After exposure to LFG, the lower pH value and higher sulfate content were observed in the top layer of the WBS cover, while there was not a significant difference in different layers of the LCS cover. The results indicated a more rapid biotransformation between sulfide and sulfate occurred in the WBS cover compared to the LCS.

  17. Permafrost, Seasonally Frozen Ground, Snow Cover and Vegetation in the USSR

    Science.gov (United States)

    1984-12-01

    Late Quaternary History and the Formation of Sedi- ments in the Marginal and Inland Seas (Pozdnechetvertichnaia Istorlia i Sedimentogenez...rasprostraneniia snezhnogo pokrova na poverkhnosti sushi zemnogo shara). In Geography of Snow Cover (Geo- grafiya Snezhnogo Prokrova). Moscow: Izdat...Papers, 18(3): 198-202. (36-1668) Vigdorchik, M.E. (1980) Arctic Pleistocene History and the Development of Submarine Permafrost. Boulder

  18. In-Situ Quantification of Methanotrophic Activity in a Landfill Cover Soil Using Gas Push-Pull Tests

    Science.gov (United States)

    Gomez, K. E.; Gonzalez-Gil, G.; Schroth, M. H.; Zeyer, J.

    2007-12-01

    Landfills are both a major anthropogenic source and a sink for the greenhouse gas CH4. Methanogenic bacteria produce CH4 during the anaerobic digestion of landfill waste, whereas, methanotrophic bacteria consume CH4 as it is transported through a landfill cover soil. Methanotrophs are thought to be ubiquitous in soils, but typically exist in large numbers at oxic/anoxic interfaces, close to anaerobic methane sources but exposed to oxygen required for metabolism. Accurate in-situ quantification of the sink strength of methanotrophs in landfill cover soils is needed for global carbon balances and for local emissions mitigation strategies. We measured in-situ CH4 concentrations at 30, 60, and 100 cm depth at 18 evenly spaced locations across a landfill cover soil. Furthermore, we performed Gas Push-Pull Tests (GPPTs) to estimate in-situ rates of methanotrophic activity in the cover soil. The GPPT is a gas-tracer test in which a gas mixture containing CH4, O2, and non-reactive tracer gases is injected (pushed) into the soil followed by extraction (pull) from the same location. Quantification of CH4 oxidation rates is based upon comparison of the breakthrough curves of CH4 and tracer gases. We present the results of a series of GPPTs conducted at two locations in the cover soil to assess the feasibility and reproducibility of this technique to quantify methanotrophic activity. Additional GPPTs were performed with a methanotrophic inhibitor in the injection gas mixture to confirm the appropriate choice of tracers to quantify CH4 oxidation. Estimated CH4 oxidation rate constants indicate that the cover soil contains a highly active methanotrophic community.

  19. The Impact of Time Difference between Satellite Overpass and Ground Observation on Cloud Cover Performance Statistics

    Directory of Open Access Journals (Sweden)

    Jędrzej S. Bojanowski

    2014-12-01

    Full Text Available Cloud property data sets derived from passive sensors onboard the polar orbiting satellites (such as the NOAA’s Advanced Very High Resolution Radiometer have global coverage and now span a climatological time period. Synoptic surface observations (SYNOP are often used to characterize the accuracy of satellite-based cloud cover. Infrequent overpasses of polar orbiting satellites combined with the 3- or 6-h SYNOP frequency lead to collocation time differences of up to 3 h. The associated collocation error degrades the cloud cover performance statistics such as the Hanssen-Kuiper’s discriminant (HK by up to 45%. Limiting the time difference to 10 min, on the other hand, introduces a sampling error due to a lower number of corresponding satellite and SYNOP observations. This error depends on both the length of the validated time series and the SYNOP frequency. The trade-off between collocation and sampling error call for an optimum collocation time difference. It however depends on cloud cover characteristics and SYNOP frequency, and cannot be generalized. Instead, a method is presented to reconstruct the unbiased (true HK from HK affected by the collocation differences, which significantly (t-test p < 0.01 improves the validation results.

  20. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Directory of Open Access Journals (Sweden)

    Xiang Li

    Full Text Available The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter, four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (p<0.05. Average runoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, p<0.05, and the efficiency in runoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h-1. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05 were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (p<0.05 with sediment yield. These results suggest that the protective role of leaf litter in runoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  1. Improved ground hydrology calculations for global climate models (GCMs) - Soil water movement and evapotranspiration

    Science.gov (United States)

    Abramopoulos, F.; Rosenzweig, C.; Choudhury, B.

    1988-01-01

    A physically based ground hydrology model is presented that includes the processes of transpiration, evaporation from intercepted precipitation and dew, evaporation from bare soil, infiltration, soil water flow, and runoff. Data from the Goddard Institute for Space Studies GCM were used as inputs for off-line tests of the model in four 8 x 10 deg regions, including Brazil, Sahel, Sahara, and India. Soil and vegetation input parameters were caculated as area-weighted means over the 8 x 10 deg gridbox; the resulting hydrological quantities were compared to ground hydrology model calculations performed on the 1 x 1 deg cells which comprise the 8 x 10 deg gridbox. Results show that the compositing procedure worked well except in the Sahel, where low soil water levels and a heterogeneous land surface produce high variability in hydrological quantities; for that region, a resolution better than 8 x 10 deg is needed.

  2. Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes.

    Science.gov (United States)

    Bae, Jichul; Benoit, Diane L; Watson, Alan K

    2016-06-01

    In southern Québec, supplement roadside ground covers (i.e. Trifolium spp.) struggle to establish near edges of major roads and thus fail to assist turf recruitment. It creates empty niches vulnerable to weed establishment such as common ragweed (Ambrosia artemisiifolia). We hypothesized that heavy metal stresses may drive such species shifts along roadside edges. A growth chamber experiment was conducted to assess effects of metals (Zn, Pb, Ni, Cu, and Cd) on germination and seedling behaviors of roadside weed (A. artemisiifolia) and ground cover legumes (Coronilla varia, Lotus corniculatus, and Trifolium arvense). All metals inhibited T. arvense germination, but the effect was least on A. artemisiifolia. Low levels of Pb and Ni promoted germination initiation of A. artemisiifolia. Germination of L. corniculatus was not affected by Zn, Pb, and Ni, but inhibited by Cu and Cd. Germination of C. varia was decreased by Ni, Cu, and Cd and delayed by Zn and Pb. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth. Seedling mortality was lowest in A. artemisiifolia but highest in T. arvense when exposed to the metal treatments. L. corniculatus and C. varia seedlings survived when subjected to high levels of Zn, Pb, and Cd. In conclusion, the successful establishment of A. artemisiifolia along roadside edges can be associated with its greater tolerance of heavy metals. The findings also revealed that L. corniculatus is a potential candidate for supplement ground cover in metal-contaminated roadside edges in southern Québec, especially sites contaminated with Zn and Pb.

  3. Monitoring soil moisture patterns in alpine meadows using ground sensor networks and remote sensing techniques

    Science.gov (United States)

    Bertoldi, Giacomo; Brenner, Johannes; Notarnicola, Claudia; Greifeneder, Felix; Nicolini, Irene; Della Chiesa, Stefano; Niedrist, Georg; Tappeiner, Ulrike

    2015-04-01

    Soil moisture content (SMC) is a key factor for numerous processes, including runoff generation, groundwater recharge, evapotranspiration, soil respiration, and biological productivity. Understanding the controls on the spatial and temporal variability of SMC in mountain catchments is an essential step towards improving quantitative predictions of catchment hydrological processes and related ecosystem services. The interacting influences of precipitation, soil properties, vegetation, and topography on SMC and the influence of SMC patterns on runoff generation processes have been extensively investigated (Vereecken et al., 2014). However, in mountain areas, obtaining reliable SMC estimations is still challenging, because of the high variability in topography, soil and vegetation properties. In the last few years, there has been an increasing interest in the estimation of surface SMC at local scales. On the one hand, low cost wireless sensor networks provide high-resolution SMC time series. On the other hand, active remote sensing microwave techniques, such as Synthetic Aperture Radars (SARs), show promising results (Bertoldi et al. 2014). As these data provide continuous coverage of large spatial extents with high spatial resolution (10-20 m), they are particularly in demand for mountain areas. However, there are still limitations related to the fact that the SAR signal can penetrate only a few centimeters in the soil. Moreover, the signal is strongly influenced by vegetation, surface roughness and topography. In this contribution, we analyse the spatial and temporal dynamics of surface and root-zone SMC (2.5 - 5 - 25 cm depth) of alpine meadows and pastures in the Long Term Ecological Research (LTER) Area Mazia Valley (South Tyrol - Italy) with different techniques: (I) a network of 18 stations; (II) field campaigns with mobile ground sensors; (III) 20-m resolution RADARSAT2 SAR images; (IV) numerical simulations using the GEOtop hydrological model (Rigon et al

  4. Influence of foundation type and soil stratification on ground vibration - a parameter study

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Prins, Joeri Nithan; Persson, Kent

    2016-01-01

    Vibration of machinery and construction work are major sources of noise and vibration pollution in the urban environment. The frequencies dominating the vibration, and the distances over which it spreads via the ground, depend on the source. However, soil stratification and foundation type have...... a significant influence. Thus, in order to achieve fair accuracy in the prediction of ground vibration caused by sources vibrating on a foundation, accurate models of the ground and foundation may be required. However, for assessment of vibration in the design phase, simple models may be preferred. The paper...... provides a parameter study regarding the influence of soil stratification and foundation type on the ground vibration at different distances away from the source. Especially, vibration levels caused by sources placed on surface footings and piles are compared, employing a three-dimensional numerical model...

  5. Experimental investigations of freezing soils at ground conditions of Astana, Kazakhstan

    Institute of Scientific and Technical Information of China (English)

    Zhussupbekov Askar; Shakhmov Zhanbolat

    2015-01-01

    Kazakhstan regions is seasonal climatic with transient freezing of soil ground during the winter. Roadbed integrity is important to resist the sustained load transmitted by traffic on the road surface. Freezing of soil ground could significantly influence roadbed integrity in the seasonal freezing climate of Kazakhstan. The proper determination magnitude of frost heave and heaving pressure by the influence of freezing temperatures during the winter season are necessary for design and construction of highways. Thus, experimental tests were conducted on specimens obtained from Astana (Kazakhstan) to determine the freezing pressure and magnitude of frost heaving.

  6. Measuring the electrical properties of soil using a calibrated ground-coupled GPR system

    Science.gov (United States)

    Oden, C.P.; Olhoeft, G.R.; Wright, D.L.; Powers, M.H.

    2008-01-01

    Traditional methods for estimating vadose zone soil properties using ground penetrating radar (GPR) include measuring travel time, fitting diffraction hyperbolae, and other methods exploiting geometry. Additional processing techniques for estimating soil properties are possible with properly calibrated GPR systems. Such calibration using ground-coupled antennas must account for the effects of the shallow soil on the antenna's response, because changing soil properties result in a changing antenna response. A prototype GPR system using ground-coupled antennas was calibrated using laboratory measurements and numerical simulations of the GPR components. Two methods for estimating subsurface properties that utilize the calibrated response were developed. First, a new nonlinear inversion algorithm to estimate shallow soil properties under ground-coupled antennas was evaluated. Tests with synthetic data showed that the inversion algorithm is well behaved across the allowed range of soil properties. A preliminary field test gave encouraging results, with estimated soil property uncertainties (????) of ??1.9 and ??4.4 mS/m for the relative dielectric permittivity and the electrical conductivity, respectively. Next, a deconvolution method for estimating the properties of subsurface reflectors with known shapes (e.g., pipes or planar interfaces) was developed. This method uses scattering matrices to account for the response of subsurface reflectors. The deconvolution method was evaluated for use with noisy data using synthetic data. Results indicate that the deconvolution method requires reflected waves with a signal/noise ratio of about 10:1 or greater. When applied to field data with a signal/noise ratio of 2:1, the method was able to estimate the reflection coefficient and relative permittivity, but the large uncertainty in this estimate precluded inversion for conductivity. ?? Soil Science Society of America.

  7. The short term influence of aboveground biomass cover crops on C sequestration and β–glucosidase in a vineyard ground under semiarid conditions

    Directory of Open Access Journals (Sweden)

    Fernando Peregrina

    2014-10-01

    Full Text Available Tillage and semiarid Mediterranean climatic conditions accelerate soil organic matter losses in Spanish vineyards. Previous studies showed that cover crops can increase soil organic carbon (SOC in Mediterranean vineyards. The objectives of this study were to evaluate the influence of two different cover crops in the short term on soil C sequestration in a semiarid vineyard and to study the potential use of both β–glucosidase enzimatic activity (GLU and the GLU/SOC ratio in order to assess the SOC increase. The experiment was carried out in a cv. Tempranillo (Vitis vinifera L. vineyard on a Oxyaquic Xerorthent soil in Rioja winegrowing region (NE, Spain. The experimental design was established in 2009 with three treatments: conventional tillage; sown barley cover crop (Hordeum vulgare, L.; sown Persian clover cover crop (Trifolium resupinatum L.. Carbon in the aboveground biomass with each cover crop was monitored. Soil was sampled in June 2011 and June 2012, and SOC, GLU and the GLU/SOC ratio were determined. After 3 years both cover crops increased SOC at soil surface with C sequestration rates of 0.47 and 1.19 t C ha-1 yr-1 for BV and CV respectively. GLU and GLU/SOC ratio increased in both cover crops at 0-5 cm soil depth. The C sequestration rates and GLU were related to the cover crops aboveground biomass. In consequence, in semiarid vineyards under cover crops GLU could be an appropriate indicator to asses the increase of SOC and the soil quality improvement in the short-term (2-3 years.

  8. Associations between land cover categories, soil concentrations of arsenic, lead and barium, and population race/ethnicity and socioeconomic status.

    Science.gov (United States)

    Davis, Harley T; Aelion, C Marjorie; Lawson, Andrew B; Cai, Bo; McDermott, Suzanne

    2014-08-15

    The potential of using land cover/use categories as a proxy for soil metal concentrations was examined by measuring associations between Anderson land cover category percentages and soil concentrations of As, Pb, and Ba in ten sampling areas. Land cover category and metal associations with ethnicity and socioeconomic status at the United States Census 2000 block and block group levels also were investigated. Arsenic and Pb were highest in urban locations; Ba was a function of geology. Consistent associations were observed between urban/built up land cover, and Pb and poverty. Land cover can be used as proxy for metal concentrations, although associations are metal-dependent. Copyright © 2014. Published by Elsevier B.V.

  9. GROUND WATER ISSUE: NATURAL ATTENUATION OF HEXA- VALENT CHROMIUM IN GROUND WATER AND SOILS

    Science.gov (United States)

    In this paper, what is known about the transformation of chromium in the subsurface is explored. This is an attempt to identify conditions where it is most likely to occur, and describe soil tests that can assist in determining the likelihood of natural attenuation of Cr(VI) in s...

  10. Estimation of ground heat flux from soil temperature over a bare soil

    Science.gov (United States)

    An, Kedong; Wang, Wenke; Wang, Zhoufeng; Zhao, Yaqian; Yang, Zeyuan; Chen, Li; Zhang, Zaiyong; Duan, Lei

    2017-08-01

    Ground soil heat flux, G 0, is a difficult-to-measure but important component of the surface energy budget. Over the past years, many methods were proposed to estimate G 0; however, the application of these methods was seldom validated and assessed under different weather conditions. In this study, three popular models (force-restore, conduction-convection, and harmonic) and one widely used method (plate calorimetric), which had well performance in publications, were investigated using field data to estimate daily G 0 on clear, cloudy, and rainy days, while the gradient calorimetric method was regarded as the reference for assessing the accuracy. The results showed that harmonic model was well reproducing the G 0 curve for clear days, but it yielded large errors on cloudy and rainy days. The force-restore model worked well only under rainfall condition, but it was poor to estimate G 0 under rain-free conditions. On the contrary, the conduction-convection model was acceptable to determine G 0 under rain-free conditions, but it generated large errors on rainfall days. More importantly, the plate calorimetric method was the best to estimate G 0 under different weather conditions compared with the three models, but the performance of this method is affected by the placement depth of the heat flux plate. As a result, the heat flux plate was recommended to be buried as close as possible to the surface under clear condition. But under cloudy and rainy conditions, the plate placed at depth of around 0.075 m yielded G 0 well. Overall, the findings of this paper provide guidelines to acquire more accurate estimation of G 0 under different weather conditions, which could improve the surface energy balance in field.

  11. An experimental investigation to characterise soil macroporosity under different land use and land covers of northeast India

    Indian Academy of Sciences (India)

    Sangeeta Shougrakpam; Rupak Sarkar; Subashisa Dutta

    2010-10-01

    Saturated macropore flow is the dominant hydrological process in tropical and subtropical hilly watersheds of northeast India.The process of infiltration into saturated macroporous soils is primarily controlled by size,network,density,connectivity,saturation of surrounding soil matrix, and depthwise distribution of macropores.To understand the effects of local land use,land cover and management practices on soil macroporosity,colour dye infiltration experiments were conducted with ten soil columns (25 × 25 × 50 cm)collected from different watersheds of the region under similar soil and agro-climatic zones.The sampling sites included two undisturbed forested hillslopes,two conventionally cultivated paddy fields,two forest lands abandoned after Jhum cultivation,and two paddy fields,one pineapple plot and one banana plot presently under active cultivation stage of the Jhum cycle.Digital image analyses of the obtained dye patterns showed that the infiltration patterns differed significantly for different sites with varying land use,land cover,and cultivation practices.Undisturbed forest soils showed high degree of soil macroporosity throughout the soil profile,paddy fields revealed sealing of macropores at the topsoil due to hard pan formation,and Jhum cultivated plots showed disconnected subsoil macropores.The important parameters related to soil macropores such as maximum and average size of macropores,number of active macropores,and depthwise distribution of macropores were estimated to characterise the soil macroporosity for the sites.These experimentally derived quantitative data of soil macro- porosity can have wide range of applications in the region such as water quality monitoring and groundwater pollution assessment due to preferential leaching of solutes and pesticides,study of soil structural properties and infiltration behaviour of soils,investigation of flash floods in rivers, and hydrological modelling of the watersheds.

  12. An experimental investigation to characterise soil macroporosity under different land use and land covers of northeast India

    Science.gov (United States)

    Shougrakpam, Sangeeta; Sarkar, Rupak; Dutta, Subashisa

    2010-10-01

    Saturated macropore flow is the dominant hydrological process in tropical and subtropical hilly watersheds of northeast India. The process of infiltration into saturated macroporous soils is primarily controlled by size, network, density, connectivity, saturation of surrounding soil matrix, and depthwise distribution of macropores. To understand the effects of local land use, land cover and management practices on soil macroporosity, colour dye infiltration experiments were conducted with ten soil columns (25 × 25 × 50 cm) collected from different watersheds of the region under similar soil and agro-climatic zones. The sampling sites included two undisturbed forested hillslopes, two conventionally cultivated paddy fields, two forest lands abandoned after Jhum cultivation, and two paddy fields, one pineapple plot and one banana plot presently under active cultivation stage of the Jhum cycle. Digital image analyses of the obtained dye patterns showed that the infiltration patterns differed significantly for different sites with varying land use, land cover, and cultivation practices. Undisturbed forest soils showed high degree of soil macroporosity throughout the soil profile, paddy fields revealed sealing of macropores at the topsoil due to hard pan formation, and Jhum cultivated plots showed disconnected subsoil macropores. The important parameters related to soil macropores such as maximum and average size of macropores, number of active macropores, and depthwise distribution of macropores were estimated to characterise the soil macroporosity for the sites. These experimentally derived quantitative data of soil macroporosity can have wide range of applications in the region such as water quality monitoring and groundwater pollution assessment due to preferential leaching of solutes and pesticides, study of soil structural properties and infiltration behaviour of soils, investigation of flash floods in rivers, and hydrological modelling of the watersheds.

  13. Effect of grass cover on water and pesticide transport through undisturbed soil columns, comparison with field study (Morcille watershed, Beaujolais)

    Energy Technology Data Exchange (ETDEWEB)

    Dousset, S., E-mail: sylvie.dousset@limos.uhp-nancy.f [Nancy-Universite, CNRS, LIMOS, BP 70239, 54506 Vandoeuvre-les-Nancy (France); Thevenot, M. [Universite de Lille 1, CNRS, Geosystemes, 59655 Villeneuve d' Ascq (France); Schrack, D. [INRA-SAD ASTER, 88500 Mirecourt (France); AFSSA, Laboratoire d' Etudes et de Recherches en Hydrologie, 54000 Nancy (France); Gouy, V.; Carluer, N. [UR Milieux Aquatiques, Ecologie et Pollution, Cemagref, 69336 Lyon Cedex (France)

    2010-07-15

    The purpose of this work is to assess the effectiveness of two grass covers (buffer zone and grass-covered inter-row), to reduce pesticide leaching, and subsequently to preserve groundwater quality. Lower amounts of pesticides leached through grass-cover soil columns (2.7-24.3% of the initial amount) than the bare soil columns (8.0-55.1%), in correspondence with their sorption coefficients. Diuron was recovered in higher amounts in leachates (8.9-32.2%) than tebuconazole (2.7-12.9%), in agreement with their sorption coefficients. However, despite having a sorption coefficient similar to that of diuron, more procymidone was recovered in the leachates (10.2-55.1%), probably due to its facilitated transport by dissolved organic matter. Thus even in this very permeable soil, higher organic matter contents associated with grass-cover reduce the amount of pesticide leaching and limit the risk of groundwater contamination by the pesticides. The results of diuron and tebuconazole transfer through undisturbed buffer zone soil columns are in agreement with field observations on the buffer zone. - Grass-covered soils reduce the amount of pesticide leaching, due mainly to their higher organic matter contents, thereby reducing the risk of groundwater contamination.

  14. The influence of vegetation covers on soil moisture dynamics at high temporal resolution in scattered tree woodlands of Mediterranean climate

    Science.gov (United States)

    Lozano-Parra, Javier; Schnabel, Susanne; Ceballos-Barbancho, Antonio

    2015-04-01

    Soil water is a key factor that controls the organization and functioning of dryland ecosystems. However, in spite of its great importance in ecohydrological processes, most of the studies focus on daily or longer timescales, while its dynamics at shorter timescales are very little known. The main objective of this work was to determine the role of vegetation covers (grassland and tree canopy) in the soil hydrological response using measurements with high temporal resolution in evergreen oak woodland with Mediterranean climate. For this, soil water content was monitored continuously with a temporal resolution of 30 minutes and by means of capacitance sensors, mainly for the hydrological years 2010-2011 and 2011-2012. They were installed at 5, 10 and 15 cm, and 5 cm above the bedrock and depending on soil profile. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 8 soil moisture stations in two contrasting situations characterized by different vegetation covers: under tree canopy and in open spaces or grasslands. Soil moisture variations were calculated at rainfall event scale at top soil layer and deepest depth by the difference between the final and initial soil moisture registered by a sensor at the finish and the beginning of the rainfall event, respectively. Besides, as soil moisture changes are strongly influenced by antecedent conditions, different antecedent soil moisture conditions or states, from driest to wettest, were also defined. The works were carried out in 3 experimental farms of the Spanish region of Extremadura. Results obtained revealed that rainwater amount bypassing vegetation covers and reaching the soil may temporarily be modified by covers according to precipitation properties and antecedent environmental conditions (from dry to wet) before the rain episode. Rainfall amounts triggering a positive soil

  15. Comparing distinct ground-based lightning location networks covering the Netherlands

    Science.gov (United States)

    de Vos, Lotte; Leijnse, Hidde; Schmeits, Maurice; Beekhuis, Hans; Poelman, Dieter; Evers, Läslo; Smets, Pieter

    2015-04-01

    Lightning can be detected using a ground-based sensor network. The Royal Netherlands Meteorological Institute (KNMI) monitors lightning activity in the Netherlands with the so-called FLITS-system; a network combining SAFIR-type sensors. This makes use of Very High Frequency (VHF) as well as Low Frequency (LF) sensors. KNMI has recently decided to replace FLITS by data from a sub-continental network operated by Météorage which makes use of LF sensors only (KNMI Lightning Detection Network, or KLDN). KLDN is compared to the FLITS system, as well as Met Office's long-range Arrival Time Difference (ATDnet), which measures Very Low Frequency (VLF). Special focus lies on the ability to detect Cloud to Ground (CG) and Cloud to Cloud (CC) lightning in the Netherlands. Relative detection efficiency of individual flashes and lightning activity in a more general sense are calculated over a period of almost 5 years. Additionally, the detection efficiency of each system is compared to a ground-truth that is constructed from flashes that are detected by both of the other datasets. Finally, infrasound data is used as a fourth lightning data source for several case studies. Relative performance is found to vary strongly with location and time. As expected, it is found that FLITS detects significantly more CC lightning (because of the strong aptitude of VHF antennas to detect CC), though KLDN and ATDnet detect more CG lightning. We analyze statistics computed over the entire 5-year period, where we look at CG as well as total lightning (CC and CG combined). Statistics that are considered are the Probability of Detection (POD) and the so-called Lightning Activity Detection (LAD). POD is defined as the percentage of reference flashes the system detects compared to the total detections in the reference. LAD is defined as the fraction of system recordings of one or more flashes in predefined area boxes over a certain time period given the fact that the reference detects at least one

  16. Transport and reaction processes affecting the attenuation of landfill gas in cover soils

    DEFF Research Database (Denmark)

    Molins, S.; Mayer, K.U.; Scheutz, Charlotte

    2008-01-01

    of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate, the contributions of various gas transport processes on methane attenuation in landfill cover soils....... For this purpose, a reactive transport model that includes advection and the Dusty Gas Model for simulation of multicomponent gas diffusion was used. The simulations are constrained by data from a series of counter-gradient laboratory experiments. Diffusion typically accounts for over 99% of methane emission....... Simulations suggest that production of water or accumulation of exopolymeric substances due to microbially mediated methane oxidation can significantly reduce diffusive fluxes. Assuming a constant rate of methane production within a landfill, reduction of the diffusive transport properties, primarily due...

  17. Soil carbon storage as influenced by tree cover in the Dehesa cork oak silvopasture of central-western Spain.

    Science.gov (United States)

    Howlett, David Scott; Moreno, Gerardo; Mosquera Losada, Maria Rosa; Nair, P K Ramachandran; Nair, Vimala D

    2011-07-01

    The extent of carbon (C) stored in soils depends on a number of factors including soil characteristics, climatic and other environmental conditions, and management practices. Such information, however, is lacking for silvopastoral systems in Spain. This study quantified the amounts of soil C stored at various depths (0-25, 25-50, 50-75, and 75-100 cm) under a Dehesa cork oak (Quercus suber L.) silvopasture at varying distances (2, 5, and 15 m) to trees. Soil C in the whole soil and three soil fractions (cork oak was 50.2, 37, and 26.5 Mg ha(-1), respectively. Taking into account proportions of land surface area containing these C stocks at varying distances to trees to 1 m depth, with a tree density of 35 stems ha(-1), estimated landscape soil C is 29.9 Mg ha(-1). Greater soil C stocks directly underneath the tree canopy suggest that maintaining or increasing tree cover, where lost from disease or management, may increase long term storage of soil C in Mediterranean silvopastoral systems. The results also demonstrate the use of soil aggregate characteristics as better indicators of soil C sequestration potential and thus a tool for environmental monitoring.

  18. Uncertainty of spatial distributions of soil magnetic susceptibility in areas of different type of land cover and anthropogenic pressure

    Science.gov (United States)

    Zawadzki, Jaroslaw; Fabijańczyk, Piotr

    2016-04-01

    There is still a high interest in the improvement of soil magnetometry procedures that would increase its accuracy. Soil magnetometry is usually used as a fast screening method that is used to assess the degree of soil pollution. As the magnetometric measurements do not provide the exact information about the concentration of elements in soil, it is very important to determine the uncertainty of the spatial distributions of soil magnetic susceptibility. The goal of this study was to analyze and present geostatistical methods of assessing the uncertainty of spatial distribution of soil magnetic susceptibility in areas of different land cover and anthropogenic pressure. In particular, spatial distributions of magnetic susceptibility measured on the soil surface using a MS2D Bartington device were calculated using indicator methods that make it possible to calculate the probability of exceeding the critical levels of soil magnetic susceptibility. Measurements were performed in areas located in the Upper Silesian Industrial Area in Poland, and in Norway. In these areas soil magnetic susceptibility was measured on the soil surface using a MS2D Bartington device. Additionally, soil samples were taken in order to perform chemical measurements that included the determination of a concentration of selected elements. Acknowledgment The research leading to these results has received funding from the Polish-Norwegian Research Programme operated by the National Centre for Research and Development underthe Norwegian Financial Mechanism 2009-2014 in the frame of Project IMPACT - Contract No Pol-Nor/199338/45/2013.

  19. Effects of continuous cover forestry on soil moisture pattern - Beginning steps of a Hungarian study

    Science.gov (United States)

    Kalicz, Péter; Bartha, Dénes; Brolly, Gábor; Csáfordi, Péter; Csiszár, Ágnes; Eredics, Attila; Gribovszki, Zoltán; Király, Géza; Kollár, Tamás; Korda, Márton; Kucsara, Mihály; Nótári, Krisztina; Kornél Szegedi, Balázs; Tiborcz, Viktor; Zagyvai, Gergely; Zagyvai-Kiss, Katalin Anita

    2014-05-01

    Nowadays Hungarian foresters encounter a new challenge. The traditional management practices do not meet anymore with the demand of the civil society. The good old clearcut is no more a supported technology in forest regeneration. The transition to the continuous cover forestry induces much higher spatial variability compared to the even aged, more or less homogeneous, monoculture stands. The gap cutting is one of the proposed key methods in the Hungarian forestry. There is an active discussion among forest professionals how to determine the optimal gap size to maintain ideal conditions for the seedlings. Among other open questions for example how the surrounding trees modify the moisture pattern of the forest floor in the gap? In the early steps of a multidisciplinary project we established four research plots to study the spatial and temporal variability of soil moisture in the forest gap and the surrounding undisturbed stand. Each plot is located in oak (Quercus spp.) stands. Natural regeneration of oak stands is more problematic in our climate compared to the beech (Fagus sylvatica) which is located in the more humid or semi-humid areas of our country. All plots are located in the western part of Hungary: close to Sopron, Bejcgyertyános, Vép and Vajszló settlements. The last plot is an extensive research area, which is located in the riparian zone of a tributary of Feketevíz River. We monitor here the close-to-surface groundwater level fluctuation with pressure transducers. With a diurnal fluctuation based method it is possible to quantify the evapotranspiration differences between the gap and the stand. In two of the remaining stands (Bejcgyertyános and Vép) the gaps were opened in 2010. The monitoring of soil moisture began in 2013. A mobile sensor is used to monitor soil-moisture in a regular grid. The spatial variability of soil-moisture time-series shows a characteristic pattern during the growing-season. The plot in Sopron was established in 2013

  20. After the fire: benefits of reduced ground cover for vervet monkeys (Cercopithecus aethiops).

    Science.gov (United States)

    Jaffe, Karin Enstam; Isbell, Lynne A

    2009-03-01

    Here we describe changes in ranging behavior and other activities of vervet monkeys (Cercopithecus aethiops) after a wildfire eliminated grass cover in a large area near the study group's home range. Soon after the fire, the vervets ranged farther away from tall trees that provide refuge from mammalian predators, and moved into the burned area where they had never been observed to go before the fire occurred. Visibility at vervet eye-level was 10 times farther in the burned area than in unburned areas. They traveled faster, and adult females spent more time feeding and less time scanning bipedally in the burned area than in the unburned area. The burned area's greater visibility may have lowered the animals' perceived risk of predation there, and may have provided them with an unusual opportunity to eat acacia ants.

  1. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

    The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (psoil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, psoil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (perosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  2. Finite Element Modeling of Unbounded Grounding System Considering Soil Ionization Characteristic

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; LI Jingli; YANG Qing; SIMA Wenxia; SUN Caixin

    2012-01-01

    The aim of this paper is to calculate accurately the grounding performance of an unbounded grounding system under high-magnitude fault current.In this work,a finite element model is presented to compute the characteristic parameters of the grounding system in frequency domain.The ionization phenomenon in the soil surrounding the grounding electrode is taken into account by setting the resistivity of every soil element while the resistivity of each element is varying with the electric field intensity;not a priori hypothesis on the geometrical shape of the ionized region around the electrodes has to be enforced.Open boundaries of the grounding system are represented by introducing a spatial transformation formulation,which translates the semi-infinite space into the finite space without shortening the domain as in the traditional approach.The suggested modeling is validated by comparison of the calculated results,which are laid out for grounding rod and grounding grid,with experimental and simulation results found in literature.

  3. Ground Water Issue: Phytoremediation of Contaminated Soil and Ground Water at Hazardous Waste Sites

    Science.gov (United States)

    2001-02-01

    phytomining. J. Geochem. Explor. 60(2):115-126. Rogers, R.D., and S.E. Williams. 1986. Vesicular- arbuscular mycorrhiza : influence on plant uptake of...surrounding plant roots). Fungi associated with some plant roots (i.e., mycorrhizae ) can also influence the chemical conditions within the soil...arundinacea Schreb.), revealed the importance of mycorrhizae and adding organic waste amendments in establishing plants on the metal-contaminated mine wastes

  4. Mechanisms of hydrogen sulfide removal by ground granulated blast furnace slag amended soil.

    Science.gov (United States)

    Xie, Mengyao; Leung, Anthony Kwan; Ng, Charles Wang Wai

    2017-02-06

    Ground granulated blast furnace slag (GGBS) amended soil has been found able to remove gaseous hydrogen sulfide (H2S). However, how H2S is removed by GGBS amended soil and why GGBS amended soil can be regenerated to remove H2S are not fully understood. In this study, laboratory column tests together with chemical analysis were conducted to investigate and reveal the mechanisms of H2S removal process in GGBS amended soil. Sulfur products formed on the surface of soil particle and in pore water were quantified. The test results reveal that the reaction between H2S and GGBS amended soil was a combined process of oxidation and acid-base reaction. The principal mechanism to remove H2S in GGBS amended soil was through the formation of acid volatile sulfide (AVS), elemental sulfur and thiosulfate. Soil pH value decreased gradually during regeneration and reuse cycles. It is found that the AVS plays a significant role in H2S removal during regeneration and reuse cycles. Adding GGBS increased the production of AVS and at the same time suppressed the formation of elemental sulfur. This mechanism is found to be more prominent when the soil water content is higher, leading to increased removal capacity.

  5. Cover crops for managing weeds, soil chemical fertility and nutritional status of organically grown orange orchard in Sicily

    Directory of Open Access Journals (Sweden)

    Rosario Paolo Mauro

    2015-06-01

    Full Text Available Cover crops can offer significant advantages in the agronomic management of citrus orchards in Mediterranean environments. Therefore, a three-year research was conducted in eastern Sicily aimed at studying the effects of four cover crop sequences (Sinapis arvensis-Trigonella foenum-graecum-T. foenum-graecum; Medicago scutellata-Avena sativa-Lolium perenne; Vicia faba minor-A. sativa-A. sativa; A. sativa-V. faba. minor-L. perenne on weeds, major soil chemical properties and nutritional status of an organically grown orange orchard. The results highlighted that, among the studied cover crop sequences, Vicia faba-Avena-Avena was the most beneficial for weeds control within the orchard (92%, of cover crop cover, and 586 and 89 g DW m–2 of cover crop aboveground biomass and weeds aboveground biomass, respectively. Overall, the chemical fertility of the soil was positively influenced. In particular, it was observed an increase of the content of total nitrogen and available phosphorus in the soil by both Sinapis-Trigonella-Trigonella (0.75 g kg–1 and 59.0 mg kg–1, respectively and Vicia faba-Avena-Avena (0.70 g kg–1 and 56.0 mg kg–1, respectively cover crop sequences. Medicago-Avena-Lolium sequence seemed to be the most useful to ensure a better nutritional status of the orange orchard.

  6. Soil moisture ground truth: Steamboat Springs, Colorado, site and Walden, Colorado, site

    Science.gov (United States)

    Jones, E. B.

    1976-01-01

    Ground-truth data taken at Steamboat Springs and Walden, Colorado in support of the NASA missions in these areas during the period March 8, 1976 through March 11, 1976 was presented. This includes the following information: snow course data for Steamboat Springs and Walden, snow pit and snow quality data for Steamboat Springs, and soil moisture report.

  7. Soils and ground waters cleaning; Depollution des sols et des eaux souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Eberentz, P. [ANTEA, 45 - Orleans (France); Cazenove, A. de [Ecole Superieure de l' Energie et des Materiaux ESEM, 45 - Orleans (France); Darmendrail, D. [Bureau de Recherches Geologiques et Minieres, BRGM, 45 - Orleans (France)] [and others

    2000-07-01

    By seven presentations of case studies and researches, this colloquium takes stock on the natural pollution control mechanisms and technic and also on the economic and juridical stakes. Many french sites, concerning the soils and the ground waters are discussed. (A.L.B.)

  8. Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing

    Science.gov (United States)

    Andrew D. Parsekian; Lee Slater; Dimitrios Ntarlagiannis; James Nolan; Stephen D. Sebestyen; Randall K. Kolka; Paul J. Hanson

    2012-01-01

    Estimating soil C stock in a peatland is highly dependent on accurate measurement of the peat volume. In this study, we evaluated the uncertainty in calculations of peat volume using high-resolution data to resolve the three-dimensional structure of a peat basin based on both direct (push probes) and indirect geophysical (ground-penetrating radar) measurements. We...

  9. Influence of foundation type and soil stratification on ground vibration - a parameter study

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Prins, Joeri Nithan; Persson, Kent

    2016-01-01

    Vibration of machinery and construction work are major sources of noise and vibration pollution in the urban environment. The frequencies dominating the vibration, and the distances over which it spreads via the ground, depend on the source. However, soil stratification and foundation type have...

  10. LRO Diviner Soil Composition Measurements - Lunar Sample Ground Truth

    Science.gov (United States)

    Allen, Carlton C.; Greenhagen, Benjamin T.; Paige, David A.

    2010-01-01

    The Diviner Lunar Radiometer Experiment on the Lunar Reconnaissance Orbiter [1,2] includes three thermal infrared channels spanning the wavelength ranges 7.55-8.05 microns 8.10-8.40 microns, and 8.38-8.68 microns. These "8 micron" bands were specifically selected to measure the "Christiansen feature". The wavelength location of this feature, referred to herein as CF, is particularly sensitive to silicate minerals including plagioclase, pyroxene, and olivine the major crystalline components of lunar rocks and soil. The general trend is that lower CF values are correlated with higher silica content and higher CF values are correlated with lower silica content. In a companion abstract, Greenhagen et al. [3] discuss the details of lunar mineral identification using Diviner data.

  11. Soil quality evaluation following the implementation of permanent cover crops in semi-arid vineyards. Organic matter, physical and biological soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Virto, I.; Imaz, M. J.; Fernandez-Ugalde, O.; Urrutia, I.; Enrique, A.; Bescansa, P.

    2012-07-01

    Changing from conventional vineyard soil management, which includes keeping bare soil through intense tilling and herbicides, to permanent grass cover (PGC) is controversial in semi-arid land because it has agronomic and environmental advantages but it can also induce negative changes in the soil physical status. The objectives of this work were (i) gaining knowledge on the effect of PGC on the soil physical and biological quality, and (ii) identifying the most suitable soil quality indicators for vineyard calcareous soils in semi-arid land. Key soil physical, organic and biological characteristics were determined in a Cambic Calcisol with different time under PGC (1 and 5 years), and in a conventionally managed control. Correlation analysis showed a direct positive relationship between greater aggregate stability (WSA), soil-available water capacity (AWC), microbial biomass and enzymatic activity in the topsoil under PGC. Total and labile organic C concentrations (SOC and POM-C) were also correlated to microbial parameters. Factor analysis of the studied soil attributes using principal component analysis (PCA) was done to identify the most sensitive soil quality indicators. Earthworm activity, AWC, WSA, SOC and POM-C were the soil attributes with greater loadings in the two factors determined by PCA, which means that these properties can be considered adequate soil quality indicators in this agrosystem. These results indicate that both soil physical and biological attributes are different under PGC than in conventionally-managed soils, and need therefore to be evaluated when assessing the consequences of PGC on vineyard soil quality. (Author) 65 refs.

  12. The impact of Pinus halepensis afforestation on Mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

    Institute of Scientific and Technical Information of China (English)

    Pasta Salvatore; Tommaso La Mantia; Juliane Rühl

    2012-01-01

    We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition,richness and evenness,and on the trend and speed of vegetation dynamics.Phytosociological relevés of three different plot typologies,i.e.(1) soil-treatment and plantation,(2) only soil-treatment,(3) no soil-treatment and no plantation,were compared by (a) multivariate analysis and (b) with reference to species richness and evenness.Moreover,in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities,we compared life form and syntaxonomic spectra between phytosociological relevés taken at 8 years of distance.DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices.Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation,canopy cover clearly plays a major role:in fact,the highest Ph cover rates correspond to the lowest values of understory species richness.This is true also if only species of biogeographical/conservation interest are considered.Regarding vegetation dynamics,sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities.The same factors invoqued to explain the patterns of floristic composition and similarity (i.e.allelopathy and competition for light,water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations.Thus,in sites where Ph cover exceeds about 80%,thinning is recommended not only in order to accelerate succession,but also to give a natural 'shape' to afforestations.

  13. The efficacy of winter cover crops to stabilize soil inorganic nitrogen after fall-applied anhydrous ammonia.

    Science.gov (United States)

    Lacey, Corey; Armstrong, Shalamar

    2015-03-01

    There is a dearth of knowledge on the ability of cover crops to increase the effectiveness of fall-applied nitrogen (N). The objective of this study was to investigate the efficacy of two cover crop species to stabilize inorganic soil N after a fall application of N. Fall N was applied at a rate of 200 kg N ha into living stands of cereal rye, tillage radish, and a control (no cover crop) at the Illinois State University Research and Teaching Farm in Lexington, Illinois. Cover crops were sampled to determine N uptake, and soil samples were collected in the spring at four depths to 80 cm to determine the distribution of inorganic N within the soil profile. Tillage radish (131.9-226.8 kg ha) and cereal rye (188.1-249.9 kg ha N) demonstrated the capacity to absorb a minimum of 60 to 80% of the equivalent rate of fall-applied N, respectively. Fall applying N without cover crops resulted in a greater percentage of soil NO-N (40%) in the 50- to 80-cm depth, compared with only 31 and 27% when tillage radish and cereal rye were present at N application. At planting, tillage radish stabilized an average of 91% of the equivalent rate of fall-applied N within the 0- to 20-cm, depth compared with 66 and 57% for the cereal rye and control treatments, respectively. This study has demonstrated that fall applying N into a living cover crop stand has the potential to reduce the vulnerability of soil nitrate and to stabilize a greater concentration of inorganic N within the agronomic depths of soil.

  14. Field-Scale Stable-Isotope Probing of Active Methanotrophs in a Landfill-Cover Soil

    Science.gov (United States)

    Schroth, M. H.; Henneberger, R.; Chiri, E.

    2012-12-01

    The greenhouse gas methane (CH4) is an important contributor to global climate change. While its atmospheric concentration is increasing, a large portion of produced CH4 never reaches the atmosphere, but is consumed by aerobic methane-oxidizing bacteria (MOB). The latter are ubiquitous in soils and utilize CH4 as sole source of energy and carbon. Among other methods, MOB may be differentiated based on characteristic phospholipid fatty acids (PLFA). Stable-isotope probing (SIP) on PLFA has been widely applied to identify active members of MOB communities in laboratory incubation studies, but results are often difficult to extrapolate to the field. Thus, novel field-scale approaches are needed to link activity and identity of MOB in their natural environment. We present results of field experiments in which we combined PLFA-SIP with gas push-pull tests (GPPTs) to label active MOB at the field-scale while simultaneously quantifying CH4 oxidation activity. During a SIP-GPPT, a mixture of reactive (here 13CH4, O2) and non-reactive tracer gases (e.g., Ar, Ne, He) is injected into the soil at a location of interest. Thereafter, gas flow is reversed and the gas mixture diluted with soil air is extracted from the same location and sampled periodically. Rate constants for CH4 oxidation can be calculated by analyzing breakthrough curves of 13CH4 and a suitable non-reactive tracer gas. SIP-GPPTs were performed in a landfill-cover soil, and feasibility of this novel approach was tested at several locations along a gradient of MOB activity and soil temperature. Soil samples were collected before and after SIP-GPPTs, total PLFA were extracted, and incorporation of 13C in the polar lipid fraction was analyzed. Potential CH4 oxidation rates derived from SIP-GPPTs were similar to those derived from regular GPPTs (using unlabeled CH4) performed at the same locations prior to SIP-GPPTs, indicating that application of 13CH4 did not adversely affect bacterial CH4 oxidation rates. Rates

  15. Soil phosphorus mobilization in the rhizosphere of cover crops has little effect on phosphorus cycling in California agricultural soils

    Science.gov (United States)

    External phosphorus (P) inputs to agricultural soils are needed to replace soil P removed by harvest and maintain soil fertility. Alternative fertilization approaches that maintain soil fertility while reducing P inputs could improve current practices that often result in excessive P application and...

  16. Cover-crops - improvement of soil fertility and provision of biomass

    Science.gov (United States)

    Kirchmeyr, Franz; Szerencsits, Manfred

    2017-04-01

    Besides climate change, erosion, inadequate crop rotation and intensive tillage may turn arable land into marginal land. On the other hand, reclamation approaches which include arable farming methods may result only in short-term success if they do not consider their effects on humus content and erosion. Additionally, effective reclamation will also have to address the growing need for food production besides biomass provision. Therefore, we investigated if cover or catch crops (CC) may accomplish both goals: Improve soil quality and humus content even if CC-biomass is used for biogas production. Humus content and soil fertility: In comparison to complete fallow in a crop rotation with silage maize and cereals the humus balance can be improved from -50 to +280 kg humus carbon (C) ha-1 year-1 through additional CC (4.5 t DM ha-1) used for biogas production and an equivalent amount of digestate returned to the field. With a CC-yield of 2.5 t DM ha-1 the humus balance results in 220 kg C ha-1 year-1. It is still slightly higher if the same CC remains on the field as green manure (170 kg C ha-1 year-1). Additionally it is important to consider that 20 - 50 % of the assimilated carbon can be found in the plant roots and that roots and root exudates as well as CC harvest residues provide fresh organic matter for soil life. Furthermore, biomass production of cover crops was considerably higher, if they were used for biogas production because of earlier cultivation and later harvest than mulching. Erosion control: The risk of erosion can be reduced by approx. 50 % in comparison to complete fallow if CC with 2.5 t DM ha-1 remain on the field as green manure. A comparable reduction can be achieved, if CC with 4.5 t DM ha-1 are harvested for biogas production. Because of better weed suppression, tilth and soil structure of CC with higher biomass, it is more likely to apply conservation tillage and avoid ploughing. Without ploughing a CC with 4.5 t DM ha-1 used for biogas the

  17. Reduction of Ground Vibration by Means of Barriers or Soil Improvement along a Railway Track

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R.K.

    2005-01-01

    Trains running in built-up areas are a source to ground-borne noise. A careful design of the track may be one way of minimizing the vibrations in the surroundings. For example, open or infilled trenches may be constructed along the track, or the soil underneath the track may be improved. In this ......Trains running in built-up areas are a source to ground-borne noise. A careful design of the track may be one way of minimizing the vibrations in the surroundings. For example, open or infilled trenches may be constructed along the track, or the soil underneath the track may be improved...... the vehicle. The computations are carried out in the frequency domain for various combinations of the vehicle speed and the excitation frequency. The analyses indicate that open trenches are more efficient than infilled trenches or soil stiffening–even at low frequencies. However, the direction of the load...

  18. Assessment of soil and ground water quality in Rewa district of Vindhyan Plateau (India).

    Science.gov (United States)

    Dwivedi, A P; Tripathi, I P; Kumar, M Suresh

    2013-01-01

    A systematic seasonal study has been carried out to assess the physico-chemical characteristics of ground water and soils in Rewa district of India. The drinking water in the study area is supplied mainly through Public Health Engineering (PHE) department from river (Bichhia, Bihar) and ground water. Water and soil samples were collected from different locations in the Rewa district, i.e. 10 hand pumps and 10 bore wells around all over the district. Regular monitoring was carried out during summer, rainy and winter seasons, to study the seasonal variation in physico-chemical parameters and metals concentration. The parameters like pH, turbidity, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate, nitrite, chloride, sulphate, phosphate and heavy metals were estimated for water and soil samples collected from the Rewa district. The results obtained are discussed, correlated with probable sources of contamination and suggested the measures to minimize the pollution.

  19. AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions

    Science.gov (United States)

    Wiegand, C. L. (Principal Investigator); Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J.

    1981-01-01

    Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures.

  20. Soil Moisture Estimation Across Scales with Mobile Sensors for Cosmic-Ray Neutrons from the Ground and Air

    Science.gov (United States)

    Schrön, Martin; Köhler, Mandy; Bannehr, Lutz; Köhli, Markus; Fersch, Benjamin; Rebmann, Corinna; Mai, Juliane; Cuntz, Matthias; Kögler, Simon; Schröter, Ingmar; Wollschläger, Ute; Oswald, Sascha; Dietrich, Peter; Zacharias, Steffen

    2016-04-01

    Soil moisture is a key variable for environmental sciences, but its determination at various scales and depths is still an open challenge. Cosmic-ray neutron sensing has become a well accepted and unique method to monitor an effective soil water content, covering tens of hectares in area and tens of centimeters in depth. The technology is famous for its low maintanance, non-invasiveness, continous measurement, and most importantly its large footprint and penetration depth. Beeing more representative than point data, and finer resolved plus deeper penetrating than remote-sensing products, cosmic-ray neutron derived soil moisture products provide unrivaled advantage for agriculture, regional hydrologic and land surface models. The method takes advantage of omnipresent neutrons which are extraordinarily sensitive to hydrogen in soil, plants, snow and air. Unwanted hydrogen sources in the footprint can be excluded by local calibration to extract the pure soil water information. However, this procedure is not feasible for mobile measurements, where neutron detectors are mounted on a car to do catchment-scale surveys. As a solution to that problem, we suggest strategies to correct spatial neutron data with the help of available spatial data of soil type, landuse and vegetation. We further present results of mobile rover campaigns at various scales and conditions, covering small sites from 0.2 km2 to catchments of 100 km2 area, and complex terrain from agricultural fields, urban areas, forests, to snowy alpine sites. As the rover is limited to accessible roads, we further investigated the applicability of airborne measurements. First tests with a gyrocopter at 150 to 200m heights proofed the concept of airborne neutron detection for environmental sciences. Moreover, neutron transport simulations confirm an improved areal coverage during these campaigns. Mobile neutron measurements at the ground or air are a promising tool for the detection of water sources across many

  1. Modelling soil moisture under different land covers in a sub-humid environment of Western Ghats, India

    Indian Academy of Sciences (India)

    B Venkatesh; Lakshman Nandagiri; B K Purandara; V B Reddy

    2011-06-01

    The objective of this study is to apply and test a simple parametric water balance model for prediction of soil moisture regime in the presence of vegetation. The intention was to evaluate the differences in model parameterization and performance when applied to small watersheds under three different types of land covers (Acacia, degraded forest and natural forest). The watersheds selected for this purpose are located in the sub-humid climate within the Western Ghats, Karnataka, India. Model calibration and validation were performed using a dataset comprising depth-averaged soil moisture content measurements made at weekly time steps from October 2004 to December 2008. In addition to this, a sensitivity analysis was carried out with respect to the water-holding capacity of the soils with the aim of explaining the suitability and adaptation of exotic vegetation types under the prevailing climatic conditions. Results indicated reasonably good performance of the model in simulating the pattern and magnitude of weekly average soil moisture content in 150 cm deep soil layer under all three land covers. This study demonstrates that a simple, robust and parametrically parsimonious model is capable of simulating the temporal dynamics of soil moisture content under distinctly different land covers. Also, results of sensitivity analysis revealed that exotic plant species such as Acacia have adapted themselves effectively to the local climate.

  2. Dynamic Characteristics of Saturated Silty Soil Ground Treated by Stone Column Composite Foundation

    Directory of Open Access Journals (Sweden)

    Yongxiang Zhan

    2014-01-01

    Full Text Available A shaking table model test was carried out to develop an understanding of the performance improvement of saturated silty soil ground using stone column composite foundation as reinforcement. It is found that at less than 0.161 g loading acceleration, soil between piles has not yet been liquefied, the response acceleration scarcely enlarges, and the shear displacement almost does not appear in silty soil. At 0.252 g loading acceleration, as a result of liquefaction of soil between piles, the response acceleration increases rapidly and reaches its peak, and the shear displacement of silty soil increases significantly. At 0.325 g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of vibration transmission and result in the response acceleration amplification coefficient is less than that at the former loading acceleration, but the shear displacement of silty soil further increases. The stone column composite foundation can greatly reduce both the shear displacement and the settlement of ground compared with untreated foundation. Under the condition of 7-degree seismic fortification, the design meets seismic resistance requirements.

  3. Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

    OpenAIRE

    2011-01-01

    Metadata only record No-till practices, in conjunction with cover crops and nitrogen fertilization, have been shown to augment soil organic carbon content and total nitrogen content. However, interactions between these components in a no-till system are not well-known. This study offers a long-term (1993-2008) comparative analysis of conventional versus no-till practices as well as a some insight regarding the synergies between no-till, nitrogen fertilization, and cover crops. Maize, wheat...

  4. Effects of soil amplification ratio and multiple wave interference for ground motion due to earthquake

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; XU Jiren; Ryuji Kubota

    2004-01-01

    Influences on the ground motion simulations by soil amplification effects and multiple seismic wave interferences in the heterogeneous medium are investigated. Detailed velocity structure obtained from the microtremor array survey is adopted in the ground motion simulation. Analyses for amplification ratios of core samples of ten drill holes with 40 m deep in the sedimentary layers show that the soil amplification ratio influences nonlinearly the seismic ground motion. Based on the above analysis results, the ground motion in the heavily damaged zone in the Japanese Kobe earthquake of 1995 is simulated in a digital SH seismic wave model by using the pseudospectral method with the staggered grid RFFT differentiation (SGRFFTD). The simulated results suggest that the heterogeneous velocity structure results in a complicated distribution of the maximum amplitudes of acceleration waveforms with multiple peaks at the surface. Spatial distribution of the maximum amplitudes coincides well with that of collapse ratios of buildings in Kobe. The dual peaks of the collapse ratios away from the earthquake fault coincide well with the double peak amplitudes of simulated seismic acceleration waves also. The cause for the first peak amplitude of the ground motion is attributable to the interference of the secondary surface wave from the bedrock propagating horizontally along the surface sedimentary layer and the body wave from the basin bottom according to analyses of wave snapshots propagating in inhomogeneous structure of the Osaka group layers. The second peak amplitude of the ground motion may be attributive to the interference of the secondary surface wave from the tunneling waves in the shallow sediments and the body wave. It is important for the study on complicated distributions of earthquake damages to investigate influences on the ground motion by soil amplification effects and multiple seismic wave interferences due to the structure. Explorations of the structure to the

  5. Greenhouse gas fluxes in different soil covers in the Caatinga in Pernambuco State, Brazil

    Science.gov (United States)

    Ribeiro, Kelly; Ometto, Jean; Sousa-Neto, Eráclito; Ferreira, Willian; Deusdara, Karinne; Avalá, Plínio; Lima, Romualdo

    2014-05-01

    The study aims to assess the changes in the fluxes of the three main greenhouse gases (CO2, CH4 and N2O) due to land use changes (LUC) in the Brazilian semi-arid region during dry season (October to December) and rainy season (April-July). This region is known as Caatinga and has unique features, and covers about 11 % of the Brazilian territory (about 850 km2). It is a densely populated region and the shifting of native vegetation to pasture stands out among the major environmental problems related to the changes in land use and land occupation. Pastures and agricultural areas cover about 27 % of the Caatinga (201,786 m²). Such drastic changes in land together with the conditions of low nutrient availability in soils and irregular rainfall events, usually leads to soil degradation with direct effects on the dynamics of CO2, N2O and CH4. This experiment was conducted in the municipality of São João, in Pernambuco State (8°52'30" S, 36°22'00" W), in an Entisol with predominantly sandy texture. Samplings were performed in April 2012 (dry season) and August 2013 (rainy season). The fluxes were measured using static PVC chambers in periods of 30 minutes, and the design of this experiment consisted of two treatments: Native Vegetation - Caatinga (C) and grassland (P), distributed in 3 blocks (replicates). The CO2 fluxes were higher during the dry season (One-way ANOVA, p=0.000), with the highest emissions found in grassland (4.6 g m-2 d-1) and the lowest in the Caatinga (3.2 g m-2 d-1). During rainy season, there was no difference between treatments, and CO2 fluxes in Caating and grassland were, respectively, 3.4 g m² d-1 and 3.6 m g -2 d-1. High emissions of N2O were found during the dry season (One-way ANOVA, p= 0.000), and the highest emissions were found in grassland (0.66 mg m² d-1) and the lowest in the Caatinga (0.33 mg m² d-1). During the rainy season there was no significant difference between treatments, and the fluxes were 0.03 mg m² d-1 in the

  6. Use of gas push-pull tests for the measurement of methane oxidation in different landfill cover soils.

    Science.gov (United States)

    Streese-Kleeberg, Jan; Rachor, Ingke; Gebert, Julia; Stegmann, Rainer

    2011-05-01

    In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push-pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH(4), O(2)) and one or more conservative tracers (e.g., argon), is injected into the soil. Following this, the mixture of injected gas and soil air is extracted from the same location and periodically sampled. The kinetic parameters for the biological oxidation taking place in the soil can be derived from the differences in the breakthrough curves. The original method of Urmann et al. (2005) was optimised for application in landfill cover soils and modified to reduce the analytical effort required. Optimised parameters included the flow rate during the injection phase and the duration of the experiment. 50 GPPTs have been conducted at different landfills in Germany during different seasons. Generally, methane oxidation rates ranged between 0 and 150 g m(soil air)(-3)h(-1). At one location, rates up to 440 g m(soil air)(-3)h(-1) were measured under particularly favourable conditions. The method is simple in operation and does not require expensive equipment besides standard laboratory gas chromatographs.

  7. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    Directory of Open Access Journals (Sweden)

    L. E. O. C. Aragão

    2009-12-01

    Full Text Available The net primary productivity (NPP of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1 How do Amazonian forests allocate productivity among its above- and below-ground components? (2 How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error, at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

  8. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    Directory of Open Access Journals (Sweden)

    L. E. O. C. Aragão

    2009-02-01

    Full Text Available The net primary productivity (NPP of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1 How do Amazonian forests allocate productivity among its above- and below-ground components? (2 How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha−1 yr−1 (mean±standard error, at a white sand plot, and 17.0±1.4 Mg C ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

  9. Remediation application strategies for depleted uranium contaminated soils at the US Army Yuma Proving Ground

    Energy Technology Data Exchange (ETDEWEB)

    Vandel, D.S.; Medina, S.M.; Weidner, J.R.

    1994-03-01

    The US Army Yuma Proving Ground (YPG), located in the southwest portion of Arizona conducts firing of projectiles into the Gunpoint (GP-20) firing range. The penetrators are composed of titanium and DU. The purpose of this project was to determine feasible cleanup technologies and disposal alternatives for the cleanup of the depleted uranium (DU) contaminated soils at YPG. The project was split up into several tasks that include (a) collecting and analyzing samples representative of the GP-20 soils, (b) evaluating the data results, (c) conducting a literature search of existing proven technologies for soil remediation, and (0) making final recommendations for implementation of this technology to the site. As a result of this study, several alternatives for the separation, treatment, and disposal procedures are identified that would result in meeting the cleanup levels defined by the Nuclear Regulatory Commission for unrestricted use of soils and would result in a significant cost savings over the life of the firing range.

  10. Urban soil exploration through multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar.

    Science.gov (United States)

    Van De Vijver, Ellen; Van Meirvenne, Marc; Vandenhaute, Laura; Delefortrie, Samuël; De Smedt, Philippe; Saey, Timothy; Seuntjens, Piet

    2015-07-01

    In environmental assessments, the characterization of urban soils relies heavily on invasive investigation, which is often insufficient to capture their full spatial heterogeneity. Non-invasive geophysical techniques enable rapid collection of high-resolution data and provide a cost-effective alternative to investigate soil in a spatially comprehensive way. This paper presents the results of combining multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar to characterize a former garage site contaminated with petroleum hydrocarbons. The sensor combination showed the ability to identify and accurately locate building remains and a high-density soil layer, thus demonstrating the high potential to investigate anthropogenic disturbances of physical nature. In addition, a correspondence was found between an area of lower electrical conductivity and elevated concentrations of petroleum hydrocarbons, suggesting the potential to detect specific chemical disturbances. We conclude that the sensor combination provides valuable information for preliminary assessment of urban soils.

  11. Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River.

    Science.gov (United States)

    Ouyang, Wei; Hao, Fanghua; Skidmore, Andrew K; Toxopeus, A G

    2010-12-15

    Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and Water Assessment Tool (SWAT) model. SWAT is a physical hydrological model which uses the RUSLE equation as a sediment algorithm. Considering the spatial and temporal scale of the relationship between soil erosion and sediment yield, simulations were undertaken at monthly and annual temporal scales and basin and sub-basin spatial scales. The corresponding temporal and spatial Normalized Difference Vegetation Index (NDVI) information was summarized from MODIS data, which can integrate regional land cover and climatic features. The SWAT simulation revealed that the annual soil erosion and sediment yield showed similar spatial distribution patterns, but the monthly variation fluctuated significantly. The monthly basin soil erosion varied from almost no erosion load to 3.92 t/ha and the maximum monthly sediment yield was 47,540 tones. The inter-annual simulation focused on the spatial difference and relationship with the corresponding vegetation NDVI value for every sub-basin. It is concluded that, for this continental monsoon climate basin, the higher NDVI vegetation zones prevented sediment transport, but at the same time they also contributed considerable soil erosion. The monthly basin soil erosion and sediment yield both correlated with NDVI, and the determination coefficients of their exponential correlation model were 0.446 and 0.426, respectively. The relationships between soil erosion and sediment yield with vegetation NDVI indicated that the vegetation status has a significant impact on sediment formation and transport. The findings can be used to develop soil erosion conservation programs for the study area.

  12. Evaluation of satellite soil moisture products over Norway using ground-based observations

    Science.gov (United States)

    Griesfeller, A.; Lahoz, W. A.; Jeu, R. A. M. de; Dorigo, W.; Haugen, L. E.; Svendby, T. M.; Wagner, W.

    2016-03-01

    In this study we evaluate satellite soil moisture products from the advanced SCATterometer (ASCAT) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) over Norway using ground-based observations from the Norwegian water resources and energy directorate. The ASCAT data are produced using the change detection approach of Wagner et al. (1999), and the AMSR-E data are produced using the VUA-NASA algorithm (Owe et al., 2001, 2008). Although satellite and ground-based soil moisture data for Norway have been available for several years, hitherto, such an evaluation has not been performed. This is partly because satellite measurements of soil moisture over Norway are complicated owing to the presence of snow, ice, water bodies, orography, rocks, and a very high coastline-to-area ratio. This work extends the European areas over which satellite soil moisture is validated to the Nordic regions. Owing to the challenging conditions for soil moisture measurements over Norway, the work described in this paper provides a stringent test of the capabilities of satellite sensors to measure soil moisture remotely. We show that the satellite and in situ data agree well, with averaged correlation (R) values of 0.72 and 0.68 for ASCAT descending and ascending data vs in situ data, and 0.64 and 0.52 for AMSR-E descending and ascending data vs in situ data for the summer/autumn season (1 June-15 October), over a period of 3 years (2009-2011). This level of agreement indicates that, generally, the ASCAT and AMSR-E soil moisture products over Norway have high quality, and would be useful for various applications, including land surface monitoring, weather forecasting, hydrological modelling, and climate studies. The increasing emphasis on coupled approaches to study the earth system, including the interactions between the land surface and the atmosphere, will benefit from the availability of validated and improved soil moisture satellite datasets, including those

  13. Satellite Based Soil Moisture Product Validation Using NOAA-CREST Ground and L-Band Observations

    Science.gov (United States)

    Norouzi, H.; Campo, C.; Temimi, M.; Lakhankar, T.; Khanbilvardi, R.

    2015-12-01

    Soil moisture content is among most important physical parameters in hydrology, climate, and environmental studies. Many microwave-based satellite observations have been utilized to estimate this parameter. The Advanced Microwave Scanning Radiometer 2 (AMSR2) is one of many remotely sensors that collects daily information of land surface soil moisture. However, many factors such as ancillary data and vegetation scattering can affect the signal and the estimation. Therefore, this information needs to be validated against some "ground-truth" observations. NOAA - Cooperative Remote Sensing and Technology (CREST) center at the City University of New York has a site located at Millbrook, NY with several insitu soil moisture probes and an L-Band radiometer similar to Soil Moisture Passive and Active (SMAP) one. This site is among SMAP Cal/Val sites. Soil moisture information was measured at seven different locations from 2012 to 2015. Hydra probes are used to measure six of these locations. This study utilizes the observations from insitu data and the L-Band radiometer close to ground (at 3 meters height) to validate and to compare soil moisture estimates from AMSR2. Analysis of the measurements and AMSR2 indicated a weak correlation with the hydra probes and a moderate correlation with Cosmic-ray Soil Moisture Observing System (COSMOS probes). Several differences including the differences between pixel size and point measurements can cause these discrepancies. Some interpolation techniques are used to expand point measurements from 6 locations to AMSR2 footprint. Finally, the effect of penetration depth in microwave signal and inconsistencies with other ancillary data such as skin temperature is investigated to provide a better understanding in the analysis. The results show that the retrieval algorithm of AMSR2 is appropriate under certain circumstances. This validation algorithm and similar study will be conducted for SMAP mission. Keywords: Remote Sensing, Soil

  14. Soil Organic Carbon and Below Ground Biomass: Development of New GLOBE Special Measurements

    Science.gov (United States)

    Levine, Elissa; Haskett, Jonathan

    1999-01-01

    A scientific consensus is building that changes in the atmospheric concentrations of radiatively active gases are changing the climate (IPCC, 1990). One of these gases CO2 has been increasing in concentration due to additions from anthropogenic sources that are primarily industrial and land use related. The soil contains a very large pool of carbon, estimated at 1550 Gt (Lal 1995) which is larger than the atmospheric and biosphere pools of carbon combined (Greenland, 1995). The flux between the soil and the atmosphere is very large, 60 Pg C/yr (Lal 1997), and is especially important because the soil can act as either a source or a sink for carbon. On any given landscape, as much as 50% of the biomass that provides the major source of carbon can be below ground. In addition, the movement of carbon in and out of the soil is mediated by the living organisms. At present, there is no widespread sampling of soil biomass in any consistent or coordinated manner. Current large scale estimates of soil carbon are limited by the number and widely dispersed nature of the data points available. A measurement of the amount of carbon in the soil would supplement existing carbon data bases as well as provide a benchmark that can be used to determine whether the soil is storing carbon or releasing it to the atmosphere. Information on the below ground biomass would be a valuable addition to our understanding of net primary productivity and standing biomass. The addition of these as special measurements within GLOBE would be unique in terms of areal extent and continuity, and make a real contribution to scientific understanding of carbon dynamics.

  15. Interaction of vegetative cover and N addition on soil CO2 efflux in an oak savanna ecosystem

    Science.gov (United States)

    Morris, Kendalynn; Wutzler, Thomas; Poehlmann, Marco; Nair, Richard; Migliavacca, Mirco; Schrumpf, Marion

    2017-04-01

    Numerous fertilization experiments have demonstrated that nitrogen (N) addition leads to shifts in soil respiration. In forest ecosystems N addition typically results in decreased soil respiration, while grasslands generally have the opposite response. Neither result is universal because the direction of the response is dictated by site-specific soil and vegetation properties. The MaNiP large scale nutrient manipulation experiment aims at studying ecosystem properties, such as soil respiration, by altering nitrogen (N) and phosphorus (P) stoichiometry. The experimental site is a dehesa, an oak-savanna ecosystem in Extremadura, Spain. The tree-grass structure results in a mosaic of two distinct soils coexisting within the same parent material and climatic conditions. Soils beneath trees are richer in organic matter, have a higher C:N, and a relatively well developed A-horizon compared to soils in the open grassland. This offers an ideal opportunity to study how soil properties modify responses to stoichiometric shifts. We established automated respiration chambers in both of these soil types within plots fertilized with N and where no nitrogen was added (Control). By comparing the magnitude of near continuous CO2 fluxes in these chambers with onsite Eddy Covariance Towers, we can quantify the relative contribution of soils under trees and in open grassland to ecosystem respiration and how the nutrient treatments moderate their responses to seasonal fluctuations in temperature and moisture. Preliminary results suggest that soil respiration increased with fertilization and that fluxes underneath tree canopies are more responsive, likely due to higher C content and microclimatic properties. Further analysis will determine if fertilization influences annual cycles in respiration or the sensitivity of respiration to climatic drivers and pulses (e.g., rain). Our initial conclusion is that vegetation cover modifies the interaction of soil C and N cycle in this ecosystem.

  16. Does grazing of cover crops impact biologically active soil C and N fractions under inversion and no tillage management

    Science.gov (United States)

    Cover crops are a key component of conservation cropping systems. They can also be a key component of integrated crop-livestock systems by offering high-quality forage during short periods between cash crops. The impact of cattle grazing on biologically active soil C and N fractions has not receiv...

  17. Mineralization of organic phosphorus in soil size fractions under different vegetation covers in the north of Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Joice Cleide de Oliveira Rita

    2013-10-01

    Full Text Available In unfertilized, highly weathered tropical soils, phosphorus (P availability to plants is dependent on the mineralization of organic P (Po compounds. The objective of this study was to estimate the mineralization of total and labile Po in soil size fractions of > 2.0, 2.0-0.25 and 2.0 and 2.0-0.25 mm fractions, respectively. In contrast, there was an average increase of 90 % of total Po in microaggregates of 2.0 (-50 % and < 0.25 mm (-76 % fractions, but labile Po increased by 35 % in the 2.0-0.25 mm fraction. The Po fraction relative to total extracted P and total labile P within the soil size fractions varied with the vegetation cover and incubation time. Therefore, the distribution of P fractions (Pi and Po in the soil size fraction revealed the distinctive ability of the cover species to recycle soil P. Consequently, the potential of Po mineralization varied with the size fraction and vegetation cover. Because Po accounted for most of the total labile P, the P availability to plants was closely related to the mineralization of this P fraction.

  18. Effects of seagulls on ecosystem respiration, soil nitrogen and vegetation cover on a pristine volcanic island, Surtsey, Iceland

    Science.gov (United States)

    Sigurdsson, B. D.; Magnusson, B.

    2010-03-01

    When Surtsey rose from the North Atlantic Ocean south of Iceland in 1963, it became a unique natural laboratory on how organisms colonize volcanic islands and form ecosystems with contrasting structures and functions. In July, 2004, ecosystem respiration rate (Re), soil properties and surface cover of vascular plants were measured in 21 permanent research plots distributed among the juvenile communities of the island. The plots were divided into two main groups, inside and outside a seagull (Larus spp.) colony established on the island. Vegetation cover of the plots was strongly related to the density of gull nests. Occurrence of nests and increased vegetation cover also coincided with significant increases in Re, soil carbon, nitrogen and C:N ratio, and with significant reductions in soil pH and soil temperatures. Temperature sensitivity (Q10 value) of Re was determined as 5.3. When compared at constant temperature the Re was found to be 59 times higher within the seagull colony, similar to the highest fluxes measured in drained wetlands or agricultural fields in Iceland. The amount of soil nitrogen, mainly brought onto the island by the seagulls, was the critical factor that most influenced ecosystem fluxes and vegetation development on Surtsey. The present study shows how ecosystem activity can be enhanced by colonization of animals that transfer resources from a nearby ecosystem.

  19. Effects of seagulls on ecosystem respiration, soil nitrogen and vegetation cover on a pristine volcanic island, Surtsey, Iceland

    Directory of Open Access Journals (Sweden)

    B. D. Sigurdsson

    2010-03-01

    Full Text Available When Surtsey rose from the North Atlantic Ocean south of Iceland in 1963, it became a unique natural laboratory on how organisms colonize volcanic islands and form ecosystems with contrasting structures and functions. In July, 2004, ecosystem respiration rate (Re, soil properties and surface cover of vascular plants were measured in 21 permanent research plots distributed among the juvenile communities of the island. The plots were divided into two main groups, inside and outside a seagull (Larus spp. colony established on the island. Vegetation cover of the plots was strongly related to the density of gull nests. Occurrence of nests and increased vegetation cover also coincided with significant increases in Re, soil carbon, nitrogen and C:N ratio, and with significant reductions in soil pH and soil temperatures. Temperature sensitivity (Q10 value of Re was determined as 5.3. When compared at constant temperature the Re was found to be 59 times higher within the seagull colony, similar to the highest fluxes measured in drained wetlands or agricultural fields in Iceland. The amount of soil nitrogen, mainly brought onto the island by the seagulls, was the critical factor that most influenced ecosystem fluxes and vegetation development on Surtsey. The present study shows how ecosystem activity can be enhanced by colonization of animals that transfer resources from a nearby ecosystem.

  20. Assessing the suitability of recycled plastics used as agricultural soil covers: migration study and experimental harvest.

    Science.gov (United States)

    Nerín, C; Batlle, R

    1999-01-01

    The present work is focused on evaluating the suitability of recycling postconsumer agricultural plastic films again for the same use. The criteria to assess the suitability was based on migration study. Both overall and specific migration tests were performed, and the results obtained (ranging from 0.14 to 1.27 mg/dm(2) for overall migration and from not detectable to 6.98 microg/dm(2) for specific migration) show how, from this point of view, the recycled material can be safely proposed to be used again as agricultural soil covers. A theoretical discussion about the migration process is also presented and a simple mathematical model was applied to the data obtained, showing how total migration which is experimentally detected is theoretically predictable. These conclusions found were used to design and develop a controlled crop of tomato by using this recycled film. The use of the recycled plastic in the whole process and the behavior and properties of the pesticides absorbed in the postconsumer film are discussed.

  1. Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Fernando Pereira Souza

    2013-12-01

    Full Text Available The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil, in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5. In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient. After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

  2. Morphometry and land cover based multi-criteria analysis for assessing the soil erosion susceptibility of the western Himalayan watershed.

    Science.gov (United States)

    Altaf, Sadaff; Meraj, Gowhar; Romshoo, Shakil Ahmad

    2014-12-01

    Complex mountainous environments such as Himalayas are highly susceptibility to natural hazards particular those that are triggered by the action of water such as floods, soil erosion, mass movements and siltation of the hydro-electric power dams. Among all the natural hazards, soil erosion is the most implicit and the devastating hazard affecting the life and property of the millions of people living in these regions. Hence to review and devise strategies to reduce the adverse impacts of soil erosion is of utmost importance to the planners of watershed management programs in these regions. This paper demonstrates the use of satellite based remote sensing data coupled with the observational field data in a multi-criteria analytical (MCA) framework to estimate the soil erosion susceptibility of the sub-watersheds of the Rembiara basin falling in the western Himalaya, using geographical information system (GIS). In this paper, watershed morphometry and land cover are used as an inputs to the MCA framework to prioritize the sub-watersheds of this basin on the basis of their different susceptibilities to soil erosion. Methodology included the derivation of a set of drainage and land cover parameters that act as the indicators of erosion susceptibility. Further the output from the MCA resulted in the categorization of the sub-watersheds into low, medium, high and very high erosion susceptibility classes. A detailed prioritization map for the susceptible sub-watersheds based on the combined role of land cover and morphometry is finally presented. Besides, maps identifying the susceptible sub-watersheds based on morphometry and land cover only are also presented. The results of this study are part of the watershed management program in the study area and are directed to instigate appropriate measures to alleviate the soil erosion in the study area.

  3. Large-scale assessment of soil erosion in Africa: satellites help to jointly account for dynamic rainfall and vegetation cover

    Science.gov (United States)

    Vrieling, Anton; Hoedjes, Joost C. B.; van der Velde, Marijn

    2015-04-01

    Efforts to map and monitor soil erosion need to account for the erratic nature of the soil erosion process. Soil erosion by water occurs on sloped terrain when erosive rainfall and consequent surface runoff impact soils that are not well-protected by vegetation or other soil protective measures. Both rainfall erosivity and vegetation cover are highly variable through space and time. Due to data paucity and the relative ease of spatially overlaying geographical data layers into existing models like USLE (Universal Soil Loss Equation), many studies and mapping efforts merely use average annual values for erosivity and vegetation cover as input. We first show that rainfall erosivity can be estimated from satellite precipitation data. We obtained average annual erosivity estimates from 15 yr of 3-hourly TRMM Multi-satellite Precipitation Analysis (TMPA) data (1998-2012) using intensity-erosivity relationships. Our estimates showed a positive correlation (r = 0.84) with long-term annual erosivity values of 37 stations obtained from literature. Using these TMPA erosivity retrievals, we demonstrate the large interannual variability, with maximum annual erosivity often exceeding two to three times the mean value, especially in semi-arid areas. We then calculate erosivity at a 10-daily time-step and combine this with vegetation cover development for selected locations in Africa using NDVI - normalized difference vegetation index - time series from SPOT VEGETATION. Although we do not integrate the data at this point, the joint analysis of both variables stresses the need for joint accounting for erosivity and vegetation cover for large-scale erosion assessment and monitoring.

  4. Assessing Fractional Tree, Grass, and Bare Soil Cover from NDVI and Rainfall Time Series along the Kalahari Transect, Africa

    Science.gov (United States)

    Scanlon, T. M.; Albertson, J. D.; Caylor, K. K.; Williams, C. A.

    2001-12-01

    Savanna ecosystems are water-limited, a characteristic that can be exploited to estimate fractional cover of trees, grass, and bare soil over large-scale areas from synthesis of remote sensing and rainfall measurements. A method is presented to estimate fractional cover components along the Kalahari Transect (KT), an aridity gradient in southern Africa, based upon the differing ways in which grasses and trees respond to rainfall. Mean wet season normalized difference vegetation index (NDVI) and the sensitivity of the NDVI to variation in wet season rainfall are used as input into a linear unmixing model, and end-members for this analysis are extracted on the basis of best fit to the observed data. The end-members for the mixing analysis are consistent with the qualitative characteristics of trees (high NDVI, low sensitivity of NDVI to interannual variations in rainfall), bare soil (low NDVI, low sensitivity), and the transient grass/ bare soil area (moderate NDVI, high sensitivity). Sensitivity of NDVI to rainfall was based upon the relationship between NDVI and the standardized anomalies, or z-score, of the wet season precipitation, resulting in a 22% improvement in the number of significant relationships (parea is limited by the tree fractional cover on the wetter end of the transect, peaks at approximately 450 mm of mean wet season rainfall, and is limited by rainfall on the more arid portion of the transect. With NDVI for grass inferred from the data, predictions of yearly tree, grass, and bare soil fractional cover can be derived. No calibration or training sets were required for this unmixing procedure, and an additional advantage of this method over traditional unmixing approaches is that cover components can be predicted for future rainfall scenarios. This remote sensing-based model framework, together with a tree/grass interaction submodel, could be used to predict long-term migration of the cover components along this gradient in response to climate

  5. Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed

    Directory of Open Access Journals (Sweden)

    F. Márquez-García

    2013-05-01

    Full Text Available The olive tree is one of the most important crops in Spain, and the main one in the region of Andalusia. Most orchards are rain-fed, with high slopes where conventional tillage (CT is the primary soil management system used. These conditions lead to high erosion and a significant transport of organic carbon (OC. Moreover, soil tillage accelerates the oxidation of the OC. Cover crops (CC are the conservation agriculture (CA approach for woody crops. They are grown in-between tree rows to protect the soil against water erosion and their organic residues also help to increase the soil carbon (C sink. Soil and OC losses associated to the sediment were measured over four seasons (2003-07 using micro-plots for the collection of runoff and sediment in five experimental fields located in rain-fed olive orchards in Andalusia. Two soil management systems were followed, CC and CT. Furthermore, the changes in soil C in both systems were analyzed at a depth of 0-25 cm. CC reduced erosion by 80.5%, and also OC transport by 67.7%. In addition, Cover crops increased soil C sink by 12.3 Mg ha-1 year-1 of carbon dioxide (CO2 equivalent, with respect to CT. CC in rainfed olive orchards in a Mediterranean climate could be an environmental friendly and profitable system for reducing erosion and increasing the soil C sink. However, C fixing rate is not regular, being very high for the initial years after shifting from CT to CC and gradually decreasing over time.

  6. Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed

    Energy Technology Data Exchange (ETDEWEB)

    Marquez-Garcia, F.; Gonzalez-Sanchez, E. J.; Castro-Garcia, S.; Ordonez-Fernandez, R.

    2013-06-01

    The olive tree is one of the most important crops in Spain, and the main one in the region of Andalusia. Most orchards are rain-fed, with high slopes where conventional tillage (CT) is the primary soil management system used. These conditions lead to high erosion and a significant transport of organic carbon (OC). Moreover, soil tillage accelerates the oxidation of the OC. Cover crops (CC) are the conservation agriculture (CA) approach for woody crops. They are grown in-between tree rows to protect the soil against water erosion and their organic residues also help to increase the soil carbon (C) sink. Soil and OC losses associated to the sediment were measured over four seasons (2003-07) using micro-plots for the collection of runoff and sediment in five experimental fields located in rain-fed olive orchards in Andalusia. Two soil management systems were followed, CC and CT. Furthermore, the changes in soil C in both systems were analyzed at a depth of 0-25 cm. CC reduced erosion by 80.5%, and also OC transport by 67.7%. In addition, CC increased soil C sink by 12.3 Mg ha{sup -}1 year{sup -}1 of carbon dioxide (CO{sub 2}) equivalent, with respect to CT. Cover crops in rainfed olive orchards in a Mediterranean climate could be an environmental friendly and profitable system for reducing erosion and increasing the soil C sink. However, C fixing rate is not regular, being very high for the initial years after shifting from CT to CC and gradually decreasing over time. (Author) 57 refs.

  7. Mapping Spatial Moisture Content of Unsaturated Agricultural Soils with Ground-Penetrating Radar

    Science.gov (United States)

    Shamir, O.; Goldshleger, N.; Basson, U.; Reshef, M.

    2016-06-01

    Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR) reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf), common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf), common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1-5% accuracy, making our method useful for the design of irrigation plans for different interfaces.

  8. MAPPING SPATIAL MOISTURE CONTENT OF UNSATURATED AGRICULTURAL SOILS WITH GROUND-PENETRATING RADAR

    Directory of Open Access Journals (Sweden)

    O. Shamir

    2016-06-01

    Full Text Available Soil subsurface moisture content, especially in the root zone, is important for evaluation the influence of soil moisture to agricultural crops. Conservative monitoring by point-measurement methods is time-consuming and expensive. In this paper we represent an active remote-sensing tool for subsurface spatial imaging and analysis of electromagnetic physical properties, mostly water content, by ground-penetrating radar (GPR reflection. Combined with laboratory methods, this technique enables real-time and highly accurate evaluations of soils' physical qualities in the field. To calculate subsurface moisture content, a model based on the soil texture, porosity, saturation, organic matter and effective electrical conductivity is required. We developed an innovative method that make it possible measures spatial subsurface moisture content up to a depth of 1.5 m in agricultural soils and applied it to two different unsaturated soil types from agricultural fields in Israel: loess soil type (Calcic haploxeralf, common in rural areas of southern Israel with about 30% clay, 30% silt and 40% sand, and hamra soil type (Typic rhodoxeralf, common in rural areas of central Israel with about 10% clay, 5% silt and 85% sand. Combined field and laboratory measurements and model development gave efficient determinations of spatial moisture content in these fields. The environmentally friendly GPR system enabled non-destructive testing. The developed method for measuring moisture content in the laboratory enabled highly accurate interpretation and physical computing. Spatial soil moisture content to 1.5 m depth was determined with 1–5% accuracy, making our method useful for the design of irrigation plans for different interfaces.

  9. 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.

  10. Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer soil cover

    Science.gov (United States)

    Song, Qing; Yanful, Ernest K.

    2010-05-01

    Engineered soil covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the soil cover. However, limited published information is available on the extent to which soil cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a soil cover. Two inclined (a slope of 20%) multilayer soil covers were examined under laboratory conditions. One cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other cover was a normal one without the channel pathway. The soil covers were installed in plastic boxes measuring 120 cm × 120 cm × 25 cm (width × height × thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The soil covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the soil cover without channel flow to 35.3% in the cover with channel flow, and percolation increased from zero in the normal soil cover to 43.0% of the total precipitation in the cover with channel flow. Gaseous oxygen transfer into the waste rock below the cover soils was 1091 times greater in the cover with channel than in the soil cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the soil cover. The spacing of the channel with respect to the length of the test box is similar to those

  11. Overview of investigations into mercury in ground water, soils, and septage, New Jersey coastal plain

    Science.gov (United States)

    Barringer, J.L.; Szabo, Z.

    2006-01-01

    Since the early 1980s, investigations by health departments of eight counties in southern New Jersey, by the NJ Department of Environmental Protection (NJDEP), and subsequently by the US Geological Survey (USGS), have shown that Hg concentrations in water tapped by about 600 domestic wells exceed the maximum contaminant level (MCL) of 2 ??g/L. The wells are finished in the areally extensive unconfined Kirkwood-Cohansey aquifer system of New Jersey's Coastal Plain; background concentrations of Hg in water from this system are point sources of Hg, such as landfills or commercial and industrial hazardous-waste sites, is lacking. During 1996-2003, the USGS collected water samples from 203 domestic, irrigation, observation, and production wells using ultraclean techniques; septage, leach-field effluent, soils, and aquifer sediments also were sampled. Elevated concentrations of NH4, B, Cl, NO3, and Na and presence of surfactants in domestic-well water indicate that septic-system effluent can affect water quality in unsewered residential areas, but neither septage nor effluent appears to be a major Hg source. Detections of hydrogen sulfide in ground water at a residential area indicate localized reducing conditions; undetectable SO4 concentrations in water from other residential areas indicate that reducing conditions, which could be conducive to Hg methylation, may be common locally. Volatile organic compounds (VOCs), mostly chlorinated solvents, also are found in ground water at the affected areas, but statistically significant associations between presence of Hg and VOCs were absent for most areas evaluated. Hg concentrations are lower in some filtered water samples than in paired unfiltered samples, likely indicating that some Hg is associated with particles or colloids. The source of colloids may be soils, which, when undisturbed, contain higher concentrations of Hg than do disturbed soils and aquifer sediments. Soil disturbance during residential development and

  12. Hydrogeology and chemical quality of water and soil at Carroll Island, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Tenbus, F.J.; Phillips, S.W.

    1996-01-01

    Carroll Island was used for open-air testing of chemical warfare agents from the late 1940's until 1971. Testing and disposal activities weresuspected of causing environmental contamination at 16 sites on the island. The hydrogeology and chemical quality of ground water, surface water, and soil at these sites were investigated with borehole logs, environmental samples, water-level measurements, and hydrologic tests. A surficial aquifer, upper confining unit, and upper confined aquifer were defined. Ground water in the surficial aquifer generally flows from the east-central part of the island toward the surface-water bodies, butgradient reversals caused by evapotranspiration can occur during dry seasons. In the confined aquifer, hydraulic gradients are low, and hydraulic head is affected by tidal loading and by seasonal pumpage from the west. Inorganic chemistry in the aquifers is affected by brackish-water intrusion from gradient reversals and by dissolution ofcarboniferous shell material in the confining unit.The concentrations of most inorganic constituents probably resulted from natural processes, but some concentrations exceeded Federal water-quality regulations and criteria. Organic compounds were detected in water and soil samples at maximum concentrations of 138 micrograms per liter (thiodiglycol in surface water) and 12 micrograms per gram (octadecanoic acid in soil).Concentrations of organic compounds in ground water exceeded Federal drinking-water regulations at two sites. The organic compounds that weredetected in environmental samples were variously attributed to natural processes, laboratory or field- sampling contamination, fallout from industrial air pollution, and historical military activities.

  13. Disturbances in the soil: finding buried bodies and other evidence using ground penetrating radar.

    Science.gov (United States)

    Miller, P S

    1996-07-01

    Ground penetrating radar (GPR) is an efficient and effective means to search for buried evidence, whether it be a clandestine grave, formal burial, or certain missing articles from a crime scene. The procedures for GPR used by the U.S. Army Central Identification Laboratory, Hawaii (CILHI), are the result of several years of experimentation on a variety of ground surfaces in Hawaii, Southeast Asia and the mainland U.S. This remote sensing method does not usually provide direct information that there is a body or other specific object beneath the ground. Most of the time the GPR has been used to determine where a target object is not located. The key feature of GPR is that it can detect recent changes in shallow soil conditions caused by the disturbance of soil and the intrusion of different material. Using the methods described here, the investigator should be able to determine the precise metric grid coordinates for a subsurface disturbance, as well as the approximate size, the general shape, and the depth of the buried material. Success will vary with soil conditions. The conditions suitable or not practical for using GPR are summarized. This remote sensing technology can have wider use in crime scene investigations due to the recent introduction of more user-friendly software and more portable hardware.

  14. Comparison of algorithms and parameterisations for infiltration into organic-covered permafrost soils

    Science.gov (United States)

    Infiltration into frozen and unfrozen soils is critical in hydrology, controlling active layer soil water dynamics and influencing runoff. Few Land Surface Models (LSMs) and Hydrological Models (HMs) have been developed, adapted or tested for frozen conditions and permafrost soils. Considering the v...

  15. The Relative Roles of Soil, Land Cover, and Precipitation Uncertainty for Watershed-scale Soil Moisture Prediction in a Semi-arid Environment

    Science.gov (United States)

    Mocko, D. M.; Peters-Lidard, C. D.; Tischler, M. A.; Wu, Y.; Garcia, M. E.; Santanello, J. A.

    2006-05-01

    Soil moisture is one of the basic links between the water and energy cycles of land surfaces through its regulation of infiltration, runoff, transpiration, and thermal capacity. In this study, soil moisture was evaluated at the watershed scale using the community NOAH land-surface model (LSM) as included in the Land Information System (LIS) framework. NOAH simulates profiles of soil moisture (both liquid and frozen) and soil temperature, skin temperature, snowpack depth, snowpack water equivalent (and hence snowpack density), canopy water content, and surface water and energy fluxes, including runoff, infiltration, and evapotranspiration. The NOAH-LIS system was tested using soil moisture data from the Monsoon '90 experiment, carried out at the Walnut Gulch Experimental Watershed (WGEW), near Tombstone, Arizona over a 18-day period during July and August 1990. The primary evaluation criterion was surface soil moisture retrieved from the NASA PushBroom Microwave Radiometer (PBMR). The effect of using global-to-continental scale boundary-condition information for soil and vegetation properties was evaluated in the system against more fine-scale property information for the watershed, which is not typically available. Also, the effect of using forcing precipitation from a high-density rain gauge network in the watershed was evaluated against precipitation from a single- gauge, from a mean of the gauge network, and from a global-to-continental scale reanalysis. Changes to the vegetation property information in this watershed, from land cover type to the prescribed albedo and greenness, had virtually no effect on the top-layer simulated soil moisture. Although differences were found in the sensible and latent heat fluxes when modifying the vegetation properties, the runoff ratio remained nearly the same between the simulations. This result indicates that a tiling approach based on vegetation type may not be appropriate in a semi-arid environment. Changes to the soil

  16. Depth-distribution patterns and control of soil organic carbon in coastal salt marshes with different plant covers

    Science.gov (United States)

    Bai, Junhong; Zhang, Guangliang; Zhao, Qingqing; Lu, Qiongqiong; Jia, Jia; Cui, Baoshan; Liu, Xinhui

    2016-01-01

    This study was carried out in three kinds of salt marshes according to the vegetation covers, including Phragmites australis salt marsh (PSM), Suaeda salus salt marsh (SSM) and Tamarix chinensis-Suaeda salus salt marsh (TSSM). We applied allometric function, exponential function and logistic function to model the depth distribution of the SOCv and SOCc for each salt marsh, respectively. The results showed that the exponential function fits the depth distribution of the SOCv more well than other two functions. The SOCc can be fitted very well by all three functions for three salt marsh (Adj. R2 > 0.99), of which the allometric function was the best one. The mean topsoil concentration factors (TCFs) of three salt marshes were beyond 0.1, which means the SOC enrichment in surface soils due to plant cycling, but TCFs in PSM were significantly higher than those in SSM (P soils. The results of general linear model (GLM) suggested that four soil properties (soil water content, pH, soil salt content and silt+clay) and their interactive effects explained about 80% of the total variation of SOC stock in the top 20 cm soils and the 20–100 cm soil layers. PMID:27708421

  17. Depth-distribution patterns and control of soil organic carbon in coastal salt marshes with different plant covers

    Science.gov (United States)

    Bai, Junhong; Zhang, Guangliang; Zhao, Qingqing; Lu, Qiongqiong; Jia, Jia; Cui, Baoshan; Liu, Xinhui

    2016-10-01

    This study was carried out in three kinds of salt marshes according to the vegetation covers, including Phragmites australis salt marsh (PSM), Suaeda salus salt marsh (SSM) and Tamarix chinensis-Suaeda salus salt marsh (TSSM). We applied allometric function, exponential function and logistic function to model the depth distribution of the SOCv and SOCc for each salt marsh, respectively. The results showed that the exponential function fits the depth distribution of the SOCv more well than other two functions. The SOCc can be fitted very well by all three functions for three salt marsh (Adj. R2 > 0.99), of which the allometric function was the best one. The mean topsoil concentration factors (TCFs) of three salt marshes were beyond 0.1, which means the SOC enrichment in surface soils due to plant cycling, but TCFs in PSM were significantly higher than those in SSM (P < 0.05). Nearly 30% of SOC was concentrated in the top 20 cm soils. The results of general linear model (GLM) suggested that four soil properties (soil water content, pH, soil salt content and silt+clay) and their interactive effects explained about 80% of the total variation of SOC stock in the top 20 cm soils and the 20–100 cm soil layers.

  18. Runoff and soil loss characteristics on loess slopes covered with aeolian sand layers of different thicknesses under simulated rainfall

    Science.gov (United States)

    Zhang, F. B.; Bai, Y. J.; Xie, L. Y.; Yang, M. Y.; Li, Z. B.; Wu, X. R.

    2017-06-01

    In the Wind-Water Erosion Crisscross Region of the northern Loess Plateau, parts of loess slopes have been covered by layers of aeolian sand of different thicknesses. Knowledge of soil erosion processes and magnitudes on these slopes is essential to understanding the coupled water-wind erosion processes and to address the resulting downstream coarse sediment problems in the Yellow River. Simulated rainfall (intensity 90 mm h-1) was performed to explore the effects of sand layer thickness on runoff and soil loss from loess slopes covered with different sand layer thicknesses (0, 0.5, 2, 5, 10, 15, 20, and 25 cm). Initial runoff time increased with increasing sand layer thickness, with greater changes occurring for the increases in the thinner (0-5 cm) than for the thicker layers (5-25 cm). Total runoff yield from the sand-covered loess slopes was 18%-55% lower than from the uncovered loess slope and decreased with increasing sand layer thickness. In contrast, total sediment yield was up to 14 times greater from the sand-covered loess slopes than from the uncovered loess slope and rapidly increased with increasing sand layer thickness. During the rainstorm, runoff and soil loss rates exhibited unimodal distributions, and they were related by a positive linear function, both before and after the maximum soil loss rate, that had a high determination coefficient (R2 > 0.8, p qualitative change in runoff and sediment production modes, appeared to be in the range of 5-10 cm. These results indicated that the thickness of the sand layer on the loess slope significantly influenced runoff and sediment production processes and mechanisms. These effects should be considered when assessing and predicting soil losses in this region and from similar slopes elsewhere.

  19. Soil cover patterns and SOC dynamics impacts on the soil processes, land management and ecosystem services in Central Region of Russia

    Science.gov (United States)

    Vasenev, Ivan; Chernikov, Vladimir; Yashin, Ivan; Geraskin, Mikhail; Morev, Dmitriy

    2014-05-01

    In the Central Region of Russia (CRR) the soil cover patterns usually play the very important role in the soil forming and degradation processes (SFP & SDP) potential and current rates, soil organic carbon (SOC) dynamics and pools, greenhouse gases (GHG) emissions and soluble SOC fluxes that we need take into attention for better assessment of the natural and especially man-changed ecosystems' services and for best land-use practices development. Central Region of Russia is the biggest one in RF according to its population and role in the economy. CRR is characterized by high spatial variability of soil cover due to as original landscape heterogeneity as complicated history of land-use practices during last 700 years. Our long-term researches include the wide zonal-provincial set of representative ecosystems and soil cover patterns with different types and history of land-use (forest, meadow-steppe and agricultural ones) from middle-taiga to steppe zones with different level of continentality. The carried out more than 30-years region- and local-scale researches of representative natural and rural landscapes in Tver', Yaroslavl', Kaluga, Moscow, Vladimir, Saransk (Mordovia), Kursk, Orel, Tambov, Voronezh and Saratov oblasts give us the interregional multi-factorial matrix of elementary soil cover patterns (ESCP) with different soil forming and degradation processes rates and soil organic carbon dynamics due to regionally specific soil-geomorphologic features, environmental and dominated microclimate conditions, land-use current practices and history. The validation and ranging of the limiting factors of SFP and SDP develop¬ment, soil carbon dynamics and sequestration potential, ecosystem (agroecosystem) principal services, land functional qualities and agroecological state have been done for dominating and most dynamical components of ESCP regional-typological forms - with application of SOC structure analysis, regional and local GIS, soil spatial patterns detail

  20. Dispersal of Rhagoletis cerasi in Commercial Cherry Orchards: Efficacy of Soil Covering Nets for Cherry Fruit Fly Control.

    Science.gov (United States)

    Daniel, Claudia; Baker, Brian

    2013-03-12

    Demand for organic cherries offers producers a premium price to improve their commercial viability. Organic standards require that producers find alternatives to pesticides. Soil treatments to control the European cherry fruit fly Rhagoletis cerasi (L.) (Diptera: Tephrididae) appear to be an attractive option. However, soil treatments can only be effective if the migration of flies is low, because mature flies may migrate from near-by trees for oviposition. To examine the general potential of soil treatments and to understand the dispersal and flight behaviour of R. cerasi within orchards, experiments using netting to cover the soil were conducted in two orchards with different pest pressure during two years. The netting reduced flight activity by 77% and fruit infestation by 91%. The data showed that the flies have a dispersal of less than 5 m within orchards, which is very low. The low thresholds for tolerance for infested fruit in the fresh market creates a strong economic incentive for control, therefore, soil covering is a promising strategy for controlling R. cerasi in commercial orchards.

  1. Soil macroinvertebrates' abundance and diversity in home gardens in Tabasco, Mexico, vary with soil texture, organic matter and vegetation cover

    NARCIS (Netherlands)

    Huerta, E.; Wal, van der J.C.

    2012-01-01

    We studied the composition of soil invertebrate communities and vegetation in 50 home gardens in the humid tropical lowlands of Tabasco, Mexico, located in five geomorphological regions. Five monoliths were made in each home garden and soil invertebrates were hand sorted, weighed and classified to m

  2. Soil Organic Carbon (SOC) distribution in two differents soil types (Podzol and Andosol) under natural forest cover.

    Science.gov (United States)

    Álvarez-Romero, Marta; Papa, Stefania; Verstraeten, Arne; Cools, Nathalie; Lozano-García, Beatriz; Parras-Alcántara, Luis; Coppola, Elio

    2017-04-01

    Andosols are young soils that shall know a successive evolution towards pedological types where the dominant pedogenetic processes are more evident. Vegetation and climate influence Andosols evolution to other order of soils. In cold and wet climates or on acid vulcanite under heavy leaching young Andosols could change into Podzols (Van Breemn and Buurman, 1998). Were investigated a Podzol soil (World References Base, 2014) at Zoniën (Belgium), were and an Andosol soil (World References Base, 2014) at Lago Laceno (Avellino, Italy). This study shows the data on the SOC (Soil Organic Carbon) fractionation in two profiles from two natural pine forest soils. Together with the conventional activities of sampling and analysis of soil profile were examined surveys meant to fractionation and characterization of SOC, in particular: Total Organic Carbon (TOC) and Total Extractable Carbon (TEC) soil contents were determined by Italian official method of soil analysis (Mi.P.A.F. (2000)). Different soil C fractions were also determined: Humic Acid Carbon (HAC), Fulvic Acid Carbon (FAC), Not Humic Carbon (NHC) and Humin Carbon (Huc) fractions were obtained by difference. In the whole profile, therefore, were also assayed cellulose and lignin contents. The aim of this work was to compare the distribution of different soil organic components in a podzol and a soil with andic properties. The data show great similarity, among the selected profiles, in the organic components distribution estudied. References: - Mi.P.A.F. - Ministero per le Politiche Agricole e Forestali - Osservatorio Nazionale Pedologico e per la Qualità del Suolo (2000): Metodi Ufficiali di Analisi Chimica del Suolo. In: Franco Angeli (Editor), Collana di metodi analitici per l'agricoltura diretta da Paolo Sequi, n. 1124.2, Milano, Italy. - Van Breemn N. and Buurman P. (1998) Chapter 12 Formation of Andisols. In: Soil formation. Kluwer Ed., Wageningen, The Netherlands, 271-289. -Ussiri D.A.N., Johnson C

  3. REQUIREMENTS FOR DEVICES FOR VERTICAL ELECTRICAL SOUNDING OF SOIL AT DIAGNOSTICS OF GROUNDING DEVICES

    Directory of Open Access Journals (Sweden)

    S. S. Rudenko

    2016-11-01

    Full Text Available Purpose. Creation the scientific requirements for technical characteristics of equipment for vertical electrical sounding based on the electrophysical characteristics of the soil of energy objects with the different voltage classes. Methodology. In work used statistical methods for the analysis database of results the soil sounding and for receiving distribution of largest size of the grounding system. To determine the required range of measurement and permissible value of circuit resistance applied the mathematical description of the electromagnetic field to calculate the apparent resistivity of the soil and the Wenner method of calculating the resistance of a vertical electrode. Also, in work used elements of probability theory to creation the stochastic correlation between device parameters and characteristics object of the research. Results. In the paper found that in the most severe cases (when the depth of sounding is the three maximal diagonal of grounding at 99% energy objects in Ukraine the lower limit of resistance measurement for the respective classes of voltage must be no more than 1.3 milliohms to 35 kV, 0.6 mOhm to 110 kV, 0.5 milliohms to 150 kV, 0.1 mOhm for ≥ 220 kV. Also it proved that the measurement equipment for vertical electrical sounding when performing electromagnetic diagnostics of grounding system the power facilities Ukraine with 35-750 kV voltage class for all possible values of soil resistivity should be with limit of measurement from 0.1 mOhm to 7.2 kOhm and resistance measuring circuit to 66 kOhm. Originality.For the first time used a statistical approach to evaluate the optimal technical requirements for equipment the soils resistivity when performing diagnostics of grounding systems energy objects of Ukraine. The results obtained in this work, establish the probabilistic dependence of the technical characteristics of measuring equipment from the actual depth of sounding in Wenners configuration (the distance

  4. Development of Neural Network Model for Predicting Peak Ground Acceleration Based on Microtremor Measurement and Soil Boring Test Data

    National Research Council Canada - National Science Library

    Kerh, T; Lin, J. S; Gunaratnam, D

    2012-01-01

    .... This paper is therefore aimed at developing a neural network model, based on available microtremor measurement and on-site soil boring test data, for predicting peak ground acceleration at a site...

  5. Forms of phosphorus in an oxisol under different soil tillage systems and cover plants in rotation with maize

    Directory of Open Access Journals (Sweden)

    Arminda Moreira de Carvalho

    2014-06-01

    Full Text Available Phosphorus fractions play a key role in sustaining the productivity of acid-savanna Oxisols and are influenced by tillage practices. The aim of this study was to quantify different P forms in an Oxisol (Latossolo Vermelho-Amarelo from the central savanna region of Brazil under management systems with cover crops in maize rotation. Three cover crops (Canavalia brasiliensis, Cajanus cajan (L., and Raphanus sativus L. were investigated in maize rotation systems. These cover crops were compared to spontaneous vegetation. The inorganic forms NaHCO3-iP and NaOH-iP represented more than half of the total P in the samples collected at the depth of 5-10 cm during the rainy season when the maize was grown. The concentration of inorganic P of greater availability (NaHCO3-iP and NaOH-iP was higher in the soil under no-tillage at the depth of 5-10 cm during the rainy season. Concentrations of organic P were higher during the dry season, when the cover crops were grown. At the dry season, organic P constituted 70 % of the labile P in the soil planted to C. cajan under no-tillage. The cover crops were able to maintain larger fractions of P available to the maize, resulting in reduced P losses to the unavailable pools, mainly in no-tillage systems.

  6. Weed science and management, in soil sciences, land cover, and land use

    Science.gov (United States)

    An integral component of conservation agriculture systems in cotton is the use of a high-residue winter cover crop; however, terminating such cover crops is a cost and planting into high-residue is a challenge. Black oat, rye, and wheat winter cover crops were flattened with a straight-blade mechan...

  7. Influence of land cover changes on the physical and chemical properties of alpine meadow soil

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Taking the alpine cold meadow grassland in the southeastern part of the Qinghai-Tibetan Plateau as an example, this research deals with the characteristics of alpine meadow soil property changes, including soil nutrients, soil physical properties and soil moisture content under different land coverage conditions. With the degradation of grassland vegetation and the decline of vegetation coverage, soil compactness reduces, gravel content increases and bulk density increases. The originally dense root-system layer is gradually denuded, making the soil coarse and gravel. The change of the organic matter contents with the vegetation coverage change in the surface soil layer (0-20 cm) has shown an obvious cubic polynomial curve process. The organic matter contents increase rapidly when land coverage is above 60%, contrarily decreases on a large scale when land coverage is below 30%. Between 30%-60% of land coverage the organic matter contents remain stable. The total N and organic matter contents in soil have shown quite similar change regularity. Following this the mathematic equations are derived to describe such change processes. Moisture content in soil changes sharply with the vegetation coverage change. Soil moisture content change with the vegetation coverage change has shown a quadratic parabola process. Results have shown that organic matter content and the total N content of the alpine meadow soil decrease by 14890 kg/hm2 and 5505 kg/hm2 respectively as the vegetation coverage reduces from 90% to less than 30%. The heavy changes of soil physical and chemical properties with grassland degradation have made the recovery of alpine meadow ecological system impossible. The protection of alpine meadow vegetation is of vital importance to the maintenance of the regional soil environment and the regional ecological system.

  8. Soil cover patterns and dynamics impact on GHG fluxes in RF native and man-changed ecosystems

    Science.gov (United States)

    Vasenev, Ivan; Nesterova, Olga

    2017-04-01

    The increased soil spatial-temporal variability is mutual feature for most mature natural and particularly man-changed terrestrial ecosystems in Central and Far-East regions of Russia with soil cover strongly pronounced bioclimatic zoning and landscape-geomorphologic differentiation. Soil cover patterns (SCP) detailed morphogenetic analysis and typification is useful tool for soil forming and degradation processes quantitative evaluation, land ecological state and functional quality quantitative assessment. Quantitative analysis and functional-ecological interpretation of representative SCP spatial variability is especially important for environmentally friendly and demand-driven land-use planning and decision making. The carried out 33-years region- and local-scale researches of the wide zonal-provincial set of representative ecosystems and SCP with different types and history of land-use (forest, meadow-steppe, agricultural and recreational ones) give us the interregional multi-factorial matrix of elementary soil cover patterns (ESCP) with different land-use practices and history, soil-geomorphologic features, environmental and microclimate conditions. Succession process-based analysis of modern evolution of man-changed and natural soils and ESCP essentially increases accuracy of quantitative assessments of dominant soil forming and degradation processes rate and potential, their influence on land and soil cover quality and ecosystem services. Their results allow developing the regional and landscape adapted versions of automated land evaluation systems and land-use DSS. The validation and ranging of the limiting factors of ESCP regulation and develop¬ment, ecosystem principal services (with especial attention on greenhouse gases emissions, soil carbon dynamics and sequestration potential, biodiversity and productivity, hydrological regimes and geomorphologic stabilization), land functional qualities and agroecological state have been done for dominating and

  9. Carbon supply and storage in tilled and nontilled soils as influenced by cover crops and nitrogen fertilization.

    Science.gov (United States)

    Sainju, Upendra M; Singh, Bharat P; Whitehead, Wayne F; Wang, Shirley

    2006-01-01

    Soil carbon (C) sequestration in tilled and nontilled areas can be influenced by crop management practices due to differences in plant C inputs and their rate of mineralization. We examined the influence of four cover crops {legume [hairy vetch (Vicia villosa Roth)], nonlegume [rye (Secale cereale L.)], biculture of legume and nonlegume (vetch and rye), and no cover crops (or winter weeds)} and three nitrogen (N) fertilization rates (0, 60 to 65, and 120 to 130 kg N ha(-1)) on C inputs from cover crops, cotton (Gossypium hirsutum L.), and sorghum [Sorghum bicolor (L.) Moench)], and soil organic carbon (SOC) at the 0- to 120-cm depth in tilled and nontilled areas. A field experiment was conducted on Dothan sandy loam (fine-loamy, siliceous, thermic Plinthic Paleudults) from 1999 to 2002 in central Georgia. Total C inputs to the soil from cover crops, cotton, and sorghum from 2000 to 2002 ranged from 6.8 to 22.8 Mg ha(-1). The SOC at 0 to 10 cm fluctuated with C input from October 1999 to November 2002 and was greater from cover crops than from weeds in no-tilled plots. In contrast, SOC values at 10 to 30 cm in no-tilled and at 0 to 60 cm in chisel-tilled plots were greater for biculture than for weeds. As a result, C at 0 to 30 cm was sequestered at rates of 267, 33, -133, and -967 kg C ha(-1) yr(-1) for biculture, rye, vetch, and weeds, respectively, in the no-tilled plot. In strip-tilled and chisel-tilled plots, SOC at 0 to 30 cm decreased at rates of 233 to 1233 kg C ha(-1) yr(-1). The SOC at 0 to 30 cm increased more in cover crops with 120 to 130 kg N ha(-1) yr(-1) than in weeds with 0 kg N ha(-1) yr(-1), regardless of tillage. In the subtropical humid region of the southeastern United States, cover crops and N fertilization can increase the amount of C input and storage in tilled and nontilled soils, and hairy vetch and rye biculture was more effective in sequestering C than monocultures or no cover crop.

  10. A comparison of ground and satellite observations of cloud cover to saturation pressure differences during a cold air outbreak

    Energy Technology Data Exchange (ETDEWEB)

    Alliss, R.J.; Raman, S. [North Carolina State Univ., Raleigh, NC (United States)

    1996-04-01

    The role of clouds in the atmospheric general circulation and the global climate is twofold. First, clouds owe their origin to large-scale dynamical forcing, radiative cooling in the atmosphere, and turbulent transfer at the surface. In addition, they provide one of the most important mechanisms for the vertical redistribution of momentum and sensible and latent heat for the large scale, and they influence the coupling between the atmosphere and the surface as well as the radiative and dynamical-hydrological balance. In existing diagnostic cloudiness parameterization schemes, relative humidity is the most frequently used variable for estimating total cloud amount or stratiform cloud amount. However, the prediction of relative humidity in general circulation models (GCMs) is usually poor. Even for the most comprehensive GCMs, the predicted relative humidity may deviate greatly from that observed, as far as the frequency distribution of relative humidity is concerned. Recently, there has been an increased effort to improve the representation of clouds and cloud-radiation feedback in GCMs, but the verification of cloudiness parameterization schemes remains a severe problem because of the lack of observational data sets. In this study, saturation pressure differences (as opposed to relative humidity) and satellite-derived cloud heights and amounts are compared with ground determinations of cloud cover over the Gulf Stream Locale (GSL) during a cold air outbreak.

  11. Soil properties and performance of landmine detection by metal detector and ground-penetrating radar — Soil characterisation and its verification by a field test

    Science.gov (United States)

    Takahashi, Kazunori; Preetz, Holger; Igel, Jan

    2011-04-01

    Metal detectors have commonly been used for landmine detection, and ground-penetrating radar (GPR) is about to be deployed for this purpose. These devices are influenced by the magnetic and electric properties of soil, since both employ electromagnetic techniques. Various soil properties and their spatial distributions were measured and determined with geophysical methods in four soil types where a test of metal detectors and GPR systems took place. By analysing the soil properties, these four soils were classified based on the expected influence of each detection technique and predicted soil difficulty. This classification was compared to the detection performance of the detectors and a clear correlation between the predicted soil difficulty and performance was observed. The detection performance of the metal detector and target identification performance of the GPR systems degraded in soils that were expected to be problematic. Therefore, this study demonstrated that the metal detector and GPR performance for landmine detection can be assessed qualitatively by geophysical analyses.

  12. Soil wettability in forested catchments in South Africa; as measured by different methods and as affected by vegetation cover and soil characteristics

    CSIR Research Space (South Africa)

    Scott

    2000-05-01

    Full Text Available stream_source_info scott 1_2000.pdf.txt stream_content_type text/plain stream_size 54451 Content-Encoding ISO-8859-1 stream_name scott 1_2000.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Soil wettability... in forested catchments in South Africa; as measured by different methods and as affected by vegetation cover and soil characteristics D.F. Scott* CSIR, Division of Water, Environment and Forestry Technology, P.O. Box 320, Stellenbosch, 7599, South Africa...

  13. Exploring Soil Layers and Water Tables with Ground-Penetrating Radar

    Institute of Scientific and Technical Information of China (English)

    K. ROTH; U. WOLLSCHLAGER; CHENG Zhu-Hua; ZHANG Jia-Bao

    2004-01-01

    Ground-penetrating radar (GPR) has been used predominantly for environments with low electrical conductivity like freshwater aquifers, glaciers, or dry sandy soils. The objective of the present study was to explore its application for mapping in subsurface agricultural soils to a depth of several meters. For a loamy sand and a clayey site on the North China Plain, clay inclusions in the sand were detected; the thickness, inclination, and continuity of the confining clay and silt layers was assessed; and a local water table was mapped. Direct sampling (soil coring and profiling) in the top meter and independent measurement of the water table were utilized to confirm the findings. Also, effective estimates of the dielectric number for the site with the dielectric number of moist clayey soils depending strongly on frequency were obtained. Thus, important properties of soils, like the arrangement and type of layers and in particular their continuity and inclination, could be explored with moderate efforts for rather large areas to help find optimal locations for the time-consuming and expensive measurements which would be necessary to detail a model of the subsurface.

  14. Use of Landsat imagery to detect land cover changes for monitoring soil sealing; case study: Bologna province (Italy)

    Science.gov (United States)

    Casciere, Rossella; Franci, Francesca; Bitelli, Gabriele

    2014-08-01

    Landsat archives (made accessible by USGS at no charge since 2011) have made available to the scientific community a large amount of satellite multispectral images, providing new opportunities for environmental information, such as the analysis of land use/cover changes, which represent important tools for planning and sustainable land management. Processing a time series images, the creation of land cover maps has been improved in order to analyze phenomena such as the soil sealing. The main topic of this work is in fact the detection of roads and buildings construction or everything that involve soil removing. This subject is highly relevant, given the impact of the phenomenon on land use planning, environmental sustainability, agricultural policies and urban runoff. The analysis, still in progress, has been applied to Bologna Province (Emilia-Romagna Region, Italy) that covers 3703 Km2. This area is strongly urbanized: 8,9% of the total surface is sealed against a national value of 6,7%, with the soil sealing rate which has been defined from recent studies as the fourth Italian value in the 2001/2011 period. Other information available for this territory derive from CORINE Land Cover and Copernicus Projects. In the first one, the minimum mapping unit is 25 ha and the one for change is 5 ha; these values are too large for an accurate detection of the soil sealing dynamics. On the other hand, the Copernicus Project provides an imperviousness layer with a better resolution (20x20 m2), but its maps start from 2006. Therefore, the potential of multispectral remote sensing analysis over large areas and the multitemporal Landsat availability have been combined for a better knowledge about land cover changes. For this work, Landsat 5 and Landsat 8 images have been acquired between 1987 and 2013, according to basic requirements as low cloud cover and a common acquisition season (summer). A supervised pixel-based classification has been performed, with maximum likelihood

  15. Impact of climate change on water balance components in Mediterranean rainfed olive orchards under tillage or cover crop soil management

    Science.gov (United States)

    Rodríguez-Carretero, María Teresa; Lorite, Ignacio J.; Ruiz-Ramos, Margarita; Dosio, Alessandro; Gómez, José A.

    2013-04-01

    The rainfed olive orchards in Southern Spain constitute the main socioeconomic system of the Mediterranean Spanish agriculture. These systems have an elevated level of complexity and require the accurate characterization of crop, climate and soil components for a correct management. It is common the inclusion of cover crops (usually winter cereals or natural cover) intercalated between the olive rows in order to reduce water erosion. Saving limited available water requires specific management, mowing or killing these cover crops in early spring. Thus, under the semi-arid conditions in Southern Spain the management of the cover crops in rainfed olive orchards is essential to avoid a severe impact to the olive orchards yield through depletion of soil water. In order to characterize this agricultural system, a complete water balance model has been developed, calibrated and validated for the semi-arid conditions of Southern Spain, called WABOL (Abazi et al., 2013). In this complex and fragile system, the climate change constitutes a huge threat for its sustainability, currently limited by the availability of water resources, and its forecasted reduction for Mediterranean environments in Southern Spain. The objective of this study was to simulate the impact of climate change on the different components of the water balance in these representative double cropping systems: transpiration of the olive orchard and cover crop, runoff, deep percolation and soil water content. Four climatic scenarios from the FP6 European Project ENSEMBLES were first bias corrected for temperatures and precipitation (Dosio and Paruolo, 2011; Dosio et al., 2012) and, subsequently, used as inputs for the WABOL model for five olive orchard fields located in Southern Spain under different conditions of crop, climate, soils and management, in order to consider as much as possible of the variability detected in the Spanish olive orchards. The first results indicate the significant effect of the cover

  16. Cover crops as a gateway to greater conservation in Iowa?: Integrating crop models, field trials, economics and farmer perspectives regarding soil resilience in light of climate change

    Science.gov (United States)

    Roesch-McNally, G. E.; Basche, A.; Tyndall, J.; Arbuckle, J. G.; Miguez, F.; Bowman, T.

    2014-12-01

    Scientists predict a number of climate changes for the US Midwest with expected declines in crop productivity as well as eco-hydrological impacts. More frequent extreme rain events particularly in the spring may well increase saturated soils thus complicating agronomic interests and also exacerbate watershed scale impairments (e.g., sediment, nutrient loss). In order to build more resilient production systems in light of climate change, farmers will increasingly need to implement conservation practices (singularly or more likely in combination) that enable farmers to manage profitable businesses yet mitigate consequential environmental impacts that have both in-field and off-farm implications. Cover crops are empirically known to promote many aspects of soil and water health yet even the most aggressive recent estimates show that only 1-2% of the total acreage in Iowa have been planted to cover crops. In order to better understand why farmers are reluctant to adopt cover crops across Iowa we combined agronomic and financial data from long-term field trials, working farm trials and model simulations so as to present comprehensive data-driven information to farmers in focus group discussions in order to understand existing barriers, perceived benefits and responses to the information presented. Four focus groups (n=29) were conducted across Iowa in four geographic regions. Focus group discussions help explore the nuance of farmers' responses to modeling outputs and their real-life agronomic realities, thus shedding light on the social and psychological barriers with cover crop utilization. Among the key insights gained, comprehensive data-driven research can influence farmer perspectives on potential cover crop impacts to cash crop yields, experienced costs are potentially quite variable, and having field/farm benefits articulated in economic terms are extremely important when farmers weigh the opportunity costs associated with adopting new practices. Our work

  17. Effect of Land Cover Change on Soil Phosphorus Fractions in Southeastern Horqin Sandy Land, Northern China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiong; ZENG De-Hui; FAN Zhi-Ping; D.K.LEE

    2008-01-01

    In the past 50 years, large areas of the Horqin sandy land were afforested to prevent desertification. Although the afforestation policy appears successful, many people now doubt whether it is suitable to plant trees with high density on the poor soils in semiarid regions. Little is known about the impacts of afforestation on the sandy soil properties, although the evaluation of these impacts is fundamental to judge the rationality of afforestation policy. Soil phosphorus (P) fractions, acid phosphomonoesterase activities, and other soil chemical properties were compared among five adjoining typical ecosystems on poor sandy soils in southeastern Horqin sandy land. The ecosystems studied are natural elm savanna, degraded grassland, Mongolian pine (Pinus sylvestris var. Mongolica) plantation, Chinese pine (Pinus tabulaeformis) plantation, and mixed plantation of Mongolian pine and poplar (Populus simonii). The results showed that organic P dominated soil P (47%-65%) was the principal source of available P. The degradation of elm savanna to grassland significantly reduced soil pH and resulted in an overall reduction in soil fertility, although slightly increased labile inorganic P. Grassland afforestation had no significant influence on soil pH, organic carbon, and total N but significantly reduced total P. Impacts of grassland afforestation on soil P fractions depended on tree species. Natural elm savanna had higher soil P conserving ability than artificial plantations. Therefore, with the aim of developing a sustainable ecosystem, we suggested that vegetations with low nutrient demand (particularly P) and efficient nutrient cycling would be more suitable for ecosystem restoration in the semiarid region.

  18. N 2O emissions at municipal solid waste landfill sites: Effects of CH 4 emissions and cover soil

    Science.gov (United States)

    Zhang, Houhu; He, Pinjing; Shao, Liming

    Municipal solid waste landfills are the significant anthropogenic sources of N 2O due to the cooxidation of ammonia by methane-oxidizing bacteria in cover soils. Such bacteria could be developed through CH 4 fumigation, as evidenced by both laboratory incubation and field measurement. During a 10-day incubation with leachate addition, the average N 2O fluxes in the soil samples, collected from the three selected landfill covers, were multiplied by 1.75 ( p landfill sites, N 2O fluxes in two landfill sites were significantly correlated with the variations of the CH 4 emissions without landfill gas recovery ( p landfill gas recovery in another landfill site ( p > 0.05). The annual average N 2O flux was 176 ± 566 μg N 2O-N m -2 h -1 ( p landfill site, which was 72% ( p landfill sites, respectively. The magnitude order of N 2O emissions in three landfill sites was also coincident by the results of laboratory incubation, suggesting the sandy soil cover could mitigate landfill N 2O emissions.

  19. Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Peace, Gerald (Jerry) L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

    2004-11-01

    A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

  20. [Effect of operational modes on community structure of type I methanotroph in the cover soil of municipal solid waste landfill].

    Science.gov (United States)

    Yu, Ting; He, Pin-Jing; Lü, Fan; Shao, Li-Ming

    2008-10-01

    Type I methanotroph is crucial for methane oxidization and it responses fast to the changes in environment. In this study, 16S rDNA-based denaturing gradient gel electrophoresis (DGGE) gene fingerprint technology was applied to investigate the effect of operational modes, i. e. high-density polyethylene liner (HDPE) isolation or subsurface irrigation of landfill leachate and vegetation, on community structure and diversity of type I methanotroph in soils covering municipal solid waste landfill. 16S rDNA based phylogenetic analysis reveals type I methanotroph in all tested soils belongs to Methylobacter. According to Shannon-Wiener diversity index and principal component analysis, landfill leachate subsurface irrigation and vegetation have more impact on type I methanotroph community structure and diversity than HDPE liner isolation does, and they reduce type I methanotroph diversity. Leachate irrigation is supposed to inhibit the growth of Methylobacter population. Community structure of type I methanotroph in landfill cover soil isolated by HDPE, i.e. invaded by landfill gas, shifts during long-term gas interference. When cover age is 1.5 years old, Shannon-Wiener diversity index of type I methanotroph reaches its maximum.

  1. Associations between land cover/use categories and soil concentrations of arsenic, lead and barium, and population race/ethnicity and socioeconomic status

    Science.gov (United States)

    Davis, Harley T.; Aelion, C. Marjorie; Lawson, Andrew B.; Cai, Bo; McDermott, Suzanne

    2015-01-01

    The potential of using land cover/use categories as a proxy for soil metal concentrations was examined by measuring associations between percentages of Anderson land cover categories with soil concentrations of As, Pb, and Ba in ten sampling areas. Land cover category and metal associations with ethnicity and socioeconomic status at the United States Census 2000 block and block group levels also were examined. Arsenic and Pb were highest in urban locations; Ba was a function of geology. Consistent associations were observed between urban/built up land cover, and Pb and poverty. Land cover can be used as proxy for metal concentrations, although associations are metal-dependent. PMID:24914533

  2. Microorganisms in small patterned ground features and adjacent vegetated soils along topographic and climatic gradients in the High Arctic, Canada

    Science.gov (United States)

    G. Gonzalez; F.J. Rivera-Figueroa; W. Gould; S.A. Cantrell; J.R. Pérez-Jiménez

    2014-01-01

    In this study, we determine differences in total biomass of soil microorganisms and community structure (using the most probable number of bacteria (MPN) and the number of fungal genera) in patterned ground features (PGF) and adjacent vegetated soils (AVS) in mesic sites from three High Arctic islands in order to characterize microbial dynamics as affected by...

  3. Validation and downscaling of Advanced Scatterometer (ASCAT) soil moisture using ground measurements in the Western Cape, South Africa

    CSIR Research Space (South Africa)

    Moller, J

    2017-09-01

    Full Text Available of Plant and Soil: DOI: 10.1080/02571862.2017.1318962 Validation and downscaling of Advanced Scatterometer (ASCAT) soil moisture using ground measurements in the Western Cape, South Africa Moller J Jovanovic N Garcia CL Bugan RDH Mazvimavi D...

  4. Quantifying the effect of lichen and bryophyte cover on permafrost soil within a global land surface model

    Science.gov (United States)

    Porada, Philipp; Ekici, Altug; Beer, Christian

    2016-04-01

    Vegetation near the surface, such as bryophytes and lichens, has an insulating effect on the soil at high latitudes and it can therefore protect permafrost conditions. Warming due to climate change, however, may change the average surface coverage of bryophytes and lichens. This can result in permafrost thawing associated with a release of soil carbon to the atmosphere, which may lead to a positive feedback on atmospheric CO2. Thus, it is important to predict how the bryophyte and lichen cover at high latitudes will react to environmental change. However, current global land surface models so far contain mostly empirical approaches to represent bryophytes and lichens, which makes it impractical to predict their future state and function. For this reason, we integrate a process-based model of bryophyte and lichen growth into the global land surface model JSBACH. We explicitly represent dynamic thermal properties of the bryophyte and lichen cover and their relation to climate. Subsequently, we compare simulations with and without bryophyte and lichen cover to quantify the insulating effect. We estimate an annual average cooling effect of the bryophyte and lichen cover of 2.7 K on topsoil temperature for the northern high latitudes under current climate. Locally, the cooling may reach up to 5.7 K. Moreover, we show that neglecting dynamic properties of the bryophyte and lichen cover by using a simple, empirical scheme only results in an average cooling of around 0.5 K. This suggests that bryophytes and lichens have a significant impact on soil temperature in high-latitude ecosystems and also that a process-based description of their thermal properties is necessary for a realistic representation of the cooling effect.

  5. Simplified method for predicating consolidation settlement of soft ground improved by floating soil-cement column

    Institute of Scientific and Technical Information of China (English)

    龚晓南; 田效军; 胡文韬

    2015-01-01

    A simplified method is presented for predicting consolidation settlement of soft ground improved by floating soil−cement column on the basis of double soil-layer consolidation theory. Combining the axisymmetric consolidation model and equal strain assumption, the governing equation was derived for the consolidation of clayey subsoil reinforced by soil−cement column. By modifying the boundary condition of the interface between the improved layer and underlying layer on seepage and pore-water pressure, the analytical solution of consolidation of soft ground improved by floating soil−cement column was developed under depth-dependent ramp load. The results of the parameter analysis of consolidation behavior show that the consolidation rate is closely related with the depth replacement ratio by the column and the permeability of upper layer. The influence of column−soil constrained modulus ratio and radius ratio of the influence zone to the column on consolidation is also affected by depth replacement ratio. The column−soil total stress ratio increases with time and approaches the final value accompanied with the dissipation of excess pore water pressure.

  6. Soil-covered strategy for ecological restoration alters the bacterial community structure and predictive energy metabolic functions in mine tailings profiles.

    Science.gov (United States)

    Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2017-03-01

    Native soil amendment has been widely used to stabilize mine tailings and speed up the development of soil biogeochemical functions before revegetation; however, it remains poorly understood about the response of microbial communities to ecological restoration of mine tailings with soil-covered strategy. In this study, microbial communities along a 60-cm profile were investigated in mine tailings during ecological restoration of two revegetation strategies (directly revegetation and native soil covered) with different plant species. The mine tailings were covered by native soils as thick as 40 cm for more than 10 years, and the total nitrogen, total organic carbon, water content, and heavy metal (Fe, Cu, and Zn) contents in the 0-40 cm intervals of profiles were changed. In addition, increased microbial diversity and changed microbial community structure were also found in the 10-40 cm intervals of profiles in soil-covered area. Soil-covered strategy rather than plant species and soil depth was the main factor influencing the bacterial community, which explained the largest portion (29.96%) of the observed variation. Compared directly to revegetation, soil-covered strategy exhibited the higher relative abundance of Acidobacteria and Deltaproteobacteria and the lower relative abundance of Bacteroidetes, Gemmatimonadetes, Betaproteobacteria, and Gammaproteobacteria. PICRUSt analysis further demonstrated that soil-covered caused energy metabolic functional changes in carbon, nitrogen, and sulfur metabolism. Given all these, the soil-covered strategy may be used to fast-track the establishment of native microbial communities and is conducive to the rehabilitation of biogeochemical processes for establishing native plant species.

  7. Land cover changes affect soil chemical attributes in the Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Murilo Rezende Machado

    2017-05-01

    Full Text Available Forest plantations may minimize the effects of deforestation in the Amazon. However, there are differences among species in terms of their influences on soil recovery. The effects of monospecific plantations of Acacia mangium, Dipteryx odorata, Jacaranda copaia, Parkia decussata,and Swietenia macrophylla, and areas of pasture and native forest on the chemical soil attributes of the Brazilian Amazon were evaluated. One bulked soil sample was collected per plot (0.00-0.05, 0.05-0.10, and 0.10-0.30 m; three plots of 128 m2 in each area. No significant differences in most of the soil attributes were observed among the forest plantations. However, soil K+ and P were higher in the Swietenia macrophylla plantations, while higher values of Ca2+, sum of bases, and pH occurred in Jacaranda copaia plantations. In the native forest, the pH, and P content were lower, whereas the soil organic matter (SOM content, soil organic carbon (SOC content, cation exchange capacity (CEC, N content, H+Al content, and Al3+ content were higher than in the plantations. The lowest values of SOM, SOC, CEC, K+, Mg2+, N, H+Al, and Al3+ occurred in the pasture. None of the forest species led to the return of the original soil chemical attributes of the native forest. However, S. macrophylla and J. copaia plantations presented the highest positive edaphic influences.

  8. Managing Cover Crops, Crop Rotation, and Poultry Manure to Increase Soil Health

    Science.gov (United States)

    Public interest has been stimulated by increasing awareness that soil is a critically important component of the earth’s biosphere, functioning not only in the production of food and fiber but also in the maintenance of local, regional, and global environmental quality. A healthy soil is also the ba...

  9. Application of Geo-Information Technology in the Study of Soil and Nutrients Loss by Water Erosion for three Different Land Cover

    Directory of Open Access Journals (Sweden)

    Mushtak T. Jabbar

    2005-01-01

    Full Text Available This research integrated the Revised Universal Soil Loss Equation (RUSLE and the soil statistical analysis with RS and GIS techniques to quantify soil and nutrient loss risk. The Letianxi watershed, located in the southwest part of Hubei Province of China was taken as a case. A system was established for rating soil erodibility, slope length/gradient, rainfall erosivity and conservation practices. The rating values serve as inputs into a Revised Universal Soil Loss Equation (RUSLE to calculate the risk for soil degradation processes, namely soil water erosion. Two Landsat TM senses in 1997 and ETM 2002, respectively, were used to produce land use/cover maps of the study area based on the maximum likelihood classification method. These maps were then used to generate the conservation practice factor in the RUSLE. In order to assess the effect of land cover and landscape position on soil nutrient consisting of Soil Organic Mater (SOM, Total N (TN, Total P (TP and Total K (TK, soil samples were collected from the top to foot of hill slope in the study area. The three categories consisted of a typical land cover structure for each polygon in the study area: Soil under forest cover (T1, soil under agriculture crops cover (T2 and soil under no vegetation cover (T3. Annual loss of total N (8.24 kg ha‾1, total P (5.88 kg ha‾1 and total K (6.98 kg ha‾1, per unit loss of soil (t ha‾1, was maximum from the soil under no vegetation cover (T3. The loss of total N ranged between 5.30 and 32.27 kg ha‾1, total P ranged between 2.14 and 12.42 kg ha‾1, total K ranged from 2.12 to 10.31 kg ha-1 whereas organic matter loss varied between 10.65 and 236.16 kg ha-1, from three different land covers. ERmapper and Arc/Info software were used to manage and manipulate thematic data, to process satellite images and tabular data source. Results showed that 110.72 km2 (27.09% was exposed to very slight soil loss and 227.01 km2 (55.55% was

  10. Variation on the amount of winter cover crops residues on weeds incidence and soil seed bank during an agricultural year

    Directory of Open Access Journals (Sweden)

    Márcia Maria Mauli

    2011-08-01

    Full Text Available This study analyzed possible interferences associated to the amount of crop residues produced by the black oats and the consortium of black oats, common vetch and forage turnip on weeds incidence and soil seed bank. It was a field trial with seven treatments and five replications. The cover crop was sown at throwing, cut at 100 days and residues were put on each respective plot, using a proportion of normal amount of produced straw, either its half and double. The heaviest weights were obtained from cover crop consortium and their application decreased weeds incidence in such area. The seeds bank and other analyzed parameters did not show statistical differences. According to these results, it was concluded that winter cover crop could be used in crops rotation with soybean.

  11. Effects of Land Cover / Land Use, Soil Texture, and Vegetation on the Water Balance of Lake Chad Basin

    Science.gov (United States)

    Babamaaji, R. A.; Lee, J.

    2013-12-01

    Lake Chad Basin (LCB) has experienced drastic changes of land cover and poor water management practices during the last 50 years. The successive droughts in the 1970s and 1980s resulted in the shortage of surface water and groundwater resources. This problem of drought has a devastating implication on the natural resources of the Basin with great consequence on food security, poverty reduction and quality of life of the inhabitants in the LCB. Therefore, understanding the effects of land use / land cover must be a first step to find how they disturb cycle especially the groundwater in the LCB. The abundance of groundwater is affected by the climate change through the interaction with surface water, such as lakes and rivers, and disuse recharge through an infiltration process. Quantifying the impact of climate change on the groundwater resource requires reliable forecasting of changes in the major climatic variables and other spatial variations including the land use/land cover, soil texture, topographic slope, and vegetation. In this study, we employed a spatially distributed water balance model WetSpass to simulate a long-term average change of groundwater recharge in the LCB of Africa. WetSpass is a water balance-based model to estimate seasonal and spatial distribution of surface runoff, interception, evapotranspiration, and groundwater recharge. The model is especially suitable for studying the effect of land use/land cover change on the water regime in the LCB. The present study describes the concept of the model and its application to the development of recharge map of the LCB. The study shows that major role in the water balance of LCB. The mean yearly actual evapotranspiration (ET) from the basin range from 60mm - 400 mm, which is 90 % (69mm - 430) of the annual precipitation from 2003 - 2010. It is striking that about 50 - 60 % of the total runoff is produced on build-up (impervious surfaces), while much smaller contributions are obtained from vegetated

  12. Simulating soil organic carbon stock as affected by land cover change and climate change, Hyrcanian forests (northern Iran).

    Science.gov (United States)

    Soleimani, Azam; Hosseini, Seyed Mohsen; Massah Bavani, Ali Reza; Jafari, Mostafa; Francaviglia, Rosa

    2017-12-01

    Soil organic carbon (SOC) contains a considerable portion of the world's terrestrial carbon stock, and is affected by changes in land cover and climate. SOC modeling is a useful approach to assess the impact of land use, land use change and climate change on carbon (C) sequestration. This study aimed to: (i) test the performance of RothC model using data measured from different land covers in Hyrcanian forests (northern Iran); and (ii) predict changes in SOC under different climate change scenarios that may occur in the future. The following land covers were considered: Quercus castaneifolia (QC), Acer velutinum (AV), Alnus subcordata (AS), Cupressus sempervirens (CS) plantations and a natural forest (NF). For assessment of future climate change projections the Fifth Assessment IPCC report was used. These projections were generated with nine Global Climate Models (GCMs), for two Representative Concentration Pathways (RCPs) leading to very low and high greenhouse gases concentration levels (RCP 2.6 and RCP 8.5 respectively), and for four 20year-periods up to 2099 (2030s, 2050s, 2070s and 2090s). Simulated values of SOC correlated well with measured data (R(2)=0.64 to 0.91) indicating a good efficiency of the RothC model. Our results showed an overall decrease in SOC stocks by 2099 under all land covers and climate change scenarios, but the extent of the decrease varied with the climate models, the emissions scenarios, time periods and land covers. Acer velutinum plantation was the most sensitive land cover to future climate change (range of decrease 8.34-21.83tCha(-1)). Results suggest that modeling techniques can be effectively applied for evaluating SOC stocks, allowing the identification of current patterns in the soil and the prediction of future conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Hydrogeologic, soil, and water-quality data for j-field, Aberdeen Proving Ground, Maryland, 1989-94

    Science.gov (United States)

    Phelan, D.J.

    1996-01-01

    Disposal of chemical-warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has resulted in ground-water, surface-water, and soil contamination. This report presents data collected by the U.S. Geological Survey from Novembr 1989 through September 1994 as part of a remedial investigation of J-Field in response to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Hydrogeologic data, soil-gas and soil-quality data, and water-qualtiy data are included.

  14. Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Yi, S.; Li, N.; Xiang, B.; Wang, X.; Ye, B.; McGuire, A.D.

    2013-01-01

    Soil surface temperature is a critical boundary condition for the simulation of soil temperature by environmental models. It is influenced by atmospheric and soil conditions and by vegetation cover. In sophisticated land surface models, it is simulated iteratively by solving surface energy budget equations. In ecosystem, permafrost, and hydrology models, the consideration of soil surface temperature is generally simple. In this study, we developed a methodology for representing the effects of vegetation cover and atmospheric factors on the estimation of soil surface temperature for alpine grassland ecosystems on the Qinghai-Tibetan Plateau. Our approach integrated measurements from meteorological stations with simulations from a sophisticated land surface model to develop an equation set for estimating soil surface temperature. After implementing this equation set into an ecosystem model and evaluating the performance of the ecosystem model in simulating soil temperature at different depths in the soil profile, we applied the model to simulate interactions among vegetation cover, freeze-thaw cycles, and soil erosion to demonstrate potential applications made possible through the implementation of the methodology developed in this study. Results showed that (1) to properly estimate daily soil surface temperature, algorithms should use air temperature, downward solar radiation, and vegetation cover as independent variables; (2) the equation set developed in this study performed better than soil surface temperature algorithms used in other models; and (3) the ecosystem model performed well in simulating soil temperature throughout the soil profile using the equation set developed in this study. Our application of the model indicates that the representation in ecosystem models of the effects of vegetation cover on the simulation of soil thermal dynamics has the potential to substantially improve our understanding of the vulnerability of alpine grassland ecosystems to

  15. Soil moisture retrieval using ground based bistatic scatterometer data at X-band

    Science.gov (United States)

    Gupta, Dileep Kumar; Prasad, Rajendra; Kumar, Pradeep; Vishwakarma, Ajeet Kumar

    2017-02-01

    Several hydrological phenomenon and applications need high quality soil moisture information of the top Earth surface. The advent of technologies like bistatic scatterometer can retrieve soil moisture information with high accuracy and hence used in present study. The radar data is acquired by specially designed ground based bistatic scatterometer system in the specular direction of 20-70° incidence angles at steps of 5° for HH and VV polarizations. This study provides first time comprehensive evaluation of different machine learning algorithms for the retrieval of soil moisture using the X-band bistatic scatterometer measurements. The comparison of different artificial neural network (ANN) models such as back propagation artificial neural network (BPANN), radial basis function artificial neural network (RBFANN), generalized regression artificial neural network (GRANN) along with linear regression model (LRM) are used to estimate the soil moisture. The performance indices such as %Bias, Root Mean Squared Error (RMSE) and Nash-Sutcliffe Efficiency (NSE) are used to evaluate the performances of the machine learning techniques. Among different models employed in this study, the BPANN is found to have marginally higher performance in case of HH polarization while RBFANN is found suitable with VV polarization followed by GRANN and LRM. The results obtained are of considerable scientific and practical value to the wider scientific community for the number of practical applications and research studies in which radar datasets are used.

  16. Radon-222 concentrations in ground water and soil gas on Indian reservations in Wisconsin

    Science.gov (United States)

    DeWild, John F.; Krohelski, James T.

    1995-01-01

    The weighted average radon-222 concentration of indoor air in homes located on Wisconsin Indian Reservations is 5.8 picocuries per liter, which exceeds the U.S. Environmental Protection Agency action limit of 4 picocuries per liter. Ground water is the principle source of drinking water on Wisconsin Indian Reservations and generally accounts for about 5 percent of the total indoor air radon-222 concentrations found in homes. To determine the distribution of radon-222, ground water from 29 private and community Wisconsin Indian Reservation wells and soil gas at a depth of about 3 feet below land surface adjacent to the wells were sampled. Sites with wells were distributed among the 11 Wisconsin Indian Reservations so that each Reservation contained at least 2 sites. The remaining seven sites were divided among the Reservation by acreage held by each tribe.

  17. Hysteresis and Soil Site Dependent Input and Hysteretic Energy Spectra for Far-Source Ground Motions

    Directory of Open Access Journals (Sweden)

    Mebrahtom Gebrekirstos Mezgebo

    2016-01-01

    Full Text Available Earthquake input energy spectra for four soil site classes, four hysteresis models, and five ductility levels are developed for far-source ground motion effect. These energy spectra are normalized by a quantity called velocity index (VI. The use of VI allows for the creation of dimensionless spectra and results in smaller coefficients of variation. Hysteretic energy spectra are then developed to address the demand aspect of an energy-based seismic design of structures with 5% critical damping and ductility that ranges from 2 to 5. The proposed input and hysteretic energy spectra are then compared with response spectra generated using nonlinear time history analyses of real ground motions and are found to produce reasonably good results over a relatively large period range.

  18. Field-scale tracking of active methane-oxidizing communities in a landfill cover soil reveals spatial and seasonal variability.

    Science.gov (United States)

    Henneberger, Ruth; Chiri, Eleonora; Bodelier, Paul E L; Frenzel, Peter; Lüke, Claudia; Schroth, Martin H

    2015-05-01

    Aerobic methane-oxidizing bacteria (MOB) in soils mitigate methane (CH4 ) emissions. We assessed spatial and seasonal differences in active MOB communities in a landfill cover soil characterized by highly variable environmental conditions. Field-based measurements of CH4 oxidation activity and stable-isotope probing of polar lipid-derived fatty acids (PLFA-SIP) were complemented by microarray analysis of pmoA genes and transcripts, linking diversity and function at the field scale. In situ CH4 oxidation rates varied between sites and were generally one order of magnitude lower in winter compared with summer. Results from PLFA-SIP and pmoA transcripts were largely congruent, revealing distinct spatial and seasonal clustering. Overall, active MOB communities were highly diverse. Type Ia MOB, specifically Methylomonas and Methylobacter, were key drivers for CH4 oxidation, particularly at a high-activity site. Type II MOB were mainly active at a site showing substantial fluctuations in CH4 loading and soil moisture content. Notably, Upland Soil Cluster-gamma-related pmoA transcripts were also detected, indicating concurrent oxidation of atmospheric CH4 . Spatial separation was less distinct in winter, with Methylobacter and uncultured MOB mediating CH4 oxidation. We propose that high diversity of active MOB communities in this soil is promoted by high variability in environmental conditions, facilitating substantial removal of CH4 generated in the waste body.

  19. Soil moisture on Polish territory - comparison of satellite and ground-based measurements

    Science.gov (United States)

    Rojek, Edyta; Łukowski, Mateusz; Marczewski, Wojciech; Usowicz, Bogusław

    2014-05-01

    Assessment of water resources due to changing climatic conditions in time and space is still very uncertain. The territory of Poland has a limited resource of waters, occasionally resulting in small agricultural droughts. From the other side intense rainfalls, floods or run-offs, causing soil erosion are observed. Therefore, it is important to predict and prevent of this adverse phenomena. Huge spatial variability of soil moisture does not allow for accurate estimation of its distribution using ground-based measurements. SMOS soil moisture data are quite much inherently consistent in time and space, but their validation is still a challenge for further use in the climate and hydrology studies. This is the motivation for the research: to examine soil moisture from SMOS and ground based stations of the SWEX network held over eastern Poland. The presented results are related to changes of the soil moisture on regional scales for Poland in the period 2010-2013. Some results with SMOS L2 data are extended on continental scales for Europe. Time series from ground and satellite SMOS data sources were compared by regression methods. The region of Poland indicates clearly some genetic spatial distributions in weekly averaged values. In continental scales, the country territory contrasts evidently to Lithuania and in Polesie, and indicates seasonal cycling observed in archives and well known traditional records. The central part of Poland is repeatedly susceptible on droughts with soil moisture values ranging from about 0.02 to 0.20 m3 m-3. SMOS data allows on creating systematic drought data for Poland and watching annual changes, and differences to other drought services kept on national scales for agricultural purposes. We bound that drought susceptibility to the content of sand clay components and the land use there. Lack of rainfall in the late 2011 summer, caused a significant deficit of water in soil moisture content (below 0.05 m3 m-3) throughout the entire country

  20. Forest and grassland cover types reduce net greenhouse gas emissions from agricultural soils.

    Science.gov (United States)

    Baah-Acheamfour, Mark; Carlyle, Cameron N; Lim, Sang-Sun; Bork, Edward W; Chang, Scott X

    2016-11-15

    Western Canada's prairie region is extensively cultivated for agricultural production, which is a large source of greenhouse gas emissions. Agroforestry systems are common land uses across Canada, which integrate trees into the agricultural landscape and could play a substantial role in sequestering carbon and mitigating increases in atmospheric GHG concentrations. We measured soil CO2, CH4 and N2O fluxes and the global warming potential of microbe-mediated net greenhouse gas emissions (GWPm) in forest and herbland (areas without trees) soils of three agroforestry systems (hedgerow, shelterbelt and silvopasture) over two growing seasons (May through September in 2013 and 2014). We measured greenhouse gas fluxes and environmental conditions at 36 agroforestry sites (12 sites for each system) located along a south-north oriented soil/climate gradient of increasing moisture availability in central Alberta, Canada. The temperature sensitivity of soil CO2 emissions was greater in herbland (4.4) than in forest (3.1), but was not different among agroforestry systems. Over the two seasons, forest soils had 3.4% greater CO2 emission, 36% higher CH4 uptake, and 66% lower N2O emission than adjacent herbland soils. Combining the CO2 equivalents of soil CH4 and N2O fluxes with the CO2 emitted via heterotrophic (microbial) respiration, forest soils had a smaller GWPm than herbland soils (68 and 89kgCO2ha(-1), respectively). While emissions of total CO2 were silvopasture>hedgerow>shelterbelt, soils under silvopasture had 5% lower heterotrophic respiration, 15% greater CH4 uptake, and 44% lower N2O emission as compared with the other two agroforestry systems. Overall, the GWPm of greenhouse gas emissions was greater in hedgerow (88) and shelterbelt (85) than in the silvopasture system (76kgCO2ha(-1)). High GWPm in the hedgerow and shelterbelt systems reflects the greater contribution from the monoculture annual crops within these systems. Opportunities exist for reducing soil

  1. Effect of earthworms on the community structure of active methanotrophic bacteria in a landfill cover soil.

    Science.gov (United States)

    Héry, Marina; Singer, Andrew C; Kumaresan, Deepak; Bodrossy, Levente; Stralis-Pavese, Nancy; Prosser, Jim I; Thompson, Ian P; Murrell, J Colin

    2008-01-01

    In the United Kingdom, landfills are the primary anthropogenic source of methane emissions. Methanotrophic bacteria present in landfill biocovers can significantly reduce methane emissions via their capacity to oxidize up to 100% of the methane produced. Several biotic and abiotic parameters regulate methane oxidation in soil, such as oxygen, moisture, methane concentration and temperature. Earthworm-mediated bioturbation has been linked to an increase in methanotrophy in a landfill biocover soil (AC Singer et al., unpublished), but the mechanism of this trophic interaction remains unclear. The aims of this study were to determine the composition of the active methanotroph community and to investigate the interactions between earthworms and bacteria in this landfill biocover soil where the methane oxidation activity was significantly increased by the earthworms. Soil microcosms were incubated with 13C-CH4 and with or without earthworms. DNA and RNA were extracted to characterize the soil bacterial communities, with a particular emphasis on methanotroph populations, using phylogenetic (16S ribosomal RNA) and functional methane monooxygenase (pmoA and mmoX) gene probes, coupled with denaturing gradient-gel electrophoresis, clone libraries and pmoA microarray analyses. Stable isotope probing (SIP) using 13C-CH4 substrate allowed us to link microbial function with identity of bacteria via selective recovery of 'heavy' 13C-labelled DNA or RNA and to assess the effect of earthworms on the active methanotroph populations. Both types I and II methanotrophs actively oxidized methane in the landfill soil studied. Results suggested that the earthworm-mediated increase in methane oxidation rate in the landfill soil was more likely to be due to the stimulation of bacterial growth or activity than to substantial shifts in the methanotroph community structure. A Bacteroidetes-related bacterium was identified only in the active bacterial community of earthworm-incubated soil but

  2. PORE SIZE DISTRIBUTION AND SOIL HYDRO PHYSICAL PROPERTIES UNDER DIFFERENT TILLAGE PRACTICES AND COVER CROPS IN A TYPIC HAPLUSULT IN NORTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Halima Mohammed Lawal

    2017-05-01

    Full Text Available Tillage practices influence soil physical, chemical and biological qualities which in-turn alters plant growth and crop yield. In the Northern Guinea Savanna (NGS ecological zone of Nigeria, agricultural production is mainly constrained by low soil nutrient and water holding capacity, it is therefore, imperative to develop appropriate management practices that will give optimal soil hydro-physical properties for proper plant growth, effective soil and water management and environmental conservation. This study investigated the effect of three tillage practices (no till, reduced till and conventional till and four cover crops (Centrosema pascuorum, Macrotyloma uniflorum, Cucurbita maxima and Glyine max and a bare/control (no cover crop on some soil physical properties of a Typic Haplusult during the rainy seasons of 2011, 2012 and 2013 in Samaru, NGS ecological zone of Nigeria. The field trials were laid out in a split plot arrangement with tillage practices in the main plots and cover crops in the subplots, all treatments were replicated three times. Auger and core soil samples were collected at the end of each cropping season each year in three replicates from each treatment plot at four depths (0-5, 5-10, 10-15 and 15-20 cm. Particle size distribution, bulk density, total pore volume and water retention at various soil matric potentials were determined using standard methods. Data obtained were compared with optimum values and fitted into a RETC computer code for quantifying soil hydraulic behavior and physical quality. Results showed that different tillage practices had varied effect on soil physical properties. No-till had the highest water holding capacity at most suction points evaluated, it had 4.3 % and 12.9 % more soil moisture than the reduced till  and conventionally tilled systems across all matric potentials while Centrosema pascuorum (3.1% and Cucurbita maxima (5.5% were best among evaluated cover crops in retaining soil moisture

  3. The influence of rainfall and soil hydrology on pipeflow in steep pasture-covered hill country

    Science.gov (United States)

    Crozier, M.; Hardenbicker, U.; Pott, A.

    2003-04-01

    This study presents some real time measurements of stormflow occurring in soil pipes. The aim of the study is to measure pipeflow runoff characteristics, determine which factors control flow behaviour, and estimate the role of pipeflow in hillslope drainage. Storms of different magnitudes are compared to assess the changing role of hydrological processes feeding pipeflow. In the study area of Hawke's Bay, North Island, New Zealand permeable soils overly low permeability marine sediments to a depth of about 1.2 m. The study area is ser-viced by an automatic climate station and five nearby sites are equipped to measure soil tension and soil moisture (at depths of 25, 50, and 100cm) as well as porewater pressure throughout the profile. The pipeflow network investigated has a catchment area of 1219 m2 and exits the base of study slope just upslope of a landslide scar. A thin-walled, 20 degree 'v'-notch weir has been installed at the pipe exit with water depth recorded by a pressure transducer / data logger system. Pipeflow is ephemeral with twenty-nine discrete pipeflow events being recorded between July 2000 and November 2001 associated with rainfall events ranging in total between 5.4mm and 296 mm. The flow events are generally very small with volumes ranging from less than one litre to 70,000 litres. The five largest events have total volumes ranging from 168 - 70,356 litres with maximum discharges recorded at one minute intervals ranging from 965 - 83,264 ml/min. In all cases pipeflow commenced several hours before soil moisture began to rise at the position in the soil where pipes were located (50cm depth). This suggests that pipeflow is not the result of the wetting front from matrix flow intersecting the pipe. However in high magnitude prolonged events results indicate that matrix flow and groundwater may contribute to pipeflow. Time lags between onset of rain and pipeflow and delays in soil moisture response indicate that bypass flow rather than matrix flow

  4. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.</