Controlled soil warming powered by alternative energy for remote field sites.

Directory of Open Access Journals (Sweden)

Jill F Johnstone

Full Text Available Experiments using controlled manipulation of climate variables in the field are critical for developing and testing mechanistic models of ecosystem responses to climate change. Despite rapid changes in climate observed in many high latitude and high altitude environments, controlled manipulations in these remote regions have largely been limited to passive experimental methods with variable effects on environmental factors. In this study, we tested a method of controlled soil warming suitable for remote field locations that can be powered using alternative energy sources. The design was tested in high latitude, alpine tundra of southern Yukon Territory, Canada, in 2010 and 2011. Electrical warming probes were inserted vertically in the near-surface soil and powered with photovoltaics attached to a monitoring and control system. The warming manipulation achieved a stable target warming of 1.3 to 2 °C in 1 m(2 plots while minimizing disturbance to soil and vegetation. Active control of power output in the warming plots allowed the treatment to closely match spatial and temporal variations in soil temperature while optimizing system performance during periods of low power supply. Active soil heating with vertical electric probes powered by alternative energy is a viable option for remote sites and presents a low-disturbance option for soil warming experiments. This active heating design provides a valuable tool for examining the impacts of soil warming on ecosystem processes.

Comparison of different soil water extraction systems for the prognoses of solute transport at the field scale using numerical simulations, field and lysimeter experiments

Energy Technology Data Exchange (ETDEWEB)

Weihermueller, L

2005-07-01

To date, the understanding of processes, factors, and interactions that influence the amount of extracted water and the solute composition sampled with suction cups is limited. But this information is required for process description of solute transport in natural soils. Improved system understanding can lead to a low cost and easy to install water sampling system which can help to predict solute transport in natural soils for the benefit of environmental protection. The main objectives of this work were to perform numerical simulations with different boundary conditions and to implement the findings in the interpretation of the lysimeter and field experiments. In a first part of this thesis, theoretical considerations on the processes affecting the spatial influence of a suction cup in soil and changes in solute transport initiated by the suction cups are presented, including testing and validation of available model and experimental approaches. In the second part, a detailed experimental study was conducted to obtain data for the comparison of the different soil water sampling systems. Finally, the numerical experiments of the suction cup influence were used for the interpretation of the experimental data. The main goals are summarized as follows: - Characterization of the suction cup activity domain (SCAD), suction cup extraction domain (SCED) and suction cup sampling area (SCSA) of active suction cups (definitions are given in Chapter 6). - Determination of the boundary conditions and soil properties [e.g. infiltration, applied suction, duration of water extraction, soil hydraulic properties and soil heterogeneity] affecting the activity domain, extraction domain and sampling area of a suction cup. - Identification of processes that change the travel time and travel time variance of solutes extracted by suction cups. - Validation of the numerically derived data with analytical and experimental data from literature. - Comparison of the experimental data obtained

Relationships between soil parameters and vegetation in abandoned terrace fields vs. non-terraced fields in arid lands (Lanzarote, Spain): An opportunity for restoration

Science.gov (United States)

Arévalo, José Ramón; Fernández-Lugo, Silvia; Reyes-Betancort, J. Alfredo; Tejedor, Marisa; Jiménez, Concepción; Díaz, Francisco J.

2017-11-01

Over 90% of terraced fields have been abandoned on the island of Lanzarote in the last 40 years. The present work analyses the effects of abandonment on the soil and vegetation recovery of terraced field agroecosystems by comparing them with adjacent non-terraced fields in Lanzarote, Canary Islands (Spain). This information is necessary to take the appropriate management actions to achieve goals such as soil protection and biodiversity conservation. Results indicate that terraced fields display better soil quality than non-terraced ones, as shown by the significant differences found in parameters such as SAR, exchangeable Na, CaCO3, B content, moisture content or soil depth. Moreover, the terraced fields' plant community has more species similarities with the native plant community when compared with non-terraced areas. Owing to characteristics such as deeper soils, more water capacity, lower salinity and less sodic soils, terraced soils provide better conditions for passive restoration of both soil and vegetation. Therefore, the recovery and maintenance of wall structures and revegetation with native/endemic species are proposed to promote the restoration of native systems and preserve a landscape with cultural and aesthetic value.

Characterization of soil chemical properties of strawberry fields using principal component analysis

Directory of Open Access Journals (Sweden)

Gláucia Oliveira Islabão

2013-02-01

Full Text Available One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component analysis (PCA. Soil sampling was based on topography, dividing the field in three thirds: upper, middle and lower. From each of these thirds, five soil samples were randomly collected in the 0-0.20 m layer, to form a composite sample for each third. Four samples were taken during the strawberry cycle and the following properties were determined: soil organic matter (OM, soil total nitrogen (N, available phosphorus (P and potassium (K, exchangeable calcium (Ca and magnesium (Mg, soil pH (pH, cation exchange capacity (CEC at pH 7.0, soil base (V% and soil aluminum saturation(m%. No spatial variation was observed for any of the studied soil fertility parameters in the strawberry fields and temporal variation was only detected for available K. Phosphorus and K contents were always high or very high from the beginning of the strawberry cycle, while pH values ranged from very low to very high. Principal component analysis allowed the clustering of all strawberry fields based on variables related to soil acidity and organic matter content.

Effects of plastic mulches and high tunnel raspberry production systems on soil physicochemical quality indicators

Science.gov (United States)

Domagała-Świątkiewicz, Iwona; Siwek, Piotr

2018-01-01

In horticulture, degradable materials are desirable alternatives to plastic films. Our aim was to study the impact of soil plastic mulching on the soil properties in the high tunnel and open field production systems of raspberry. The raised beds were mulched with a polypropylene non-woven and two degradable mulches: polypropylene with a photodegradant and non-woven polylactide. The results indicated that the system of raspberry production, as well as the type of mulching had significant impact on soil organic carbon stock, moisture content and water stable aggregate amount. Soils taken from the open field system had a lower bulk density and water stability aggregation index, but higher organic carbon and capillary water content as compared to soils collected from high tunnel conditions. In comparison with the open field system, soil salinity was also found to be higher in high tunnel, as well as with higher P, Mg, Ca, S, Na and B content. Furthermore, mulch covered soils had more organic carbon amount than the bare soils. Soil mulching also enhanced the water capacity expressed as a volume of capillary water content. In addition, mulching improved the soil structure in relation to the bare soil, in particular, in open field conditions. The impact of the compared mulches on soil quality indicators was similar.

Inter-Annual Variability of Soil Moisture Stress Function in the Wheat Field

Science.gov (United States)

Akuraju, V. R.; Ryu, D.; George, B.; Ryu, Y.; Dassanayake, K. B.

2014-12-01

Root-zone soil moisture content is a key variable that controls the exchange of water and energy fluxes between land and atmosphere. In the soil-vegetation-atmosphere transfer (SVAT) schemes, the influence of root-zone soil moisture on evapotranspiration (ET) is parameterized by the soil moisture stress function (SSF). Dependence of actual ET: potential ET (fPET) or evaporative fraction to the root-zone soil moisture via SSF can also be used inversely to estimate root-zone soil moisture when fPET is estimated by remotely sensed land surface states. In this work we present fPET versus available soil water (ASW) in the root zone observed in the experimental farm sites in Victoria, Australia in 2012-2013. In the wheat field site, fPET vs ASW exhibited distinct features for different soil depth, net radiation, and crop growth stages. Interestingly, SSF in the wheat field presented contrasting shapes for two cropping years of 2012 and 2013. We argue that different temporal patterns of rainfall (and resulting soil moisture) during the growing seasons in 2012 and 2013 are responsible for the distinctive SSFs. SSF of the wheat field was simulated by the Agricultural Production Systems sIMulator (APSIM). The APSIM was able to reproduce the observed fPET vs. ASW. We discuss implications of our findings for existing modeling and (inverse) remote sensing approaches relying on SSF and alternative growth-stage-dependent SSFs.

Soil erodibility variability in laboratory and field rainfall simulations

Science.gov (United States)

Szabó, Boglárka; Szabó, Judit; Jakab, Gergely; Centeri, Csaba; Szalai, Zoltán

2017-04-01

Rainfall simulation experiments are the most common way to observe and to model the soil erosion processes in in situ and ex situ circumstances. During modelling soil erosion, one of the most important factors are the annual soil loss and the soil erodibility which represent the effect of soil properties on soil loss and the soil resistance against water erosion. The amount of runoff and soil loss can differ in case of the same soil type, while it's characteristics determine the soil erodibility factor. This leads to uncertainties regarding soil erodibility. Soil loss and soil erodibility were examined with the investigation of the same soil under laboratory and field conditions with rainfall simulators. The comparative measurement was carried out in a laboratory on 0,5 m2, and in the field (Shower Power-02) on 6 m2 plot size where the applied slope angles were 5% and 12% with 30 and 90 mm/h rainfall intensity. The main idea was to examine and compare the soil erodibility and its variability coming from the same soil, but different rainfall simulator type. The applied model was the USLE, nomograph and other equations which concern single rainfall events. The given results show differences between the field and laboratory experiments and between the different calculations. Concerning for the whole rainfall events runoff and soil loss, were significantly higher at the laboratory experiments, which affected the soil erodibility values too. The given differences can originate from the plot size. The main research questions are that: How should we handle the soil erodibility factors and its significant variability? What is the best solution for soil erodibility determination?

Implications of soil mixing for NAPL source zone remediation: Column studies and modeling of field-scale systems.

Science.gov (United States)

Olson, Mitchell R; Sale, Tom C

2015-01-01

Soil remediation is often inhibited by subsurface heterogeneity, which constrains contaminant/reagent contact. Use of soil mixing techniques for reagent delivery provides a means to overcome contaminant/reagent contact limitations. Furthermore, soil mixing reduces the permeability of treated soils, thus extending the time for reactions to proceed. This paper describes research conducted to evaluate implications of soil mixing on remediation of non-aqueous phase liquid (NAPL) source zones. The research consisted of column studies and subsequent modeling of field-scale systems. For column studies, clean influent water was flushed through columns containing homogenized soils, granular zero valent iron (ZVI), and trichloroethene (TCE) NAPL. Within the columns, NAPL depletion occurred due to dissolution, followed by either column-effluent discharge or ZVI-mediated degradation. Complete removal of TCE NAPL from the columns occurred in 6-8 pore volumes of flow. However, most of the TCE (>96%) was discharged in the column effluent; less than 4% of TCE was degraded. The low fraction of TCE degraded is attributed to the short hydraulic residence time (10 m) and reducing permeability by one-or-more orders of magnitude, the residence time could be greatly extended, potentially for periods of years to decades. Model output indicates that the fraction of TCE degraded can be increased to >99.9%, given typical post-mixing soil permeability values. These results suggest that remediation performance can be greatly enhanced by combining contaminant degradation with an extended residence time. Copyright © 2015 Elsevier B.V. All rights reserved.

Mulching as a strategy to improve soil properties and reduce soil erodibility in coffee farming systems of Rwanda

NARCIS (Netherlands)

Nzeyimana, I.; Hartemink, A.E.; Ritsema, C.J.; Stroosnijder, L.; Huerta Lwanga, Esperanza; Geissen, V.

2017-01-01

In Rwanda, mulch is applied in coffee fields to control soil erosion. The objective of this paper is to quantify the effects of different types of mulch on soil properties and soil erodibility in coffee farming systems in three different agro-ecological zones of the highlands of Rwanda. The

A method to assess soil erosion from smallholder farmers' fields: a case study from Malawi.

Science.gov (United States)

Mohamoud, Yusuf M

2013-09-01

Soil erosion by water is a major threat to sustainable food production systems in Africa. This study presents a qualitative soil erosion assessment method that links the number of broken ridges (NBRS) observed on a smallholder farmer's field after a rain event to factors of soil erosion (e.g., rainfall intensity, slope steepness, crop canopy height, and conservation practice) and to soil loss data measured from a runoff plot and receiving small streams. The assessment method consists of a rapid survey of smallholder farmers combined with field monitoring. Results show an indirect relationship between NBRS and factors of soil erosion. Results also show a direct relationship between NBRS and suspended sediment concentrations measured from an experimental runoff plot and receiving streams that drain the sub-watersheds where farmers' fields are located. Given the limited human and financial resources available to soil erosion research in developing countries, monitoring NBRS is a simple, cost-effective, and reliable erosion assessment method for regions where smallholder farmers practice contour ridging.

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

A sensor array system for monitoring moisture dynamics inunsaturated soil

Energy Technology Data Exchange (ETDEWEB)

Salve, R.; Cook, P.J.

2007-05-15

To facilitate investigations of moisture dynamics inunsaturated soil, we have developed a technique to qualitatively monitorpatterns of saturation changes. Field results suggest that this device,the sensor array system (SAS), is suitable for determining changes inrelative wetness along vertical soil profiles. The performance of theseprobes was compared with that of the time domain reflectometry (TDR)technique under controlled and field conditions. Measurements from bothtechniques suggest that by obtaining data at high spatial and temporalresolution, the SAS technique was effective in determining patterns ofsaturation changes along a soil profile. In addition, hardware used inthe SAS technique was significantly cheaper than the TDR system, and thesensor arrays were much easier to install along a soilprofile.

FUELS IN SOIL TEST KIT: FIELD USE OF DIESEL DOG SOIL TEST KITS

Energy Technology Data Exchange (ETDEWEB)

Susan S. Sorini; John F. Schabron; Joseph F. Rovani, Jr.

2002-09-30

Western Research Institute (WRI) has developed a new commercial product ready for technology transfer, the Diesel Dog{reg_sign} Portable Soil Test Kit, for performing analysis of fuel-contaminated soils in the field. The technology consists of a method developed by WRI (U.S. Patents 5,561,065 and 5,976,883) and hardware developed by WRI that allows the method to be performed in the field (patent pending). The method is very simple and does not require the use of highly toxic reagents. The aromatic components in a soil extract are measured by absorption at 254 nm with a field-portable photometer. WRI added significant value to the technology by taking the method through the American Society for Testing and Materials (ASTM) approval and validation processes. The method is designated as ASTM Method D 5831-96, Standard Test Method for Screening Fuels in Soils. This ASTM designation allows the method to be used for federal compliance activities. In June 2001, the Diesel Dog technology won an American Chemical Society Regional Industrial Innovations Award. To gain field experience with the new technology, Diesel Dog kits have been used for a variety of site evaluation and cleanup activities. Information gained from these activities has led to improvements in hardware configurations and additional insight into correlating Diesel Dog results with results from laboratory methods. The Wyoming Department of Environmental Quality (DEQ) used Diesel Dog Soil Test Kits to guide cleanups at a variety of sites throughout the state. ENSR, of Acton, Massachusetts, used a Diesel Dog Portable Soil Test Kit to evaluate sites in the Virgin Islands and Georgia. ChemTrack and the U.S. Army Corps of Engineers successfully used a test kit to guide excavation at an abandoned FAA fuel-contaminated site near Fairbanks, Alaska. Barenco, Inc. is using a Diesel Dog Portable Soil Test Kit for site evaluations in Canada. A small spill of diesel fuel was cleaned up in Laramie, Wyoming using a Diesel

Computation of wave fields and soil structure interaction

International Nuclear Information System (INIS)

Lysmer, J.W.

1982-01-01

The basic message of the lecture is that the determination of the temporal and spatial variation of the free-field motions is the most important part of any soil-structure interaction analysis. Any interaction motions may be considered as small aberrations superimposed on the free-field motions. The current definition of the soil-structure interaction problem implies that superposition must be used, directly or indirectly, in any rational method of analysis of this problem. This implies that the use of nonlinear procedures in any part of a soil-structure interaction analysis must be questioned. Currently the most important part of the soil-structure interaction analysis, the free-field problem, cannot be solved by nonlinear methods. Hence, it does not seem reasonable to spend a large effort on trying to obtain nonlinear solutions for the interaction part of the problem. Even if such solutions are obtained they cannot legally be superimposed on the free-field motions to obtain the total motions of the structure. This of course does not preclude the possibility that such an illegal procedure may lead to solutions which are close enough for engineering purposes. However, further research is required to make a decision on this issue

Improvements of the Profil Cultural Method for a better Low-tech Field Assessment of Soil Structure under no-till

Science.gov (United States)

Roger-Estrade, Jean; Boizard, Hubert; Peigné, Josephine; Sasal, Maria Carolina; Guimaraes, Rachel; Piron, Denis; Tomis, Vincent; Vian, Jean-François; Cadoux, Stephane; Ralisch, Ricardo; Filho, Tavares; Heddadj, Djilali; de Battista, Juan; Duparque, Annie

2016-04-01

In France, agronomists have studied the effects of cropping systems on soil structure, using a field method based on a visual description of soil structure. The "profil cultural" method (Manichon and Gautronneau, 1987) has been designed to perform a field diagnostic of the effects of tillage and compaction on soil structure dynamics. This method is of great use to agronomists improving crop management for a better preservation of soil structure. However, this method was developed and mainly used in conventional tillage systems, with ploughing. As several forms of reduced, minimum and no tillage systems are expanding in many parts of the world, it is necessary to re-evaluate the ability of this method to describe and interpret soil macrostructure in unploughed situations. In unploughed fields, soil structure dynamics of untilled layers is mainly driven by compaction and regeneration by natural agents (climatic conditions, root growth and macrofauna) and it is of major importance to evaluate the importance of these natural processes on soil structure regeneration. These concerns have led us to adapt the standard method and to propose amendments based on a series of field observations and experimental work in different situations of cropping systems, soil types and climatic conditions. We improved the description of crack type and we introduced an index of biological activity, based on the visual examination of clods. To test the improved method, a comparison with the reference method was carried out and the ability of the "profil cultural" method to make a diagnosis was tested on five experiments in France, Brazil and Argentina. Using the improved method, the impact of cropping systems on soil functioning was better assessed when natural processes were integrated into the description.

Tillage System and Cover Crop Effects on Soil Quality

DEFF Research Database (Denmark)

Abdollahi, Lotfollah; Munkholm, Lars Juhl

2014-01-01

), 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......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...

Sampling Design of Soil Physical Properties in a Conilon Coffee Field

Directory of Open Access Journals (Sweden)

Eduardo Oliveira de Jesus Santos

Full Text Available ABSTRACT Establishing the number of samples required to determine values of soil physical properties ultimately results in optimization of labor and allows better representation of such attributes. The objective of this study was to analyze the spatial variability of soil physical properties in a Conilon coffee field and propose a soil sampling method better attuned to conditions of the management system. The experiment was performed in a Conilon coffee field in Espírito Santo state, Brazil, under a 3.0 × 2.0 × 1.0 m (4,000 plants ha-1 double spacing design. An irregular grid, with dimensions of 107 × 95.7 m and 65 sampling points, was set up. Soil samples were collected from the 0.00-0.20 m depth from each sampling point. Data were analyzed under descriptive statistical and geostatistical methods. Using statistical parameters, the adequate number of samples for analyzing the attributes under study was established, which ranged from 1 to 11 sampling points. With the exception of particle density, all soil physical properties showed a spatial dependence structure best fitted to the spherical model. Establishment of the number of samples and spatial variability for the physical properties of soils may be useful in developing sampling strategies that minimize costs for farmers within a tolerable and predictable level of error.

Effect of long-term organic fertilization on the soil pore characteristics of greenhouse vegetable fields converted from rice-wheat rotation fields.

Science.gov (United States)

Xu, L Y; Wang, M Y; Shi, X Z; Yu, Q B; Shi, Y J; Xu, S X; Sun, W X

2018-08-01

The shift from rice-wheat rotation (RWR) to greenhouse vegetable soils has been widely practiced in China. Several studies have discussed the changes in soil properties with land-use changes, but few studies have sought to address the differences in soil pore properties, especially for fields based on long-term organic fertilization under greenhouse vegetable system from RWR fields. This study uses the X-ray computed tomography (CT) scanning and statistical analysis to compare the long-term effects of the conversion of organic greenhouse vegetable fields (over one year, nine years, and fourteen years) from RWR fields on the soil macropore structure as well as the influencing factors from samples obtained in Nanjing, Jiangsu, China, using the surface soil layer and triplicate samples. The results demonstrated that the macropore structure became more complex and stable, with a higher connectivity, fractal dimension (FD) and a lower degree of anisotropy (DA), as the greenhouse vegetable planting time increased. The total topsoil macroporosity increased considerably, but the rate of increase gradually decelerated with time. The transmission pores (round pores ranging from 50 to 500μm) increased with time, but the biopores (>2000μm) clearly decreased after nine years of use as greenhouse vegetable fields. Soil organic matter (OM) has a significant relationship with the soil pore structure characteristics, especially for the transmission pores. In addition, organic fertilization on the topsoil had a short-term effect on the pores, but the effect stabilized and had a weak influence on the pores over longer periods. These results suggested that organic fertilization was conducive for controlling soil degradation regarding it physical quality for water and oxygen availability in the short term. Copyright © 2018 Elsevier B.V. All rights reserved.

Reflecting on the structure of soil classification systems: insights from a proposal for integrating subsoil data into soil information systems

Science.gov (United States)

Dondeyne, Stefaan; Juilleret, Jérôme; Vancampenhout, Karen; Deckers, Jozef; Hissler, Christophe

2017-04-01

Classification of soils in both World Reference Base for soil resources (WRB) and Soil Taxonomy hinges on the identification of diagnostic horizons and characteristics. However as these features often occur within the first 100 cm, these classification systems convey little information on subsoil characteristics. An integrated knowledge of the soil, soil-to-substratum and deeper substratum continuum is required when dealing with environmental issues such as vegetation ecology, water quality or the Critical Zone in general. Therefore, we recently proposed a classification system of the subsolum complementing current soil classification systems. By reflecting on the structure of the subsoil classification system which is inspired by WRB, we aim at fostering a discussion on some potential future developments of WRB. For classifying the subsolum we define Regolite, Saprolite, Saprock and Bedrock as four Subsolum Reference Groups each corresponding to different weathering stages of the subsoil. Principal qualifiers can be used to categorize intergrades of these Subsoil Reference Groups while morphologic and lithologic characteristics can be presented with supplementary qualifiers. We argue that adopting a low hierarchical structure - akin to WRB and in contrast to a strong hierarchical structure as in Soil Taxonomy - offers the advantage of having an open classification system avoiding the need for a priori knowledge of all possible combinations which may be encountered in the field. Just as in WRB we also propose to use principal and supplementary qualifiers as a second level of classification. However, in contrast to WRB we propose to reserve the principal qualifiers for intergrades and to regroup the supplementary qualifiers into thematic categories (morphologic or lithologic). Structuring the qualifiers in this manner should facilitate the integration and handling of both soil and subsoil classification units into soil information systems and calls for paying

A field method for soil erosion measurements in agricultural and natural lands

Science.gov (United States)

Y.P. Hsieh; K.T. Grant; G.C. Bugna

2009-01-01

Soil erosion is one of the most important watershed processes in nature, yet quantifying it under field conditions remains a challenge. The lack of soil erosion field data is a major factor hindering our ability to predict soil erosion in a watershed. We present here the development of a simple and sensitive field method that quantifies soil erosion and the resulting...

Content Of 2,4-D-14C Herbicide Residue In Water And Soil Of Irrigated Rice Field System

International Nuclear Information System (INIS)

Chairul, Sofnie M.; Djabir, Elida; Magdalena, Nelly

2000-01-01

The investigation of 2,4-D exp.-14C herbicide residue in water and soil of irrigated rice field system was carried out. Rice plant and weeds (Monochoria vaginalis Burn. F. Presl) were planted in 101 buckets using two kinds of soil condition, I.e. normal soil and 30 % above normal compact soil. After one week planting, the plants were sprayed with 1 u Ci of 2,4-D exp.-14C and 0,4 mg non labeled 2,4-D. The herbicide residue content was determined 0, 2, 4, 8 and 10 weeks after spraying with 2,4-D herbicide. The analysis was done using Combustion Biological Oxidizer merk Harvey ox-400, and counted with Liquid Scintillation Counter merk Beckman model LS-1801. The results indicates that the herbicide contents in water and soil decrease from the first spraying with herbicide until harvest herbicide Residue content in water after harvest was 0.87 x 10 exp.-6 ppm for soil normal condition, and 0.59 x 10 exp.-6 pm for the soil 30 % up normal condition, while herbicide content in soil was 1.54 x 10 exp.-6 ppm for soil normal condition and 1.48 x 10 exp.-6 ppm for soil 30 % up normal. 2,4-D herbicide residue content in rice after harvest was 0.27 x 10 exp.-6 ppm for normal soil condition and 0.25 x 10 exp.-6 ppm for the soil 30 % up normal. 2,4-D herbicide residue content in roots and leaves of weeds after harvest were respectively 0.29 x 10 exp.-6 ppm and 0.18 x 10 exp.-6 for normal soil condition, while for 30 % up normal soil were 0.25 x 10 exp.-5 ppm and 0.63 x 10 exp.-7 ppm. This result indicates that there is no effect pollution to surrounding area, because the herbicide content is still bellow the allowed detection limit, 0.05 ppm

Air encapsulation. I. Measurement in a field soil

International Nuclear Information System (INIS)

Fayer, M.J.; Hillel, D.

1986-01-01

Encapsulated air is an important component of shallow water table fluctuations. Their objective was to measure the quantity and persistence of encapsulated air in a field setting. Using sprinkling rates of either 3.5 x 10 -6 or 3.8 x 10 -5 m s -1 , they brought the water table in a field soil from a depth of 1.5 m to the surface on several occasions. Moisture contents during and after sprinkling were monitored with a neutron probe. Twice following sprinkling, the water table was maintained at the surface for more than 20 d, during which time they continued to monitor moisture contents. With the water table at the surface, differences between the porosity and the measured moisture content were attributed to encapsulated air. Encapsulated air contents ranged from 1.1 to 6.3% of the bulk soil volume, depending on the rate of sprinkling, soil depth, and initial soil moisture content. During ponding, encapsulated air persisted at the 0.3-m depth for up to 28 d. The results indicate that encapsulated air is measurable in a field situation and that its quantity and persistence should be considered in analyzing the results of similar field experiments. 16 references

Evaluating lysimeter drainage against soil deep percolation modeled with profile soil moisture, field tracer propagation, and lab measured soil hydraulic properties

DEFF Research Database (Denmark)

Vasquez, Vicente; Thomsen, Anton Gårde; Iversen, Bo Vangsø

them have been reported. To compare among methods, one year of four large-scale lysimeters drainage (D) was evaluated against modeled soil deep percolation using either profile soil moisture, bromide breakthrough curves from suction cups, or measured soil hydraulic properties in the laboratory....... Measured volumetric soil water content (q) was 3-4% higher inside lysimeters than in the field probably due to a zero tension lower boundary condition inside lysimeters. D from soil hydraulic properties measured in the laboratory resulted in a 15% higher evapotranspiration and 12% lower drainage...... predictions than the model calibrated with field measured q. Bromide (Br) breakthrough curves indicated high variability between lysimeters and field suction cups with mean Br velocities at first arrival time of 110 and 33 mm/d, respectively. D was 520 mm/yr with lysimeters, 613 mm/yr with the calibrated...

A soil-specific agro-ecological strategy for sustainable production in Argentina farm fields

Science.gov (United States)

Zamora, Martin; Barbera, Agustin; Castro-Franco, Mauricio; Hansson, Alejandro; Domenech, Marisa

2017-04-01

The continuous increment of frequencies and doses of pesticides, glyphosate and fertilizers, the deterioration of the structure, biotic balance and fertility of soils and the ground water pollution are characteristics of the current Argentinian agricultural model. In this context, agro-ecological innovations are needed to develop a real sustainable agriculture, enhancing the food supply. Precision agriculture technologies can strengthen the expansion of agro-ecological farming in experimental farm fields. The aim of this study was to propose a soil-specific agro-ecological strategy for sustainable production at field scale focused on the use of soil sensors and digital soil mapping techniques. This strategy has been developed in 15 hectares transition agro-ecological farm field, located at Barrow Experimental Station (Lat:-38.322844, Lon:-60.25572) Argentina. The strategy included five steps: (i) to measure apparent electrical conductivity (ECa) and elevation within agro-ecological farm field; (ii) to apply a clustering method using MULTISPATI-PCA algorithm to delimitate three soil-specific zones (Z1, Z2 and Z3); (iii) to determine three soil sampling points by zone, using conditioned Latin hypercube method, in addition to elevation and ECa as auxiliary information; (iv) to collect soil samples at 2-10 cm depth in each point and to determine in laboratory: total organic carbon content (TOC), cation-exchange capacity (CEC), pH and phosphorus availability (P-Bray). In addition, soil bulk density (SBD) was measured at 0-20 cm depth. Finally, (v) according to each soil-specific zone, a management strategy was recommended. Important differences in soil properties among zones could suggest that the strategy developed was able to apply an agro ecological soil-specific practice management. pH and P-Bray were significantly (pfertilizer and also rotating plots with high stocking rate. The aim is to increase soil organic matter content and CEC. Furthermore, P content will be

MAPPING OF SOIL DEGRADATION POTENCY IN PADDY FIELD WONOGIRI, INDONESIA

Directory of Open Access Journals (Sweden)

Mujiyo

2016-06-01

Full Text Available Sustainability of paddy field becomes the main concern as the media of biomass production, thus it is needed a datum and information about land characteristics to find out its degradation. Mapping of soil degradation potency in paddy field is an identification of initial soil condition to discover the land degradation potency. Mapping was done by overlaying map of soil, slope, rainfall and land use with standard procedures to obtain its value and status of soil degradation potency. Area mapping is an effective land for biomass production (natural forest, mixed farm, savanna, paddy field, shrub and dry field with approximately 43,291.00 hectares (ha in Sidoharjo, Girimarto, Jatipurno, Jatisrono, Jatiroto, Tirtomoyo, Nguntoronadi and Ngadirojo District. The result shows that soil degradation potency (SDP in Districts of Sidoharjo, Girimarto, Jatipurno, Jatisrono, Jatiroto, Tirtomoyo, Nguntoronadi and Ngadirojo are very low, low (DP II 20,702.47 ha (47.82%, moderate (DP III 15,823.80 ha (36,55% and high (DP IV 6,764.73 ha (15.63%. Paddy field covered 22,036.26 ha or about 50.90% of all area as effective biomass production, its SDP considers as low (DP II 16,021.04 ha (37.01% and moderate (DP III 6,015.22 ha (13,89%. Paddy field has a low SDP because it is commonly lies on flat area and conservation method by the farmer is maintaining the paddy bund and terrace. This study needs an advanced study to identify actual SDP through detail verification in the field, and also support by soil sample analysis in the laboratory.

Field soil-water properties measured through radiation techniques

International Nuclear Information System (INIS)

1984-07-01

This report shows a major effort to make soil physics applicable to the behaviour of the field soils and presents a rich and diverse set of data which are essential for the development of effective soil-water management practices that improve and conserve the quality and quantity of agricultural lands. This piece of research has shown that the neutron moisture meter together with some complementary instruments like tensiometers, can be used not only to measure soil water contents but also be extremely handy to measure soil hydraulic characteristics and soil water flow. It is, however, recognized that hydraulic conductivity is highly sensitive to small changes in soil water content and texture, being extremely variable spatially and temporally

Laboratory tests on sorption and transformation of the insecticide flubendiamide in Japanese tea field soil

Energy Technology Data Exchange (ETDEWEB)

Hartung, Susen [Technische Universität Braunschweig, Institute of Environmental and Sustainable Chemistry, Hagenring 30, 38106 Braunschweig (Germany); Iwasaki, Masahide; Ogawa, Naoto [Shizuoka University, Faculty of Agriculture, Department of Biological and Environmental Science, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Kreuzig, Robert, E-mail: r.kreuzig@tu-bs.de [Technische Universität Braunschweig, Institute of Environmental and Sustainable Chemistry, Hagenring 30, 38106 Braunschweig (Germany)

2013-01-15

Flubendiamide belongs to the modern insecticides applied in Japanese tea cultivation to control smaller tea tortrix and tea leaf roller. Since fate and behavior in soil have been only monitored sparsely and fragmentarily until today, laboratory tests were performed on sorption, leaching, biotransformation and photo-induced biotransformation of flubendiamide in two different soils. In batch equilibrium tests, K{sub d} and K{sub OC} values were 15 and 298 L kg{sup −1} for the Japanese tea field soil as well as 16 and 1610 L kg{sup −1} for the German arable field soil classifying flubendiamide to be moderately mobile and slightly mobile, respectively. The affinity to the tea field soil was additionally confirmed by soil column tests where flubendiamide was predominantly retarded in the topsoil layers resulting in a percolate contamination of only 0.002 mg L{sup −1}. In the aerobic biotransformation tests, flubendiamide did not substantially disappear within the 122-d incubation period. Due to DT{sub 50} > 122 d, flubendiamide was assessed very persistent. Supplementary, photo-induced impacts on biotransformation were studied in a special laboratory irradiation system. Despite a 14-d irradiation period, photo-induced biotransformation in the tea field soil was not identifiable, neither by HPLC/DAD nor by LC/MS/MS. 3-d irradiation tests in photosensibilizing acetone, however, showed that the primary photo-transformation product desiodo-flubendiamide was formed. How far this photochemical reaction may also occur in soil of perennial tea plant stands, however, has to be checked in field studies. - Highlights: ► Laboratory tests on sorption, leaching, microbial and photo-induced microbial transformation were performed. ► Strong sorption was revealed by batch equilibrium and column tests. ► High persistence was found in aerobic biotransformation tests. ► An enhanced biotransformation by photo-induced impacts could not be confirmed. ► Field studies are

Laboratory tests on sorption and transformation of the insecticide flubendiamide in Japanese tea field soil

International Nuclear Information System (INIS)

Hartung, Susen; Iwasaki, Masahide; Ogawa, Naoto; Kreuzig, Robert

2013-01-01

Flubendiamide belongs to the modern insecticides applied in Japanese tea cultivation to control smaller tea tortrix and tea leaf roller. Since fate and behavior in soil have been only monitored sparsely and fragmentarily until today, laboratory tests were performed on sorption, leaching, biotransformation and photo-induced biotransformation of flubendiamide in two different soils. In batch equilibrium tests, K d and K OC values were 15 and 298 L kg −1 for the Japanese tea field soil as well as 16 and 1610 L kg −1 for the German arable field soil classifying flubendiamide to be moderately mobile and slightly mobile, respectively. The affinity to the tea field soil was additionally confirmed by soil column tests where flubendiamide was predominantly retarded in the topsoil layers resulting in a percolate contamination of only 0.002 mg L −1 . In the aerobic biotransformation tests, flubendiamide did not substantially disappear within the 122-d incubation period. Due to DT 50 > 122 d, flubendiamide was assessed very persistent. Supplementary, photo-induced impacts on biotransformation were studied in a special laboratory irradiation system. Despite a 14-d irradiation period, photo-induced biotransformation in the tea field soil was not identifiable, neither by HPLC/DAD nor by LC/MS/MS. 3-d irradiation tests in photosensibilizing acetone, however, showed that the primary photo-transformation product desiodo-flubendiamide was formed. How far this photochemical reaction may also occur in soil of perennial tea plant stands, however, has to be checked in field studies. - Highlights: ► Laboratory tests on sorption, leaching, microbial and photo-induced microbial transformation were performed. ► Strong sorption was revealed by batch equilibrium and column tests. ► High persistence was found in aerobic biotransformation tests. ► An enhanced biotransformation by photo-induced impacts could not be confirmed. ► Field studies are necessary to elucidate fate and

Measurement of trifluralin volatilization in the field: Relation to soil residue and effect of soil incorporation

International Nuclear Information System (INIS)

Bedos, C.; Rousseau-Djabri, M.F.; Gabrielle, B.; Flura, D.; Durand, B.; Barriuso, E.; Cellier, P.

2006-01-01

Volatilization may represent a major dissipation pathway for pesticides applied to soils or crops. A field experiment (September, 2002), consisted in volatilization fluxes measurements during 6 days, covering the periods before and after soil incorporation carried out 24 h after trifluralin spraying on bare soil. Evolution of concentration in soil was measured during 101 days, together with soil physical and meteorological variables. Volatilization fluxes were very high immediately after application (1900 ng m -2 s -1 ), decreased down to 100 ng m -2 s -1 in the following 24 h. Soil incorporation strongly abated trifluralin concentration in the air. 99% of the total volatilization losses recorded over the 6 days following application occurred before incorporation. Volatilization fluxes evidenced a diurnal cycle driven by environmental conditions. Soil trifluralin residues could still be quantified 101 days after application. Our results highlight the caution required when using soil degradation half-life values in the field for volatile compounds. - Losses by volatilization contribute significantly to soil dissipation of the herbicide trifluralin before its soil incorporation

Soil quality assessment in rice production systems: establishing a minimum data set.

NARCIS (Netherlands)

Rodrigues de Lima, A.C.; Hoogmoed, W.B.; Brussaard, L.

2008-01-01

Soil quality, as a measure of the soil's capacity to function, can be assessed by indicators based on physical, chemical, and biological properties. Here we report on the assessment of soil quality in 21 rice (Oryza sativa) fields under three rice production systems (semi-direct, pre-germinated, and

Australian Soil Moisture Field Experiments in Support of Soil Moisture Satellite Observations

Science.gov (United States)

Kim, Edward; Walker, Jeff; Rudiger, Christopher; Panciera, Rocco

2010-01-01

Large-scale field campaigns provide the critical fink between our understanding retrieval algorithms developed at the point scale, and algorithms suitable for satellite applications at vastly larger pixel scales. Retrievals of land parameters must deal with the substantial sub-pixel heterogeneity that is present in most regions. This is particularly the case for soil moisture remote sensing, because of the long microwave wavelengths (L-band) that are optimal. Yet, airborne L-band imagers have generally been large, heavy, and required heavy-lift aircraft resources that are expensive and difficult to schedule. Indeed, US soil moisture campaigns, have been constrained by these factors, and European campaigns have used non-imagers due to instrument and aircraft size constraints. Despite these factors, these campaigns established that large-scale soil moisture remote sensing was possible, laying the groundwork for satellite missions. Starting in 2005, a series of airborne field campaigns have been conducted in Australia: to improve our understanding of soil moisture remote sensing at large scales over heterogeneous areas. These field data have been used to test and refine retrieval algorithms for soil moisture satellite missions, and most recently with the launch of the European Space Agency's Soil Moisture Ocean Salinity (SMOS) mission, to provide validation measurements over a multi-pixel area. The campaigns to date have included a preparatory campaign in 2005, two National Airborne Field Experiments (NAFE), (2005 and 2006), two campaigns to the Simpson Desert (2008 and 2009), and one Australian Airborne Cal/val Experiment for SMOS (AACES), just concluded in the austral spring of 2010. The primary airborne sensor for each campaign has been the Polarimetric L-band Microwave Radiometer (PLMR), a 6-beam pushbroom imager that is small enough to be compatible with light aircraft, greatly facilitating the execution of the series of campaigns, and a key to their success. An

IDENTIFICATION OF FREE-FIELD SOIL PROPERTIES USING NUPEC RECORDED GROUND MOTIONS

International Nuclear Information System (INIS)

Xu, J.; Costantino, C.; Hofmayer, C.; Murphy, A.; Chokshi, N.; Kitada, Y.

2001-01-01

Over the past twenty years, the Nuclear Power Engineering Corporation (NUPEC) of Japan has conducted a series of field model test programs to investigate various aspects of soil-structure interaction (SSI) effects on nuclear power plant structures, including embedment and dynamic structure-soil-structure interaction (SSSI) effects. As part of a collaborative agreement between the US Nuclear Regulatory Commission (NRC) and NUPEC, Brookhaven National Laboratory (BNL) performed a numerical analysis to predict the free field soil profile using industry standard methods and the recorded free field responses to actual earthquake events. This paper describes the BNL free-field analyses, including the methods and the analysis results and their comparison to recorded data in the free field. The free-field soil profiles determined from the BNL analyses are being used for both the embedment and SSSI studies, the results of which will be made available upon their completion

Spatial Variability of Physical Soil Quality Index of an Agricultural Field

Directory of Open Access Journals (Sweden)

Sheikh M. Fazle Rabbi

2014-01-01

Full Text Available A field investigation was carried out to evaluate the spatial variability of physical indicators of soil quality of an agricultural field and to construct a physical soil quality index (SQIP map. Surface soil samples were collected using 10  m×10 m grid from an Inceptisol on Ganges Tidal Floodplain of Bangladesh. Five physical soil quality indicators, soil texture, bulk density, porosity, saturated hydraulic conductivity (KS, and aggregate stability (measured as mean weight diameter, MWD were determined. The spatial structures of sand, clay, and KS were moderate but the structure was strong for silt, bulk density, porosity, and MWD. Each of the physical soil quality indicators was transformed into 0 and 1 using threshold criteria which are required for crop production. The transformed indicators were the combined into SQIP. The kriged SQIP map showed that the agricultural field studied could be divided into two parts having “good physical quality” and “poor physical soil quality.”

Field classes: key to involve and attract students to soils

Science.gov (United States)

Muggler, Cristine Carole; Cardoso, Irene Maria; da Silva Lopes, Angelica

2015-04-01

Soil genesis is a subject taught to students of Agrarian Sciences and Geography at the Federal University of Viçosa in Minas Gerais, Brazil. Each semester 200 to 250 students inscribe for it. It is organized as the first 60 hours course on soils for 1st and 2nd year's students. The course has a distinct pedagogical approach, which is based on Paulo Freire's education principles, known as socio constructivism. In such approach, learning environments and materials are prepared to stimulate dialogues and exchange of knowledge between students themselves, strengthening that their role is crucial to their own learning. During the course, students have different types of practical classes: indoors, in a class room or at the Earth Sciences museum and outdoors, in the field. In the class room they have the opportunity to handle materials -minerals, rocks, soils and maps-, follow demonstrations and perform small experiments. The classes given in the museum intend a broadening of the subjects approached in theoretical and practical classes. In the field classes the students are organized in small groups with the task to investigate soil formation by observation and description of geology, landscape, land use, soil expositions and some of the soil properties. Attracting students to soils involves looking at meanings and perceptions related to soils they bring with themselves and follow this up to sensitize and create awareness about their importance. With this aim, it is also included, as part of the evaluation, a final voluntary presentation that many of the students do. The presentation can be a song, a poem, a sketch or whatever they propose and create. Many of the presentations bring topics related to the new perception about soils they get during the semester and to ideas or questions raised in the field classes. A survey with the students showed that field classes are by far the preferred classes and they are considered more dynamic. Since students have less and less

Field manual for reclamation of salt contaminated soils

International Nuclear Information System (INIS)

Burley, M.J.; Lesky, M.; Warren, R.J.

1988-01-01

Saltwater is often produced with crude oil and must be separated from it at a processing facility prior to deep-well injection. Increasing volumes of saltwater have led to pipeline corrosion and an increasing frequency of saltwater spills. A field manual for treating saltwater-contaminated soil was prepared by the Production Research Department of Esso Resources Canada Limited and Husky Oil Operations Limited. The purpose of the manual is to provide field and plant operations with a practical guide for reclaiming brine spills on mineral (agricultural) soil. The manual covers background scientific theory about how saltwater affects the soil, initial steps for treating new spills, site assessment, and reclamation program design, implementation and monitoring. A sample spill site assessment form is included. 8 refs

Predicting Soil Organic Carbon at Field Scale Using a National Soil Spectral Library

DEFF Research Database (Denmark)

Peng, Yi; Knadel, Maria; Gislum, René

2013-01-01

and the spectral library, 2718 samples) and (iii) three sub-sets selected from the spectral library. In an attempt to improve prediction accuracy, sub-sets of the soil spectral library were made using three different sample selection methods: those geographically closest (84 samples), those with the same landscape......Visible and near infrared diffuse reflectance (vis-NIR) spectroscopy is a low-cost, efficient and accurate soil analysis technique and is thus becoming increasingly popular. Soil spectral libraries are commonly constructed as the basis for estimating soil texture and properties. In this study......, partial least squares regression was used to develop models to predict the soil organic carbon (SOC) content of 35 soil samples from one field using (i) the Danish soil spectral library (2688 samples), (ii) a spiked spectral library (a combination of 30 samples selected from the local area...

Retrieving soil moisture for non-forested areas using PALS radiometer measurements in SMAPVEX12 field campaign

Science.gov (United States)

In this paper we investigate retrieval of soil moisture based on L-band brightness temperature under diverse conditions and land cover types. We apply the PALS (Passive Active L-band System) radiometer data collected in the SMAPVEX12 (Soil Moisture Active Passive Validation Experiment 2012) field ex...

Field verification of advanced transport models of radionuclides in heterogeneous soils

International Nuclear Information System (INIS)

Visser, W.; Meurs, G.A.M.; Weststrate, F.A.

1991-01-01

This report deals with a verification study of advanced transport models of radionuclides in heterogeneous soils. The study reported here is the third phase of a research program carried out by Delft Geotechnics concerning the influence of soil heterogeneities on the migration of radionuclides in the soil and soil-water system. Phases 1 and 2 have been reported earlier in the EC Nuclear Science and technology series (EUR 12111 EN, 1989). The verification study involves the predictive modelling of a field tracer experiment carried out by the British Geological Survey (BGS) at Drigg, Cumbria (UK). Conservative (I 131 , Cl-, H 3 ) as well as non-conservative (Co-EDTA) tracers were used. The inverse modelling shows that micro dispersion may be considered as a soil constant related to grainsize. Micro dispersion shows a slow increase with distance from the source. This increase is caused by mass transfer between adjacent layers of different permeability. Macro dispersion is observed when sampling over a larger interval then permitted by the detail with which the heterogeneity is described in the model. The prediction of the migration of radionuclides through heterogeneous soils is possible. The advection dispersion equation seems to be an adequate description of the migration of conservative tracers. The models based on this equation give comparable results on a small field test scale (3.5 m). The prediction of the migration of adsorbing species is more difficult. The mathematical descriptions seem appropriate, but the heterogeneity in soils seems to create a higher order of uncertainty which can not be described as yet with calculation strategies available at this moment

Soil structure and microbial activity dynamics in 20-month field-incubated organic-amended soils

DEFF Research Database (Denmark)

Arthur, Emmanuel; Schjønning, Per; Møldrup, Per

2014-01-01

to determine compressive strength. During incubation, the amount of WDC depended on soil carbon content while the trends correlated with moisture content. Organic amendment only yielded modest decreases (mean of 14% across all sampling times and soils) in WDC, but it was sufficient to stimulate the microbial......Soil structure formation is essential to all soil ecosystem functions and services. This study aims to quantify changes in soil structure and microbial activity during and after field incubation and examine the effect of carbon, organic amendment and clay on aggregate characteristics. Five soils...... community (65–100% increase in FDA). Incubation led to significant macroaggregate formation (>2 mm) for all soils. Friability and strength of newly-formed aggregates were negatively correlated with clay content and carbon content, respectively. Soil workability was best for the kaolinite-rich soil...

Uranium facilitated transport by water-dispersible colloids in field and soil columns

International Nuclear Information System (INIS)

Crancon, P.; Pili, E.; Charlet, L.

2010-01-01

The transport of uranium through a sandy podzolic soil has been investigated in the field and in column experiments. Field monitoring, numerous years after surface contamination by depleted uranium deposits, revealed a 20 cm deep uranium migration in soil. Uranium retention in soil is controlled by the 238 U initially present in the soil column and 233 U brought by input solution are desorbed. The mobilization process observed experimentally after a drop of ionic strength may account for a rapid uranium migration in the field after a rainfall event, and for the significant uranium concentrations found in deep soil horizons and in groundwater, 1 km downstream from the pollution source.

Effects of the stress field induced by a running tyre on the soil pore system

DEFF Research Database (Denmark)

Berisso, Feto Esimo; Schjønning, Per; Lamandé, Mathieu

2013-01-01

state in the soil profile beneath the harvester tyre was calculated using the SoilFlex model. Pore continuity index (N) and blocked air-filled porosity (εb) were estimated from the relationship between ka and air-filled porosity (εa) for a range of matric potentials. Calculated and measured stresses...... repeated wheelings were performed by a forage harvester (wheel load 6100 kg; tyre width 80 cm). Mean normal and horizontal stresses were measured with Bolling probes (at 10, 20 and 40 cm depth) and load cells (at 40, 50, 60 cm lateral distance from the centreline of the wheel rut at 10, 30 and 50 cm depth......), respectively. Intact soil cores of 100 cm3 sampled at 10, 30 and 50 cm depth in a soil transcet running from the centreline of the wheel rut to the unwheeled part of the field were used for measurements of water retention and air permeability (ka) at −30, −100 and −300 hPa matric potential. The complete stress...

Evaluation of Three Field-Based Methods for Quantifying Soil Carbon

Energy Technology Data Exchange (ETDEWEB)

Izaurralde, Roberto C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rice, Charles W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wielopolski, Lucien [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ebinger, Michael H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Reeves, James B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thomson, Allison M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Harris, Ron [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Francis, Barry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mitra, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rappaport, Aaron [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Etchevers, Jorge [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sayre, Ken D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Govaerts, Bram [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCarty, G. W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-01-31

Three advanced technologies to measure soil carbon (C) density (g C m22) are deployed in the field and the results compared against those obtained by the dry combustion (DC) method. The advanced methods are: a) Laser Induced Breakdown Spectroscopy (LIBS), b) Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS), and c) Inelastic Neutron Scattering (INS). The measurements and soil samples were acquired at Beltsville, MD, USA and at Centro International para el Mejoramiento del Maiz y el Trigo (CIMMYT) at El Bata´n, Mexico. At Beltsville, soil samples were extracted at three depth intervals (0–5, 5–15, and 15–30 cm) and processed for analysis in the field with the LIBS and DRIFTS instruments. The INS instrument determined soil C density to a depth of 30 cm via scanning and stationary measurements. Subsequently, soil core samples were analyzed in the laboratory for soil bulk density (kg m23), C concentration (g kg21) by DC, and results reported as soil C density (kg m22). Results from each technique were derived independently and contributed to a blind test against results from the reference (DC) method. A similar procedure was employed at CIMMYT in Mexico employing but only with the LIBS and DRIFTS instruments. Following conversion to common units, we found that the LIBS, DRIFTS, and INS results can be compared directly with those obtained by the DC method. The first two methods and the standard DC require soil sampling and need soil bulk density information to convert soil C concentrations to soil C densities while the INS method does not require soil sampling. We conclude that, in comparison with the DC method, the three instruments (a) showed acceptable performances although further work is needed to improve calibration techniques and (b) demonstrated their portability and their capacity to perform under field conditions.

Examination plan for the soils and low-level radioactive waste forms of the NRC field testing lysimeters

International Nuclear Information System (INIS)

McConnell, J.W. Jr.; Rogers, R.D.; Jastrow, J.D.

1996-01-01

The Field Lysimeter Investigations: Low-Level Waste Data Base Development Program is obtaining information on the performance of radioactive waste forms. These experiments were recently shut down and have been examined in accordance with a detailed waste form and soil sampling plan. Ion-exchange resins from a commercial nuclear power station were solidified into waste forms using portland cement and vinyl ester-styrene. These waste forms were tested to (a) obtain information on performance of waste forms in typical disposal environments, (b) compare field results with bench leach studies, (c) develop a low-level waste data base for use in performance assessment source term calculations, and (d) apply the DUST computer code to compare predicted cumulative release to actual field data. The program, funded by the Nuclear Regulatory Commission (NRC), includes observed radionuclide releases from waste forms at two test sites over 10 years of successful operation. Lysimeters are ideal systems for obtaining actual field test data because, when properly designed and operated, they can be used to isolate soil and waste systems under actual environmental conditions. The purpose of this paper is to present the experimental plan for the examination of the waste forms and soils of the two lysimeter arrays, which have now been shut down. Vertical soil cores have been taken from the soil columns and will be analyzed with radiochemistry to define movement of radionuclides after release from the waste forms. A comparison is made of the DUST-predicted releases to those previously determined and reported from the lysimeter leachate analyses. That comparison uses new partition coefficients (Kd) recently obtained from laboratory analysis of the lysimeter soils and sand. Those DUST code results also will be compared to actual radionuclide movements through the soil columns as determined from soil core analysis

Response of the soil microbial community to imazethapyr application in a soybean field.

Science.gov (United States)

Xu, Jun; Guo, Liqun; Dong, Fengshou; Liu, Xingang; Wu, Xiaohu; Sheng, Yu; Zhang, Ying; Zheng, Yongquan

2013-01-01

The objective of this study was to determine the effects of imazethapyr on soil microbial communities combined with its effect on soybean growth. A short-term field experiment was conducted, and imazethapyr was applied to the soil at three different doses [1-fold, 10-fold, and 50-fold of the recommended field rate (H1, H10, H50)] during the soybean seedling period (with two leaves). Soil sampling was performed after 1, 7, 30, 60, 90, and 120 days of application to determine the imazethapyr concentration and microbial community structure by investigating phospholipid fatty acids (PLFA) and microbial biomass carbon (MBC). The half-lives of the imazethapyr in the field soil varied from 30.1 to 43.3 days. Imazethapyr at H1 was innocuous to soybean plants, but imazethapyr at H10 and H50 led to a significant inhibition in soybean plant height and leaf number. The soil MBC, total PLFA, and bacterial PLFA were decreased by the application of imazethapyr during the initial period and could recover by the end of the experiment. The ratio of Gram-negative/Gram-positive (GN/GP) bacteria during the three treatments went through increases and decreases, and then recovered at the end of the experiment. The fungal PLFA of all three treatments increased during the initial period and then declined, and only the fungal PLFA at H50 recovered by the end of the treatment. A principal component analysis (PCA) of the PLFA clearly separated the treatments and sampling times, and the results demonstrate that imazethapyr alters the microbial community structure. This is the first systemic study reporting the effects of imazethapyr on the soil microbial community structure under soybean field conditions.

Biological and chemical assessments of zinc ageing in field soils

International Nuclear Information System (INIS)

Donner, Erica; Broos, Kris; Heemsbergen, Diane; Warne, Michael St. J.; McLaughlin, Mike J.; Hodson, Mark E.; Nortcliff, Stephen

2010-01-01

As zinc (Zn) is both an essential trace element and potential toxicant, the effects of Zn fixation in soil are of practical significance. Soil samples from four field sites amended with ZnSO 4 were used to investigate ageing of soluble Zn under field conditions over a 2-year period. Lability of Zn measured using 65 Zn radioisotope dilution showed a significant decrease over time and hence evidence of Zn fixation in three of the four soils. However, 0.01 M CaCl 2 extractions and toxicity measurements using a genetically modified lux-marked bacterial biosensor did not indicate a decrease in soluble/bioavailable Zn over time. This was attributed to the strong regulatory effect of abiotic properties such as pH on these latter measurements. These results also showed that Zn ageing occurred immediately after Zn spiking, emphasising the need to incubate freshly spiked soils before ecotoxicity assessments. - Ageing effects were detected in Zn-amended field soils using 65 Zn isotopic dilution as a measure of lability, but not with either CaCl 2 extractions or a lux-marked bacterial biosensor.

Fate of triclosan in field soils receiving sewage sludge

International Nuclear Information System (INIS)

Butler, E.; Whelan, M.J.; Sakrabani, R.; Egmond, R. van

2012-01-01

The anti-microbial substance triclosan can partition to sewage sludge during wastewater treatment and subsequently transfer to soil when applied to land. Here, we describe the fate of triclosan in a one-year plot experiment on three different soils receiving sludge. Triclosan and methyl-triclosan concentrations were measured in soil samples collected monthly from three depths. A large fraction of triclosan loss appeared to be explained by transformation to methyl-triclosan. After 12 months less than 20% of the initial triclosan was recovered from each soil. However, the majority was recovered as methyl-triclosan. Most of the chemical recovered at the end of the experiment (both triclosan and methyl-triclosan) was still in the top 10 cm layer, although there was translocation to lower soil horizons in all three soils. Between 16.5 and 50.6% of the applied triclosan was unaccounted for after 12 months either as a consequence of degradation or the formation of non-extractable residues. - Highlights: ► We study the fate of triclosan in 3 different field soils amended with biosolids. ► Triclosan concentrations were measured over 12 months at 3 depths of soil. ► Methyl-triclosan was identified as a main biotransformation product. ► There was very little movement of triclosan through the soil. ► Only between 16 and 50% of triclosan applied was degraded or leached out of the soil. - This paper investigates the mobility and degradation of triclosan in three field soils after receiving an application of biosolids and the persistence of methyl-triclosan.

Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

Science.gov (United States)

Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

2014-11-01

Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. © 2014 SETAC.

Earthquake response analyses of soil-structure system considering kinematic interaction

International Nuclear Information System (INIS)

Murakami, H.; Yokono, K.; Miura, S.; Ishii, K.

1985-01-01

Improvement of soil-structure interaction analysis has been one of major concerns in earthquake engineering field, especially in nuclear industries, to evaluate the safety of structure accurately under earthquake events. This research aims to develop a rational analytical tool which considers effect of the 'kinematic interaction' satisfactory with a proposed simple low-pass filter. In this paper, first the effect of the kinematic interaction is investigated based on earthquake response analysis of a reactor building using the practical design models: the spring-mass-dashpot system and the 'lattice model', in which a building and soil medium are modeled by a system of lumped masses. Next, the filter is developed based on parametrical studies with various sizes of depth and width of foundations embedded in two-layers soil, which represents more general soil condition in practical designs compared with a homogeneous soil medium. (orig.)

CHANGES IN SOIL CHEMICAL PROPERTIES OF ORGANIC PADDY FIELD WITH AZOLLA APPLICATION

Directory of Open Access Journals (Sweden)

Jauhari Syamsiyah

2016-12-01

Full Text Available The use of organic fertilizer is a way to improve soil fertility. Azolla can be used as organic fertilizer. This study aims to determine the effect of Azolla (Azolla mycrophylla. L on some soil chemical properties on organic paddy field. The field experiments used factorial complete randomized block design of three factors, namely Azolla (0 and 2 tons/ha, Manure (0 and 10 tons/ha and Rice Varieties (Mira1, Mentik Wangi and Merah Putih, with three times replication. Using Azolla on an organic paddy field does not significantly increase the levels of soil N, organic C, Cation Exchange Capacity and soil pH. However Azolla’s influence on soil available P is significant.

Comparison of field screening techniques with fuel-contaminated soils

International Nuclear Information System (INIS)

Klopp, C.; Turriff, D.

1995-01-01

This paper presents the results of a comparison of four field screening techniques. Field screenings, is an important part of conducting cost-effective and comprehensive site investigations. Regulators limit the use of field screening in lieu of laboratory analyses, in part, because there is little information on the accuracy and precision of field screening techniques. The results here represent a step forward towards a better understanding of the accuracy and practicality of field screening methods. The authors hope that the role of field screening in site investigation will increase as this type of information becomes more available. Innovative techniques for homogenizing soils were used to allow simultaneous analysis of hydrocarbon contaminated soils using field GCs, immunoassays, ''jar headspace'' and ''Lab in a Bag.'' The results shown here illustrate the variability of field screening results and the importance of good method development and operator competency. Certainly more work in this area is needed to truly characterize field screening techniques

Field Scale Studies on the Spatial Variability of Soil Quality Indicators in Washington State, USA

Directory of Open Access Journals (Sweden)

Jeffrey L. Smith

2011-01-01

Full Text Available Arable lands are needed for sustainable agricultural systems to support an ever-growing human population. Soil quality needs to be defined to assure that new land brought into crop production is sustainable. To evaluate soil quality, a number of soil attributes will need to be measured, evaluated, and integrated into a soil-quality index using the multivariable indicator kriging (MVIK procedure. This study was conducted to determine the spatial variability and correlation of indicator parameters on a field scale with respect to soil quality and suitability for use with MVIK. The variability of the biological parameters decreased in the order of respiration > enzyme assays and qCO2 > microbial biomass C. The distribution frequency of all parameters except respiration were normal although the spatial distribution across the landscape was highly variable. The biological parameters showed little correlation with each other when all data points were considered; however, when grouped in smaller sections, the correlations were more consistent with observed patterns across the field. To accurately assess soil quality, and arable land use, consideration of spatial and temporal variability, soil conditions, and other controlling factors must be taken into account.

Soil CO2 flux baseline in an urban monogenetic volcanic field: the Auckland Volcanic Field, New Zealand

Science.gov (United States)

Mazot, Agnès; Smid, Elaine R.; Schwendenmann, Luitgard; Delgado-Granados, Hugo; Lindsay, Jan

2013-11-01

The Auckland Volcanic Field (AVF) is a dormant monogenetic basaltic field located in Auckland, New Zealand. Though soil gas CO2 fluxes are routinely used to monitor volcanic regions, there have been no published studies of soil CO2 flux or soil gas CO2 concentrations in the AVF to date or many other monogenetic fields worldwide. We measured soil gas CO2 fluxes and soil gas CO2 concentrations in 2010 and 2012 in varying settings, seasons, and times of day to establish a baseline soil CO2 flux and to determine the major sources of and controlling influences on Auckland's soil CO2 flux. Soil CO2 flux measurements varied from 0 to 203 g m-2 day-1, with an average of 27.1 g m-2 day-1. Higher fluxes were attributed to varying land use properties (e.g., landfill). Using a graphical statistical approach, two populations of CO2 fluxes were identified. Isotope analyses of δ13CO2 confirmed that the source of CO2 in the AVF is biogenic with no volcanic component. These data may be used to assist with eruption forecasting in the event of precursory activity in the AVF, and highlight the importance of knowing land use history when assessing soil gas CO2 fluxes in urban environments.

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

OpenAIRE

Schreiter, Susanne; Ding, Guo-Chun; Heuer, Holger; Neumann, Günter; Sandmann, Martin; Grosch, Rita; Kropf, Siegfried; Smalla, Kornelia

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years under the same agricultural management to reveal differences directly linked to the soil type and no...

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

OpenAIRE

Susanne eSchreiter; Susanne eSchreiter; Guo-chun eDing; Guo-chun eDing; Holger eHeuer; Günter eNeumann; Martin eSandmann; Rita eGrosch; Siegfried eKropf; Kornelia eSmalla

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for ten years under the same agricultural management to reveal differences directly linked to the soil type and n...

Phytotoxic effects of (+/--catechin in vitro, in soil, and in the field.

Directory of Open Access Journals (Sweden)

Inderjit

Full Text Available BACKGROUND: Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants. METHODOLOGY/PRINCIPAL FINDINGS: We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (+/--catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (+/--catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (+/--catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (+/--catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (+/--Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (+/--catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 microg l(-1. Multiple pulses of (+/--catechin were inhibitory at very low concentrations in Indian soil. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that (+/--catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied

Linking soil systems to societal value systems

Science.gov (United States)

Helming, Katharina; Daedlow, Katrin; Techen, Anja; Kaiser, David Brian

2017-04-01

Sustainable management of soils is needed to avoid soil degradation and to maintain soil functions. This requires the assessment of how human activities drive soil management, how soil management affect soil functions and soil degradation, which trade-offs occur and how they compromise sustainable development targets. In the frame of the German research programme "Soils as a sustainable resource for the bio-economy - BonaRes", we developed an enhanced approach of the DPSIR (driver-pressure-state-impact-response) cycle which helps to assess these interrelations. Because not all soil functions can be maximized simultaneously in space and time and trade-offs are inevitable, it depends on the societal value system to decide which management practices and respective soil functional performances are valued sustainably. We analysed the applicability of three valuation concepts being prominent in research about social-ecological systems, namely resource efficiency, ecosystem services, and ethics and equity. The concept of resource efficiency is based in the life-cycle thinking and is often applied at the level of the farming systems and in the context of bio-economy strategies. It covers the use of natural (water, energy, nutrients, land) and economic resources. At the landscape level, the concept of ecosystem services is prominent. Here, the contribution of soils to the provisioning, regulating and cultural services of the natural ecosystems is considered. Ethical considerations include the intrinsic values of nature as well as issues of local and global equity between different societal groups, generations, and localities. The three concepts cover different problem dimensions and complexity levels of soil management and decision making. Alone, none of them are capable to discover complex questions of sustainable soil management and development. Rather, the exact spatial and temporal framing of the sustainability problem at stake determines which combination of the value

Simulation of large-scale soil water systems using groundwater data and satellite based soil moisture

Science.gov (United States)

Kreye, Phillip; Meon, Günter

2016-04-01

Complex concepts for the physically correct depiction of dominant processes in the hydrosphere are increasingly at the forefront of hydrological modelling. Many scientific issues in hydrological modelling demand for additional system variables besides a simulation of runoff only, such as groundwater recharge or soil moisture conditions. Models that include soil water simulations are either very simplified or require a high number of parameters. Against this backdrop there is a heightened demand of observations to be used to calibrate the model. A reasonable integration of groundwater data or remote sensing data in calibration procedures as well as the identifiability of physically plausible sets of parameters is subject to research in the field of hydrology. Since this data is often combined with conceptual models, the given interfaces are not suitable for such demands. Furthermore, the application of automated optimisation procedures is generally associated with conceptual models, whose (fast) computing times allow many iterations of the optimisation in an acceptable time frame. One of the main aims of this study is to reduce the discrepancy between scientific and practical applications in the field of hydrological modelling. Therefore, the soil model DYVESOM (DYnamic VEgetation SOil Model) was developed as one of the primary components of the hydrological modelling system PANTA RHEI. DYVESOMs structure provides the required interfaces for the calibrations made at runoff, satellite based soil moisture and groundwater level. The model considers spatial and temporal differentiated feedback of the development of the vegetation on the soil system. In addition, small scale heterogeneities of soil properties (subgrid-variability) are parameterized by variation of van Genuchten parameters depending on distribution functions. Different sets of parameters are operated simultaneously while interacting with each other. The developed soil model is innovative regarding concept

Fate of triclosan in field soils receiving sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Butler, E [Department of Environmental Science and Technology, School of Applied Sciences, Cranfield University, College Road, Cranfield, Bedfordshire MK43 0AL (United Kingdom); Whelan, M J; Sakrabani, R [Department of Environmental Science and Technology, School of Applied Sciences, Cranfield University, College Road, Cranfield, Bedfordshire MK43 0AL (United Kingdom); Egmond, R van [Safety and Environmental Assurance Centre, Unilever Colworth Laboratory, Colworth Park, Sharnbrook, Bedfordshire MK44 1LQ (United Kingdom)

2012-08-15

The anti-microbial substance triclosan can partition to sewage sludge during wastewater treatment and subsequently transfer to soil when applied to land. Here, we describe the fate of triclosan in a one-year plot experiment on three different soils receiving sludge. Triclosan and methyl-triclosan concentrations were measured in soil samples collected monthly from three depths. A large fraction of triclosan loss appeared to be explained by transformation to methyl-triclosan. After 12 months less than 20% of the initial triclosan was recovered from each soil. However, the majority was recovered as methyl-triclosan. Most of the chemical recovered at the end of the experiment (both triclosan and methyl-triclosan) was still in the top 10 cm layer, although there was translocation to lower soil horizons in all three soils. Between 16.5 and 50.6% of the applied triclosan was unaccounted for after 12 months either as a consequence of degradation or the formation of non-extractable residues. - Highlights: Black-Right-Pointing-Pointer We study the fate of triclosan in 3 different field soils amended with biosolids. Black-Right-Pointing-Pointer Triclosan concentrations were measured over 12 months at 3 depths of soil. Black-Right-Pointing-Pointer Methyl-triclosan was identified as a main biotransformation product. Black-Right-Pointing-Pointer There was very little movement of triclosan through the soil. Black-Right-Pointing-Pointer Only between 16 and 50% of triclosan applied was degraded or leached out of the soil. - This paper investigates the mobility and degradation of triclosan in three field soils after receiving an application of biosolids and the persistence of methyl-triclosan.

Spatial distribution of soil moisture in precision farming using integrated soil scanning and field telemetry data

Science.gov (United States)

Kalopesas, Charalampos; Galanis, George; Kalopesa, Eleni; Katsogiannos, Fotis; Kalafatis, Panagiotis; Bilas, George; Patakas, Aggelos; Zalidis, George

2015-04-01

Mapping the spatial variation of soil moisture content is a vital parameter for precision agriculture techniques. The aim of this study was to examine the correlation of soil moisture and conductivity (EC) data obtained through scanning techniques with field telemetry data and to spatially separate the field into discrete irrigation management zones. Using the Veris MSP3 model, geo-referenced data for electrical conductivity and organic matter preliminary maps were produced in a pilot kiwifruit field in Chrysoupoli, Kavala. Data from 15 stratified sampling points was used in order to produce the corresponding soil maps. Fusion of the Veris produced maps (OM, pH, ECa) resulted on the delineation of the field into three zones of specific management interest. An appropriate pedotransfer function was used in order to estimate a capacity soil indicator, the saturated volumetric water content (θs) for each zone, while the relationship between ECs and ECa was established for each zone. Validation of the uniformity of the three management zones was achieved by measuring specific electrical conductivity (ECs) along a transect in each zone and corresponding semivariograms for ECs within each zone. Near real-time data produced by a telemetric network consisting of soil moisture and electrical conductivity sensors, were used in order to integrate the temporal component of the specific management zones, enabling the calculation of time specific volumetric water contents on a 10 minute interval, an intensity soil indicator necessary to be incorporated to differentiate spatially the irrigation strategies for each zone. This study emphasizes the benefits yielded by fusing near real time telemetric data with soil scanning data and spatial interpolation techniques, enhancing the precision and validity of the desired results. Furthermore the use of telemetric data in combination with modern database management and geospatial software leads to timely produced operational results

Evaluating the soil physical quality under long-term field experiments in Southern Italy

Science.gov (United States)

Castellini, Mirko; Stellacci, Anna Maria; Iovino, Massimo; Rinaldi, Michele; Ventrella, Domenico

2017-04-01

Long-term field experiments performed in experimental farms are important research tools to assess the soil physical quality (SPQ) given that relatively stable conditions can be expected in these soils. However, different SPQ indicators may sometimes provide redundant or conflicting results, making difficult an SPQ evaluation (Castellini et al., 2014). As a consequence, it is necessary to apply appropriate statistical procedures to obtain a minimum set of key indicators. The study was carried out at the Experimental Farm of CREA-SCA (Foggia) in two long-term field experiments performed on durum wheat. The first long-term experiment is aiming at evaluating the effects of two residue management systems (burning, B or soil incorporation of crop residues, I) while the second at comparing the effect of tillage (conventional tillage, CT) and sod-seeding (direct drilling, DD). In order to take into account both optimal and non-optimal soil conditions, five SPQ indicators were monitored at 5-6 sampling dates during the crop season (i.e., between November and June): soil bulk density (BD), macroporosity (PMAC), air capacity (AC), plant available water capacity (PAWC) and relative field capacity (RFC). Two additional data sets, collected on DD plot in different cropping seasons and in Sicilian soils differing for texture, depth and land use (N=140), were also used with the aim to check the correlation among indicators. Impact of soil management was assessed by comparing SPQ evaluated under different management systems with optimal reference values reported in literature. Two techniques of multivariate analysis (principal component analysis, PCA and stepwise discriminant analysis, SDA) were applied to select the most suitable indicator to facilitate the judgment on SPQ. Regardless of the considered management system, sampling date or auxiliary data set, correlation matrices always showed significant negative relationships between RFC and AC. Decreasing RFC at increasing AC is

Ecopiling: A combined Phytoremediation and Passive Biopiling System for Remediating Hydrocarbon Impacted Soils at Field Scale

Directory of Open Access Journals (Sweden)

Kieran J Germaine

2015-01-01

Full Text Available Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil (1613 mg Total Petroleum Hydrocarbons (TPH kg-1 soil. The contaminated soil was amended with chemical fertilisers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium multiflorum and white clover (Trifolium repens was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but 1 subsample (152mg TPH kg-1 soil. The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labour and maintenance (although the longer process time may incur additional monitoring costs. The other major advantage is that many ecological functions are rapidly restored to the site and the process is aesthetically pleasing.

Ecopiling: a combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale.

Science.gov (United States)

Germaine, Kieran J; Byrne, John; Liu, Xuemei; Keohane, Jer; Culhane, John; Lally, Richard D; Kiwanuka, Samuel; Ryan, David; Dowling, David N

2014-01-01

Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg(-1) soil]. The contaminated soil was amended with chemical fertilizers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium perenne) and white clover (Trifolium repens) was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but one subsample (152 mg TPH kg(-1) soil). The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labor and maintenance (although the longer process time may incur additional monitoring costs). The other major advantage is that many ecological functions are rapidly restored to the site and the process is esthetically pleasing.

Field screening procedures for determining the presence of volatile organic compounds in soil

International Nuclear Information System (INIS)

Crockett, A.B.; DeHaan, M.S.

1991-01-01

Many field screening procedures have been used to detect the presence of volatile organic compounds (VOC) in soils but almost none have been documented and verified. Users of these procedures have not really known whether their objectives in screening were met. A reliable VOC screening procedure could significantly reduce the number of samples currently being submitted to laboratories, thereby reducing costs and improving site characterization. The Environmental Protection Agency's Environmental Monitoring Systems Laboratory in Las Vegas (EMSL-LV) has therefore sponsored a research effort to evaluate and improve headspace methods for screening soils for VOC in the field. The research involved comparing several extraction procedures using soils from actual waste sites, and determining the agitation and mixing necessary to achieve equilibrium. Headspace was analyzed using a relatively simple portable gas chromatograph with a short column. The results were variable and show that several procedures should be attempted and the results evaluated before selecting a screening procedure. 10 refs., 6 tabs

Pedotransfer functions to estimate soil water content at field capacity ...

Indian Academy of Sciences (India)

20

available scarce water resources in dry land agriculture, but direct measurement thereof for multiple locations in the field is not always feasible. Therefore, pedotransfer functions (PTFs) were developed to estimate soil water retention at FC and PWP for dryland soils of India. A soil database available for Arid Western India ...

Distribution of hydrogen-metabolizing bacteria in alfalfa field soil

International Nuclear Information System (INIS)

Cunningham, S.D.; Kapulnik, Y.; Phillips, D.A.

1986-01-01

H 2 evolved by alfalfa root nodules during the process of N 2 fixation may be an important factor influencing the distribution of soil bacteria. To test this hypothesis under field conditions, over 700 bacterial isolates were obtained from fallow soil or from the 3-mm layer of soil surrounding alfalfa (Medicago sativa L.) root nodules, alfalfa roots, or bindweed (Convolvulus arvensis L.) roots. Bacteria were isolated under either aerobic or microaerophilic conditions and were tested for their capacity to metabolize H 2 . Isolates showing net H 2 uptake and 3 H 2 incorporation activity under laboratory conditions were assigned a Hup + phenotype, whereas organisms with significant H 2 output capacity were designated as a Hout + phenotype. Under aerobic isolation conditions two Hup + isolates were obtained, whereas under microaerophilic conditions five Hup + and two Hout + isolates were found. The nine isolates differed on the basis of 24 standard bacteriological characteristics or fatty acid composition. Five of the nine organisms were isolated from soil around root nodules, whereas the other four were found distributed among the other three soil environments. On the basis of the microaerophilic isolations, 4.8% of the total procaryotic isolates from soil around root nodules were capable of oxidizing H 2 , and 1.2% could produce H 2 . Two of the Hup + isolates were identified as Rhizobium meliloti by root nodulation tests, but the fact that none of the isolates reduced C 2 H 2 under the assay conditions suggested that the H 2 metabolism traits were associated with various hydrogenase systems rather than with nitrogenase activity

Cokriging of Electromagnetic Induction Soil Electrical Conductivity Measurements and Soil Textural Properties to Demarcate Sub-field Management Zones for Precision Irrigation.

Science.gov (United States)

Ding, R.; Cruz, L.; Whitney, J.; Telenko, D.; Oware, E. K.

2017-12-01

There is the growing need for the development of efficient irrigation management practices due to increasing irrigation water scarcity as a result of growing population and changing climate. Soil texture primarily controls the water-holding capacity of soils, which determines the amount of irrigation water that will be available to the plant. However, while there are significant variabilities in the textural properties of the soil across a field, conventional irrigation practices ignore the underlying variability in the soil properties, resulting in over- or under-irrigation. Over-irrigation leaches plant nutrients beyond the root-zone leading to fertilizer, energy, and water wastages with dire environmental consequences. Under-irrigation, in contrast, causes water stress of the plant, thereby reducing plant quality and yield. The goal of this project is to leverage soil textural map of a field to create water management zones (MZs) to guide site-specific precision irrigation. There is increasing application of electromagnetic induction methods to rapidly and inexpensively map spatially continuous soil properties in terms of the apparent electrical conductivity (ECa) of the soil. ECa is a measure of the bulk soil properties, including soil texture, moisture, salinity, and cation exchange capacity, making an ECa map a pseudo-soil map. Data for the project were collected from a farm site at Eden, NY. The objective is to leverage high-resolution ECa map to predict spatially dense soil textural properties from limited measurements of soil texture. Thus, after performing ECa mapping, we conducted particle-size analysis of soil samples to determine the textural properties of soils at selected locations across the field. We cokriged the high-resolution ECa measurements with the sparse soil textural data to estimate a soil texture map for the field. We conducted irrigation experiments at selected locations to calibrate representative water-holding capacities of each

Changes in soil carbon cycling accompanying conversion of row-crop fields to grazing dairy pastures

Science.gov (United States)

Thompson, A.; Kramer, M. G.; Hill, N.; Machmuller, M. B.; Cyle, K.

2011-12-01

Increasingly, the dairy industry in the eastern US is transitioning from total confinement dairy systems (TCD) toward pasture-based, management intensive grazing dairy (MiGD) systems. This transition is driven by the fact that MiGDs require substantially less operating capital and are more economically efficient than TCD systems. Consequently, the impact of this transition and shift in land-use practice on carbon dynamics may be considerable. Land-use in a Management intensive Grazing Dairy (MiGD) system is fundamentally different than conventional confinement dairies and conventional no-till pastures. The forage system involves rotational grazing at optimal digestibility, when the plants are immature (~20-days) and consequently protein-rich. MiGD cows spend >90% of their time in the field and deposit > 90% of their waste directly to the soil surface. Thus, little above ground plant residues are directly returned to the soil, but rather substantial C inputs derive from bovine manure. We sampled a MiGD-chronosequence of row-crop to MiGD conversion established in 2007 in eastern Georgia. All soils across the MiGD-chronosequence, all occur in relative (40 km) close proximity to one another, are deep, well-drained, fine and fine sandy loam Ultisols formed on Coastal Plain sediments. Prior to MiGD established, the soils were farmed for > 50 yrs using conventional tillage techniques. Our current sampling to 1m depths captures fields at 0, 2, 3, and 5 yrs since conversion. Total soil carbon (C) and the carbon concentration of the clay fraction increased following conversion, with the greatest increases occurring between 3 and 5 yrs since conversion. These C increases were limited to the upper 40cm of the soil, with minimal change occurring at depth. Characterization of the protein and ligand content of these soils via 13C NMR and chemolytic techniques as a function of soil particle density and size is in progress and will be presented along with estimates of carbon

Implementation of Controlled Traffic in the Canadian Prairies: Soil and Plant Dynamics under Simulated and Field Conditions

Science.gov (United States)

Guenette, Kris; Hernandez-Ramirez, Guillermo

2017-04-01

Achieving resiliency in agroecosystems may be accomplished through the incorporation of contemporary management systems and the diversification of crop rotations with pulse crops, such as controlled traffic farming (CTF) and faba beans (Vicia faba L.). As these practices become more common in the Canadian Prairies, it is imperative to have a well-rounded understanding of how faba beans interact with the soil-plant-atmosphere continuum in conditions found in contemporary management systems. Simulated field conditions emulated soil compaction found in both the trafficked and un-trafficked areas of a CTF system, in which the presence of high water availability was shown to offset the negative results of large applications of compactive effort. Furthermore, low water availability exacerbated differences in plant responses between compaction treatments. The simulated treatment of 1.2 gcm-3 coupled with high water content yielded the most optimal results for most measured parameters, with a contrasting detrimental treatment of 1.4 gcm-3 at low water availability. The simulated field conditions were further bridged through an analysis of two commercial sites in Alberta, Canada that compared both trafficked and un-trafficked soil properties. Soil properties such as available nitrogen (AN), pH, soil total nitrogen (STN), soil organic carbon (SOC), bulk density, macroporosity, soil quality S-Index, plant available water capacity (PAWC) and unsaturated hydraulic conductivity (Km) were analysed and compared among trafficked and un-trafficked areas. The measured soil physical and hydraulic properties of bulk density, macroporosity, S-Index, PAWC and Km were shown to be heavily influenced by the CTF traffic regime, while soil nutrient properties of AN, pH, STN SOC were determined to be dependent on both management and landscape features.

FUELS IN SOIL TEST KIT: FIELD USE OF DIESEL DOG SOIL TEST KITS

Energy Technology Data Exchange (ETDEWEB)

Unknown

2001-05-31

Western Research Institute (WRI) is commercializing Diesel Dog Portable Soil Test Kits for performing analysis of fuel-contaminated soils in the field. The technology consists of a method developed by WRI (U.S. Patents 5,561,065 and 5,976,883) and hardware developed by WRI that allows the method to be performed in the field (patent pending). The method is very simple and does not require the use of highly toxic reagents. The aromatic components in a soil extract are measured by absorption at 254 nm with a field-portable photometer. WRI added significant value to the technology by taking the method through the American Society for Testing and Materials (ASTM) approval and validation processes. The method is designated ASTM Method D-5831-96, Standard Test Method for Screening Fuels in Soils. This ASTM designation allows the method to be used for federal compliance activities. In FY 99, twenty-five preproduction kits were successfully constructed in cooperation with CF Electronics, Inc., of Laramie, Wyoming. The kit components work well and the kits are fully operational. In the calendar year 2000, kits were provided to the following entities who agreed to participate as FY 99 and FY 00 JSR (Jointly Sponsored Research) cosponsors and use the kits as opportunities arose for field site work: Wyoming Department of Environmental Quality (DEQ) (3 units), F.E. Warren Air Force Base, Gradient Corporation, The Johnson Company (2 units), IT Corporation (2 units), TRC Environmental Corporation, Stone Environmental, ENSR, Action Environmental, Laco Associates, Barenco, Brown and Caldwell, Dames and Moore Lebron LLP, Phillips Petroleum, GeoSyntek, and the State of New Mexico. By early 2001, ten kits had been returned to WRI following the six-month evaluation period. On return, the components of all ten kits were fully functional. The kits were upgraded with circuit modifications, new polyethylene foam inserts, and updated instruction manuals.

Residence half-time of {sup 137}Cs in the top-soils of Japanese paddy and upland fields

Energy Technology Data Exchange (ETDEWEB)

Komamura, Misako [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan); Tsumura, Akito; Kodaira, Kiyoshi

1999-03-01

A series of top-soil samples of 14 paddy fields and 10 upland fields in Japan, were annually collected during more than 30 years, to be examined in the contents of {sup 137}Cs. The data, which were obtained by the use of a gamma spectrometric system, received some statistical treatments to distinguish the annual decline of {sup 137}Cs contents from deviations. Then the authors calculated `residence half-time of {sup 137}Cs` within top-soil, and `eluviation rate of {sup 137}Cs` from top to the sub-layer of the soil. The following nationwide results were obtained irrespective of paddy or upland field: (1) The `apparent residence half-time` was estimated as 16 - 17 years. This consists of both effects of eluviation and nuclear disintegration. (2) The true residence half-time` was reported as 41 - 42 years. This depends on the eluviation speed of {sup 137}Cs exclusively, because the influence of nuclear disintegration has been compensated. (3) The eluviation rate of {sup 137}Cs from top-soil down to the sub-soil was 1.6 - 1.7% per year. (4) The ratio of distribution of {sup 137}Cs between top-soil and the sub-soil was estimated to be 6:4 as average at the date of 1996. (author)

Successful field and laboratory tests of advanced phytoremediation systems for decontamination of petroleum and salt impacted soils

Energy Technology Data Exchange (ETDEWEB)

Greenberg, B.; Huang, X.D.; Gerhardt, K.; Gurska, J.; Yu, X.M.; MacNeill, G.; Lu, X.; Nykamp, J.; Glick, B.; Wang, W.; Wang, H.; Wu, S.; Knezevich, N.; Gerwing, P. [Waterloo Univ., ON (Canada)]|[Earthmaster Environmental Strategies Inc., Calgary, AB (Canada)]|[Waterloo Environmental Biotechnology Inc., Waterloo, ON (Canada)

2008-07-01

This presentation discussed the advantages of phytoremediation and provided an overview of a phytoremediation tests results for petroleum and salt remediation. Several examples of remediation methods were discussed, including the dig and dump method; soil incineration; chemical extraction; electrokinetic separation and land farming/natural attenuation. The advantages of phytoremediation include improved natural structure and texture of soil; suitability to most regions and climates because it is driven by solar energy; cost effectiveness and technically feasible; reasonable time frame for restoration; promotion of high rhizosphere activity by plants; and effective use at remote sites. The development and proof of plant growth promoting rhizobacteria (PGPR) enhanced phytoremediation systems (PEPS) was then addressed. A description of the PEPS was provided. This presentation also reviewed the interaction of a PGPR containing ACC deaminase with a plant seed or root; research and development of the PEPS for PHC remediation; the use of petroleum remediation on an Imperial Oil Sarnia land farm; proof of concept of the application of the PEPS for PHC remediation in Hinton, Alberta; and development of the PEPS for salt impacted sites. Field work and the characteristics of soils were also examined. It was concluded that the PEPS has great potential for efficient remediation of organic, salt and metal contaminated sites and that PGPR alleviates stress and promotes growth resulting in low ethylene and high auxin content. tabs., figs.

Variability of Measured Runoff and Soil Loss from Field Plots

Directory of Open Access Journals (Sweden)

F. Asadzadeh

2016-02-01

Full Text Available Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes. Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on

Cover crops impact on excess rainfall and soil erosion rates in orchards and potato fields, Israel

Science.gov (United States)

Egozi, Roey; Gil, Eshel

2015-04-01

Bare soil and high drainage densities are common characteristics of intensive agriculture land. The couplings of these characteristics lead to high runoff and eroded soil volumes leaving the field or the orchard via the local drainage system into the fluvial system. This process increase flood risk due to massive deposition of the coarse fraction of the eroded soil and therefore reduces channel capacity to discharge the increase volumes of concentrated runoff. As a result drainage basin authorities are forced to invest large amount of money in maintaining and enlarging the drainage network. However this approach is un-sustainable. On the other hand, implementing cover crops (CC) and modification to current agricultural practices over the contributing area of the watershed seems to have more benefits and provide sustainable solution. A multi-disciplinary approach applied in commercial potatoes fields and orchards that utilize the benefit of CC shows great success as means of soil and water conservation and weed disinfestation without reduction in the yield, its quality or its profitability. The results indicate that it is possible to grow potatoes and citrus trees under CC with no reduction in yield or nutrient uptake, with more than 95% reduction in soil loss and more than 60% in runoff volumes and peak discharges.

Simulating maize yield and bomass with spatial variability of soil field capacity

Science.gov (United States)

Ma, Liwang; Ahuja, Lajpat; Trout, Thomas; Nolan, Bernard T.; Malone, Robert W.

2015-01-01

Spatial variability in field soil properties is a challenge for system modelers who use single representative values, such as means, for model inputs, rather than their distributions. In this study, the root zone water quality model (RZWQM2) was first calibrated for 4 yr of maize (Zea mays L.) data at six irrigation levels in northern Colorado and then used to study spatial variability of soil field capacity (FC) estimated in 96 plots on maize yield and biomass. The best results were obtained when the crop parameters were fitted along with FCs, with a root mean squared error (RMSE) of 354 kg ha–1 for yield and 1202 kg ha–1 for biomass. When running the model using each of the 96 sets of field-estimated FC values, instead of calibrating FCs, the average simulated yield and biomass from the 96 runs were close to measured values with a RMSE of 376 kg ha–1 for yield and 1504 kg ha–1 for biomass. When an average of the 96 FC values for each soil layer was used, simulated yield and biomass were also acceptable with a RMSE of 438 kg ha–1 for yield and 1627 kg ha–1 for biomass. Therefore, when there are large numbers of FC measurements, an average value might be sufficient for model inputs. However, when the ranges of FC measurements were known for each soil layer, a sampled distribution of FCs using the Latin hypercube sampling (LHS) might be used for model inputs.

Field fluxes and speciation of arsines emanating from soils.

Science.gov (United States)

Mestrot, Adrien; Feldmann, Joerg; Krupp, Eva M; Hossain, Mahmud S; Roman-Ross, Gabriela; Meharg, Andrew A

2011-03-01

The biogeochemical cycle of arsenic (As) has been extensively studied over the past decades because As is an environmentally ubiquitous, nonthreshold carcinogen, which is often elevated in drinking water and food. It has been known for over a century that micro-organisms can volatilize inorganic As salts to arsines (arsine AsH(3), mono-, di-, and trimethylarsines, MeAsH(2), Me(2)AsH, and TMAs, respectively), but this part of the As cycle, with the exception of geothermal environs, has been almost entirely neglected because of a lack of suited field measurement approaches. Here, a validated, robust, and low-level field-deployable method employing arsine chemotrapping was used to quantify and qualify arsines emanating from soil surfaces in the field. Up to 240 mg/ha/y arsines was released from low-level polluted paddy soils (11.3 ± 0.9 mg/kg As), primarily as TMAs, whereas arsine flux below method detection limit was measured from a highly contaminated mine spoil (1359 ± 212 mg/kg As), indicating that soil chemistry is vital in understanding this phenomenon. In microcosm studies, we could show that under reducing conditions, induced by organic matter (OM) amendment, a range of soils varied in their properties, from natural upland peats to highly impacted mine-spoils, could all volatilize arsines. Volatilization rates from 0.5 to 70 μg/kg/y were measured, and AsH(3), MeAsH(2), Me(2)AsH, and TMAs were all identified. Addition of methylated oxidated pentavalent As, namely monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), to soil resulted in elevated yearly rates of volatilization with up to 3.5% of the total As volatilized, suggesting that the initial conversion of inorganic As to MMAA limits the rate of arsine and methylarsines production by soils. The nature of OM amendment altered volatilization quantitatively and qualitatively, and total arsines release from soil showed correlation between the quantity of As and the concentration of dissolved organic

Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields

Directory of Open Access Journals (Sweden)

A. Marais

2012-01-01

Full Text Available Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN, community level physiological profiling (CLPP, and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.

Adsorption Kinetics of Carbamate Pesticide in Rice Field Soil

Directory of Open Access Journals (Sweden)

Soontree Khuntong

2010-07-01

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

Soil nutrient content of old-field and agricultural ecosystems exposed to chronic gamma irradiation

International Nuclear Information System (INIS)

Armentano, T.V.; Holt, B.R.; Bottino, P.J.

1975-01-01

Soil nutrients (extractable P. and NO 3 -N, exchangeable Ca, Mg and K), exchangeable Al, pH and organic matter content were measured over the top six inches of the soils of the seven-year old-field portion and the cultivated portion of the Brookhaven gamma field. Although concentrations of all nutrient elements were higher in the agricultural soil, the distributions of Ca, P, Al, pH and organic matter were similar along the radiation gradient in both fields. There was also a regular reduction in the phosphorus with decreasing exposure, but distribution of other elements was not clearly related to radiation effects. The distribution of all elements except K was significantly correlated with pH in the agricultural soil. In the old-field only Ca, Mg and Al showed this relationship. The most conspicuous effects of nearly 25 yr of chronic irradiation of the site were a reduction in soil organic matter content and an increase in soil P in both fields. (author)

Phytotoxic Effects of (±)-Catechin In vitro, in Soil, and in the Field

Science.gov (United States)

Inderjit; Pollock, Jarrod L.; Callaway, Ragan M.; Holben, William

2008-01-01

Background Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants. Methodology/Principal Findings We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (±)-catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (±)-catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (±)-catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (±)-catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (±)-Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (±)-catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 µg l−1. Multiple pulses of (±)-catechin were inhibitory at very low concentrations in Indian soil. Conclusions/Significance Our results demonstrate that (±)-catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied at low concentrations in

Modelling soil water dynamics and crop water uptake at the field level

NARCIS (Netherlands)

Kabat, P.; Feddes, R.A.

1995-01-01

Parametrization approaches to model soil water dynamics and crop water uptake at field level were analysed. Averaging and numerical difficulties in applying numerical soil water flow models to heterogeneous soils are highlighted. Simplified parametrization approaches to the soil water flow, such as

National Soil Information System in Turkey

Science.gov (United States)

Emrah Erdogan, Hakki; Sahin, Mehmet; Sahin, Yuksel

2013-04-01

Land consolidation (LC) represents complexity if management, legal, economic and technical procedures realized in order to adjust the land structure according to actual human preferences and needs. It includes changes in ownership rights to land and other real estate property, exchange of parcels among owners, changes in parcel borders, parcel size and shape, joining and dividing of parcels, changes in land use, construction works as roads, bridges, water changes etc.. Since the subject of LC is agricultural lands, the quality of consolidation depends on the quality of soil data. General Directorate of Agrarian Reform (GDAR) is the responsible institution on land consolidation whole of Turkey. Under GDAR, National Soil Information System (NSIS) has been build up with base soil data in relevant scale (1:5000). NSIS contain detailed information on soil chemical and physical properties, current land use, parent material, land capability class, Storie Index Values. SI were used on land consolidation, land use planning and farm development services. LCC was used for land distribution, rental land; define of village settlement, consolidation, expropriation, reconstruction, reclamation, non-agricultural usage. LCC were also specified to subclasses in four different limited factors as i) flow and erosion risk ii) requirement of drainage and soil moisture iii) Limits of soil tillage and root (shallow soils, low water retention capacity, stony, salty .etc) iv) climatic limits. In this study, digital soil survey and mapping project located in Yumurtalik, Adana is presented as an example of NSIS data structure. The project cover an area of 45709 ha that include crop lands as an area of 28528 ha and other land use (urban, roads..etc) as an area of 17181 ha. Soil profiles were described in 45 different points and totally 1279 soil samples were collected in field study and the check bore hole were made in 3170 points.

Heat pulse probe measurements of soil water evaporation in a corn field

Science.gov (United States)

Latent heat fluxes from cropped fields consist of soil water evaporation and plant transpiration. It is difficult to accurately separate evapotranspiration into evaporation and transpiration. Heat pulse probes have been used to measure bare field subsurface soil water evaporation, however, the appl...

BIOCHEMICAL PROCESSES IN CHERNOZEM SOIL UNDER DIFFERENT FERTILIZATION SYSTEMS

Directory of Open Access Journals (Sweden)

Ecaterina Emnova

2012-06-01

Full Text Available The paper deals with the evaluation of the intensity of certain soil biochemical processes (e.g. soil organic C mineralization at Organic and mixed Mineral+Organic fertilization of typical chernozem in crop rotation dynamics (for 6 years by use of eco-physiological indicators of biological soil quality: microbial biomass carbon, basal soil respiration, as well as, microbial and metabolic quotients. Soil sampling was performed from a long-term field crop experiment, which has been established in 1971 at the Balti steppe (Northern Moldova. The crop types had a more considerable impact on the soil microbial biomass accumulation and community biochemical activity compared to long-term Organic or mixed Mineral + Organic fertilizers amendments. The Org fertilization system doesn’t make it possible to avoid the loss of organic C in arable typical chernozem. The organic fertilizer (cattle manure is able to mitigate the negative consequences of long-term mineral fertilization.

Methane and nitrous oxide cycling microbial communities in soils above septic leach fields: Abundances with depth and correlations with net surface emissions.

Science.gov (United States)

Fernández-Baca, Cristina P; Truhlar, Allison M; Omar, Amir-Eldin H; Rahm, Brian G; Walter, M Todd; Richardson, Ruth E

2018-05-31

Onsite septic systems use soil microbial communities to treat wastewater, in the process creating potent greenhouse gases (GHGs): methane (CH 4 ) and nitrous oxide (N 2 O). Subsurface soil dispersal systems of septic tank overflow, known as leach fields, are an important part of wastewater treatment and have the potential to contribute significantly to GHG cycling. This study aimed to characterize soil microbial communities associated with leach field systems and quantify the abundance and distribution of microbial populations involved in CH 4 and N 2 O cycling. Functional genes were used to target populations producing and consuming GHGs, specifically methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) for CH 4 and nitric oxide reductase (cnorB) and nitrous oxide reductase (nosZ) for N 2 O. All biomarker genes were found in all soil samples regardless of treatment (leach field, sand filter, or control) or depth (surface or subsurface). In general, biomarker genes were more abundant in surface soils than subsurface soils suggesting the majority of GHG cycling is occurring in near-surface soils. Ratios of production to consumption gene abundances showed a positive relationship with CH 4 emissions (mcrA:pmoA, p  0.05). Of the three measured soil parameters (volumetric water content (VWC), temperature, and conductivity), only VWC was significantly correlated to a biomarker gene, mcrA (p = 0.0398) but not pmoA or either of the N 2 O cycling genes (p > 0.05 for cnorB and nosZ). 16S rRNA amplicon library sequencing results revealed soil VWC, CH 4 flux and N 2 O flux together explained 64% of the microbial community diversity between samples. Sequencing of mcrA and pmoA amplicon libraries revealed treatment had little effect on diversity of CH 4 cycling organisms. Overall, these results suggest GHG cycling occurs in all soils regardless of whether or not they are associated with a leach field system. Copyright © 2018 Elsevier B

Soil process-oriented modelling of within-field variability based on high-resolution 3D soil type distribution maps.

Science.gov (United States)

Bönecke, Eric; Lück, Erika; Gründling, Ralf; Rühlmann, Jörg; Franko, Uwe

2016-04-01

Today, the knowledge of within-field variability is essential for numerous purposes, including practical issues, such as precision and sustainable soil management. Therefore, process-oriented soil models have been applied for a considerable time to answer question of spatial soil nutrient and water dynamics, although, they can only be as consistent as their variation and resolution of soil input data. Traditional approaches, describe distribution of soil types, soil texture or other soil properties for greater soil units through generalised point information, e.g. from classical soil survey maps. Those simplifications are known to be afflicted with large uncertainties. Varying soil, crop or yield conditions are detected even within such homogenised soil units. However, recent advances of non-invasive soil survey and on-the-go monitoring techniques, made it possible to obtain vertical and horizontal dense information (3D) about various soil properties, particularly soil texture distribution which serves as an essential soil key variable affecting various other soil properties. Thus, in this study we based our simulations on detailed 3D soil type distribution (STD) maps (4x4 m) to adjacently built-up sufficient informative soil profiles including various soil physical and chemical properties. Our estimates of spatial STD are based on high-resolution lateral and vertical changes of electrical resistivity (ER), detected by a relatively new multi-sensor on-the-go ER monitoring device. We performed an algorithm including fuzzy-c-mean (FCM) logic and traditional soil classification to estimate STD from those inverted and layer-wise available ER data. STD is then used as key input parameter for our carbon, nitrogen and water transport model. We identified Pedological horizon depths and inferred hydrological soil variables (field capacity, permanent wilting point) from pedotransferfunctions (PTF) for each horizon. Furthermore, the spatial distribution of soil organic carbon

Soil microbial C:N ratio is a robust indicator of soil productivity for paddy fields

Science.gov (United States)

Li, Yong; Wu, Jinshui; Shen, Jianlin; Liu, Shoulong; Wang, Cong; Chen, Dan; Huang, Tieping; Zhang, Jiabao

2016-10-01

Maintaining good soil productivity in rice paddies is important for global food security. Numerous methods have been developed to evaluate paddy soil productivity (PSP), most based on soil physiochemical properties and relatively few on biological indices. Here, we used a long-term dataset from experiments on paddy fields at eight county sites and a short-term dataset from a single field experiment in southern China, and aimed at quantifying relationships between PSP and the ratios of carbon (C) to nutrients (N and P) in soil microbial biomass (SMB). In the long-term dataset, SMB variables generally showed stronger correlations with the relative PSP (rPSP) compared to soil chemical properties. Both correlation and variation partitioning analyses suggested that SMB N, P and C:N ratio were good predictors of rPSP. In the short-term dataset, we found a significant, negative correlation of annual rice yield with SMB C:N (r = -0.99), confirming SMB C:N as a robust indicator for PSP. In treatments of the short-term experiment, soil amendment with biochar lowered SMB C:N and improved PSP, while incorporation of rice straw increased SMB C:N and reduced PSP. We conclude that SMB C:N ratio does not only indicate PSP but also helps to identify management practices that improve PSP.

Effect of crop rotation on soil nutrient balance and weediness in soddy podzolic organic farming fields

Science.gov (United States)

Zarina, Livija; Zarina, Liga

2017-04-01

The nutrient balance in different crop rotations under organic cropping system has been investigated in Latvia at the Institute of Agricultural Resources and Economics since 2006. Latvia is located in a humid and moderate climatic region where the rainfall exceeds evaporation (soil moisture coefficient > 1) and the soil moisture regime is characteristic with percolation. The average annual precipitation is 670-850 mm. The average temperature varies from -6.7° C in January to 16.5 °C in July. The growing season is 175 - 185 days. The most widespread are podzolic soils and mainly they are present in agricultural fields in all regions of Latvia. In a wider sense the goal of the soil management in organic farming is a creation of the biologically active flora and fauna in the soil by maintaining a high level of soil organic matter which is good for crops nutrient balance. Crop rotation is a central component of organic farming systems and has many benefits, including growth of soil microbial activity, which may increase nutrient availability. The aim of the present study was to calculate nutrient balance for each crop in the rotations and average in each rotation. Taking into account that crop rotations can limit build-up of weeds, additionally within the ERA-net CORE Organic Plus transnational programs supported project PRODIVA the information required for a better utilization of crop diversification for weed management in North European organic arable cropping systems was summarized. It was found that the nutrient balance was influenced by nutrients uptake by biomass of growing crops in crop rotation. The number of weeds in the organic farming fields with crop rotation is dependent on the cultivated crops and the succession of crops in the crop rotation.

Field Guide to Soils. Earth Science Curriculum Project Pamphlet Series PS-2.

Science.gov (United States)

Foth, Henry; Jacobs, Hyde S.

Discussed are the importance of soil to plant and animal life, the evolution of a soil profile, and the major kinds of soil in the United States. On a suggested field trip, students examine different kinds of soil profiles; they also measure soil acidity and water-holding capacity. Suggestions for further study are provided along with references…

Modeling soil organic carbon stocks and changes in Spain using the GEFSOC system

Science.gov (United States)

Álvaro-Fuentes, Jorge; Easter, Mark; Cantero-Martínez, Carlos; Paustian, Keith

2010-05-01

Currently, there is little information about soil organic carbon (SOC) stocks in Spain. To date the effects of land-use and soil management on SOC stocks in Spain have been evaluated in experimental fields under certain soil and climate conditions. However, these field experiments do not account for the spatial variability in management, cropping systems and soil and climate characteristics that exist in the whole territory. More realistic approaches like ecosystem-level dynamic simulation systems linked to geographic information systems (GIS) allow better assessments of SOC stocks at a regional or national level. The Global Environmental Facility Soil Organic Carbon (GEFSOC) system was recently built for this purpose (Milne et al., 2007) and it incorporates three widely used models for estimating SOC dynamics: (a) the Century ecosystem model; (b) the RothC soil C decomposition model; and (c) the Intergovernmental Panel on Climate Change (IPCC) method for assessing soil C at regional scales. We modeled 9.5 Mha in northeast Spain using the GEFSOC system to predict SOC stocks and changes comprising: pasture, forest, cereal-fallow, cereal monoculture, orchards, rice, irrigated land and grapes and olives. The spatial distribution of the different land use categories and their change over time was obtained from the European Corine database and from Spanish census data on land use from 1926 to 2007. At the same time, current and historical management information was collected from different sources in order to have a fairly well picture of changes in land use and management for this area. Soil parameters needed by the system were obtained from the European soil map (1 km x 1 km) and climate data was produced by the Meteorology State Agency (Ministry of the Environment and Rural and Marine Environs of Spain). The SOC stocks simulated were validated with SOC values from the European SOC map and from other national studies. Modeled SOC results suggested that spatial

Geographical information system for radon gas from soil measurement

International Nuclear Information System (INIS)

Orlando, P.; Amici, M.; Altieri, A.; Massari, P.; Miccadei, E.; Onofri, A.; Orlando, C.; Paolelli, C.; Paron, P.; Perticaroli, P.; Piacentini, T.; Silvestri, C.; Minach, L.; Verdi, L.; Bertolo, A.; Trotti, F.

2000-03-01

The working program foresees the realization of an geographical information system for the check in field of the geological parameters and determination of uranium and radium contents in various type of rocks. It is here also pointed out a measuring method for radon concentration in soil [it

Field Scale Spatial Modelling of Surface Soil Quality Attributes in Controlled Traffic Farming

Science.gov (United States)

Guenette, Kris; Hernandez-Ramirez, Guillermo

2017-04-01

The employment of controlled traffic farming (CTF) can yield improvements to soil quality attributes through the confinement of equipment traffic to tramlines with the field. There is a need to quantify and explain the spatial heterogeneity of soil quality attributes affected by CTF to further improve our understanding and modelling ability of field scale soil dynamics. Soil properties such as available nitrogen (AN), pH, soil total nitrogen (STN), soil organic carbon (SOC), bulk density, macroporosity, soil quality S-Index, plant available water capacity (PAWC) and unsaturated hydraulic conductivity (Km) were analysed and compared among trafficked and un-trafficked areas. We contrasted standard geostatistical methods such as ordinary kriging (OK) and covariate kriging (COK) as well as the hybrid method of regression kriging (ROK) to predict the spatial distribution of soil properties across two annual cropland sites actively employing CTF in Alberta, Canada. Field scale variability was quantified more accurately through the inclusion of covariates; however, the use of ROK was shown to improve model accuracy despite the regression model composition limiting the robustness of the ROK method. The exclusion of traffic from the un-trafficked areas displayed significant improvements to bulk density, macroporosity and Km while subsequently enhancing AN, STN and SOC. The ability of the regression models and the ROK method to account for spatial trends led to the highest goodness-of-fit and lowest error achieved for the soil physical properties, as the rigid traffic regime of CTF altered their spatial distribution at the field scale. Conversely, the COK method produced the most optimal predictions for the soil nutrient properties and Km. The use of terrain covariates derived from light ranging and detection (LiDAR), such as of elevation and topographic position index (TPI), yielded the best models in the COK method at the field scale.

Microbial Diversity in Soil Treatment Systems for Wastewater

Science.gov (United States)

Van Cuyk, S.; Spear, J.; Siegrist, R.; Pace, N.

2002-05-01

There is an increasing awareness and concern over land based wastewater system performance with respect to the removal of bacteria and virus. The goal of this work is to describe and identify the organismal composition of the microbiota in the applied wastewater effluent, the rich biomat that develops at the infiltrative surface, and in the soil percolate in order to aid in the understanding of bacterial and virus purification in soil treatment systems. The traditional reliance on pure culture techniques to describe microbiota is circumvented by the employment of a molecular approach. Microbial community characterization is underway based on cloning and sequencing of 16S rRNA genes for phylogenetic analyses, to determine the nature and quantity of microbiota that constitute these ecosystems. Knowledge of the organisms naturally present can influence the design and treatment capacity of these widely used land based systems. Laboratory, intermediate and field scale systems are currently under study. Since human pathogens are known to exist in sewage effluents, their removal in wastewater infiltration systems and within the underlying soil are in need of a more fundamental understanding. The relationship between design parameters and environmental conditions, including a microbial characterization, is essential for the prevention of contamination in groundwater sources. Preliminary results indicate the presence of uncultured organisms and phylogenetic kinds that had not been detected in these systems using other methods. Acinetobacter johnsonii and Acrobacter cryaerophilus were the two dominant species found in septic tank effluent, comprising 20% and 11% of the library respectively. In soil samples collected from the infiltrative surface of a column dosed with STE, there was no dominant bacterial species present. Percolate samples collected from the outflow of the column showed that a tuber borchii symbiont, a common soil microorganism, dominated the bacterial

Distribution and Downward Movement of Pasteuria penetrans in Field Soil.

Science.gov (United States)

Cetintas, R; Dickson, D W

2005-06-01

Endospores of Pasteuria penetrans were evaluated for their vertical distribution in field soil and their downward movement through soil in the laboratory. In the field trial, the number of endospores attached to second-stage juveniles (J2) of Meloidogyne arenaria race 1 varied greatly in different soil depths. There were higher percentages of J2 with endospores attached in former weed fallow plots during the first 3 years of growing peanut than in former bahiagrass and rhizomal peanut plots (P 0.05). In laboratory trials, P. penetrans endospores were observed to move throughout the soil through the percolation of water. After one application of water, some endospores were detected 25 to 37.5 cm deep. Endospores were present at the greatest depth, 37.5 to 50 cm, after the third application of water. These results indicate that rain or water applications by irrigation are likely to move endospores to deeper levels of the soil, but the majority of endospores remain in the upper 0-to-30-cm depth.

Field trials to evaluate effects of continuously planted transgenic insect-resistant cottons on soil invertebrates.

Science.gov (United States)

Li, Xiaogang; Liu, Biao; Wang, Xingxiang; Han, Zhengmin; Cui, Jinjie; Luo, Junyu

2012-03-01

Impacts on soil invertebrates are an important aspect of environmental risk assessment and post-release monitoring of transgenic insect-resistant plants. The purpose of this study was to research and survey the effects of transgenic insect-resistant cottons that had been planted over 10 years on the abundance and community structure of soil invertebrates under field conditions. During 3 consecutive years (2006-2008), eight common taxa (orders) of soil invertebrates belonging to the phylum Arthropoda were investigated in two different transgenic cotton fields and one non-transgenic cotton field (control). Each year, soil samples were taken at four different growth stages of cotton (seedling, budding, boll forming and boll opening). Animals were extracted from the samples using the improved Tullgren method, counted and determined to the order level. The diversity of the soil fauna communities in the different fields was compared using the Simpson's, Shannon's diversity indices and evenness index. The results showed a significant sampling time variation in the abundance of soil invertebrates monitored in the different fields. However, no difference in soil invertebrate abundance was found between the transgenic cotton fields and the control field. Both sampling time and cotton treatment had a significant effect on the Simpson's, Shannon's diversity indices and evenness index. They were higher in the transgenic fields than the control field at the growth stages of cotton. Long-term cultivation of transgenic insect-resistant cottons had no significant effect on the abundance of soil invertebrates. Collembola, Acarina and Araneae could act as the indicators of soil invertebrate in this region to monitor the environmental impacts of transgenic plants in the future. This journal is © The Royal Society of Chemistry 2012

Variation of Bacterial Community Diversity in Rhizosphere Soil of Sole-Cropped versus Intercropped Wheat Field after Harvest.

Science.gov (United States)

Yang, Zhenping; Yang, Wenping; Li, Shengcai; Hao, Jiaomin; Su, Zhifeng; Sun, Min; Gao, Zhiqiang; Zhang, Chunlai

2016-01-01

As the major crops in north China, spring crops are usually planted from April through May every spring and harvested in fall. Wheat is also a very common crop traditionally planted in fall or spring and harvested in summer year by year. This continuous cropping system exhibited the disadvantages of reducing the fertility of soil through decreasing microbial diversity. Thus, management of microbial diversity in the rhizosphere plays a vital role in sustainable crop production. In this study, ten common spring crops in north China were chosen sole-cropped and four were chosen intercropped with peanut in wheat fields after harvest. Denaturing gradient gel electrophoresis (DGGE) and DNA sequencing of one 16S rDNA fragment were used to analyze the bacterial diversity and species identification. DGGE profiles showed the bacterial community diversity in rhizosphere soil samples varied among various crops under different cropping systems, more diverse under intercropping system than under sole-cropping. Some intercropping-specific bands in DGGE profiles suggested that several bacterial species were stimulated by intercropping systems specifically. Furthermore, the identification of these dominant and functional bacteria by DNA sequencing indicated that intercropping systems are more beneficial to improve soil fertility. Compared to intercropping systems, we also observed changes in microbial community of rhizosphere soil under sole-crops. The rhizosphere bacterial community structure in spring crops showed a strong crop species-specific pattern. More importantly, Empedobacter brevis, a typical plant pathogen, was only found in the carrot rhizosphere, suggesting carrot should be sown prudently. In conclusion, our study demonstrated that crop species and cropping systems had significant effects on bacterial community diversity in the rhizosphere soils. We strongly suggest sorghum, glutinous millet and buckwheat could be taken into account as intercropping crops with peanut

Solute movement observation in the field soils by means of radioactive tracers

International Nuclear Information System (INIS)

Lichner, L.

1986-01-01

The radioactive tracer method is discussed as applied to transfer velocity measurements of solutions in unsaturated soils, its applicability and the criteria for the choice of the tracer. The method is based on measurement of the radioactive tracer velocity in the field and on laboratory determination of the equilibrium distribution coefficients of the tracer and the solute in the same field soil. From these results and from the soil characteristics (porosity, bulk density) the solute transfer velocity in the field soil can be calculated. The results are presented of 131 I - velocity measurements in the loamy soil in the region of water source Cunovo near Bratislava, which equals 9.29x10 -9 m/s, and in the downstream slope of the earth dam Rozgrund near Banska Stiavnica where the velocity of 131 I - near the dam foot was found to be 2.03 - 2.86 times greater than near the top. Results are also presented of 131 I - , [ 60 Co-EDTA] - and 60 Co 2+ velocity measurements in clay-loam soil at the experimental field of the Research Institute of Irrigation in Most near Bratislava. The results are applicable to evaluation of surface damage to embankments and earth dams, to determination of the conservation zone around water sources, and the establishment of the level of ground water pollution from different sources (waste disposal, agriculture, etc.)

Simulating emissions of 1,3-dichloropropene after soil fumigation under field conditions.

Science.gov (United States)

Yates, S R; Ashworth, D J

2018-04-15

Soil fumigation is an important agricultural practice used to produce many vegetable and fruit crops. However, fumigating soil can lead to atmospheric emissions which can increase risks to human and environmental health. A complete understanding of the transport, fate, and emissions of fumigants as impacted by soil and environmental processes is needed to mitigate atmospheric emissions. Five large-scale field experiments were conducted to measure emission rates for 1,3-dichloropropene (1,3-D), a soil fumigant commonly used in California. Numerical simulations of these experiments were conducted in predictive mode (i.e., no calibration) to determine if simulation could be used as a substitute for field experimentation to obtain information needed by regulators. The results show that the magnitude of the volatilization rate and the total emissions could be adequately predicted for these experiments, with the exception of a scenario where the field was periodically irrigated after fumigation. In addition, the timing of the daily peak 1,3-D emissions was not accurately predicted for these experiments due to the peak emission rates occurring during the night or early-morning hours. This study revealed that more comprehensive mathematical models (or adjustments to existing models) are needed to fully describe emissions of soil fumigants from field soils under typical agronomic conditions. Published by Elsevier B.V.

Dissipation and phytoremediation of polycyclic aromatic hydrocarbons in freshly spiked and long-term field-contaminated soils.

Science.gov (United States)

Wei, Ran; Ni, Jinzhi; Li, Xiaoyan; Chen, Weifeng; Yang, Yusheng

2017-03-01

Pot experiments were used to compare the dissipation and phytoremediation effect of alfalfa (Medicago sativa L.) for polycyclic aromatic hydrocarbons (PAHs) in a freshly spiked soil and two field-contaminated soils with different soil organic carbon (SOC) contents (Anthrosols, 1.41% SOC; Phaeozems, 8.51% SOC). In spiked soils, the dissipation rates of phenanthrene and pyrene were greater than 99.5 and 94.3%, respectively, in planted treatments and 95.0 and 84.5%, respectively, in unplanted treatments. In field-contaminated Anthrosols, there were limited but significant reductions of 10.2 and 15.4% of total PAHs in unplanted and planted treatments, respectively. In field-contaminated Phaeozems, there were no significant reductions of total PAHs in either unplanted or planted treatments. A phytoremediation effect was observed for the spiked soils and the Anthrosols, but not for the Phaeozems. The results indicated that laboratory tests with spiked soils cannot reflect the real state of field-contaminated soils. Phytoremediation efficiency of PAHs in field-contaminated soils was mainly determined by the content of SOC. Phytoremediation alone has no effect on the removal of PAHs in field-contaminated soils with high SOC content.

[Research on characteristics of soil clay mineral evolution in paddy field and dry land by XRD spectrum].

Science.gov (United States)

Zhang, Zhi-dan; Li, Qiao; Luo, Xiang-li; Jiang, Hai-chao; Zheng, Qing-fu; Zhao, Lan-po; Wang, Ji-hong

2014-08-01

The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture-->vermiculite, while in paddy field it was S/I mixture-->vermiculite-->kaolinite. One kind of hydroxylated 'chlorite' mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two'kinds of land use comparatively, and was a new perspective of soil minerals study.

Soil properties mapping with the DIGISOIL multi-sensor system

Science.gov (United States)

Grandjean, G.

2012-04-01

The multidisciplinary DIGISOIL project aimed to integrate and improve in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the DIGISOIL project allows to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The system was tested on different field tests, and validated the proposed technologies and solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from geophysical data to soil properties maps. For two test sites, located respectively in Luxembourg (LU) and Mugello (IT) a set of soil properties maps have been produced. They give

Soil CO 2 fluxes from direct seeding rice fields under two tillage practices in central China

Science.gov (United States)

Li, Cheng-fang; Kou, Zhi-kui; Yang, Jin-hua; Cai, Ming-li; Wang, Jin-ping; Cao, Cou-gui

2010-07-01

Agricultural practices affect the production and emission of carbon dioxide (CO 2) from paddy soils. It is crucial to understand the effects of tillage and N fertilization on soil CO 2 flux and its influencing factors for a better comprehension of carbon dynamics in subtropical paddy ecosystems. A 2-yr field study was conducted to assess the effects of tillage (conventional tillage [CT] and no-tillage [NT]) and N fertilization (0 and 210 kg N ha -1) on soil CO 2 fluxes during the 2008 and 2009 rice growing seasons in central China. Treatments were established following a split-plot design of a randomized complete block with tillage practices as the main plot and N fertilizer level as the split-plot treatment. The soil CO 2 fluxes were measured 24 times in 2008 and 17 times in 2009. N fertilization did not affect soil CO 2 emissions while tillage affected soil CO 2 emissions, where NT had similar soil CO 2 emissions to CT in 2008, but in 2009, NT significantly increased soil CO 2 emissions. Cumulative CO 2 emissions were 2079-2245 kg CO 2-C ha -1 from NT treatments, and 2084-2141 kg CO 2-C ha -1 from CT treatments in 2008, and were 1257-1401 kg CO 2-C ha -1 from NT treatments, and 1003-1034 kg CO 2-C ha -1 from CT treatments in 2009, respectively. Cumulative CO 2 emissions were significantly related to aboveground biomass and soil organic C. Before drainage of paddy fields, soil CO 2 fluxes were significantly related to soil temperature with correlation coefficients ( R) of 0.67-0.87 in 2008 and 0.69-0.85 in 2009; moreover, the Q 10 values ranged from 1.28 to 1.55 and from 2.10 to 5.21 in 2009, respectively. Our results suggested that NT rice production system appeared to be ineffective in decreasing carbon emission, which suggested that CO 2 emissions from integrated rice-based system should be taken into account to assess effects of tillage.

Three New Records of Ascomycetes Isolates from Field Soils in Korea

OpenAIRE

Adhikari, Mahesh; Gurung, Sun Kumar; Kim, Hyun Seung; Bazie, Setu; Lee, Hyun Gu; Lee, Hyang Burm; Lee, Youn Su

2017-01-01

Three new records of Ascomycota species (Chaetomium acropullum, Phialemonium globosum, Phialemonium atrogriseum) from field soils in Korea are presented in this study. These newly discovered fungal isolates were isolated from field soils from various places across Gyeongnam, Korea in 2016. All the isolates were identified and described based on morphological characteristics, and rDNA internal transcribed spacer and β-tubulin gene sequence data. Morphological features of these fungal species w...

Methodologically controlled variations in laboratory and field pH measurements in waterlogged soils

DEFF Research Database (Denmark)

Elberling, Bo; Matthiesen, Henning

2007-01-01

artefacts is critical. But the study includes agricultural and forest soils for comparison. At a waterlogged site, Laboratory results were compared with three different field methods: calomel pH probes inserted in the soil from pits, pH measurements of soil solution extracted from the soil, and pH profiles...... using a solid-state pH electrode pushed into the soil from the surface. Comparisons between in situ and laboratory methods revealed differences of more than 1 pH unit. The content of dissolved ions in soil solution and field observations of O2 and CO2 concentrations were used in the speciation model...... PHREEQE in order to predict gas exchange processes. Changes in pH in soil solution following equilibrium in the laboratory could be explained mainly by CO2 degassing. Only soil pH measured in situ using either calomel or solid-state probes inserted directly into the soil was not affected by gas exchange...

New strategies to strengthen the soil science knowledge of student during field activities

Science.gov (United States)

Benito, Marta; Hontoria, Chiquinquirá; Masaguer, Alberto; Diéguez, Carmen; Almorox, Javier; Pérez, Juana; Santano, Jesús; Mariscal, Ignacio; Gutiérrez, Jesús; Moliner, Ana

2013-04-01

Soil Science can be considered a discipline that serves as a fundamental base for other disciplines such as ecology, agronomy, plant production, etc. In order to demonstrate the relevance and connection to real world it is important to develop field and practical activities. Field activities help student to comprehend soil as part of the landscape and the natural ecosystems. These activities also help them to realize the importance of historical soil use on the quality of todaýs soil and landscapes. It is well known that fieldwork practices are essential to strengthen the soil science knowledge of students and their learning process. These fieldwork practices involve doing a physical activity rather than passively attending lectures or watching demonstrations. The simple visual and tactile observations in the field could be used to predict soil behavior and these direct observations are best made in the field. Students who learned in the field using an active work are more motivated, have more positive attitudes, and place more value in their work than those that learn passively. Therefore, when scheduling the coursework an important time is assigned to field work, which sometimes is not sufficiently profited from the standpoint of student learning taking into consideration the economic effort involved. We are aware that part of the students are simple spectators in the field so we encourage their participation by making them responsible for obtaining part of the information about the place and the types of soils that will be visited. On the other hand, we will invite the students to do some game based exercises, which are fun and force them to work in groups and to pay attention to explanations. Our objective is to present the information in a more attractive way, making the learning of soil profile description and easier task. The exercises that we propose are both field and problem-based learning to make sure that the knowledge is more memorable (non

Differential effects of biochar on soils within an eroded field

Science.gov (United States)

Schumacher, Thomas; Chintala, Rajesh; Sandhu, Saroop; Kumar, Sandeep; Clay, Dave; Gelderman, Ron; Papiernik, Sharon; Malo, Douglas; Clay, Sharon; Julson, Jim

2015-04-01

Future uses of biochar will in part be dependent not only on the effects of biochar on soil processes but also on the availability and economics of biochar production. If pyrolysis for production of bio-oil and syngas becomes wide-spread, biochar as a by-product of bio-oil production will be widely available and relatively inexpensive compared to the production of biochar as primary product. Biochar produced as a by-product of optimized bio-oil production using regionally available feedstocks was examined for properties and for use as an amendment targeted to contrasting soils within an eroded field in an on-farm study initiated in 2013 at Brookings, South Dakota, USA. Three plant based biochar materials produced from carbon optimized gasification of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were applied at a 1% (w/w) rate to a Maddock soil (Sandy, Mixed, Frigid Entic Hapludolls) located in an eroded upper landscape position and a Brookings soil (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) located in a depositional landscape position. The cropping system within this agricultural landscape was a corn (Zea mays L.) and soybean (Glycine max L.) rotation. Biochar physical and chemical properties for each of the feedstocks were determined including pH, surface area, surface charge potential, C-distribution, ash content, macro and micro nutrient composition. Yields, nutrient content, and carbon isotope ratio measurements were made on the harvested seed. Soil physical properties measured included water retention, bulk density, and water infiltration from a ponded double ring infiltrometer. Laboratory studies were conducted to determine the effects of biochar on partitioning of nitrate and phosphorus at soil surface exchange complex and the extracellular enzymes activity of C and N cycles. Crop yields were increased only in the Maddock soil. Biochar interacted with each

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...

Poly-use multi-level sampling system for soil-gas transport analysis in the vadose zone.

Science.gov (United States)

Nauer, Philipp A; Chiri, Eleonora; Schroth, Martin H

2013-10-01

Soil-gas turnover is important in the global cycling of greenhouse gases. The analysis of soil-gas profiles provides quantitative information on below-ground turnover and fluxes. We developed a poly-use multi-level sampling system (PMLS) for soil-gas sampling, water-content and temperature measurement with high depth resolution and minimal soil disturbance. It is based on perforated access tubes (ATs) permanently installed in the soil. A multi-level sampler allows extraction of soil-gas samples from 20 locations within 1 m depth, while a capacitance probe is used to measure volumetric water contents. During idle times, the ATs are sealed and can be equipped with temperature sensors. Proof-of-concept experiments in a field lysimeter showed good agreement of soil-gas samples and water-content measurements compared with conventional techniques, while a successfully performed gas-tracer test demonstrated the feasibility of the PMLS to determine soil-gas diffusion coefficients in situ. A field application of the PMLS to quantify oxidation of atmospheric CH4 in a field lysimeter and in the forefield of a receding glacier yielded activity coefficients and soil-atmosphere fluxes well in agreement with previous studies. With numerous options for customization, the presented tool extends the methodological choices to investigate soil-gas transport in the vadose zone.

Stability performance and interface shear strength of geocomposite drain/soil systems

Science.gov (United States)

Othman, Maidiana; Frost, Matthew; Dixon, Neil

2018-02-01

Landfill covers are designed as impermeable caps on top of waste containment facilities after the completion of landfill operations. Geocomposite drain (GD) materials consist of a geonet or geospacer (as a drainage core) sandwiched between non-woven geotextiles that act as separators and filters. GD provides a drainage function as part of the cover system. The stability performance of landfill cover system is largely controlled by the interface shear strength mobilized between the elements of the cover. If a GD is used, the interface shear strength properties between the upper surface of the GD and the overlying soil may govern stability of the system. It is not uncommon for fine grained materials to be used as cover soils. In these cases, understanding soil softening issues at the soil interface with the non-woven geotextile is important. Such softening can be caused by capillary break behaviour and build-up of water pressures from the toe of the drain upwards into the cover soil. The interaction processes to allow water flow into a GD core through the soil-geotextile interface is very complex. This paper reports the main behaviour of in-situ interface shear strength of soil-GD using field measurements on the trial landfill cover at Bletchley, UK. The soil softening at the interface due to soaked behaviour show a reduction in interface shear strength and this aspect should be emphasized in design specifications and construction control. The results also help to increase confidence in the understanding of the implications for design of cover systems.

Managing soil microbial communities in grain production systems through cropping practices

Science.gov (United States)

Gupta, Vadakattu

2013-04-01

Cropping practices can significantly influence the composition and activity of soil microbial communities with consequences to plant growth and production. Plant type can affect functional capacity of different groups of biota in the soil surrounding their roots, rhizosphere, influencing plant nutrition, beneficial symbioses, pests and diseases and overall plant health and crop production. The interaction between different players in the rhizosphere is due to the plethora of carbon and nutritional compounds, root-specific chemical signals and growth regulators that originate from the plant and are modulated by the physico-chemical properties of soils. A number of plant and environmental factors and management practices can influence the quantity and quality of rhizodeposition and in turn affect the composition of rhizosphere biota communities, microbe-fauna interactions and biological processes. Some of the examples of rhizosphere interactions that are currently considered important are: proliferation of plant and variety specific genera or groups of microbiota, induction of genes involved in symbiosis and virulence, promoter activity in biocontrol agents and genes correlated with root adhesion and border cell quality and quantity. The observation of variety-based differences in rhizodeposition and associated changes in rhizosphere microbial diversity and function suggests the possibility for the development of varieties with specific root-microbe interactions targeted for soil type and environment i.e. designer rhizospheres. Spatial location of microorganisms in the heterogeneous field soil matrix can have significant impacts on biological processes. Therefore, for rhizosphere research to be effective in variable seasonal climate and soil conditions, it must be evaluated in the field and within a farming systems context. With the current focus on security of food to feed the growing global populations through sustainable agricultural production systems there is a

A soil technological study on effectuating and maintaining adequate playing conditions of grass sports fields

NARCIS (Netherlands)

Wijk, van A.L.M.

1980-01-01

Playing conditions of grass sports fields have been studied focusing on top layer soil strength meeting the requirements of usage. In a field investigation a reproducible soil strength criterion was found from firmness appraisals and simultaneous measurements of soil strength. From

Distribution of uranium in soil components of agricultural fields after long-term application of phosphate fertilizers

International Nuclear Information System (INIS)

Yamaguchi, N.; Kawasaki, A.; Iiyama, I.

2009-01-01

Long-term application of phosphate fertilizers causes accumulation of U in the surface soil of agricultural fields. We investigated the soil constituents that contribute to the accumulation of U by using chemical extraction methods. Surface soil samples were obtained from upland fields, pastures, and paddy fields cultivated without any phosphate fertilizer (control site), with NPK fertilizer (NPK site), and with both NPK fertilizer and compost (NPK + compost site) for more than 20 years. In addition to the total U (U t ) concentration in soil, the concentrations of pyrophosphate- and acid oxalate-extractable U were determined as a measure of U associated with soil organic matter and poorly crystalline Fe/Al minerals in soil, respectively. The total, pyrophosphate-extractable, and acid oxalate-extractable U concentrations were higher in the soil obtained from the NPK and NPK + compost sites than in that obtained from the control site. The difference in the U concentrations between the NPK or NPK + compost site and the control site corresponded with the increased U concentration observed after the application of the phosphate fertilizer or both the fertilizer and compost. In the upland field and pasture soil, the increase in pyrophosphate-extractable U was 83-94% of that in U t . On the other hand, the increase in acid oxalate-extractable U was 44-58% of that in U t in the upland field and pasture soil, but it was almost equivalent to the increase in U t in the paddy soil with NPK. In conclusion, most of the phosphate fertilizer-derived U was either incorporated into the soil organic matter or poorly crystalline Fe/Al minerals in the surface soil of agricultural fields. Thus, soil organic matter is an important pool of U in upland field and pasture soil, whereas poorly crystalline Fe/Al minerals are important pools of U in paddy soil experiencing alternating changes in redox conditions

Soil organic carbon mapping of partially vegetated agricultural fields with imaging spectroscopy

NARCIS (Netherlands)

Bartholomeus, H.; Kooistra, L.; Stevens, A.; Leeuwen, van M.; Wesemael, van B.; Ben-Dor, E.; Tychon, B.

2011-01-01

Soil Organic Carbon (SOC) is one of the key soil properties, but the large spatial variation makes continuous mapping a complex task. Imaging spectroscopy has proven to be an useful technique for mapping of soil properties, but the applicability decreases rapidly when fields are partially covered

Apparent soil electrical conductivity in two different soil types

Directory of Open Access Journals (Sweden)

Wilker Nunes Medeiros

Full Text Available ABSTRACT Mapping the apparent soil electrical conductivity (ECa has become important for the characterization of the soil variability in precision agriculture systems. Could the ECa be used to locate the soil sampling points for mapping the chemical and physical soil attributes? The objective of this work was to examine the relations between ECa and soil attributes in two fields presenting different soil textures. In each field, 50 sampling points were chosen using a path that presented a high variability of ECa obtained from a preliminary ECa map. At each sampling point, the ECa was measured in soil depths of 0-20, 0-40 and 0-60 cm. In addition, at each point, soil samples were collected for the determination of physical and chemical attributes in the laboratory. The ECa data obtained for different soil depths was very similar. A large number of significant correlations between ECa and the soil attributes were found. In the sandy clay loam texture field there was no correlation between ECa and organic matter or between ECa and soil clay and sand content. However, a significant positive correlation was shown for the remaining phosphorus. In the sandy loam texture field the ECa had a significant positive correlation with clay content and a significant negative correlation with sand content. The results suggest that the mapping of apparent soil electrical conductivity does not replace traditional soil sampling, however, it can be used as information to delimit regions in a field that have similar soil attributes.

Soil food web properties explain ecosystem services across European land use systems.

Science.gov (United States)

de Vries, Franciska T; Thébault, Elisa; Liiri, Mira; Birkhofer, Klaus; Tsiafouli, Maria A; Bjørnlund, Lisa; Bracht Jørgensen, Helene; Brady, Mark Vincent; Christensen, Søren; de Ruiter, Peter C; d'Hertefeldt, Tina; Frouz, Jan; Hedlund, Katarina; Hemerik, Lia; Hol, W H Gera; Hotes, Stefan; Mortimer, Simon R; Setälä, Heikki; Sgardelis, Stefanos P; Uteseny, Karoline; van der Putten, Wim H; Wolters, Volkmar; Bardgett, Richard D

2013-08-27

Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world.

Modeling of 137Cs and 90Sr behavior in the soil-plant system within the territory adjacent to 'Experimental field' technical site in the Semipalatinsk test site

International Nuclear Information System (INIS)

Spiridonov, S.I.; Gontarenko, I.A.; Mukusheva, M.K.

2005-01-01

Modelling of 137 Cs and 90 Sr behavior in the soil-plant system is presented. Models have been parameterized for the area adjacent to the 'Experimental Field' Technical Site of the Semipalatinsk Test Site. The models describe the main processes responsible for changes of 137 Cs and 90 Sr content in the soil solution and, thereby, dynamics of radionuclides intake by vegetation. Results are presented from perspective and retrospective calculations, that reflect the dynamics of 137 and 90 Sr distribution by species in soil after nuclear explosions. The importance of factors governing radionuclide accumulation in plants within Semipalatinsk test site area is assessed. The analysis of sensitivity of model output variable to change in its parameters has revealed that the key soil properties significantly influence the results of prediction of radionuclide content in plants. (author)

Soil properties differently influence estimates of soil CO2 efflux from three chamber-based measurement systems

Science.gov (United States)

John R. Butnor; Kurt H. Johnsen; Chris A. Maier

2005-01-01

Soil C02 efflux is a major component of net ecosystem productivity (NEP) of forest systems. Combining data from multiple researchers for larger-scale modeling and assessment will only be valid if their methodologies provide directly comparable results. We conducted a series of laboratory and field tests to assess the presence and magnitude of...

Organics removal of combined wastewater through shallow soil infiltration treatment: a field and laboratory study.

Science.gov (United States)

Zhang, Zhiyin; Lei, Zhongfang; Zhang, Zhenya; Sugiura, Norio; Xu, Xiaotian; Yin, Didi

2007-11-19

Soil infiltration treatment (SIT) was proved to be an effective and low-cost treatment technique for decentralized effluents in the areas without perfect sewage systems. Field-scale experiments were conducted under several conditions to assess organics removals through a shallow soil infiltration treatment (SSIT, with effective depth 0.3m) of combined wastewater (discharge from toilets, restaurants and a gas station), while bench-scale soil column experiments were performed in laboratory in parallel to investigate biological and abiological effects of this kind of system. From the start-up to the 10th month, the field SSIT trenches experienced the lowest and highest temperatures of the operation period in Shanghai and exhibited effective organics removals after maturation, with the highest removal rate 75.8% of chemical oxygen demand (COD), highest ultraviolet absorption at 254 nm (UV(254)) decrease by 67.2% and 35.2-100% removals of phenolic and phthalate pollutants. The laboratory results indicated that more organics could be removed in room-temperatured (25+/-2 degrees C) SSIT systems under different influent COD concentrations from 45 mg/l to 406 mg/l, and the highest total COD removal rate could reach 94.0%, in which biological effect accounted for 57.7-71.9%. The results showed that temperature and hydraulic loading rate were the most important factors influencing the removals of COD and organic pollutants in SSIT.

Bio-mechanical removing of contaminated soils: a field experiment

International Nuclear Information System (INIS)

Jouve, A.; Maubert, H.; Schulte, E.

1992-01-01

If, in spite of safety precautions, a major nuclear accident would occur, countermeasures should be taken to attenuate the impact of radioactive deposits. The European RESSAC program (REhabilitation of Soils and Surfaces after an ACcident) aims at studying actions for normal life return in contaminated zones. One of them, called the Decontaminating Vegetal Network (D.V.N.) associates the biological action of turfing plants, producing a dense root-network capable to trap the top contaminated soil particles, and the mechanical efficiency of a turf harvester which can remove only 1 cm of soil. This performance, not associated with other techniques of soil removal such as scrapers or bulldozers, leads to minimize the waste production. The D.V.N is a vegetal cover spread over the contaminated soil, using the hydro-seeding technique. The growing plants are forming a pleasant lawn which may have a positive impact on the public opinion compared to techniques using bitumen mixtures to cover the soil. Field experiments involving labelling solutions of stable molybdenum salts simulating the contamination of the soil have shown that this technique can be applied as well on homogeneous cultivated soil surfaces as on roughly ploughed soils. 4 refs., 3 figs., 2 tabs

Fitting maize into sustainable cropping systems on acid soils of the tropics

International Nuclear Information System (INIS)

Horst, W.J.

2000-01-01

One of the key elements of sustainable cropping systems is the integration of crops and/or crop cultivars with high tolerance of soil acidity and which make most efficient use of the nutrients supplied by soil and fertilizer. This paper is based mainly on on-going work within an EU-funded project combining basic research on plant adaptation mechanisms by plant physiologists, and field experimentation on acid soils in Brazil, Cameroon, Colombia and Guadeloupe by breeders, soil scientists and a agronomists. The results suggest that large genetic variability exists in adaptation of plants to acid soils. A range of morphological and physiological plant characteristics contribute to tolerance of acid soils, elucidation of which has contributed to the development of rapid techniques for screening for tolerance. Incorporation of acid-soil-tolerant species and cultivars into cropping systems contributes to improved nutrient efficiency overall, and thus reduces fertilizer needs. This may help to minimize maintenance applications of fertiliser through various pathways: (i) deeper root growth resulting in more-efficient uptake of nutrients from the sub-soil and less leaching, (ii) more biomass production resulting in less seepage and less leaching, with more intensive nutrient cycling, maintenance of higher soil organic-matter content, and, consequently, less erosion owing to better soil protection by vegetation and mulch. (author)

Different influences of field aging on nickel toxicity to Folsomia candida in two types of soil.

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Liu, Yu-Rong; Li, Jing; He, Ji-Zheng; Ma, Yi-Bing; Zheng, Yuan-Ming

2015-06-01

Metal aging in soils has been considered an important factor influencing its availability and toxicity to organisms. In this study, we report the influence of 5 years field aging on the nickel (Ni) toxicity to collembolan Folsomia candida based on two different types of soil from Dezhou (DZ) and Qiyang (QY) counties in China. Acute and chronic toxicity of Ni to F. candida was assessed in both freshly spiked and field aging contaminated soils. We found that 5 years field aging increased the EC50 and 2d-LC50 values of Ni to F. candida in the DZ soil, while little influence on the Ni toxicity was observed in the QY soil. There was no adverse effect of the long-term field aging on the Ni toxicity to the survival of F. candida in the two tested soils. In addition, field aging of the two soils impacted differently the water-soluble Ni concentrations, which were significantly correlated to the juvenile production of F. candida based on a logistic model. Our study highlights different effects of long-term field aging on the Ni toxicity to F. candida between divergent types of soil, and this should be taken into account in future toxicity testing and risk assessment practices.

Development of soil taxation and soil classification as furthered by the Austrian Soil Science Society

Science.gov (United States)

Baumgarten, Andreas

2013-04-01

Soil taxation and soil classification are important drivers of soil science in Austria. However, the tasks are quite different: whereas soil taxation aims at the evaluation of the productivity potential of the soil, soil classification focusses on the natural development and - especially nowadays - on functionality of the soil. Since the foundation of the Austrian Soil Science Society (ASSS), representatives both directions of the description of the soil have been involved in the common actions of the society. In the first years it was a main target to improve and standardize field descriptions of the soil. Although both systems differ in the general layout, the experts should comply with identical approaches. According to this work, a lot of effort has been put into the standardization of the soil classification system, thus ensuring a common basis. The development, state of the art and further development of both classification and taxation systems initiated and carried out by the ASSS will be shown.

[Effects of controlled release blend bulk urea on soil nitrogen and soil enzyme activity in wheat and rice fields].

Science.gov (United States)

Zhang, Jing Sheng; Wang, Chang Quan; Li, Bing; Liang, Jing Yue; He, Jie; Xiang, Hao; Yin, Bin; Luo, Jing

2017-06-18

A field experiment was conducted to investigate the effect of controlled-release fertilizer (CRF) combined with urea (UR) on the soil fertility and environment in wheat-rice rotation system. Changes in four forms of nitrogen (total nitrogen, ammonium nitrogen, nitrate nitrogen, and microbial biomass nitrogen) and in activities of three soil enzymes participating in nitrogen transformation (urease, protease, and nitrate reductase) were measured in seven fertilization treatments (no fertilization, routine fertilization, 10%CRF+90%UR, 20%CRF+80%UR, 40%CRF+60%UR, 80%CRF+20%UR, and 100%CRF). The results showed that soil total nitrogen was stable in the whole growth period of wheat and rice. There was no significant difference among the treatments of over 20% CRF in soil total nitrogen content of wheat and rice. The soil inorganic nitrogen content was increased dramatically in treatments of 40% or above CRF during the mid-late growing stages of wheat and rice. With the advance of the growth period, conventional fertilization significantly decreased soil microbial biomass nitrogen, but the treatments of 40% and above CRF increased the soil microbial biomass nitrogen significantly. The soil enzyme activities were increased with over 40% of CRF in the mid-late growing stage of wheat and rice. By increasing the CRF ratio, the soil protease activity and nitrate reductase activity were improved gradually, and peaked in 100% CRF. The treatments of above 20% CRF could decrease the urease activity in tillering stage of rice and delay the peak of ammonium nitrogen, which would benefit nitrogen loss reduction. The treatments of 40% and above CRF were beneficial to improving soil nitrogen supply and enhancing soil urease and protease activities, which could promote the effectiveness of nitrogen during the later growth stages of wheat and rice. The 100% CRF treatment improved the nitrate reductase activity significantly during the later stage of wheat and rice. Compared with the

Field application of a rapid spectrophotometric method for determination of persulfate in soil.

Directory of Open Access Journals (Sweden)

Colin J Cunningham

Full Text Available Remediation of hydrocarbon contaminated soils can be performed both in situ and ex situ using chemical oxidants such as sodium persulfate. Standard methods for quantifying persulfate require either centrifugation or prolonged settling times. An optimized soil extraction procedure was developed for persulfate involving simple water extraction using a modified disposable syringe. This allows considerable saving of time and removes the need for centrifugation. The extraction time was reduced to only 5 min compared to 15 min for the standard approach. A comparison of the two approaches demonstrated that each provides comparable results. Comparisons were made using high (93 g kg(-1 soil and low (9.3 g kg(-1 soil additions of sodium persulfate to a petroleum hydrocarbon-contaminated soil, as well as sand spiked with diesel. Recoveries of 95±1% and 96±10% were observed with the higher application rate in the contaminated soil and spiked sand, respectively. Corresponding recoveries of 86±5% and 117±19% were measured for the lower application rate. Results were obtained in only 25 min and the method is well suited to batch analyses. In addition, it is suitable for application in a small field laboratory or even a mobile, vehicle-based system, as it requires minimal equipment and reagents.

Field Application of a Rapid Spectrophotometric Method for Determination of Persulfate in Soil

Science.gov (United States)

Cunningham, Colin J.; Pitschi, Vanessa; Anderson, Peter; Barry, D. A.; Patterson, Colin; Peshkur, Tanya A.

2013-01-01

Remediation of hydrocarbon contaminated soils can be performed both in situ and ex situ using chemical oxidants such as sodium persulfate. Standard methods for quantifying persulfate require either centrifugation or prolonged settling times. An optimized soil extraction procedure was developed for persulfate involving simple water extraction using a modified disposable syringe. This allows considerable saving of time and removes the need for centrifugation. The extraction time was reduced to only 5 min compared to 15 min for the standard approach. A comparison of the two approaches demonstrated that each provides comparable results. Comparisons were made using high (93 g kg−1 soil) and low (9.3 g kg−1 soil) additions of sodium persulfate to a petroleum hydrocarbon-contaminated soil, as well as sand spiked with diesel. Recoveries of 95±1% and 96±10% were observed with the higher application rate in the contaminated soil and spiked sand, respectively. Corresponding recoveries of 86±5% and 117±19% were measured for the lower application rate. Results were obtained in only 25 min and the method is well suited to batch analyses. In addition, it is suitable for application in a small field laboratory or even a mobile, vehicle-based system, as it requires minimal equipment and reagents. PMID:23776446

Use of Airborne Hyperspectral Imagery to Map Soil Properties in Tilled Agricultural Fields

International Nuclear Information System (INIS)

Hively, W.D; McCarty, G.W; Reeves, J.B; Lang, M.W; Oesterling, R.A; Delwiche, S.R

2011-01-01

Soil hyperspectral reflectance imagery was obtained for six tilled (soil) agricultural fields using an airborne imaging spectrometer (400-2450 nm, -10 nm resolution, 2.5 m spatial resolution). Surface soil samples (n=315) were analyzed for carbon content, particle size distribution, and 15 agronomically important elements (Mehlich-III extraction). When partial least squares (PLS) regression of imagery-derived reflectance spectra was used to predict analyte concentrations, 13 of the 19 analytes were predicted with R 2 >0.50, including carbon (0.65), aluminum (0.76), iron (0.75), and silt content (0.79). Comparison of 15 spectral math preprocessing treatments showed that a simple first derivative worked well for nearly all analytes. The resulting PLS factors were exported as a vector of coefficients and used to calculate predicted maps of soil properties for each field. Image smoothing with a 3 x 3 low-pass filter prior to spectral data extraction improved prediction accuracy. The resulting raster maps showed variation associated with topographic factors, indicating the effect of soil redistribution and moisture regime on in-field spatial variability. High-resolution maps of soil analyte concentrations can be used to improve precision environmental management of farmlands.

Remediation Of Radioactive Contaminated Soil in Oil Fields

International Nuclear Information System (INIS)

Taha, A.A.; Hassib, G.M.; Ibrahim, Z.A.

2011-01-01

Radioactive contamination by naturally occurring radioactive materials (NORM) in evaporation pond has been evaluated. At several onshore oil field locations, the produced water is discharged to form artificial lagoons or ponds. Subsequently, the released waters drain to the ground leaving radioactive deposits associated with the soil that eventually require remedial action in accordance with radiation protection principles. The present study aims to investigate the remediation of contaminated soil in some oil fields and in this concern, two scenarios were proposed. The first scenario is studying the feasibility of using soil washing technique (a physical-chemical separation process) for removing radium-226 from the contaminated soil samples collected from an evaporating pond. The size/activity distribution analyses were carried out. The data obtained showed that almost 68 % of the investigated soil was coarse sand (≥ 300 μm), 28 % was medium and fine sand (≤300 μm and (≥75 μm) and only small fraction of 4 % was silt and clay (≤75 μm). A series of mild acids such as HCl and mild NaCl/HCl (chloride washing) were used for washing the investigated soil fractions. The obtained data showed that the coarse fraction ≥ 300 μm can be re mediated below a regulatory level of 1Bq/g. and the radium from this coarse fraction could be easily removed by screening and chloride washing. For the remediation of (≤ 300 μm and (≥ 75 μm soil fractions, a series of mild chloride washing experiments also showed that the chloride base (NaCl/HCl) was found to be potentially useful. However, there was a difficulty in achieving a low radium value in the fine (≥ 75 μm size fractions using chloride washing. The second scenario is to get rid of all contaminated soil and store it in a concrete basin through the program of radiological protection of personnel and environment. Preliminary gamma survey of contaminated soil showed that the significant area of the investigated

Variation of Bacterial Community Diversity in Rhizosphere Soil of Sole-Cropped versus Intercropped Wheat Field after Harvest.

Directory of Open Access Journals (Sweden)

Zhenping Yang

Full Text Available As the major crops in north China, spring crops are usually planted from April through May every spring and harvested in fall. Wheat is also a very common crop traditionally planted in fall or spring and harvested in summer year by year. This continuous cropping system exhibited the disadvantages of reducing the fertility of soil through decreasing microbial diversity. Thus, management of microbial diversity in the rhizosphere plays a vital role in sustainable crop production. In this study, ten common spring crops in north China were chosen sole-cropped and four were chosen intercropped with peanut in wheat fields after harvest. Denaturing gradient gel electrophoresis (DGGE and DNA sequencing of one 16S rDNA fragment were used to analyze the bacterial diversity and species identification. DGGE profiles showed the bacterial community diversity in rhizosphere soil samples varied among various crops under different cropping systems, more diverse under intercropping system than under sole-cropping. Some intercropping-specific bands in DGGE profiles suggested that several bacterial species were stimulated by intercropping systems specifically. Furthermore, the identification of these dominant and functional bacteria by DNA sequencing indicated that intercropping systems are more beneficial to improve soil fertility. Compared to intercropping systems, we also observed changes in microbial community of rhizosphere soil under sole-crops. The rhizosphere bacterial community structure in spring crops showed a strong crop species-specific pattern. More importantly, Empedobacter brevis, a typical plant pathogen, was only found in the carrot rhizosphere, suggesting carrot should be sown prudently. In conclusion, our study demonstrated that crop species and cropping systems had significant effects on bacterial community diversity in the rhizosphere soils. We strongly suggest sorghum, glutinous millet and buckwheat could be taken into account as intercropping

Arsenic transport in irrigation water across rice-field soils in Bangladesh

International Nuclear Information System (INIS)

Polizzotto, Matthew L.; Lineberger, Ethan M.; Matteson, Audrey R.; Neumann, Rebecca B.; Badruzzaman, A. Borhan M.; Ashraf Ali, M.

2013-01-01

Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes. -- Highlights: •We analyzed the processes impacting arsenic transport in flowing irrigation water. •Arsenic in Bangladesh rice-field irrigation water varied over space and time. •Arsenic was correlated with Fe, P, and Si in flowing and static water. •Oxidation, adsorption and desorption reactions controlled arsenic concentrations. •Land-based arsenic removal from water will be impacted by hydraulic conditions. -- Arsenic concentrations in flowing and static irrigation water in Bangladesh varied over space and time, suggesting careful design is required for land-based pre-treatment schemes that aim to remove As from solution

Standardization of soil apparent electrical conductivity using multi-temporal surveys across multiple production fields

Science.gov (United States)

Apparent soil electrical conductivity (ECa) is an efficient technique for understanding within-field variability of physical and chemical soil characteristics. Commercial devices are readily available for collecting ECa on whole fields and used broadly for crop management in precision agriculture; h...

Soil microorganisms determine the sorption of radionuclides within organic soil systems

International Nuclear Information System (INIS)

Parekh, N.R.; Poskitt, J.M.; Dodd, B.A.; Potter, E.D.; Sanchez, A.

2008-01-01

The potential of soil microorganisms to enhance the retention of 137 Cs and 85 Sr in organic systems was assessed in a series of experiments. A biologically active, 'mineral-free', organic material, produced under laboratory conditions from leaves, was used as the uptake matrix in all experiments to minimise potential interference from competing clay minerals. Biological uptake and release were differentiated from abiotic processes by comparing the sorption of radionuclides in sterilised organic material with sterile material inoculated with soil extracts or single fungal strains. Our results show conclusively that living components of soil systems are of primary importance in the uptake of radionuclides in organic material. The presence of soil microorganisms significantly enhanced the retention of Cs in organic systems and ∼70% of the Cs spike was strongly (irreversibly) bound (remained non-extractable) in the presence of microorganisms compared to only ∼10% in abiotic systems. Sorption of 85 Sr was not significantly influenced by the presence of soil microorganisms. A non-linear temperature response was observed for the retention in biotic systems with increased uptake at between 10 and 30 deg. C and lower retention at temperatures above or below the optimum range. The optimum temperatures for biological uptake were between 15 and 20 deg. C for Cs, and 25 and 30 deg. C for Sr. Our results indicate that single strains of soil and saprotrophic fungi make an important contribution to the sorption of Cs and Sr in organic systems, but can only account for part of the strong, irreversible binding observed in biotic systems. Single strains of soil fungi increased the amount of non-extractable 137 Cs (by ∼30%) and 85 Sr (by ∼20%) in the organic systems as compared to abiotic systems, but the major fraction of 137 Cs and 85 Sr sorbed in systems inoculated with saprotrophic fungi remained extractable

Green roof soil system affected by soil structural changes: A project initiation

Science.gov (United States)

Jelínková, Vladimíra; Dohnal, Michal; Šácha, Jan; Šebestová, Jana; Sněhota, Michal

2014-05-01

Anthropogenic soil systems and structures such as green roofs, permeable or grassed pavements comprise appreciable part of the urban watersheds and are considered to be beneficial regarding to numerous aspects (e.g. carbon dioxide cycle, microclimate, reducing solar absorbance and storm water). Expected performance of these systems is significantly affected by water and heat regimes that are primarily defined by technology and materials used for system construction, local climate condition, amount of precipitation, the orientation and type of the vegetation cover. The benefits and potencies of anthropogenic soil systems could be considerably threatened in case when exposed to structural changes of thin top soil layer in time. Extensive green roof together with experimental green roof segment was established and advanced automated monitoring system of micrometeorological variables was set-up at the experimental site of University Centre for Energy Efficient Buildings as an interdisciplinary research facility of the Czech Technical University in Prague. The key objectives of the project are (i) to characterize hydraulic and thermal properties of soil substrate studied, (ii) to establish seasonal dynamics of water and heat in selected soil systems from continuous monitoring of relevant variables, (iii) to detect structural changes with the use of X-ray Computed Tomography, (iv) to identify with the help of numerical modeling and acquired datasets how water and heat dynamics in anthropogenic soil systems are affected by soil structural changes. Achievements of the objectives will advance understanding of the anthropogenic soil systems behavior in conurbations with the temperate climate.

Multitracing Experiment With Solved and Particulate Tracers In An Unsaturated Field Soil

Science.gov (United States)

Burkhardt, M.; Kasteel, R.; Vereecken, H.

Solute movement and colloid migration follow preferential flow paths in structured soils at the field scale. The use of microsphreres is a possible option to mimic colloid transport through the vadose zone into the groundwater. We present results of multi- tracing experiments conducted in an Orthic Luvisol using bromide (Br-), the reactive dye tracer Brilliant Blue (BB) and microspheres. The fluorescent microspheres (1 and 10 µm in diameter) were functionalized with a negative surface charge. Eight field plots (about 2 m2) were irrigated with 10 mm and 40 mm during 6 h. Four field plots were sampled directly after the irrgation, the others were exposed for 90 days to natural wheather conditions. Photographs of horizontal cross-sections and disturbed soil sam- ples were taken every 5 to 10 cm down to a depth of 160 cm. Image analysis was used to derive concentration distributions of BB using a calibration relationship between concentration and color spectra. The microspheres were quantified after desorption of the soil samples by fluorescent microscopy and image analysis. We used moment analysis to characterize transport phenomena. We found that transport through the soil matrix was affected by sorption, but all of the applied compounds were transported through preferential flow paths (earthworm burrows) down to a depth of 160 cm irre- spective of their chemical properties. Furthermore, this study shows that microspheres can be used to mimic colloid facilitated transport under unsaturated conditions in a field soil.

Soil Properties and Plant Biomass Production in Natural Rangeland Management Systems

Directory of Open Access Journals (Sweden)

Romeu de Souza Werner

Full Text Available ABSTRACT Improper management of rangelands can cause land degradation and reduce the economic efficiency of livestock activity. The aim of this study was to evaluate soil properties and quantify plant biomass production in four natural rangeland management systems in the Santa Catarina Plateau (Planalto Catarinense of Brazil. The treatments, which included mowed natural rangeland (NR, burned natural rangeland (BR, natural rangeland improved through the introduction of plant species after harrowing (IH, and natural rangeland improved through the introduction of plant species after chisel plowing (IC, were evaluated in a Nitossolo Bruno (Nitisol. In the improved treatments, soil acidity was corrected, phosphate fertilizer was applied, and intercropped annual ryegrass (Lolium multiflorum, velvet grass (Holcus lanatus, and white clover (Trifolium repens were sown. Management systems with harrowed or chisel plowed soil showed improved soil physical properties; however, the effect decreased over time and values approached those of burned and mowed natural rangelands. Natural rangeland systems in the establishment phase had little influence on soil organic C. The mowed natural rangeland and improved natural rangeland exhibited greater production of grazing material, while burning the field decreased production and increased the proportion of weeds. Improvement of the natural rangelands increased leguminous biomass for pasture.

Electricity Generation in Microbial Fuel Cell (MFC) by Bacterium Isolated from Rice Paddy Field Soil

Science.gov (United States)

Fakhirruddin, Fakhriah; Amid, Azura; Salim, Wan Wardatul Amani Wan; Suhaida Azmi, Azlin

2018-03-01

Microbial fuel cell (MFC) is an alternative approach in generating renewable energy by utilising bacteria that will oxidize organic or inorganic substrates, producing electrons yielded as electrical energy. Different species of exoelectrogenic bacteria capable of generating significant amount of electricity in MFC has been identified, using various organic compounds for fuel. Soil sample taken from rice paddy field is proven to contain exoelectrogenic bacteria, thus electricity generation using mixed culture originally found in the soil, and pure culture isolated from the soil is studied. This research will isolate the exoelectrogenic bacterial species in the rice paddy field soil responsible for energy generation. Growth of bacteria isolated from the MFC is observed by measuring the optical density (OD), cell density weight (CDW) and viable cell count. Mixed bacterial species found in paddy field soil generates maximum power of 77.62 μW and 0.70 mA of current. In addition, the research also shows that the pure bacterium in rice paddy field soil can produce maximum power and current at 51.32 μW and 0.28 mA respectively.

Simulating soil greenhouse emissions from Swiss long-term cropping system trials

Science.gov (United States)

Necpalova, Magdalena; Lee, Juhwan; Skinner, Colin; Büchi, Lucie; Berner, Alfred; Mäder, Paul; Mayer, Jochen; Charles, Raphael; van der Heijden, Marcel; Wittwer, Raphael; Gattinger, Andreas; Six, Johan

2017-04-01

There is an urgent need to identify and evaluate management practices for their bio-physical potential to mitigate greenhouse gas (GHG) emissions from agriculture. The cost and time required for direct management-specific GHG measurements limit the spatial and temporal resolution and the extent of data that can be collected. Biogeochemical process-based models such as DayCent can be used to bridge data gaps over space and time and estimate soil GHG emissions relevant to various climate change mitigation strategies. Objectives of this study were (a) to parameterize DayCent for common Swiss crops and crop-specific management practices using the Swiss long-term experimental data collected at four sites (Therwil, Frick, Changins, and Reckenholz); (b) to evaluate the model's ability to predict crop productivity, long-term soil carbon dynamics and N2O emissions from Swiss cropping systems; (c) to calculate a net soil GHG balance for all treatments (except for bio-dynamic) studied in long-term field experiments in Switzerland; and (d) to study the management effects and their interactions on soil GHG emissions at each experimental site. Model evaluation indicated that DayCent predicted crop productivity (rRMSE=0.29 r2=0.81, n=2614), change in soil carbon stock (rRMSE=0.14, r2=0.72, n=1289) and cumulative N2O emissions (rRMSE=0.25, r2=0.89, n=8) satisfactorily across all treatments and sites. Net soil GHG emissions were derived from changes in soil carbon, N2O emissions and CH4 oxidation on an annual basis using IPCC (2014) global warming potentials. Modelled net soil GHG emissions calculated for individual treatments over 30 years ranged from -594 to 1654 kg CO2 eq ha-1 yr-1. The highest net soil GHG emissions were predicted for conventional tillage and slurry application treatment at Frick, while soils under organic and reduced tillage management at Reckenholz acted as a net GHG sink. The statistical analyses using linear MIXED models indicated that net soil GHG

Soil organic carbon sequestration and tillage systems in Mediterranean environments

Science.gov (United States)

Francaviglia, Rosa; Di Bene, Claudia; Marchetti, Alessandro; Farina, Roberta

2016-04-01

Soil carbon sequestration is of special interest in Mediterranean areas, where rainfed cropping systems are prevalent, inputs of organic matter to soils are low and mostly rely on crop residues, while losses are high due to climatic and anthropic factors such as intensive and non-conservative farming practices. The adoption of reduced or no tillage systems, characterized by a lower soil disturbance in comparison with conventional tillage, has proved to be positively effective on soil organic carbon (SOC) conservation and other physical and chemical processes, parameters or functions, e.g. erosion, compaction, ion retention and exchange, buffering capacity, water retention and aggregate stability. Moreover, soil biological and biochemical processes are usually improved by the reduction of tillage intensity. The work deals with some results available in the scientific literature, and related to field experiment on arable crops performed in Italy, Greece, Morocco and Spain. Data were organized in a dataset containing the main environmental parameters (altitude, temperature, rainfall), soil tillage system information (conventional, minimum and no-tillage), soil parameters (bulk density, pH, particle size distribution and texture), crop type, rotation, management and length of the experiment in years, initial SOCi and final SOCf stocks. Sampling sites are located between 33° 00' and 43° 32' latitude N, 2-860 m a.s.l., with mean annual temperature and rainfall in the range 10.9-19.6° C and 355-900 mm. SOC data, expressed in t C ha-1, have been evaluated both in terms of Carbon Sequestration Rate, given by [(SOCf-SOCi)/length in years], and as percentage change in comparison with the initial value [(SOCf-SOCi)/SOCi*100]. Data variability due to the different environmental, soil and crop management conditions that influence SOC sequestration and losses will be examined.

Soil spectral measurements in the field: problems and solutions in light of the GEO-CARDEL project

Science.gov (United States)

Dor, E. Ben; Granot, Amihai

2017-09-01

The GEO-CRADEL project aims to establish several knowhow for GEO applications. One of them is food security in which soil spectroscopy plays a major role. To that end we had developed a new assembly for measuring surface reflectance in the field. This was done in order to fill the gap between laboratory and field soil spectral measurements. This device, named SoilPRO (SP) can be connected to any field spectrometer fiber's tip and used to measure representative and undisturbed surfaces of different soil types. The SoilPRO's performance was evaluated against laboratory measurements under optimal conditions and demonstrated high performance in the field. As the SP measurement is not dependent on main factors such as the sun's radiation, atmospheric variations, operator stability or measurement geometry, and it does not disturb the surface being measured, its measurement can be used with laboratory soil spectral data (SSL). To that end the SSL that is generated under the GEO-CARDEL project is now can be used for agro- application in the field.

Determination of Soil Moisture Content using Laboratory Experimental and Field Electrical Resistivity Values

Science.gov (United States)

Hazreek, Z. A. M.; Rosli, S.; Fauziah, A.; Wijeyesekera, D. C.; Ashraf, M. I. M.; Faizal, T. B. M.; Kamarudin, A. F.; Rais, Y.; Dan, M. F. Md; Azhar, A. T. S.; Hafiz, Z. M.

2018-04-01

The efficiency of civil engineering structure require comprehensive geotechnical data obtained from site investigation. In the past, conventional site investigation was heavily related to drilling techniques thus suffer from several limitations such as time consuming, expensive and limited data collection. Consequently, this study presents determination of soil moisture content using laboratory experimental and field electrical resistivity values (ERV). Field and laboratory electrical resistivity (ER) test were performed using ABEM SAS4000 and Nilsson400 soil resistance meter. Soil sample used for resistivity test was tested for characterization test specifically on particle size distribution and moisture content test according to BS1377 (1990). Field ER data was processed using RES2DINV software while laboratory ER data was analyzed using SPSS and Excel software. Correlation of ERV and moisture content shows some medium relationship due to its r = 0.506. Moreover, coefficient of determination, R2 analyzed has demonstrate that the statistical correlation obtain was very good due to its R2 value of 0.9382. In order to determine soil moisture content based on statistical correlation (w = 110.68ρ-0.347), correction factor, C was established through laboratory and field ERV given as 19.27. Finally, this study has shown that soil basic geotechnical properties with particular reference to water content was applicably determined using integration of laboratory and field ERV data analysis thus able to compliment conventional approach due to its economic, fast and wider data coverage.

Inter- and Intra- Field variations in soil compaction levels and subsequent impacts on hydrological extremes

Science.gov (United States)

Pattison, Ian; Coates, Victoria

2015-04-01

The rural landscape in the UK is dominated by pastoral agriculture, with about 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Intensification has resulted in greater levels of compaction associated with higher stocking densities. However, there is likely to be a great amount of variability in compaction levels within and between fields due to multiple controlling factors. This research focusses in on two of these factors; firstly animal species, namely sheep, cattle and horses; and secondly field zonation e.g. feeding areas, field gates, open field. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK, which has an area of 140km2. The effect on physical and hydrologic soil characteristics such as bulk density and moisture contents have been quantified using a wide range of field and laboratory based experiments. Results have highlighted statistically different properties between heavily compacted areas where animals congregate and less-trampled open areas. Furthermore, soil compaction has been hypothesised to contribute to increased flood risk at larger spatial scales. Previous research (Pattison, 2011) on a ~40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. Here we report results from spatially distributed hydrological modelling using soil parameters gained from the field experimentation. Results highlight the importance of both the percentage of the catchment which is heavily compacted and also the spatial distribution of these fields.

Low-field NMR logging sensor for measuring hydraulic parameters of model soils

Science.gov (United States)

Sucre, Oscar; Pohlmeier, Andreas; Minière, Adrien; Blümich, Bernhard

2011-08-01

SummaryKnowing the exact hydraulic parameters of soils is very important for improving water management in agriculture and for the refinement of climate models. Up to now, however, the investigation of such parameters has required applying two techniques simultaneously which is time-consuming and invasive. Thus, the objective of this current study is to present only one technique, i.e., a new non-invasive method to measure hydraulic parameters of model soils by using low-field nuclear magnetic resonance (NMR). Hereby, two model clay or sandy soils were respectively filled in a 2 m-long acetate column having an integrated PVC tube. After the soils were completely saturated with water, a low-field NMR sensor was moved up and down in the PVC tube to quantitatively measure along the whole column the initial water content of each soil sample. Thereafter, both columns were allowed to drain. Meanwhile, the NMR sensor was set at a certain depth to measure the water content of that soil slice. Once the hydraulic equilibrium was reached in each of the two columns, a final moisture profile was taken along the whole column. Three curves were subsequently generated accordingly: (1) the initial moisture profile, (2) the evolution curve of the moisture depletion at that particular depth, and (3) the final moisture profile. All three curves were then inverse analyzed using a MATLAB code over numerical data produced with the van Genuchten-Mualem model. Hereby, a set of values ( α, n, θr and θs) was found for the hydraulic parameters for the soils under research. Additionally, the complete decaying NMR signal could be analyzed through Inverse Laplace Transformation and averaged on the 1/ T2 space. Through measurement of the decay in pure water, the effect on the relaxation caused by the sample could be estimated from the obtained spectra. The migration of the sample-related average with decreasing saturation speaks for a enhancement of the surface relaxation as the soil dries, in

SPATIAL CORRELATION BETWEEN PHYSICAL PROPERTIES OF SOIL AND WEEDS IN TWO MANAGEMENT SYSTEMS

Directory of Open Access Journals (Sweden)

Valter Roberto Schaffrath

2015-02-01

Full Text Available The spatial correlation between soil properties and weeds is relevant in agronomic and environmental terms. The analysis of this correlation is crucial for the interpretation of its meaning, for influencing factors such as dispersal mechanisms, seed production and survival, and the range of influence of soil management techniques. This study aimed to evaluate the spatial correlation between the physical properties of soil and weeds in no-tillage (NT and conventional tillage (CT systems. The following physical properties of soil and weeds were analyzed: soil bulk density, macroporosity, microporosity, total porosity, aeration capacity of soil matrix, soil water content at field capacity, weed shoot biomass, weed density, Commelina benghalensis density, and Bidens pilosa density. Generally, the ranges of the spatial correlations were higher in NT than in CT. The cross-variograms showed that many variables have a structure of combined spatial variation and can therefore be mapped from one another by co-kriging. This combined variation also allows inferences about the physical and biological meanings of the study variables. Results also showed that soil management systems influence the spatial dependence structure significantly.

Evaluation of different field methods for measuring soil water infiltration

Science.gov (United States)

Pla-Sentís, Ildefonso; Fonseca, Francisco

2010-05-01

Soil infiltrability, together with rainfall characteristics, is the most important hydrological parameter for the evaluation and diagnosis of the soil water balance and soil moisture regime. Those balances and regimes are the main regulating factors of the on site water supply to plants and other soil organisms and of other important processes like runoff, surface and mass erosion, drainage, etc, affecting sedimentation, flooding, soil and water pollution, water supply for different purposes (population, agriculture, industries, hydroelectricity), etc. Therefore the direct measurement of water infiltration rates or its indirect deduction from other soil characteristics or properties has become indispensable for the evaluation and modelling of the previously mentioned processes. Indirect deductions from other soil characteristics measured under laboratory conditions in the same soils, or in other soils, through the so called "pedo-transfer" functions, have demonstrated to be of limited value in most of the cases. Direct "in situ" field evaluations have to be preferred in any case. In this contribution we present the results of past experiences in the measurement of soil water infiltration rates in many different soils and land conditions, and their use for deducing soil water balances under variable climates. There are also presented and discussed recent results obtained in comparing different methods, using double and single ring infiltrometers, rainfall simulators, and disc permeameters, of different sizes, in soils with very contrasting surface and profile characteristics and conditions, including stony soils and very sloping lands. It is concluded that there are not methods universally applicable to any soil and land condition, and that in many cases the results are significantly influenced by the way we use a particular method or instrument, and by the alterations in the soil conditions by the land management, but also due to the manipulation of the surface

Soil Labile Organic Matter under Long-term Crop Rotation System

Science.gov (United States)

Saljnikov, E.

2009-04-01

Temperate grassland soils, typically Mollisols, have remained agriculturally productive with limited inputs for many years, despite the mining of energy and nutrients reserves contained within the soil organic fraction (Janzen, 1987; Tiessen et al., 1994). Such system can be considered resilient, at least initially, but one must question for how long such systems can be sustained. Effect of long-term land-use on biologically active fractions of soil organic matter is not well understood. Investigations were conducted in more than 40-year static experiments in northern Kazakhstan. We examined five fallow-wheat (Triticum aestivum L.) cropping systems with different frequencies of the fallow phase: continuous wheat (CW), 6-y rotation (6R), 4-y rotation (4R), 2-y rotation (2R) and continuous fallow (CF). A unique sample from nationally protected virgin steppe near the experimental field was sampled for comparison with long-term cultivated soils. Soil samples were collected from the two phases of each rotation, pre- and post-fallow, and analyzed for biological soil properties that are potentially mineralizable C (PMC), potentially mineralizable N (PMN), microbial biomass C (MBC) and N (MBN) and "light fraction" C (LFC) and N (LFN). Potentially mineralizable C was inversely proportional to the frequency of fallow and was highest in CW. Potentially mineralizable N was more responsive to rotation phase than other indices of SOM. Light fraction OM was negatively correlated to the frequency of fallow and was higher in pre-fallow than in post-fallow phases. All studied biological characteristics were drastically greater in the soil from the natural steppe. The results suggested that the yearly input of plant residues in a less frequently fallowed system built up more PMC, whereas PMN was closely correlated to recent inputs of substrate added as plant residue. We concluded that a frequent fallowing for long period may deplete SOM via accelerated mineralization. The results may

Field Performance of the Disk Harrow, Power Harrow and Rotary Tiller at Different Soil Moisture Contents on a Clay Loam Soil in Mazandaran

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M Rajabi Vandechali

2015-03-01

Full Text Available About 60% of the mechanical energy consumed in mechanized agriculture is used for tillage operations and seedbed preparation. On the other hand, unsuitable tillage system resulted in soil degradation, affecting soil physical properties and destroying soil structure. The objective of this research was to compare the effects of three types of secondary tillage machines on soil physical properties and their field performances. An experiment was conducted in a wheat farm in Jouybar area of Mazandaran as split plots based on randomized complete block design with three replications. The main independent variable (plot was soil moisture with three levels (23.6-25, 22.2-23.6 and 20.8-22.2 percent based on dry weight and the subplot was three types of machine (two-disk perpendicular passing harrow, Power harrow and Rotary tiller. The measured parameters included: clod mean weight diameter, soil bulk density, specific fuel consumption, machine efficiency and machine capacity. The effects of treatments and their interactions on the specific fuel consumption, machine efficiency and machine capacity and also the effects of treatments on bulk density were significant (P

[Effects of plastic film mulching on soil CO2 efflux and CO2 concentration in an oasis cotton field].

Science.gov (United States)

Yu, Yong-xiang; Zhao, Cheng-yi; Jia, Hong-tao; Yu, Bo; Zhou, Tian-he; Yang, Yu-guang; Zhao, Hua

2015-01-01

A field study was conducted to compare soil CO2 efflux and CO2 concentration between mulched and non-mulched cotton fields by using closed chamber method and diffusion chamber technique. Soil CO2 efflux and CO2 concentration exhibited a similar seasonal pattern, decreasing from July to October. Mulched field had a lower soil CO2 efflux but a higher CO2 concentration, compared to those of non-mulched fields. Over the measurement period, cumulative CO2 efflux was 1871.95 kg C . hm-2 for mulched field and 2032.81 kg C . hm-2 for non-mulched field. Soil CO2 concentration was higher in mulched field (ranging from 5137 to 25945 µL . L-1) than in non- mulched field (ranging from 2165 to 23986 µL . L-1). The correlation coefficients between soil CO2 concentrations at different depths and soil CO2 effluxes were 0.60 to 0.73 and 0.57 to 0.75 for the mulched and non-mulched fields, indicating that soil CO2 concentration played a crucial role in soil CO2 emission. The Q10 values were 2.77 and 2.48 for the mulched and non-mulched fields, respectively, suggesting that CO2 efflux in mulched field was more sensitive to the temperature.

Effect of chemical and mechanical weed control on cassava yield, soil quality and erosion under cassava cropping system

Science.gov (United States)

Islami, Titiek; Wisnubroto, Erwin; Utomo, Wani

2016-04-01

Three years field experiments were conducted to study the effect of chemical and mechanical weed control on soil quality and erosion under cassava cropping system. The experiment were conducted at University Brawijaya field experimental station, Jatikerto, Malang, Indonesia. The experiments were carried out from 2011 - 2014. The treatments consist of three cropping system (cassava mono culture; cassava + maize intercropping and cassava + peanut intercropping), and two weed control method (chemical and mechanical methods). The experimental result showed that the yield of cassava first year and second year did not influenced by weed control method and cropping system. However, the third year yield of cassava was influence by weed control method and cropping system. The cassava yield planted in cassava + maize intercropping system with chemical weed control methods was only 24 t/ha, which lower compared to other treatments, even with that of the same cropping system used mechanical weed control. The highest cassava yield in third year was obtained by cassava + peanuts cropping system with mechanical weed control method. After three years experiment, the soil of cassava monoculture system with chemical weed control method possessed the lowest soil organic matter, and soil aggregate stability. During three years of cropping soil erosion in chemical weed control method, especially on cassava monoculture, was higher compared to mechanical weed control method. The soil loss from chemical control method were 40 t/ha, 44 t/ha and 54 t/ha for the first, second and third year crop. The soil loss from mechanical weed control method for the same years was: 36 t/ha, 36 t/ha and 38 t/ha. Key words: herbicide, intercropping, soil organic matter, aggregate stability.

High-resolution, real-time mapping of surface soil moisture at the field scale using ground penetrating radar

Science.gov (United States)

Lambot, S.; Minet, J.; Slob, E.; Vereecken, H.; Vanclooster, M.

2008-12-01

Measuring soil surface water content is essential in hydrology and agriculture as this variable controls important key processes of the hydrological cycle such as infiltration, runoff, evaporation, and energy exchanges between the earth and the atmosphere. We present a ground-penetrating radar (GPR) method for automated, high-resolution, real-time mapping of soil surface dielectric permittivity and correlated water content at the field scale. Field scale characterization and monitoring is not only necessary for field scale management applications, but also for unravelling upscaling issues in hydrology and bridging the scale gap between local measurements and remote sensing. In particular, such methods are necessary to validate and improve remote sensing data products. The radar system consists of a vector network analyzer combined with an off-ground, ultra-wideband monostatic horn antenna, thereby setting up a continuous-wave steeped-frequency GPR. Radar signal analysis is based on three-dimensional electromagnetic inverse modelling. The forward model accounts for all antenna effects, antenna-soil interactions, and wave propagation in three-dimensional multilayered media. A fast procedure was developed to evaluate the involved Green's function, resulting from a singular, complex integral. Radar data inversion is focused on the surface reflection in the time domain. The method presents considerable advantages compared to the current surface characterization methods using GPR, namely, the ground wave and common reflection methods. Theoretical analyses were performed, dealing with the effects of electric conductivity on the surface reflection when non-negligible, and on near-surface layering, which may lead to unrealistic values for the surface dielectric permittivity if not properly accounted for. Inversion strategies are proposed. In particular the combination of GPR with electromagnetic induction data appears to be promising to deal with highly conductive soils

Multifractal analysis of vertical profiles of soil penetration resistance at the field scale

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G. M. Siqueira

2013-07-01

Full Text Available Soil penetration resistance (PR is widely used as an indirect indicator of soil strength. Soil PR is linked to basic soil properties and correlated to root growth and plant production, and as such it is extensively used as a practical tool for assessing soil compaction and to evaluate the effects of soil management. This study investigates how results from multifractal analysis can quantify key elements of depth-dependent soil PR profiles and how this information can be used at the field scale. We analysed multifractality of 50 PR vertical profiles, measured from 0 to 60 cm depth and randomly located on a 6.5 ha sugar cane field in northeastern Brazil. The scaling property of each profile was typified by singularity, and Rényi spectra estimated by the method of moments. The Hurst exponent was used to parameterize the autocorrelation of the vertical PR data sets. The singularity and Rènyi spectra showed that the vertical PR data sets exhibited a well-defined multifractal structure. Hurst exponent values were close to 1, ranging from 0.944 to 0.988, indicating strong persistence in PR variation with soil depth. Also, the Hurst exponent was negatively and significantly correlated to coefficient of variation (CV, skewness and maximum values of the depth-dependent PR. Multifractal analysis added valuable information to describe the spatial arrangement of depth-dependent penetrometer data sets, which was not taken into account by classical statistical indices. Multifractal parameters were mapped over the experimental field and compared with mean and maximum values of PR. Combination of spatial variability survey and multifractal analysis appear to be useful to manage soil compaction.

Multifractal analysis of vertical profiles of soil penetration resistance at the field scale

Science.gov (United States)

Siqueira, G. M.; Silva, E. F. F.; Montenegro, A. A. A.; Vidal Vázquez, E.; Paz-Ferreiro, J.

2013-07-01

Soil penetration resistance (PR) is widely used as an indirect indicator of soil strength. Soil PR is linked to basic soil properties and correlated to root growth and plant production, and as such it is extensively used as a practical tool for assessing soil compaction and to evaluate the effects of soil management. This study investigates how results from multifractal analysis can quantify key elements of depth-dependent soil PR profiles and how this information can be used at the field scale. We analysed multifractality of 50 PR vertical profiles, measured from 0 to 60 cm depth and randomly located on a 6.5 ha sugar cane field in northeastern Brazil. The scaling property of each profile was typified by singularity, and Rényi spectra estimated by the method of moments. The Hurst exponent was used to parameterize the autocorrelation of the vertical PR data sets. The singularity and Rènyi spectra showed that the vertical PR data sets exhibited a well-defined multifractal structure. Hurst exponent values were close to 1, ranging from 0.944 to 0.988, indicating strong persistence in PR variation with soil depth. Also, the Hurst exponent was negatively and significantly correlated to coefficient of variation (CV), skewness and maximum values of the depth-dependent PR. Multifractal analysis added valuable information to describe the spatial arrangement of depth-dependent penetrometer data sets, which was not taken into account by classical statistical indices. Multifractal parameters were mapped over the experimental field and compared with mean and maximum values of PR. Combination of spatial variability survey and multifractal analysis appear to be useful to manage soil compaction.

Profiling nematode communities in unmanaged flowerbed and agricultural field soils in Japan by DNA barcode sequencing.

Directory of Open Access Journals (Sweden)

Hisashi Morise

Full Text Available Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU rDNA fragments were directly amplified from each of 68 (flowerbed samples and 48 (field samples isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs, indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis.

Profiling Nematode Communities in Unmanaged Flowerbed and Agricultural Field Soils in Japan by DNA Barcode Sequencing

Science.gov (United States)

Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

2012-01-01

Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis. PMID:23284767

Predicting Soil Physical Parameters and Copper Transport in a Polluted Field From X Ray CT-Images

DEFF Research Database (Denmark)

Paradelo Pérez, Marcos; Naveed, Muhammad; Møldrup, Per

2013-01-01

in soils is strongly controlled by the soil structure, the capabilities of these visualization techniques could be used to predict the risk of pollutants leaching. This work was carried out using soils from a field site (Hygum) in Jutland, Denmark, a historical copper (Cu) polluted field cultivated for 80...

Soil Water Measurement Using Actively Heated Fiber Optics at Field Scale.

Science.gov (United States)

Vidana Gamage, Duminda N; Biswas, Asim; Strachan, Ian B; Adamchuk, Viacheslav I

2018-04-06

Several studies have demonstrated the potential of actively heated fiber optics (AHFO) to measure soil water content (SWC) at high spatial and temporal resolutions. This study tested the feasibility of the AHFO technique to measure soil water in the surface soil of a crop grown field over a growing season using an in-situ calibration approach. Heat pulses of five minutes duration were applied at a rate of 7.28 W m -1 along eighteen fiber optic cable transects installed at three depths (0.05, 0.10 and 0.20 m) at six-hour intervals. Cumulative temperature increase (T cum ) during heat pulses was calculated at locations along the cable. While predicting commercial sensor measurements, the AHFO showed root mean square errors (RMSE) of 2.8, 3.7 and 3.7% for 0.05, 0.10 and 0.20 m depths, respectively. Further, the coefficients of determination (R²) for depth specific relationships were 0.87 (0.05 m depth), 0.46 (0.10 m depth), 0.86 (0.20 m depth) and 0.66 (all depths combined). This study showed a great potential of the AHFO technique to measure soil water at high spatial resolutions (<1 m) and to monitor soil water dynamics of surface soil in a crop grown field over a cropping season with a reasonable compromise between accuracy and practicality.

Grey water treatment by the slanted soil system with unsorted soil media.

Science.gov (United States)

Ushijima, Ken; Tanaka, Erina; Suzuki, Laís Yuko; Hijikata, Nowaki; Funamizu, Naoyuki; Ito, Ryusei

2015-01-01

This study evaluated the performance of unsorted soil media in the slanted soil treatment system, in terms of removal efficiency in suspended solids (SS), chemical oxygen demand (COD), linear alkylbenzene sulphonate (LAS) and Escherichia coli, and lifetime until clogging occurs. Unsorted soil performed longer lifetime until clogging than sorted fine soil. Removal of SS, COD, and LAS also performed same or better level in unsorted soil than fine soil. As reaction coefficients of COD and LAS were described as a function of the hydraulic loading rate, we can design a slanted soil system according to the expected hydraulic loading rate and the targeted level of COD or LAS in effluent. Regarding bacteria removal, unsorted soil performed sufficient reduction of E. coli for 5 weeks; however, the removal process occurred throughout all four chambers, while that of fine soil occurred in one to two chambers.

Relationships between the long-term mobility of Sr-90 in ploughed soil of upland field and soil properties

International Nuclear Information System (INIS)

Yamaguchi, N.; Seki, K.; Kurishima, K.

2006-01-01

Though more than 25 years have elapsed since the latest atmospheric nuclear test, long-lived artificial radionuclides, such as 137 Cs and 90 Sr, still remain in the soil. We evaluated the mobility of 90 Sr in ploughed upland soil, which affects the residual amount in the soil and plant uptake on the basis of long-term monitoring data. Soil was taken annually from 1961 to 1995 from 8 agricultural fields, and the concentration of exchangeable 90 Sr in soil was determined. The concentration of exchangeable 90 Sr in soil decreased exponentially with time. The environmental factor responsible for the decrease of 90 Sr, λe, was determined by the exponential fit of the exchangeable 90 Sr in ploughed soil vs. year followed by subtraction of the physical decay constant. The main factor controlling λe, the long-term mobility of 90 Sr from ploughed soil, was the cation exchange capacity of soil. It was indicated that the entrapment of 90 Sr on a cation exchange site retards the downward migration and wheat uptake of 90 Sr from ploughed soil. (author)

Reduction of soil erosion and mercury losses in agroforestry systems compared to forests and cultivated fields in the Brazilian Amazon.

Science.gov (United States)

Béliveau, Annie; Lucotte, Marc; Davidson, Robert; Paquet, Serge; Mertens, Frédéric; Passos, Carlos J; Romana, Christine A

2017-12-01

In addition to causing physical degradation and nutrient depletion, erosion of cultivated soils in the Amazon affects aquatic ecosystems through the release of natural soil mercury (Hg) towards lakes and rivers. While traditional agriculture is generally cited as being among the main causes of soil erosion, agroforestry practices are increasingly appreciated for soil conservation. This study was carried out in family farms of the rural Tapajós region (Brazil) and aimed at evaluating soil erosion and associated Hg release for three land uses. Soils, runoff water and eroded sediments were collected at three sites representing a land cover gradient: a recently burnt short-cycle cropping system (SCC), a 2-year-old agroforestry system (AFS) and a mature forest (F). At each site, two PVC soil erosion plots (each composed of three 2 × 5 m isolated subplots) were implemented on steep and moderate slopes respectively. Sampling was done after each of the 20 rain events that occurred during a 1-month study period, in the peak of the 2011 rain season. Runoff volume and rate, as well as eroded soil particles with their Hg and cation concentrations were determined. Total Hg and cation losses were then calculated for each subplot. Erosion processes were dominated by land use type over rainfall or soil slope. Eroded soil particles, as well as the amount of Hg and cations (CaMgK) mobilized at the AFS site were similar to those at the F site, but significantly lower than those at the SCC site (p agroforestry systems, even in their early stages of implementation, are characterized by low erosion levels resembling those of local forest environments, thus contributing to the maintenance of soil integrity and to the reduction of Hg and nutrient mobility. Copyright © 2017 Elsevier Ltd. All rights reserved.

Field dissipation of oxyfluorfen in onion and its dynamics in soil under Indian tropical conditions.

Science.gov (United States)

Janaki, P; Sathya Priya, R; Chinnusamy, C

2013-01-01

Oxyfluorfen, a diphenyl-ether herbicide is being used to control annual and perennial broad-leaved weeds and sedges in a variety of field crops including onion. The present study was aimed to investigate the dynamics and field persistence of oxyfluorfen in onion plant, bulb and soil under Indian tropical conditions. Application of four rates of oxyfluorfen viz., 200, 250, 300 and 400 g AI ha(-1) as pre-emergence gave good weed control in field experiment with onion. The oxyfluorfen residue dissipated faster in plant than in soil respectively, with a mean half-life of 6.1 and 11.2 days. Dissipation followed first-order kinetics. In laboratory column leaching experiments, 17 percent of the applied oxyfluorfen was recovered from the soil and indicates its solubility in water and mobility in sandy clay loam soil was low. A sorption study revealed that the adsorption of oxyfluorfen to the soil was highly influenced by the soil organic carbon with the Koc value of 5450. The study concludes that the dissipation of oxyfluorfen in soil and onion was dependent on the physico-chemical properties of the soil and environmental conditions.

Volume reduction system by soil classifying. Soil-washing system and problems to be solved

International Nuclear Information System (INIS)

Oshino, Yoshio

2016-01-01

Radioactive contamination of ground surfaces, buildings and forests in a broad area was caused by the accident at the Fukushima Daiichi Nuclear Power Plant in Japan. The national government and municipalities have still been carrying out the decontamination works for livelihood areas after five years from the accident. The government estimated that the amounts of soils and wastes removed by the decontamination works would be about 28,000,000 cubic meters maximum including 20,000,000 cubic meters maximum of soils. The removed soils will be stored in “Interim Storage Facility” then will be finally disposed outside of Fukushima prefecture within 30 years. On the other hand, shortage of the soils as materials needed for the revitalization in Fukushima prefecture is expected. Technical Advisory Council on Remediation and Waste Management, which consists of about 90 companies, started a working group to investigate solutions to these problems. The working group focused on the investigation of the possibility to recycle the soils by washing and classification to use them as the materials for civil engineering works, and to reduce the volume of the interim storage. In the first part of this report, we have evaluated the applicability of various technologies for purification and volume reduction of the removed soils, and have researched usages, required quantities and specifications of the recycled soils. In the second part, we have made trial calculations of the volume reduction effects and costs using the washing and classification system. The calculated results showed the possibilities of reducing the storage capacity of the interim storage facility, as well as the construction and the operation costs by recycling the removed soils with the washing and classification system inside the interim storage facility. At the end of this report, we proposed problems to be solved in order to adopt the washing and classification system. (author)

Study of soil redistribution in cultivated fields using fallout cesium-137 at Fateh Jang, Attock, Pakistan

International Nuclear Information System (INIS)

Ahmad, M.; Rafique, M.; Iqbal, N.; Akram, W.; Aasi, M.R.

2009-11-01

The study was carried out to investigate soil redistribution and net soil losses from two cultivated fields located in the dissected loess plains in the Pothwar Plateau at Mangial (33.6 N; 72.8 E), District Attock, Pakistan. For reference site, soil samples were collected by scrapper plate at 2 cm intervals and bulk cores in a grid, while the cultivated fields were sampled taking bulk cores in grid and along transect. /sup 137/Cs was measured by gamma spectroscopy using Soil 6 (IAEA) as a standard. The established reference inventory of /sup 137/Cs for this area is 3204 Bq/m/sup 2/. The technique provides very clear quantitative information on medium-term erosion and deposition rates at different locations, and net soil loss from cultivated fields, while no other methods available can be applied so simply. Gradient of the cultivated fields play an important role in the soil redistribution and net soil loss. Due to higher gradient of Field 2, the net soil losses determined by PM and MBM-1 using 20 cm plough layer (14.18 t ha/sup -1/ yr/sup -1/ and 16.37 t ha/sup -1/ yr/sup -1/ respectively) are much higher than that for Field 1 determined by the same models (0.24 t ha-1 yr-1 and 3.84 t ha/sup -1/ yr/sup -1/). Therefore, the cultivated fields should be as much leveled as possible. Major implication arises in using soil conversion models when thickness of /sup 137/Cs bearing layer becomes more than the normal plough layer due to deposition of eroded soil at low-lying areas. In case of Field 2, using 30 cm thickness of plough layer having significant /sup 137/Cs in the deposition areas the net erosion estimates using by PM and MBM-1 are 8.71 t ha/sup -1/ yr/sup -1/ and 10.05 t ha-1 yr/sup -1/, respectively, which seem more reliable because maximum /sup 137/Cs inventory is taken into accounted. The herbicide residue varies spatially in the field, but these three distributions corresponding to the three sampling dates indicate reduction in the residue with time. The

Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils.

Science.gov (United States)

Rosenfeld, Carla E; Chaney, Rufus L; Martínez, Carmen E

2018-03-01

Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts

Generalized stress field in granular soils heap with Rayleigh–Ritz method

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Gang Bi

2017-02-01

Full Text Available The stress field in granular soils heap (including piled coal will have a non-negligible impact on the settlement of the underlying soils. It is usually obtained by measurements and numerical simulations. Because the former method is not reliable as pressure cells instrumented on the interface between piled coal and the underlying soft soil do not work well, results from numerical methods alone are necessary to be doubly checked with one more method before they are extended to more complex cases. The generalized stress field in granular soils heap is analyzed with Rayleigh–Ritz method. The problem is divided into two cases: case A without horizontal constraint on the base and case B with horizontal constraint on the base. In both cases, the displacement functions u(x, y and v(x, y are assumed to be cubic polynomials with 12 undetermined parameters, which will satisfy the Cauchy's partial differential equations, generalized Hooke's law and boundary equations. A function is built with the Rayleigh–Ritz method according to the principle of minimum potential energy, and the problem is converted into solving two undetermined parameters through the variation of the function, while the other parameters are expressed in terms of these two parameters. By comparison of results from the Rayleigh–Ritz method and numerical simulations, it is demonstrated that the Rayleigh–Ritz method is feasible to study the generalized stress field in granular soils heap. Solutions from numerical methods are verified before being extended to more complicated cases.

Field demonstration of technologies for delineating uranium contaminated soils

International Nuclear Information System (INIS)

Tidwell, V.C.; Cunnane, J.C.; Schwing, J.; Lee, S.Y.; Perry, D.L.; Morris, D.E.

1993-01-01

An Integrated Demonstration Program, hosted by the Fernald Environmental Restoration Management Corporation (FERMCO), has been established for investigating technologies applicable to the characterization and remediation of soils contaminated with uranium. An important part of this effort is the evaluation of field screening tools capable of acquiring high resolution information on the distribution of uranium contamination in surface soils in a cost-and-time efficient manner. Consistent with this need, four field screening technologies have been demonstrated at two hazardous waste sites at the FERMCO. The four technologies tested are wide-area gamma spectroscopy, beta scintillation counting, laser ablation-inductively coupled plasma-atomic emission spectroscopy (LA-ICP-AES), and long-range alpha detection (LRAD). One of the important findings of this demonstration was just how difficult it is to compare data collected by means of multiple independent measurement techniques. Difficulties are attributed to differences in measurement scale, differences in the basic physics upon which the various measurement schemes are predicated, and differences in the general performance of detector instrumentation. It follows that optimal deployment of these techniques requires the development of an approach for accounting for the intrinsic differences noted above. As such, emphasis is given in this paper to the development of a methodology for integrating these techniques for use in site characterization programs as well as the development of a framework for interpreting the collected data. The methodology described here also has general application to other field-based screening technologies and soil sampling programs

Weeds of cereal stubble-fields on various soils in the Kielce region. P. 1. Podzolic and brown soils developed from sands and loams

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Franciszek Pawłowski

2013-12-01

Full Text Available Occupying cereal stubble-fields weed flora is the most characteristic of the environmental (especially soil conditions. Because of its developing and accomplishing the reproductive stages there it can threatens cultivated plants. They are considered to complete the seed store in a soil by 393 min per ha. The results presented in the paper concern the species composition, number and constancy (S and indice of coverage (D of the cereal stubble-field weed species on various soils in the Kielce region (the central part of Poland. The report was based upon 885 phytosociological records collected in the 268 stands. The records were carried out after the crop harvest, in the latter part of September, in 1976-1980. Soil were chosen on the base of soil maps. The analyse of soil samples, taken at the investigation process, were done in order to confirm the soil quality. The worked out material was divided into three parts. The first part, including 369 phytosociological records collected in the 112 stands (in 90 localities concerns stubble-field weeds on podzolic and brown soils developed from sands (loose, weakly loamy and loamy and loams (light and medium. It was found that these soils were grown by 108 (loamy sands to 132 (weakly loamy sands weed species. Among them 66 species were common for all of the soils. Species composition was not differentiated by the soil type (brown, podzolic within kind of the. soil (sand or loams. Among soil examined, the brown loams was the most abundant with species of high constancy degree (30 species but brown loose sands and podzolic loamy sands was the poorest one with (16 species.

Uranium facilitated transport by water-dispersible colloids in field and soil columns

Energy Technology Data Exchange (ETDEWEB)

Crancon, P., E-mail: pierre.crancon@cea.fr [CEA, DAM, DIF, F-91297 Arpajon (France); Pili, E. [CEA, DAM, DIF, F-91297 Arpajon (France); Charlet, L. [Laboratoire de Geophysique Interne et Tectonophysique (LGIT-OSUG), University of Grenoble-I, UMR5559-CNRS-UJF, BP53, 38041 Grenoble cedex 9 (France)

2010-04-01

The transport of uranium through a sandy podzolic soil has been investigated in the field and in column experiments. Field monitoring, numerous years after surface contamination by depleted uranium deposits, revealed a 20 cm deep uranium migration in soil. Uranium retention in soil is controlled by the < 50 {mu}m mixed humic and clayey coatings in the first 40 cm i.e. in the E horizon. Column experiments of uranium transport under various conditions were run using isotopic spiking. After 100 pore volumes elution, 60% of the total input uranium is retained in the first 2 cm of the column. Retardation factor of uranium on E horizon material ranges from 1300 (column) to 3000 (batch). In parallel to this slow uranium migration, we experimentally observed a fast elution related to humic colloids of about 1-5% of the total-uranium input, transferred at the mean porewater velocity through the soil column. In order to understand the effect of rain events, ionic strength of the input solution was sharply changed. Humic colloids are retarded when ionic strength increases, while a major mobilization of humic colloids and colloid-borne uranium occurs as ionic strength decreases. Isotopic spiking shows that both {sup 238}U initially present in the soil column and {sup 233}U brought by input solution are desorbed. The mobilization process observed experimentally after a drop of ionic strength may account for a rapid uranium migration in the field after a rainfall event, and for the significant uranium concentrations found in deep soil horizons and in groundwater, 1 km downstream from the pollution source.

Mapping spatial variability of soil salinity in a coastal paddy field based on electromagnetic sensors.

Science.gov (United States)

Guo, Yan; Huang, Jingyi; Shi, Zhou; Li, Hongyi

2015-01-01

In coastal China, there is an urgent need to increase land area for agricultural production and urban development, where there is a rapid growing population. One solution is land reclamation from coastal tidelands, but soil salinization is problematic. As such, it is very important to characterize and map the within-field variability of soil salinity in space and time. Conventional methods are often time-consuming, expensive, labor-intensive, and unpractical. Fortunately, proximal sensing has become an important technology in characterizing within-field spatial variability. In this study, we employed the EM38 to study spatial variability of soil salinity in a coastal paddy field. Significant correlation relationship between ECa and EC1:5 (i.e. r >0.9) allowed us to use EM38 data to characterize the spatial variability of soil salinity. Geostatistical methods were used to determine the horizontal spatio-temporal variability of soil salinity over three consecutive years. The study found that the distribution of salinity was heterogeneous and the leaching of salts was more significant in the edges of the study field. By inverting the EM38 data using a Quasi-3D inversion algorithm, the vertical spatio-temporal variability of soil salinity was determined and the leaching of salts over time was easily identified. The methodology of this study can be used as guidance for researchers interested in understanding soil salinity development as well as land managers aiming for effective soil salinity monitoring and management practices. In order to better characterize the variations in soil salinity to a deeper soil profile, the deeper mode of EM38 (i.e., EM38v) as well as other EMI instruments (e.g. DUALEM-421) can be incorporated to conduct Quasi-3D inversions for deeper soil profiles.

Mapping spatial variability of soil salinity in a coastal paddy field based on electromagnetic sensors.

Directory of Open Access Journals (Sweden)

Yan Guo

Full Text Available In coastal China, there is an urgent need to increase land area for agricultural production and urban development, where there is a rapid growing population. One solution is land reclamation from coastal tidelands, but soil salinization is problematic. As such, it is very important to characterize and map the within-field variability of soil salinity in space and time. Conventional methods are often time-consuming, expensive, labor-intensive, and unpractical. Fortunately, proximal sensing has become an important technology in characterizing within-field spatial variability. In this study, we employed the EM38 to study spatial variability of soil salinity in a coastal paddy field. Significant correlation relationship between ECa and EC1:5 (i.e. r >0.9 allowed us to use EM38 data to characterize the spatial variability of soil salinity. Geostatistical methods were used to determine the horizontal spatio-temporal variability of soil salinity over three consecutive years. The study found that the distribution of salinity was heterogeneous and the leaching of salts was more significant in the edges of the study field. By inverting the EM38 data using a Quasi-3D inversion algorithm, the vertical spatio-temporal variability of soil salinity was determined and the leaching of salts over time was easily identified. The methodology of this study can be used as guidance for researchers interested in understanding soil salinity development as well as land managers aiming for effective soil salinity monitoring and management practices. In order to better characterize the variations in soil salinity to a deeper soil profile, the deeper mode of EM38 (i.e., EM38v as well as other EMI instruments (e.g. DUALEM-421 can be incorporated to conduct Quasi-3D inversions for deeper soil profiles.

Mapping Spatial Variability of Soil Salinity in a Coastal Paddy Field Based on Electromagnetic Sensors

Science.gov (United States)

Guo, Yan; Huang, Jingyi; Shi, Zhou; Li, Hongyi

2015-01-01

In coastal China, there is an urgent need to increase land area for agricultural production and urban development, where there is a rapid growing population. One solution is land reclamation from coastal tidelands, but soil salinization is problematic. As such, it is very important to characterize and map the within-field variability of soil salinity in space and time. Conventional methods are often time-consuming, expensive, labor-intensive, and unpractical. Fortunately, proximal sensing has become an important technology in characterizing within-field spatial variability. In this study, we employed the EM38 to study spatial variability of soil salinity in a coastal paddy field. Significant correlation relationship between ECa and EC1:5 (i.e. r >0.9) allowed us to use EM38 data to characterize the spatial variability of soil salinity. Geostatistical methods were used to determine the horizontal spatio-temporal variability of soil salinity over three consecutive years. The study found that the distribution of salinity was heterogeneous and the leaching of salts was more significant in the edges of the study field. By inverting the EM38 data using a Quasi-3D inversion algorithm, the vertical spatio-temporal variability of soil salinity was determined and the leaching of salts over time was easily identified. The methodology of this study can be used as guidance for researchers interested in understanding soil salinity development as well as land managers aiming for effective soil salinity monitoring and management practices. In order to better characterize the variations in soil salinity to a deeper soil profile, the deeper mode of EM38 (i.e., EM38v) as well as other EMI instruments (e.g. DUALEM-421) can be incorporated to conduct Quasi-3D inversions for deeper soil profiles. PMID:26020969

Effects of agricultural practices of three crops on the soil communities under Mediterranean conditions: field evaluation.

Science.gov (United States)

Leitão, Sara; José Cerejeira, Maria; Abreu, Manuela; Sousa, José Paulo

2014-05-01

Sustainable agricultural production relies on soil communities as the main actors in key soil processes necessary to maintain sustainable soil functioning. Soil biodiversity influences soil physical and chemical characteristics and thus the sustainability of crop and agro-ecosystems functioning. Agricultural practices (e.g.: soil tillage, pesticides and fertilizer applications, irrigation) may affects negatively or positively soil biodiversity and abundances by modifying the relationships between organisms in the soil ecosystem. The present study aimed to study the influence of agricultural practices of three crops (potato, onion and maize) under Mediterranean climate conditions on soil macro- and mesofauna during their entire crop cycles. Effects on soil communities were assessed at a higher tier of environmental risk assessment comprising field testing of indigenous edaphic communities in a selected study-site located in a major agriculture region of Central Portugal, Ribatejo e Oeste, neighbouring protected wetlands. A reference site near the agricultural field site was selected as a Control site to compare the terrestrial communities' composition and variation along the crop cycle. The field soil and Control site soil are sandy loam soils. Crops irrigation was performed by center-pivot (automated sprinkler that rotates in a half a circle area) and by sprinklers. Soil macro- and mesofauna were collected at both sites (field and Control) using two methodologies through pitfall trapping and soil sampling. The community of soil macro- and mesofauna of the three crops field varied versus control site along the crops cycles. Main differences were due to arachnids, coleopterans, ants and adult Diptera presence and abundance. The feeding activity of soil fauna between control site and crop areas varied only for potato and onion crops vs. control site but not among crops. Concentration of pesticides residues in soil did not cause apparent negative effects on the soil

Biochar Decelerates Soil Organic Nitrogen Cycling but Stimulates Soil Nitrification in a Temperate Arable Field Trial

Science.gov (United States)

Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

2014-01-01

Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50–80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies. PMID:24497947

Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

Directory of Open Access Journals (Sweden)

Judith Prommer

Full Text Available Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

Science.gov (United States)

Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

2014-01-01

Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

Mississippi exploration field trials using microbial, radiometrics, free soil gas, and other techniques

Energy Technology Data Exchange (ETDEWEB)

Moody, J.S.; Brown, L.R.; Thieling, S.C.

1995-12-31

The Mississippi Office of Geology has conducted field trials using the surface exploration techniques of geomicrobial, radiometrics, and free soil gas. The objective of these trials is to determine if Mississippi oil and gas fields have surface hydrocarbon expression resulting from vertical microseepage migration. Six fields have been surveyed ranging in depth from 3,330 ft to 18,500 ft. The fields differ in trapping styles and hydrocarbon type. The results so far indicate that these fields do have a surface expression and that geomicrobial analysis as well as radiometrics and free soil gas can detect hydrocarbon microseepage from pressurized reservoirs. All three exploration techniques located the reservoirs independent of depth, hydrocarbon type, or trapping style.

Field estimation of soil water content. A practical guide to methods, instrumentation and sensor technology

International Nuclear Information System (INIS)

2008-01-01

appreciable amounts of clays with high ion exchange capacities, even when using soil specific calibrations; (3) all sensors must be field calibrated (factory calibrations were inaccurate in most soils studied) in order to obtain reasonable accuracy; (4) the one exception to conclusion (3) is conventional time domain reflectometry (TDR, with waveform capture and graphical analysis), which is accurate to ±0.02 m 3 m -3 in most soils when using a calibration in travel time, effective frequency and bulk electrical conductivity (see Chapter 4); (5) with the possible exception of tensiometers and the granular matrix resistance sensors, none of the sensors studied is practical for on-farm irrigation scheduling; they are either too inaccurate (capacitance sensors) or too costly and difficult to use (TDR and NMM); (6) for research studies, only the NMM, conventional TDR and direct measurements have acceptable accuracy. In light of the intense commercial introduction of electromagnetic (EM) soil water sensors in the 1990s and to date, these conclusions are somewhat disappointing. However, the joint work of the expert group has resulted in numerous scientific publications detailing the problems with EM sensors, including the theoretical underpinnings of these problems, and sparked a special issue of the Vadose Zone Journal (Evett and Parkin, 2005) summarizing much of the fundamental work to date. Now that the problems are well understood, research and development of new sensor systems to overcome these problems can, and will, proceed to a satisfactory conclusion for both scientific studies and on-farm irrigation management

[Effects of diurnal warming on soil N2O emission in soybean field].

Science.gov (United States)

Hu, Zheng-Hua; Zhou, Ying-Ping; Cui, Hai-Ling; Chen, Shu-Tao; Xiao, Qi-Tao; Liu, Yan

2013-08-01

To investigate the impact of experimental warming on N2O emission from soil of soybean field, outdoor experiments with simulating diurnal warming were conducted, and static dark chamber-gas chromatograph method was used to measure N2O emission fluxes. Results indicated that: the diurnal warming did not change the seasonal pattern of N2O emissions from soil. In the whole growing season, comparing to the control treatment (CK), the warming treatment (T) significantly enhanced the N2O flux and the cumulative amount of N2O by 17.31% (P = 0.019), and 20.27% (P = 0.005), respectively. The significant correlations were found between soil N2O emission and soil temperature, moisture. The temperature sensitivity values of soil N2O emission under CK and T treatments were 3.75 and 4.10, respectively. In whole growing stage, T treatment significantly increased the crop aboveground and total biomass, the nitrate reductase activity, and total nitrogen in leaves, while significantly decreased NO3(-) -N content in leaves. T treatment significantly increased soil NO3(-) -N content, but had no significant effect on soil organic carbon and total nitrogen contents. The results of this study suggested that diurnal warming enhanced N2O emission from soil in soybean field.

Assimilation of SMOS Retrieved Soil Moisture into the Land Information System

Science.gov (United States)

Blankenship, Clay; Case, Jonathan; Zavodsky, Bradley; Jedlovec, Gary

2014-01-01

Soil moisture retrievals from the Soil Moisture and Ocean Salinity (SMOS) instrument are assimilated into the Noah land surface model (LSM) within the NASA Land Information System (LIS). Before assimilation, SMOS retrievals are bias-corrected to match the model climatological distribution using a Cumulative Distribution Function (CDF) matching approach. Data assimilation is done via the Ensemble Kalman Filter. The goal is to improve the representation of soil moisture within the LSM, and ultimately to improve numerical weather forecasts through better land surface initialization. We present a case study showing a large area of irrigation in the lower Mississippi River Valley, in an area with extensive rice agriculture. High soil moisture value in this region are observed by SMOS, but not captured in the forcing data. After assimilation, the model fields reflect the observed geographic patterns of soil moisture. Plans for a modeling experiment and operational use of the data are given. This work helps prepare for the assimilation of Soil Moisture Active/Passive (SMAP) retrievals in the near future.

Root systems and soil microbial biomass under no-tillage system

Directory of Open Access Journals (Sweden)

Venzke Filho Solismar de Paiva

2004-01-01

Full Text Available Some root parameters such as distribution, length, diameter and dry matter are inherent to plant species. Roots can influence microbial population during vegetative cycle through the rhizodeposits and, after senescence, integrating the soil organic matter pool. Since they represent labile substrates, especially regarding nitrogen, they can determine the rate of nutrient availability to the next crop cultivated under no-tillage (NT. The root systems of two crop species: maize (Zea mays L. cultivar Cargill 909 and soybean [Glycine max (L. Merr.] cultivar Embrapa 59, were compared in the field, and their influence on spatial distribution of the microbial C and N in a clayey-textured Typic Hapludox cultivated for 22 years under NT, at Tibagi, State of Paraná (PR, Brazil, was determined. Digital image processing and nail-plate techniques were used to evaluate 40 plots of a 80 ´ 50 ´ 3 cm soil profile. It was observed that 36% and 30% of the maize and soybeans roots, respectively, are concentrated in the 0 to 10 cm soil layer. The percent distribution of root dry matter was similar for both crops. The maize roots presented a total of 1,324 kg C ha-1 and 58 kg N ha-1, with higher root dry matter density and more roots in decomposition in the upper soil layer, decreasing with depth. The soybean roots (392 kg C ha-1 and 21 kg N ha-1 showed higher number of thinner roots and higher density per length unity compared to the maize. The maize roots enhanced microbial-C down to deeper soil layers than did the soybean roots. The microbial N presented a better correlation with the concentration of thin active roots and with roots in decomposition or in indefinite shape, possibly because of higher concentration of C and N easily assimilated by soil microorganisms.

Cost comparison of laboratory methods and four field screening technologies for uranium-contaminated soil

International Nuclear Information System (INIS)

Douthat, D.M.; Armstrong, A.Q.

1994-01-01

To address the problem of characterizing uranium-contaminated surface soil at federal facilities, the Department of Energy has the development of four uranium field screening technologies, under the direction of the Uranium-in-Soils Integrated Demonstration (USID) Program. These four technologies include: a long-range alpha detector a beta scintillation detector, an in situ gamma detector, and a mobile laser ablation-inductively coupled plasma/atomic emission spectrometry (LA-ICP/AES) laboratory. As part of the performance assessment for these field screening technologies, cost estimates for the development and operation of each technology were created. A cost study was conducted to compare three of the USID field screening technologies to the use of traditional field surveying equipment to adequately characterize surface soils of a one-acre site. The results indicate that the use of traditional equipment costs more than the in situ gamma detector, but less than the beta scintillation detector and LRAD. The use of traditional field surveying equipment results in cost savings of 4% and 34% over the use of the beta scintillation and LRAD technologies, respectively. A study of single-point surface soil sampling and laboratory analysis costs was also conducted. Operational costs of the mobile LA-ICP/AES laboratory were compared with operational costs of traditional sampling and analysis, which consists of collecting soil samples and conducting analysis in a radiochemical laboratory. The cost study indicates that the use of the mobile LA-ICP/AES laboratory results in cost savings of 23% and 40% over traditional field sampling and laboratory analysis conducted by characterization groups at two DOE facilities

Dissipation of the Herbicide Benzobicyclon Hydrolysate in a Model California Rice Field Soil.

Science.gov (United States)

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

2017-10-25

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

Radioactivity levels in soil of salt field area Kelambakkam, Tamil Nadu, India

International Nuclear Information System (INIS)

Ravisankar, R.; Rajalakshmi, A.; Manikandan, E.; Gajendiran, V.; Meenakshisundaram, V.

2006-01-01

Mother nature has gifted mankind with lot of precious gifts. Common salt is one of them. In the globe, Tamilnadu is one of the ideal locations for producing salt. Kelambakkam salt field area is one of the leading producers of salt in global market. The climate, soil and availability of brine are a great asset for producing quality salts. In the present work, the primordial radionuclides concentration in soil samples collected in and around the salt field area, Kelambakkam, Tamilnadu was measured using gamma ray spectrometer

Effects of nitrogen and phosphorus fertilizer on crop yields in a field pea-spring wheat-potato rotation system with calcareous soil in semi-arid environments

Directory of Open Access Journals (Sweden)

Chang-An Liu

2016-06-01

Full Text Available The object of the present study was to investigate the yield-affecting mechanisms influenced by N and P applications in rainfed areas with calcareous soil. The experimental treatments were as follows: NF (no fertilizer, N (nitrogen, P (phosphorus, and NP (nitrogen plus phosphorus in a field pea-spring wheat-potato cropping system. This study was conducted over six years (2003-2008 on China’s semi-arid Loess Plateau. The fertilizer treatments were found to decrease the soil water content more than the NF treatment in each of the growing seasons. The annual average yields of the field pea crops during the entire experimental period were 635, 677, 858, and 1117 kg/ha for the NF, N, P, and NP treatments, respectively. The annual average yields were 673, 547, 966, and 1056 kg/ha for the spring wheat crops for the NF, N, P, and NP treatments, respectively. Also, the annual average yields were 1476, 2120, 1480, and 2424 kg/ha for the potato crops for the NF, N, P, and NP treatments, respectively. In the second cycle of the three-year rotation, the pea and spring wheat yields in the P treatment were 1.2 and 2.8 times higher than that in the N treatment, respectively. Meanwhile, the potato crop yield in the N treatment was 3.1 times higher than that in the P treatment. In conclusion, the P fertilizer was found to increase the yields of the field pea and wheat crops, and the N fertilizer increased the potato crop yield in rainfed areas with calcareous soil.

Effects of nitrogen and phosphorus fertilizer on crop yields in a field pea-spring wheat-potato rotation system with calcareous soil in semi-arid environments

Energy Technology Data Exchange (ETDEWEB)

Liu, C.A.; Zhang, S.; Hua, S.; Rao, X.

2016-11-01

The object of the present study was to investigate the yield-affecting mechanisms influenced by N and P applications in rainfed areas with calcareous soil. The experimental treatments were as follows: NF (no fertilizer), N (nitrogen), P (phosphorus), and NP (nitrogen plus phosphorus) in a field pea-spring wheat-potato cropping system. This study was conducted over six years (2003-2008) on China’s semi-arid Loess Plateau. The fertilizer treatments were found to decrease the soil water content more than the NF treatment in each of the growing seasons. The annual average yields of the field pea crops during the entire experimental period were 635, 677, 858, and 1117 kg/ha for the NF, N, P, and NP treatments, respectively. The annual average yields were 673, 547, 966, and 1056 kg/ha for the spring wheat crops for the NF, N, P, and NP treatments, respectively. Also, the annual average yields were 1476, 2120, 1480, and 2424 kg/ha for the potato crops for the NF, N, P, and NP treatments, respectively. In the second cycle of the three-year rotation, the pea and spring wheat yields in the P treatment were 1.2 and 2.8 times higher than that in the N treatment, respectively. Meanwhile, the potato crop yield in the N treatment was 3.1 times higher than that in the P treatment. In conclusion, the P fertilizer was found to increase the yields of the field pea and wheat crops, and the N fertilizer increased the potato crop yield in rainfed areas with calcareous soil. (Author)

Enhanced treatment of refinery soils with open-system slurry reactors

International Nuclear Information System (INIS)

Blackburn, J.W.; Lee, M.K.; Horn, W.C.

1995-01-01

Refinery site cleanups of residual hydrocarbons arising from long-term operations have become a concern. Because contaminated soil has been generated over many years from spills of many types of materials, it is often difficult to identify the actual spilled material. Because many of these materials are weathered, the less degradable fractions can predominate, creating a challenge for bioremedial process solutions. Open-system slurry reactors were run with an aged refinery soil after a 6-month period of field bioremediation in which 23% TPH removal resulted. The open system (a system where the liquid medium was replaced daily and the solids were retained in the reactor for 2 weeks) achieved 60 to 80% total petroleum hydrocarbon (TPH) removal based on the initial, prefield bioremediation soil concentration. A process concept twice as effective as other bioremediation schemes has been devised that takes advantage of the formation and removal of small black particulate solids in an open or continuous slurry reactor configuration. These small black particles are chemically or biologically produced in the open system and with their small size and low density are easily elutriated from the bioreactor as the liquid medium is changed. A statistically designed experiment has determined optimal values of nutrients, temperature, and mixing

Laboratory and field evaluation of the gas treatment approach for insitu remediation of chromate-contaminated soils

International Nuclear Information System (INIS)

Thornton, E.C.; Jackson, R.L.

1994-04-01

Laboratory scale soil treatment tests have been conducted as part of an effort to develop and implement an in situ chemical treatment approach to the remediation of chromate-contaminated soils through the use of reactive gases. These tests involved three different soil samples that were contaminated with Cr(VI) at the 200 ppM level. Treatment of the contaminated soils was performed by passing 100 ppM and 2000 ppM concentrations of hydrogen sulfide in nitrogen through soil columns until a S:Cr mole ratio of 10:1 was achieved. The treated soils were then leached with groundwater or deionized water and analyzed to assess the extent of chromium immobilization. Test results indicate >90% immobilization of chromium and demonstrate that the treatment process is irreversible. Ongoing developmental efforts are being directed towards the demonstration and evaluation of the gas treatment approach in a field test at a chromate-contaminated site. Major planned activities associated with this demonstration include laboratory testing of waste site soil samples, design of the treatment system and injection/extraction well network, geotechnical and geochemical characterization of the test site, and identification and resolution of regulatory and safety requirements

Soil-Carbon Measurement System Based on Inelastic Neutron Scattering

International Nuclear Information System (INIS)

Orion, I.; Wielopolski, L.

2002-01-01

Increase in the atmospheric CO 2 is associated with concurrent increase in the amount of carbon sequestered in the soil. For better understanding of the carbon cycle it is imperative to establish a better and extensive database of the carbon concentrations in various soil types, in order to develop improved models for changes in the global climate. Non-invasive soil carbon measurement is based on Inelastic Neutron Scattering (INS). This method has been used successfully to measure total body carbon in human beings. The system consists of a pulsed neutron generator that is based on D-T reaction, which produces 14 MeV neutrons, a neutron flux monitoring detector and a couple of large NaI(Tl), 6'' diameter by 6'' high, spectrometers [4]. The threshold energy for INS reaction in carbon is 4.8 MeV. Following INS of 14 MeV neutrons in carbon 4.44 MeV photons are emitted and counted during a gate pulse period of 10 μsec. The repetition rate of the neutron generator is 104 pulses per sec. The gamma spectra are acquired only during the neutron generator gate pulses. The INS method for soil carbon content measurements provides a non-destructive, non-invasive tool, which can be optimized in order to develop a system for in field measurements

Salinity management using an anionic polymer in a pecan field with calcareous-sodic soil.

Science.gov (United States)

Ganjegunte, Girisha K; Sheng, Zhuping; Braun, Robert J

2011-01-01

Soil salinity and sodicity have long been recognized as the major concerns for irrigated agriculture in the Trans-Pecos Basin, where fields are being flood irrigated with Rio Grande River water that has elevated salinity. Reclamation of these salt-affected lands is difficult due to fine-texture, high shrink-swell soils with low permeability. Conventional practice of subsoiling to improve soil permeability is expensive and has had limited success on the irrigated soils that have appreciable amounts of readily weatherable Ca minerals. If these native Ca sources can be effectively used to counter sodicity, it can improve soil permeability and reduce amelioration costs. This study evaluated the effects of 3 yr of polyacrylamide (PAM) application at 10 mg L concentration during the first irrigation of the season to evaluate soil permeability, in situ Ca mineral dissolution, and leaching of salts from the effective root zone in a pecan field of El Paso County, TX. Results indicated that PAM application improved water movement throughout the effective root zone that resulted in Na leaching. Polymer application significantly decreased CaCO (estimated based on inorganic C analysis) concentrations in the top 45 cm compared with baseline levels, indicating solubilization and redistribution of calcite. The PAM application also reduced soil electrical conductivity (EC) in the top 60 cm (4.64-2.76 dS m) and sodium adsorption ratio (SAR) from 13.1 to 5.7 mmol L in the top 75-cm depths. As evidence of improved soil conditions, pecan nut yields increased by 34% in PAM-treated fields over the control. Results suggested that PAM application helped in effective use of native Ca sources present in soils of the study site and reduced Na by improving soil permeability. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

A systemic approach for modeling soil functions

Science.gov (United States)

Vogel, Hans-Jörg; Bartke, Stephan; Daedlow, Katrin; Helming, Katharina; Kögel-Knabner, Ingrid; Lang, Birgit; Rabot, Eva; Russell, David; Stößel, Bastian; Weller, Ulrich; Wiesmeier, Martin; Wollschläger, Ute

2018-03-01

The central importance of soil for the functioning of terrestrial systems is increasingly recognized. Critically relevant for water quality, climate control, nutrient cycling and biodiversity, soil provides more functions than just the basis for agricultural production. Nowadays, soil is increasingly under pressure as a limited resource for the production of food, energy and raw materials. This has led to an increasing demand for concepts assessing soil functions so that they can be adequately considered in decision-making aimed at sustainable soil management. The various soil science disciplines have progressively developed highly sophisticated methods to explore the multitude of physical, chemical and biological processes in soil. It is not obvious, however, how the steadily improving insight into soil processes may contribute to the evaluation of soil functions. Here, we present to a new systemic modeling framework that allows for a consistent coupling between reductionist yet observable indicators for soil functions with detailed process understanding. It is based on the mechanistic relationships between soil functional attributes, each explained by a network of interacting processes as derived from scientific evidence. The non-linear character of these interactions produces stability and resilience of soil with respect to functional characteristics. We anticipate that this new conceptional framework will integrate the various soil science disciplines and help identify important future research questions at the interface between disciplines. It allows the overwhelming complexity of soil systems to be adequately coped with and paves the way for steadily improving our capability to assess soil functions based on scientific understanding.

Practical improvements in soil redox potential (Eh) measurement for characterisation of soil properties. Application for comparison of conventional and conservation agriculture cropping systems

Energy Technology Data Exchange (ETDEWEB)

Husson, Olivier, E-mail: Olivier.husson@cirad.fr [CIRAD/PERSYST/UPR 115 AIDA and AfricaRice Centre, 01 BP 2031 Cotonou (Benin); Husson, Benoit, E-mail: bhusson@ideeaquaculture.com [IDEEAQUACULTURE, Parc Euromédecine 2, 39 Rue Jean Giroux, 34080 Montpellier (France); Brunet, Alexandre, E-mail: brunet.alexandre@outlook.com [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Babre, Daniel, E-mail: Daniel.babre@cirad.fr [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Alary, Karine, E-mail: Karine.alary@cirad.fr [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Sarthou, Jean-Pierre, E-mail: sarthou@ensat.fr [ENSAT/INRA/INP UMR AGIR. BP 52627, Chemin de Borde Rouge, 31326 Castanet-Tolosan Cedex (France); Charpentier, Hubert, E-mail: Charpentier.hub@wanadoo.fr [La Boisfarderie, Brives 36100 (France); Durand, Michel, E-mail: earldeslacs@orange.fr [Le Cazals, Castanet 81 150 (France); Benada, Jaroslav, E-mail: benada@vukrom.cz [Agrotest fyto, Kromeriz Institute, Havlíckova 2787, 76701 Kromeriz (Czech Republic); Henry, Marc, E-mail: henry@unistra.fr [UMR CNRS/UdS 7140, Université de Strasbourg, Institut Le Bel, 4, rue Blaise Pascal, CS 90032, Strasbourg 67081 (France)

2016-02-04

The soil redox potential (Eh) can provide essential information to characterise soil conditions. In practice, however, numerous problems may arise regarding: (i) Eh determination in soils, especially aerobic soils, e.g. variations in the instrumentation and methodology for Eh measurement, high spatial and temporal Eh variability in soils, irreversibility of the redox reaction at the surface electrode, chemical disequilibrium; and (ii) measurement interpretation. This study aimed at developing a standardised method for redox potential measurement in soils, in order to use Eh as a soil quality indicator. This paper presents practical improvements in soil Eh measurement, especially regarding the control of electromagnetic perturbations, electrode choice and preparation, soil sample preparation (drying procedure) and soil:water extraction rate. The repeatability and reproducibility of the measurement method developed are highlighted. The use of Eh corrected at pH7, pe+pH or rH{sub 2}, which are equivalent notions, is proposed to facilitate interpretation of the results. The application of this Eh measurement method allows characterisation of soil conditions with sufficient repeatability, reproducibility and accuracy to demonstrate that conservation agriculture systems positively alter the protonic and electronic balance of soil as compared to conventional systems. - Highlights: • Electromagnetic fields can dramatically perturb soil Eh measurement. • Our method overcomes the main difficulties in soil Eh measurement. • Accurate and reproducible measurement of mean soil Eh are achieved. • Eh{sub pH7}, pe+pH and rH{sub 2} are equivalent notions characterising electron activity. • Agricultural practices alter soil protonic and electronic characteristics.

Uranium facilitated transport by water-dispersible colloids in field and soil columns

Energy Technology Data Exchange (ETDEWEB)

Crancon, P.; Pili, E. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Charlet, L. [Univ Grenoble 1, Lab Geophys Interne and Tectonophys LGIT OSUG, CNRS, UJF, UMR5559, F-38041 Grenoble 9 (France)

2010-07-01

The transport of uranium through a sandy podsolic soil has been investigated in the field and in column experiments. Field monitoring, numerous years after surface contamination by depleted uranium deposits, revealed a 20 cm deep uranium migration in soil. Uranium retention in soil is controlled by the {<=} 50 {mu}m mixed humic and clayey coatings in the first 40 cm i.e. in the E horizon. Column experiments of uranium transport under various conditions were run using isotopic spiking. After 100 pore volumes elution, 60% of the total input uranium is retained in the first 2 cm of the column. Retardation factor of uranium on E horizon material ranges from 1300 (column) to 3000 (batch). In parallel to this slow uranium migration, we experimentally observed a fast elution related to humic colloids of about 1-5% of the total-uranium input, transferred at the mean pore-water velocity through the soil column. In order to understand the effect of rain events, ionic strength of the input solution was sharply changed. Humic colloids are retarded when ionic strength increases, while a major mobilization of humic colloids and colloid-borne uranium occurs as ionic strength decreases. Isotopic spiking shows that both {sup 238}U initially present in the soil column and {sup 233}U brought by input solution are desorbed. The mobilization process observed experimentally after a drop of ionic strength may account for a rapid uranium migration in the field after a rainfall event, and for the significant uranium concentrations found in deep soil horizons and in groundwater, 1 km downstream from the pollution source. (authors)

Roundup Ready soybean gene concentrations in field soil aggregate size classes.

Science.gov (United States)

Levy-Booth, David J; Gulden, Robert H; Campbell, Rachel G; Powell, Jeff R; Klironomos, John N; Pauls, K Peter; Swanton, Clarence J; Trevors, Jack T; Dunfield, Kari E

2009-02-01

Roundup Ready (RR) soybeans containing recombinant Agrobacterium spp. CP4 5-enol-pyruvyl-shikimate-3-phosphate synthase (cp4 epsps) genes tolerant to the herbicide glyphosate are extensively grown worldwide. The concentration of recombinant DNA from RR soybeans in soil aggregates was studied due to the possibility of genetic transformation of soil bacteria. This study used real-time PCR to examine the concentration of cp4 epsps in four field soil aggregate size classes (>2000 microm, 2000-500 microm, 500-250 microm and 2000 mum fraction contained between 66.62% and 99.18% of total gene copies, although it only accounted for about 30.00% of the sampled soil. Aggregate formation may facilitate persistence of recombinant DNA.

Real-Time Soils Characterization and Analyses Systems Used at Ohio Closure Sites

International Nuclear Information System (INIS)

Roybal, Lyle Gene; Carpenter, Michael Vance; Giles, John Robert; Hartwell, John Kelvin; Danahy, R.

2003-01-01

The Idaho National Engineering and Environmental Laboratory (INEEL) and the Fernald Environmental Management Project (FEMP) have jointly developed a field-deployed analytical system to rapidly scan, characterize, and analyze surface soil contamination. The basic system consists of a sodium iodide (NaI) spectrometer and global positioning system (GPS) hardware. This hardware can be deployed from any of four different platforms depending on the scope of the survey at hand. These platforms range from a large tractor-based unit (the RTRAK) used to survey large, relatively flat areas to a hand-pushed unit where maneuverability is important, to an excavator mounted system used to scan pits and trenches. The mobile sodium iodide concept was initially developed by the FEMP to provide pre-screening analyses for soils contaminated with uranium, thorium, and radium. The initial study is documented in the RTRAK Applicability Study and provides analyses supporting the field usage of the concept. The RTRAK system produced data that required several days of post-processing and analyses to generate an estimation of field coverage and activity levels. The INEEL has provided integrated engineering, computer hardware and software support to greatly streamline the data acquisition and analysis process to the point where real-time activity and coverage maps are available to the field technicians. On-line analyses have been added to automatically convert GPS data to Ohio State-Plane coordinates, examine and correct collected spectra for energy calibration drifts common to NaI spectrometers, and strip spectra in regions of interest to provide moisture corrected activity levels for total uranium, thorium-232, and radium-226. Additionally, the software provides a number of checks and alarms to alert operators that a hand-examination of spectral data in a particular area may be required. The FEMP has estimated that this technology has produced projected site savings in excess of $34M

Reliability and stability of immobilization remediation of Cd polluted soils using sepiolite under pot and field trials

International Nuclear Information System (INIS)

Sun, Yuebing; Xu, Yi; Xu, Yingming; Wang, Lin; Liang, Xuefeng; Li, Ye

2016-01-01

Long-term effectiveness and persistence are two important criterias to evaluate alternative remediation technology of heavy metal polluted soils. Pot and field studies showed addition of sepiolite was effective in immobilizing Cd in polluted soils, with significant reduction in TCLP extracts (0.6%–49.6% and 4.0%–32.5% reduction in pot and field experiments, respectively) and plant uptake (14.4%–84.1% and 22.8%–61.4% declines in pot and field studies, correspondingly). However, the applications of sepiolite offered a limited guarantee for the safety of edible vegetables in Cd-polluted soils, depending on the soil type, the Cd pollution type and level, and the dose and application frequency of chemical amendments. Bioassays, such as plant growth, soil enzymatic activities and microbial community diversity, indicated a certain degree of recovery of soil metabolic function. Therefore, sepiolite-assisted in situ remediation is cost-effective, environmentally friendly, and technically applicable, and can be successfully used to reduce Cd enter into the food chain on field scale. - Highlights: • Sepiolite has reliability and stability for remediation of contaminated Cd. • Sepiolite significantly decreases Cd bioavailability in soil and uptake in plant. • The treatment of sepiolite improves soil quality. - Sepiolite not only decreased soil Cd bioavailability and plant Cd uptake, but also improved soil quality.

Variation in soil aggregate-size distribution affects the dissipation of polycyclic aromatic hydrocarbons in long-term field-contaminated soils.

Science.gov (United States)

Wei, Ran; Ni, Jinzhi; Chen, Weifeng; Yang, Yusheng

2017-10-01

Soil organic matter (SOM) is the main adsorbent for polycyclic aromatic hydrocarbons (PAHs) and the principal aggregating agent for soil aggregation that can affect PAH bioavailability and bioaccessibility in soils. The objective of this study was to analyze the relationship between PAH dissipation and variation in soil aggregate-size distribution in two field-contaminated soils with different soil organic C (SOC) content (Anthrosols, 1.41% SOC; Phaeozems, 8.51% SOC) in phytoremediation with alfalfa. The results showed that there were significant reductions of 10.2 and 15.4% of the total PAHs in unplanted and planted treatments, respectively, for Anthrosols. However, there was no significant reduction of total PAHs in either unplanted or planted treatment for Phaeozems. For Anthrosols, mass percentages of coarse sand and fine sand were significantly reduced while coarse silt and fine silt were significantly increased for the planted soil compared to the initial soil (p soil was slightly reduced. The main reason for the dissipation of PAHs in Anthrosols could be that macroaggregates were broken into microaggregates, which made some trapped PAHs become bioaccessible to soil microorganisms.

Rice production in relation to soil quality under different rice-based cropping systems

Science.gov (United States)

Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

2016-04-01

Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P < 0.01) between rice plant parameters, rice yield and soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal

Soil Temperature and Moisture Profile (STAMP) System Handbook

Energy Technology Data Exchange (ETDEWEB)

Cook, David R. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-11-01

The soil temperature and moisture profile system (STAMP) provides vertical profiles of soil temperature, soil water content (soil-type specific and loam type), plant water availability, soil conductivity, and real dielectric permittivity as a function of depth below the ground surface at half-hourly intervals, and precipitation at one-minute intervals. The profiles are measured directly by in situ probes at all extended facilities of the SGP climate research site. The profiles are derived from measurements of soil energy conductivity. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil. The STAMP system replaced the SWATS system in early 2016.

Rapid Measurement of Soil Carbon in Rice Paddy Field of Lombok Island Indonesia Using Near Infrared Technology

Science.gov (United States)

Kusumo, B. H.; Sukartono, S.; Bustan, B.

2018-02-01

Measuring soil organic carbon (C) using conventional analysis is tedious procedure, time consuming and expensive. It is needed simple procedure which is cheap and saves time. Near infrared technology offers rapid procedure as it works based on the soil spectral reflectance and without any chemicals. The aim of this research is to test whether this technology able to rapidly measure soil organic C in rice paddy field. Soil samples were collected from rice paddy field of Lombok Island Indonesia, and the coordinates of the samples were recorded. Parts of the samples were analysed using conventional analysis (Walkley and Black) and some other parts were scanned using near infrared spectroscopy (NIRS) for soil spectral collection. Partial Least Square Regression (PLSR) Models were developed using data of soil C analysed using conventional analysis and data from soil spectral reflectance. The models were moderately successful to measure soil C in rice paddy field of Lombok Island. This shows that the NIR technology can be further used to monitor the C change in rice paddy soil.

Non-invasive Field Measurements of Soil Water Content Using a Pulsed 14 MeV Neutron Generator

Energy Technology Data Exchange (ETDEWEB)

Mitra S.; Wielopolski L.; Omonode, R.; Novak, J.; Frederick, J.; Chan, A.

2012-01-26

Current techniques of soil water content measurement are invasive and labor-intensive. Here, we demonstrate that an in situ soil carbon (C) analyzer with a multi-elemental analysis capability, developed for studies of terrestrial C sequestration, can be used concurrently to non-invasively measure the water content of large-volume ({approx}0.3 m{sup 3}) soil samples. Our objectives were to investigate the correlations of the hydrogen (H) and oxygen (O) signals with water to the changes in the soil water content in laboratory experiments, and in an agricultural field. Implementing prompt gamma neutron activation analyses we showed that in the field, the signal from the H nucleus better indicates the soil water content than does that from the O nucleus. Using a field calibration, we were able to use the H signal to estimate a minimum detectable change of {approx}2% volumetric water in a 0-30 cm depth of soil.

Soil phosphorus dynamics in a humid tropical silvopastoral system

Energy Technology Data Exchange (ETDEWEB)

Cooperband, L.R.

1992-01-01

In developing countries of the humid tropics, timber exploitation and agricultural expansion frequently result in deforestation. Extensive land management, coupled with inherently low soil fertility invariably produce declines in agricultural/livestock productivity which eventually lead to land abandonment and further deforestation. Phosphorus is often the major nutrient limiting plant growth in tropical soils. Agroforestry systems have been considered as viable alternatives to current land use practices. Several hypotheses suggest that combining trees with crops or pasture, especially leguminous species will improve soil nutrient cycling, soil structure and soil organic matter. In this experiment Erythrina berteroana (an arboreous legume) was grown in native grass pastures in Costa Rica to determine the effects of tree pruning and cattle grazing on soil P availability. I measured soil P fluxes as well as changes in pasture biomass over an 18-month period. In a separate field experiment, I determined decomposition rates and P release characteristics of Erythrina leaves, pasture grass clippings and cattle dung. Erythrina leaves decomposed faster than both pasture grass and cattle dung. Erythrina and pasture residues released 4-5 times less P than dung. Phosphorus fluxes after tree pruning and grazing were highly dynamic for all treatments. Tree pruning increased labile soil P over time when coupled with grazing. Pasture biomass production was greatest in the grazed tree treatment. Pasture biomass P production and concentration was greatest in the non-grazed treatment. Trees and grazing together tended to increase nutrient (P) turnover which stimulated biomass production. In contrast, trees without grazing promoted nutrient (P) accumulation in pasture biomass.

Soil phosphorus dynamics in a humid tropical silvopastoral system

International Nuclear Information System (INIS)

Cooperband, L.R.

1992-01-01

In developing countries of the humid tropics, timber exploitation and agricultural expansion frequently result in deforestation. Extensive land management, coupled with inherently low soil fertility invariably produce declines in agricultural/livestock productivity which eventually lead to land abandonment and further deforestation. Phosphorus is often the major nutrient limiting plant growth in tropical soils. Agroforestry systems have been considered as viable alternatives to current land use practices. Several hypotheses suggest that combining trees with crops or pasture, especially leguminous species will improve soil nutrient cycling, soil structure and soil organic matter. In this experiment Erythrina berteroana (an arboreous legume) was grown in native grass pastures in Costa Rica to determine the effects of tree pruning and cattle grazing on soil P availability. I measured soil P fluxes as well as changes in pasture biomass over an 18-month period. In a separate field experiment, I determined decomposition rates and P release characteristics of Erythrina leaves, pasture grass clippings and cattle dung. Erythrina leaves decomposed faster than both pasture grass and cattle dung. Erythrina and pasture residues released 4-5 times less P than dung. Phosphorus fluxes after tree pruning and grazing were highly dynamic for all treatments. Tree pruning increased labile soil P over time when coupled with grazing. Pasture biomass production was greatest in the grazed tree treatment. Pasture biomass P production and concentration was greatest in the non-grazed treatment. Trees and grazing together tended to increase nutrient (P) turnover which stimulated biomass production. In contrast, trees without grazing promoted nutrient (P) accumulation in pasture biomass

Triclosan affects the microbial community in simulated sewage-drain-field soil and slows down xenobiotic degradation

Energy Technology Data Exchange (ETDEWEB)

Svenningsen, Hanne [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); Department of Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K (Denmark); Henriksen, Trine [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); Prieme, Anders [Department of Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K (Denmark); Johnsen, Anders R., E-mail: arj@geus.dk [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark)

2011-06-15

Effects of the common antibacterial agent triclosan on microbial communities and degradation of domestic xenobiotics were studied in simulated sewage-drain-field soil. Cultivable microbial populations decreased 22-fold in the presence of 4 mg kg{sup -1} of triclosan, and triclosan-resistant Pseudomonas strains were strongly enriched. Exposure to triclosan also changed the general metabolic profile (Ecoplate substrate profiling) and the general profile (T-RFLP) of the microbial community. Triclosan degradation was slow at all concentrations tested (0.33-81 mg kg{sup -1}) during 50-days of incubation. Mineralization experiments ({sup 14}C-tracers) and chemical analyses (LC-MS/MS) showed that the persistence of a linear alkylbenzene sulfonate (LAS) and a common analgesic (ibuprofen) increased with increasing triclosan concentrations (0.16-100 mg kg{sup -1}). The largest effect was seen for LAS mineralization which was severely reduced by 0.16 mg kg{sup -1} of triclosan. Our findings indicate that environmentally realistic concentrations of triclosan may affect the efficiency of biodegradation in percolation systems. - Highlights: > Triclosan may enter the soil environment through sewage. > Triclosan impacts the microbial community in sewage-drain-field soil. > Triclosan-resistant pseudomonads are strongly enriched. > Degradation of co-occurring LAS and ibuprofen is reduced. - Environmentally realistic triclosan concentrations in percolation systems may reduce the biodegradation of other xenobiotics and select for triclosan-resistant bacteria.

Triclosan affects the microbial community in simulated sewage-drain-field soil and slows down xenobiotic degradation

International Nuclear Information System (INIS)

Svenningsen, Hanne; Henriksen, Trine; Prieme, Anders; Johnsen, Anders R.

2011-01-01

Effects of the common antibacterial agent triclosan on microbial communities and degradation of domestic xenobiotics were studied in simulated sewage-drain-field soil. Cultivable microbial populations decreased 22-fold in the presence of 4 mg kg -1 of triclosan, and triclosan-resistant Pseudomonas strains were strongly enriched. Exposure to triclosan also changed the general metabolic profile (Ecoplate substrate profiling) and the general profile (T-RFLP) of the microbial community. Triclosan degradation was slow at all concentrations tested (0.33-81 mg kg -1 ) during 50-days of incubation. Mineralization experiments ( 14 C-tracers) and chemical analyses (LC-MS/MS) showed that the persistence of a linear alkylbenzene sulfonate (LAS) and a common analgesic (ibuprofen) increased with increasing triclosan concentrations (0.16-100 mg kg -1 ). The largest effect was seen for LAS mineralization which was severely reduced by 0.16 mg kg -1 of triclosan. Our findings indicate that environmentally realistic concentrations of triclosan may affect the efficiency of biodegradation in percolation systems. - Highlights: → Triclosan may enter the soil environment through sewage. → Triclosan impacts the microbial community in sewage-drain-field soil. → Triclosan-resistant pseudomonads are strongly enriched. → Degradation of co-occurring LAS and ibuprofen is reduced. - Environmentally realistic triclosan concentrations in percolation systems may reduce the biodegradation of other xenobiotics and select for triclosan-resistant bacteria.

Soil and Foliar Arthropod Abundance and Diversity in Five Cropping Systems in the Coastal Plains of North Carolina.

Science.gov (United States)

Adams, Paul R; Orr, David B; Arellano, Consuelo; Cardoza, Yasmin J

2017-08-01

Soil and foliar arthropod populations in agricultural settings respond to environmental disturbance and degradation, impacting functional biodiversity in agroecosystems. The objective of this study was to evaluate system level management effects on soil and foliar arthropod abundance and diversity in corn and soybean. Our field experiment was a completely randomized block design with three replicates for five farming systems which included: Conventional clean till, conventional long rotation, conventional no-till, organic clean till, and organic reduced till. Soil arthropod sampling was accomplished by pitfall trapping. Foliar arthropod sampling was accomplished by scouting corn and sweep netting soybean. Overall soil arthropod abundance was significantly impacted by cropping in corn and for foliar arthropods in soybeans. Conventional long rotation and organic clean till systems were highest in overall soil arthropod abundance for corn while organic reduced till systems exceeded all other systems for overall foliar arthropod abundance in soybeans. Foliar arthropod abundance over sampling weeks was significantly impacted by cropping system and is suspected to be the result of in-field weed and cover crop cultivation practices. This suggests that the sum of management practices within production systems impact soil and foliar arthropod abundance and diversity and that the effects of these systems are dynamic over the cropping season. Changes in diversity may be explained by weed management practices as sources of disturbance and reduced arthropod refuges via weed reduction. Furthermore, our results suggest agricultural systems lower in management intensity, whether due to organic practices or reduced levels of disturbance, foster greater arthropod diversity. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Modeling Spatial Patterns of Soil Respiration in Maize Fields from Vegetation and Soil Property Factors with the Use of Remote Sensing and Geographical Information System

Science.gov (United States)

Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

2014-01-01

To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m−2 s−1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China. PMID:25157827

Development of methods for remediation of artificial polluted soils and improvement of soils for ecologically clean agricultural production systems

International Nuclear Information System (INIS)

Bogachev, V.; Adrianova, G.; Zaitzev, V.; Kalinin, V.; Kovalenko, E.; Makeev, A.; Malikova, L.; Popov, Yu.; Savenkov, A.; Shnyakina, V.

1996-01-01

The purpose of the research: Development of methods for the remediation of artificial polluted soils and the improvement of polluted lands to ecologically clean agricultural production.The following tasks will be implemented in this project to achieve viable practical solutions: - To determine the priority pollutants, their ecological pathways, and sources of origin. - To form a supervised environmental monitoring data bank throughout the various geo system conditions. - To evaluate the degree of the bio geo system pollution and the influence on the health of the local human populations. - To establish agricultural plant tolerance levels to the priority pollutants. - To calculate the standard concentrations of the priority pollutants for main agricultural plant groups. - To develop a soil remediation methodology incorporating the structural, functional geo system features. - To establish a territory zone division methodology in consideration of the degree of component pollution, plant tolerance to pollutants, plant production conditions, and human health. - Scientific grounding of the soil remediation proposals and agricultural plant material introductions with soil pollution levels and relative plant tolerances to pollutants. Technological Means, Methods, and Approaches Final proposed solutions will be based upon geo system and ecosystem approaches and methodologies. The complex ecological valuation methods of the polluted territories will be used in this investigation. Also, laboratory culture in vitro, application work, and multi-factor field experiments will be conducted. The results will be statistically analyzed using appropriate methods. Expected Results Complex biogeochemical artificial province assessment according to primary pollutant concentrations. Development of agricultural plant tolerance levels relative to the priority pollutants. Assessment of newly introduced plant materials that may possess variable levels of pollution tolerance. Remediation

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

DEFF Research Database (Denmark)

Koestel, J. K.; Nørgaard, Trine; Loung, N. M.

2013-01-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables......, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field...... to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column...

From Process Understanding Via Soil Functions to Sustainable Soil Management - A Systemic Approach

Science.gov (United States)

Wollschlaeger, U.; Bartke, S.; Bartkowski, B.; Daedlow, K.; Helming, K.; Kogel-Knabner, I.; Lang, B.; Rabot, E.; Russell, D.; Stößel, B.; Weller, U.; Wiesmeier, M.; Rabot, E.; Vogel, H. J.

2017-12-01

Fertile soils are central resources for the production of biomass and the provision of food and energy. A growing world population and latest climate targets lead to an increasing demand for both, food and bio-energy, which requires preserving and improving the long-term productivity of soils as a bio-economic resource. At the same time, other soil functions and ecosystem services need to be maintained: filter for clean water, carbon sequestration, provision and recycling of nutrients, and habitat for biological activity. All these soil functions result from the interaction of a multitude of physical, chemical and biological processes that are not yet sufficiently understood. In addition, we lack understanding about the interplay between the socio-economic system and the soil system and how soil functions benefit human wellbeing. Hence, a solid and integrated assessment of soil quality requires the consideration of the ensemble of soil functions and its relation to soil management to finally be able to develop site-specific options for sustainable soil management. We present an integrated modeling approach that investigates the influence of soil management on the ensemble of soil functions. It is based on the mechanistic relationships between soil functional attributes, each explained by a network of interacting processes as derived from scientific evidence. As the evidence base required for feeding the model is for the most part stored in the existing scientific literature, another central component of our work is to set up a public "knowledge-portal" providing the infrastructure for a community effort towards a comprehensive knowledge base on soil processes as a basis for model developments. The connection to the socio-economic system is established using the Drivers-Pressures-Impacts-States-Responses (DPSIR) framework where our improved understanding about soil ecosystem processes is linked to ecosystem services and resource efficiency via the soil functions.

Chemical stabilization of subgrade soil for the strategic expeditionary landing field

Science.gov (United States)

Conaway, M. H.

1983-06-01

The Strategic Expeditionary Landing Field (SELF) is a military expeditionary-type airfield with an aluminum matted surface that is designed for sustained tactical and cargo airlift operations in an amphibious objective area. Because of the operational traffic parameters such as loads of the various types of aircraft, tire pressures and volume of traffic, a base layer must be constructed over subgrade soil support conditions which may be only marginal. The base layer could be constructed with conventional soil construction techniques (compaction) and yield the required strength. It would be difficult, however, to maintain this strength for the required one-year service life under many climatic conditions due to the degrading effects of water on the support capacity of many soils. Chemical soil stabilization with lime, portland cement and asphalt stabilizing agents could be used to treat the soil. These additives, when properly mixed with certain types of soils, initiate reactions which will increase soil support strength and enhance durability (resistance to the degrading effects of water). Technically, this procedure is quite viable but logistically, it may not be feasible.

Estimating field-scale soil water dynamics at a heterogeneous site using multi-channel GPR

Directory of Open Access Journals (Sweden)

X. Pan

2012-11-01

Full Text Available We explore the feasibility to quantify the field-scale soil water dynamics through time series of GPR (ground-penetrating radar measurements, which bridge the gap between point measurements and field measurements. Working on a 40 m × 50 m area in a heterogeneous agricultural field, we obtain a time series of radargrams after a heavy rainfall event. The data are analysed to simultaneously yield (i a three-dimensional representation of the subsurface architecture and (ii the total soil water volume between the surface and a reflection boundary associated with the presence of paleo sand dunes or clay inclusions in a rather uniform sand matrix. We assess the precision and the accuracy of these quantities and conclude that the method is sensitive enough to capture the spatial structure of the changing soil water content in a three-dimensional heterogeneous soil during a short-duration infiltration event. While the sensitivity of the method needs to be improved, it already produced useful information to understand the observed patterns in crop height and it yielded insight into the dynamics of soil water content at this site including the effect of evaporation.

Experimental Study of Soil Organic Matter Loss From Cultivated Field Plots In The Venezuelan Andes.

Science.gov (United States)

Bellanger, B.; Huon, S.; Velasquez, F.; Vallès, V.; Girardin A, C.; Mariotti, A. B.

The question of discriminating sources of organic matter in suspended particles of stream flows can be addressed by using total organic carbon (TOC) concentration and stable isotope (13C, 15N) measurements when constant fluxes of organic matter supply can be assumed. However, little is known on the dynamics of organic matter release during soil erosion and on the temporal stability of its isotopic signature. In this study, we have monitored soil organic carbon loss and water runoff using natural rainfall events on three experimental field plots with different vegetation cover (bare soil, maize and coffee fields), set up on natural slopes of a tropical mountainous watershed in NW Venezuela (09°13'32'' ­ 09°10'00''N, 70°13'49'' ­ 70°18'34''W). Runoff and soil loss are markedly superior for the bare field plot than for the coffee field plot: by a factor 15 ­ 36, respectively, for the five-month experiment, and by a factor 30 ­ 120, respectively, during a single rainfall event experiment. Since runoff and soil organic matter loss are closely linked during most of the flow (at the time scales of this study), TOC concentration in suspended matter is constant. Furthermore, stable isotope compositions reflect those of top-soil organic matter from which they originate.

Soil Quality Indicators as Affected by a Long Term Barley-Maize and Maize Cropping Systems

Directory of Open Access Journals (Sweden)

Barbara Manachini

2009-03-01

Full Text Available Most soil studies aim a better characterization of the system through indicators. In the present study nematofauna and soil structure were chosen as indicators to be assess soil health as related to agricultural practices. The field research was carried out on the two fodder cropping systems continuous maize (CM, Zea mays L. and a 3-year rotation of silage-maize – silage-barley (Hordeum vulgare L. with Italian ryegrass (R3 and grain-maize maintained in these conditions for 18 years. Each crop system was submitted to two management options: 1 the high input level (H, done as a conventional tillage, 2 the low input level (L, where the tillage was replaced by harrowing and the manure was reduced by 30%. The effects of the two different cropping systems was assessed on soil nematofauna and soil physic parameters (structure or aggregate stability. Comparison was made of general composition, trophic structure and biodiversity of the nematofauna collected in both systems. Differences in nematode genera composition and distribution between the two systems were also recorded. The monoculture, compared to the three year rotation, had a negative influence on the nematofauna composition and its ecological succession. The Structural Stability Index (SSI values indicate that both the cropping systems had a negative effect on the aggregate stability. The results indicate that nematofauna can be used to assess the effects of cropping systems on soil ecosystem, and therefore be considered a good indicator of soil health to integrate information from different chemical or physical indicators.

Soil Quality Indicators as Affected by a Long Term Barley-Maize and Maize Cropping Systems

Directory of Open Access Journals (Sweden)

Anna Corsini

2011-02-01

Full Text Available Most soil studies aim a better characterization of the system through indicators. In the present study nematofauna and soil structure were chosen as indicators to be assess soil health as related to agricultural practices. The field research was carried out on the two fodder cropping systems continuous maize (CM, Zea mays L. and a 3-year rotation of silage-maize – silage-barley (Hordeum vulgare L. with Italian ryegrass (R3 and grain-maize maintained in these conditions for 18 years. Each crop system was submitted to two management options: 1 the high input level (H, done as a conventional tillage, 2 the low input level (L, where the tillage was replaced by harrowing and the manure was reduced by 30%. The effects of the two different cropping systems was assessed on soil nematofauna and soil physic parameters (structure or aggregate stability. Comparison was made of general composition, trophic structure and biodiversity of the nematofauna collected in both systems. Differences in nematode genera composition and distribution between the two systems were also recorded. The monoculture, compared to the three year rotation, had a negative influence on the nematofauna composition and its ecological succession. The Structural Stability Index (SSI values indicate that both the cropping systems had a negative effect on the aggregate stability. The results indicate that nematofauna can be used to assess the effects of cropping systems on soil ecosystem, and therefore be considered a good indicator of soil health to integrate information from different chemical or physical indicators.

Simulated optimization of crop yield through irrigation system design and operation based on the spatial variability of soil hydrodynamic properties

International Nuclear Information System (INIS)

Gurovich, L.; Stern, J.; Ramos, R.

1983-01-01

Spatial autocorrelation and kriging techniques were applied to soil infiltrability data from a 20 hectare field, to separate homogeneous irrigation units. Border irrigation systems were designed for each unit and combinations of units by using DESIGN, a computer model based on soil infiltrability and hydraulics of surface water flow, which enables optimal irrigation systems to be designed. Water depths effectively infiltrated at different points along the irrigation run were determined, and the agronomic irrigation efficiency of the unit evaluated. A modification of Hanks' evapotranspiration model, PLANTGRO, was used to evaluate plant growth, relative crop yield and soil-water economy throughout the growing season, at several points along each irrigation unit. The effect of different irrigation designs on total field yield and total water used for irrigation was evaluated by integrating yield values corresponding to each point, volume and inflow time during each irrigation. For relevant data from winter wheat grown in the central area of Chile during 1981, simulation by an interactive and sequentially recurrent use of DESIGN and PLANTGRO models, was carried out. The results obtained indicate that, when a field is separated into homogeneous irrigation units on the basis of the spatial variability of soil infiltrability and the border irrigation systems are designed according to soil characteristics, both a significant yield increase and less water use can be obtained by comparison with other criteria of field zonification for irrigation management. The use of neutrometric determinations to assess soil-water content during the growing season, as a validation of the results obtained in this work, is discussed. (author)

Plant-uptake of uranium: Hydroponic and soil system studies

Science.gov (United States)

Ramaswami, A.; Carr, P.; Burkhardt, M.

2001-01-01

Limited information is available on screening and selection of terrestrial plants for uptake and translocation of uranium from soil. This article evaluates the removal of uranium from water and soil by selected plants, comparing plant performance in hydroponic systems with that in two soil systems (a sandy-loam soil and an organic-rich soil). Plants selected for this study were Sunflower (Helianthus giganteus), Spring Vetch (Vicia sativa), Hairy Vetch (Vicia villosa), Juniper (Juniperus monosperma), Indian Mustard (Brassica juncea), and Bush Bean (Phaseolus nanus). Plant performance was evaluated both in terms of the percent uranium extracted from the three systems, as well as the biological absorption coefficient (BAC) that normalized uranium uptake to plant biomass. Study results indicate that uranium extraction efficiency decreased sharply across hydroponic, sandy and organic soil systems, indicating that soil organic matter sequestered uranium, rendering it largely unavailable for plant uptake. These results indicate that site-specific soils must be used to screen plants for uranium extraction capability; plant behavior in hydroponic systems does not correlate well with that in soil systems. One plant species, Juniper, exhibited consistent uranium extraction efficiencies and BACs in both sandy and organic soils, suggesting unique uranium extraction capabilities.

Reliability and stability of immobilization remediation of Cd polluted soils using sepiolite under pot and field trials.

Science.gov (United States)

Sun, Yuebing; Xu, Yi; Xu, Yingming; Wang, Lin; Liang, Xuefeng; Li, Ye

2016-01-01

Long-term effectiveness and persistence are two important criterias to evaluate alternative remediation technology of heavy metal polluted soils. Pot and field studies showed addition of sepiolite was effective in immobilizing Cd in polluted soils, with significant reduction in TCLP extracts (0.6%-49.6% and 4.0%-32.5% reduction in pot and field experiments, respectively) and plant uptake (14.4%-84.1% and 22.8%-61.4% declines in pot and field studies, correspondingly). However, the applications of sepiolite offered a limited guarantee for the safety of edible vegetables in Cd-polluted soils, depending on the soil type, the Cd pollution type and level, and the dose and application frequency of chemical amendments. Bioassays, such as plant growth, soil enzymatic activities and microbial community diversity, indicated a certain degree of recovery of soil metabolic function. Therefore, sepiolite-assisted in situ remediation is cost-effective, environmentally friendly, and technically applicable, and can be successfully used to reduce Cd enter into the food chain on field scale. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chlorinated hydrocarbons and PCBs in field soils, sediments and sewage sludges

International Nuclear Information System (INIS)

Schaaf, H.

1992-01-01

As requested by the Ministry of Agriculture of the FRG, the 'Verband Deutscher Landwirtschaftlicher Untersuchungs- und Forschungsanstalten (VDLUFA)' built up a data collection over chlorinated hydrocarbons and PCBs in field soils, sediments, sewage sludges. Nearly 70.000 samples were collected and statistically evaluated. The results of these investigations will be described. The major constituents of the chlorinated hydrocarbons generally were Lindane, DDT(total) and HCB. In sewage sludges PCBs could be detected in nearly every sample. The contents of PCBs in field soils are smaller than in sewage sludges. Rather 'high contents', greater than 100-200 μg/kg d.m./organic pollutants, were detected only in 2% of the samples. 7 refs., 5 figs., 2 tabs

Flora in abandoned fields and adjacent crop fields on rendzina soils in the Zamość region

Directory of Open Access Journals (Sweden)

Marta Ziemińska-Smyk

2015-10-01

Full Text Available A floristic inventory of segetal flora was carried out in abandoned fields and adjacent crop fields on rendzina soils in the Zamość region in the year 2010. This study found a total of 130 weed species belonging to 30 botanical families. The following families were represented most frequently: Asteraceae, Fabaceae, Poaceae, Lamiaceae, Scrophulariaceae, and Brassicaceae. In the segetal flora, apophytes are dominant (55% of the total flora, with the highest number of meadow and xerothermic grassland species among them. Archeophytes (38% predominate in the group of anthropophytes. The species characterized by the highest constancy classes and reaching the highest cover indices posed the greatest threat to crops in the study area. The following weeds are most frequently found in fallow fields: Consolida regalis, Cichorium intybus, and Sinapis arvensis, while Papaver rhoeas is the greatest threat to cereal crops grown on rendzina soils.

A multiple soil ecosystem services approach to evaluate the sustainability of reduced tillage systems

Science.gov (United States)

Pérès, Guénola; Menasseri, Safya; Hallaire, Vincent; Cluzeau, Daniel; Heddadj, Djilali; Cotinet, Patrice; Manceau, Olivier; Pulleman, Mirjam

2017-04-01

In the current context of soil degradation, reduced tillage systems (including reduced soil disturbance, use of cover crops and crop rotation, and improved organic matter management) are expected to be good alternatives to conventional system which have led to a decrease of soil multi-functionality. Many studies worldwide have analysed the impact of tillage systems on different soil functions, but overran integrated view of the impact of these systems is still lacking. The SUSTAIN project (European SNOWMAN programme), performed in France and the Netherlands, proposes an interdisciplinary collaboration. The goals of SUSTAIN are to assess the multi-functionality of soil and to study how reduced-tillage systems impact on multiple ecosystem services such as soil biodiversity regulation (earthworms, nematodes, microorganisms), soil structure maintenance (aggregate stability, compaction, soil erosion), water regulation (run-off, transfer of pesticides) and food production. Moreover, a socio-economic study on farmer networks has been carried out to identify the drivers of adoption of reduced-tillage systems. Data have been collected in long-term experimental fields (5 - 13 years), representing conventional and organic farming strategies, and were complemented with data from farmer networks. The impact of different reduced tillage systems (direct seeding, minimum tillage, non-inverse tillage, superficial ploughing) were analysed and compared to conventional ploughing. Measurements (biological, chemical, physical, agronomical, water and element transfer) have been done at several dates which allow an overview of the evolution of the soil properties according to climate variation and crop rotation. A sociological approach was performed on several farms covering different production types, different courses (engagement in reduced tillage systems) and different geographical locations. Focusing on French trials, this multiple ecosystem services approach clearly showed that

Long-term field phytoextraction of zinc/cadmium contaminated soil by Sedum plumbizincicola under different agronomic strategies.

Science.gov (United States)

Deng, Lin; Li, Zhu; Wang, Jie; Liu, Hongyan; Li, Na; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Christie, Peter

2016-01-01

In two long-term field experiments the zinc (Zn)/cadmium (Cd) hyperaccumulator Sedum plumbizincicola (S. plumbizincicola) was examined to optimize the phytoextraction of metal contaminated soil by two agronomic strategies of intercropping with maize (Zea mays) and plant densities. Soil total Zn and Cd concentrations decreased markedly after long-term phytoextraction. But shoot biomass and Cd and Zn concentrations showed no significant difference with increasing remediation time. In the intercropping experiment the phytoremediation efficiency in the treatment "S. plumbizincicola intercropped with maize" was higher than in S. plumbizincicola monocropping, and Cd concentrations of corn were below the maximum national limit. In the plant density experiment the phytoremediation efficiency increased with increasing plant density and 440,000 plants ha(-1) gave the maximum rate. These results indicated that S. plumbizincicola at an appropriate planting density and intercropped with maize can achieve high remediation efficiency to contaminated soil without affecting the cereal crop productivity. This cropping system combines adequate agricultural production with soil heavy metal phytoextraction.

Asymmetric flow field-flow fractionation of manufactured silver nanoparticles spiked into soil solution.

Science.gov (United States)

Koopmans, G F; Hiemstra, T; Regelink, I C; Molleman, B; Comans, R N J

2015-05-01

Manufactured metallic silver nanoparticles (AgNP) are intensively utilized in consumer products and this will inevitably lead to their release to soils. To assess the environmental risks of AgNP in soils, quantification of both their concentration and size in soil solution is essential. We developed a methodology consisting of asymmetric flow field-flow fractionation (AF4) in combination with on-line detection by UV-vis spectroscopy and off-line HR-ICP-MS measurements to quantify the concentration and size of AgNP, coated with either citrate or polyvinylpyrrolidone (PVP), in water extracts of three different soils. The type of mobile phase was a critical factor in the fractionation of AgNP by AF4. In synthetic systems, fractionation of a series of virgin citrate- and PVP-coated AgNP (10-90 nm) with reasonably high recoveries could only be achieved with ultrahigh purity water as a mobile phase. For the soil water extracts, 0.01% (w:v) sodium dodecyl sulfate (SDS) at pH 8 was the key to a successful fractionation of the AgNP. With SDS, the primary size of AgNP in all soil water extracts could be determined by AF4, except for PVP-coated AgNP when clay colloids were present. The PVP-coated AgNP interacted with colloidal clay minerals, leading to an overestimation of their primary size. Similar interactions between PVP-coated AgNP and clay colloids can take place in the environment and facilitate their transport in soils, aquifers, and surface waters. In conclusion, AF4 in combination with UV-vis spectroscopy and HR-ICP-MS measurements is a powerful tool to characterize AgNP in soil solution if the appropriate mobile phase is used. Copyright © 2015 Elsevier B.V. All rights reserved.

Soil Microbial Activity in Conventional and Organic Agricultural Systems

Directory of Open Access Journals (Sweden)

Romero F.V. Carneiro

2009-06-01

Full Text Available The aim of this study was to evaluate microbial activity in soils under conventional and organic agricultural system management regimes. Soil samples were collected from plots under conventional management (CNV, organic management (ORG and native vegetation (AVN. Soil microbial activity and biomass was significantly greater in ORG compared with CNV. Soil bulk density decreased three years after adoption of organic system. Soil organic carbon (SOC was higher in the ORG than in the CNV. The soil under organic agricultural system presents higher microbial activity and biomass and lower bulk density than the conventional agricultural system.

Using dye tracer for visualizing roots impact on soil structure and soil porous system

Czech Academy of Sciences Publication Activity Database

Kodešová, R.; Němeček, K.; Žigová, Anna; Nikodem, A.; Fér, M.

2015-01-01

Roč. 70, č. 11 (2015), s. 1439-1443 ISSN 0006-3088 R&D Projects: GA ČR GA526/08/0434 Institutional support: RVO:67985831 Keywords : field sections * macro-scale * micro-scale, * micromorphological images * plant * ponding dye infiltration * roots * soil structure Subject RIV: DF - Soil Science Impact factor: 0.719, year: 2015

Mapping fields of 137Cs contamination in soils in the context of their stability and hierarchical spatial structure

Science.gov (United States)

Korobova, E.; Romanov, S.

2009-04-01

Technogenic radioisotopes now dispersed in the environment are involved in natural and technogenic processes forming specific geochemical fields and serving as tracers of modern mass migration and geofield transformation. Cs-137 radioisotopes having a comparatively long life time are known for a fast fixation by the top soil layer; radiocesium activity can be measured in the surface layer in field conditions. This makes 137Cs rather convenient for the study and modeling a behavior of toxic elements in soils [1-3, 5] and for the investigation of relative stability and hierarchical fractal structures of the soil contamination of the atmospheric origin [2]. The objective of the experimental study performed on the test site in Bryansk region was to find and prove polycentric regularities in the structure of 137Cs contamination field formed after the Chernobyl accident in natural conditions. Such a character of spatial variability can be seen on the maps showing different soil parameters and chemical element distribution measured in grids [3-5]. The research was undertaken to support our idea of the regular patterns in the contamination field structure that enables to apply a mathematical theory of the field to the geochemical fields modeling on the basis of a limited number of direct measurements sufficient to reproduce the configuration and main parameters of the geochemical field structure on the level of the elementary landscape geochemical system (top-slope-bottom). Cs-137 field measurements were verified by a direct soil sampling. Soil cores dissected into subsamples with increments of 2, 5 and 10 cm, were taken to the depth of 40 cm at points with various surface activity located at different elements of relief. According to laboratory measurements 137Cs inventory in soils varied from 344 to 3448 kBq/m2 (983 kBq/m2 on the average). From 95,1% to 98,0% to of the total inventory was retained in the top 20-cm soil layer. This confirmed that field gamma spectrometry

Species composition and density of weeds in a wheat crop depending on the soil tillage system in crop rotation

Directory of Open Access Journals (Sweden)

P. Yankov

2015-03-01

Full Text Available Abstract. The investigation was carried out in the trial field of Dobrudzha Agricultural Institute, General Toshevo on slightly leached chernozem soil type. For the purposes of this investigation, variants from a stationary field experiment initiated in 1987 and based on various soil tillage tools and operations were analyzed. The species composition and density of weeds were followed in a wheat crop grown after grain maize using the following soil tillage systems: plowing at 24 – 26 cm (for maize – disking at 10 – 12 cm (for wheat; cutting at 24 – 26 cm (for maize – cutting at 8 – 10 cm (for wheat; disking at 10 – 12 cm (for maize – disking at 10 – 12 cm (for wheat; no-tillage (for maize – no-tillage (for wheat.Weed infestation was read at the fourth rotation since the initiation of the trial. The observations were made in spring before treatment of the crop with herbicides. The soil tillage system had a significant effect on the species composition and density of weeds in the field with wheat grown after previous crop maize. The long-term alternation of plowing with disking in parallel with the usage of chemicals for weed control lead to lower weed infestation of the weed crop. The lower weed density after this soil tillage system was not related to changes in the species composition and the relative percent of the individual species in the total weed infestation. The long-term application in crop rotation of systems without turning of the soil layer and of minimal and no-tillage increased the amount of weeds. The reason is the greater variability of weed species which typically occur after shallow soil tillage.

Soil Gas Sampling

Science.gov (United States)

Field Branches Quality System and Technical Procedures: This document describes general and specific procedures, methods and considerations to be used and observed when collecting soil gas samples for field screening or laboratory analysis.

The Effect of Soil Type and Moisture Content on Head Impacts on Natural Grass Athletic Fields

Directory of Open Access Journals (Sweden)

Kyley Dickson

2018-02-01

Full Text Available Studies are warranted to evaluate head injury criterion (HIC on athletic fields to determine baseline numbers and compare those findings to current critical thresholds for impact attenuation. A two year (2016 and 2017 study was conducted on University of Tennessee athletic fields (Knoxville, TN, USA to determine the effect of soil type (cohesive soil, United States Golf Association sand specifications and grass species (Poa pratensis and Cynodon dactylon × C. transvaalensis on HIC. Additionally soil moisture conditions monitored were: dry (0.06–0.16 m3/m3, acceptable (0.17–0.29 m3/m3, and wet (0.30–0.40 m3/m3. A linear relationship (r = 0.91 was identified between drop height (0.5–2.9 M and HIC value (35-1423 HIC on granular root zones of both grass types. However, HIC on cohesive soil is a function of soil water content in addition to drop height. These results demonstrate to aid in head injury prevention on cohesive soil athletic fields the HIC can be lowered by managing soil water content.

Effect of soil washing with only chelators or combining with ferric chloride on soil heavy metal removal and phytoavailability: Field experiments.

Science.gov (United States)

Guo, Xiaofang; Wei, Zebin; Wu, Qitang; Li, Chunping; Qian, Tianwei; Zheng, Wei

2016-03-01

In a field experiment on multi-metal contaminated soil, we investigated the efficiency of Cd, Pb, Zn, and Cu removal by only mixture of chelators (MC) or combining with FeCl3. After washing treatment, a co-cropping system was performed for heavy metals to be extracted by Sedum alfredii and to produce safe food from Zea mays. We analyzed the concentration of heavy metals in groundwater to evaluate the leashing risk of soil washing with FeCl3 and MC. Results showed that addition of FeCl3 was favorable to the removal of heavy metals in the topsoil. Metal leaching occurred mainly in rain season during the first co-cropping. The removal rates of Cd, Zn, Pb, and Cu in topsoil were 28%, 53%, 41%, and 21% with washing by FeCl3+MC after first harvest. The application of FeCl3 reduced the yield of S. alfredii and increased the metals concentration of Z. mays in first harvest. However, after amending soil, the metals concentration of Z. mays in FeCl3+MC treatment were similar to that only washing by MC. The grains and shoots of Z. mays were safe for use in feed production. Soil washing did not worsen groundwater contamination during the study period. But the concentration of Cd in groundwater was higher than the limit value of Standard concentrations for Groundwater IV. This study suggests that soil washing using FeCl3 and MC for the remediation of multi-metal contaminated soil is potential feasibility. However, the subsequent measure to improve the washed soil environment for planting crop is considered. Copyright © 2016. Published by Elsevier Ltd.

Using Multispectral and Elevation Data to Predict Soil Properties for a Better Management of Fertilizers at Field Scale

Science.gov (United States)

Drouin, Ariane; Michaud, Aubert; Sylvain, Jean-Daniel; N'Dayegamiye, Adrien; Gasser, Marc-Olivier; Nolin, Michel; Perron, Isabelle; Grenon, Lucie; Beaudin, Isabelle; Desjardins, Jacques; Côté, Noémi

2013-04-01

This project aims at developing and validating an operational integrated management and localized approach at field scale using remote sensing data. It is realized in order to support the competitiveness of agricultural businesses, to ensure soil productivity in the long term and prevent diffuse contamination of surface waters. Our intention is to help agrienvironmental advisors and farmers in the consideration of spatial variability of soil properties in the management of fields. The proposed approach of soil properties recognition is based on the combination of elevation data and multispectral satellite imagery (Landsat) within statistical models. The method is based on the use of the largest possible number of satellite images to cover the widest range of soil moisture variability. Several spectral indices are calculated for each image (normalized brightness index, soil color index, organic matter index, etc.). The assignation of soils is based on a calibration procedure making use of the spatial soil database available in Canada. It includes soil profile point data associated to a database containing the information collected in the field. Three soil properties are predicted and mapped: A horizon texture, B horizon texture and drainage class. All the spectral indices, elevation data and soil data are combined in a discriminant analysis that produces discriminant functions. These are then used to produce maps of soil properties. In addition, from mapping soil properties, management zones are delineated within the field. The delineation of management zones with relatively similar soil properties is created to enable farmers to manage their fertilizers by taking greater account of their soils. This localized or precision management aims to adjust the application of fertilizer according to the real needs of soils and to reduce costs for farmers and the exports of nutrients to the stream. Mapping of soil properties will be validated in three agricultural regions in

Detecting and enumerating soil-transmitted helminth eggs in soil: New method development and results from field testing in Kenya and Bangladesh.

Directory of Open Access Journals (Sweden)

Lauren Steinbaum

2017-04-01

Full Text Available Globally, about 1.5 billion people are infected with at least one species of soil-transmitted helminth (STH. Soil is a critical environmental reservoir of STH, yet there is no standard method for detecting STH eggs in soil. We developed a field method for enumerating STH eggs in soil and tested the method in Bangladesh and Kenya. The US Environmental Protection Agency (EPA method for enumerating Ascaris eggs in biosolids was modified through a series of recovery efficiency experiments; we seeded soil samples with a known number of Ascaris suum eggs and assessed the effect of protocol modifications on egg recovery. We found the use of 1% 7X as a surfactant compared to 0.1% Tween 80 significantly improved recovery efficiency (two-sided t-test, t = 5.03, p = 0.007 while other protocol modifications-including different agitation and flotation methods-did not have a significant impact. Soil texture affected the egg recovery efficiency; sandy samples resulted in higher recovery compared to loamy samples processed using the same method (two-sided t-test, t = 2.56, p = 0.083. We documented a recovery efficiency of 73% for the final improved method using loamy soil in the lab. To field test the improved method, we processed soil samples from 100 households in Bangladesh and 100 households in Kenya from June to November 2015. The prevalence of any STH (Ascaris, Trichuris or hookworm egg in soil was 78% in Bangladesh and 37% in Kenya. The median concentration of STH eggs in soil in positive samples was 0.59 eggs/g dry soil in Bangladesh and 0.15 eggs/g dry soil in Kenya. The prevalence of STH eggs in soil was significantly higher in Bangladesh than Kenya (chi-square, χ2 = 34.39, p < 0.001 as was the concentration (Mann-Whitney, z = 7.10, p < 0.001. This new method allows for detecting STH eggs in soil in low-resource settings and could be used for standardizing soil STH detection globally.

Emissions of N2O from peat soils under different cropping systems

Science.gov (United States)

Norberg, Lisbet; Berglund, Örjan; Berglund, Kerstin

2016-04-01

Drainage of peatlands for agriculture use leads to an increase in nitrogen turnover rate causing emissions of N2O to the atmosphere. Agriculture contributes to a substantial part of the anthropogenic emissions of N2O therefore mitigation options for the farmers are important. Here we present a field study with the aim to investigate if the choice of cropping system can mitigate the emission of N2O from cultivated organic soils. The sites used in the study represent fen peat soils with a range of different soil properties located in different parts of southern Sweden. All sites are on active farms with good drainage. N2O emissions from the soil under two different crops grown on the same field, with the same soil type, drainage intensity and weather conditions, are compared by gas sampling. The crops included are oat, barley, carrot, potato and grassland. Three or four sampling occasions during the growing season in 2010 were carried out with static chambers. The N2O emission is calculated from the linear increase of gas concentration in the chamber headspace during the incubation time of 40 minutes. Parallel to the gas sampling soil temperature and soil moisture are measured and some soil properties determined. The result from the gas sampling and measurements show no significant difference in seasonal average N2O emission between the compared crops at any site. There are significant differences in N2O emissions between the compared crops at some of the single sampling occasions but the result vary and no crop can be pointed out as a mitigation option. The seasonal average N2O emissions varies from 16±17 to 1319±1971 μg N2O/m2/h with peaks up to 3317 μg N2O/m2/h. The N2O emission rate from peat soils are determined by other factors than the type of crops grown on the field. The emission rates vary during the season and especially between sites. Although all sites are fen peat soil the soil properties are different, e.g. carbon content varies between 27-43% and

Effect of biochar and liming on soil nitrous oxide emissions from a temperate maize cropping system

Science.gov (United States)

Hüppi, R.; Felber, R.; Neftel, A.; Six, J.; Leifeld, J.

2015-12-01

Biochar, a carbon-rich, porous pyrolysis product of organic residues may positively affect plant yield and can, owing to its inherent stability, promote soil carbon sequestration when amended to agricultural soils. Another possible effect of biochar is the reduction in emissions of nitrous oxide (N2O). A number of laboratory incubations have shown significantly reduced N2O emissions from soil when mixed with biochar. Emission measurements under field conditions however are more scarce and show weaker or no reductions, or even increases in N2O emissions. One of the hypothesised mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH following the application of alkaline biochar. To test the effect of biochar on N2O emissions in a temperate maize cropping system, we set up a field trial with a 20t ha-1 biochar treatment, a limestone treatment adjusted to the same pH as the biochar treatment (pH 6.5), and a control treatment without any addition (pH 6.1). An automated static chamber system measured N2O emissions for each replicate plot (n = 3) every 3.6 h over the course of 8 months. The field was conventionally fertilised at a rate of 160 kg N ha-1 in three applications of 40, 80 and 40 kg N ha-1 as ammonium nitrate. Cumulative N2O emissions were 52 % smaller in the biochar compared to the control treatment. However, the effect of the treatments overall was not statistically significant (p = 0.27) because of the large variability in the data set. Limed soils emitted similar mean cumulative amounts of N2O as the control. There is no evidence that reduced N2O emissions with biochar relative to the control is solely caused by a higher soil pH.

Soil cover by natural trees in agroforestry systems

Science.gov (United States)

Diaz-Ambrona, C. G. H.; Almoguera Millán, C.; Tarquis Alfonso, A.

2009-04-01

The dehesa is common agroforestry system in the Iberian Peninsula. These open oak parklands with silvo-pastoral use cover about two million hectares. Traditionally annual pastures have been grazed by cows, sheep and also goats while acorns feed Iberian pig diet. Evergreen oak (Quercus ilex L.) has other uses as fuelwood collection and folder after tree pruning. The hypothesis of this work is that tree density and canopy depend on soil types. We using the spanish GIS called SIGPAC to download the images of dehesa in areas with different soil types. True colour images were restoring to a binary code, previously canopy colour range was selected. Soil cover by tree canopy was calculated and number of trees. Processing result was comparable to real data. With these data we have applied a dynamic simulation model Dehesa to determine evergreen oak acorn and annual pasture production. The model Dehesa is divided into five submodels: Climate, Soil, Evergreen oak, Pasture and Grazing. The first three require the inputs: (i) daily weather data (maximum and minimum temperatures, precipitation and solar radiation); (ii) the soil input parameters for three horizons (thickness, field capacity, permanent wilting point, and bulk density); and (iii) the tree characterization of the dehesa (tree density, canopy diameter and height, and diameter of the trunk). The influence of tree on pasture potential production is inversely proportional to the canopy cover. Acorn production increase with tree canopy cover until stabilizing itself, and will decrease if density becomes too high (more than 80% soil tree cover) at that point there is competition between the trees. Main driving force for dehesa productivity is soil type for pasture, and tree cover for acorn production. Highest pasture productivity was obtained on soil Dystric Planosol (Alfisol), Dystric Cambisol and Chromo-calcic-luvisol, these soils only cover 22.4% of southwest of the Iberian peninssula. Lowest productivity was

Implementing a physical soil water flow model with minimal soil characteristics and added value offered by surface soil moisture measurements assimilation.

Science.gov (United States)

Chanzy, André

2010-05-01

Soil moisture is a key variable for many soil physical and biogeochemical processes. Its dynamic results from water fluxes in soil and at its boundaries, as well as soil water storage properties. If the water flows are dominated by diffusive processes, modelling approaches based on the Richard's equation or the Philip and de Vries coupled heat and water flow equations lead to a satisfactory representation of the soil moisture dynamic. However, It requires the characterization of soil hydraulic functions, the initialisation and the boundary conditions, which are expensive to obtain. The major problem to assess soil moisture for decision making or for representing its spatiotemporal evolution over complex landscape is therefore the lack of information to run the models. The aim of the presentation is to analyse how a soil moisture model can be implemented when only climatic data and basic soil information are available (soil texture, organic matter) and what would be the added of making a few soil moisture measurements. We considered the field scale, which is the key scale for decision making application (the field being the management unit for farming system) and landscape modelling (field size being comparable to the computation unit of distributed hydrological models). The presentation is limited to the bare soil case in order to limit the complexity of the system and the TEC model based on Philip and De Vries equations is used in this study. The following points are addressed: o the within field spatial variability. This spatial variability can be induced by the soil hydraulic properties and/or by the amount of infiltrated water induced by water rooting towards infiltration areas. We analyse how an effective parameterization of soil properties and boundary conditions can be used to simulate the field average moisture. o The model implementation with limited information. We propose strategies that can be implemented when information are limited to soil texture and

The fate of cadmium in field soils of the Danubian Lowland

Czech Academy of Sciences Publication Activity Database

Lichner, Ľ.; Dlapa, P.; Šír, Miloslav; Čipáková, A.; Houšková, B.; Faško, P.; Nagy, V.

2006-01-01

Roč. 85, 1-2 (2006), s. 154-165 ISSN 0167-1987 Grant - others:Czech program of bilateral cooperation in science and technology KONTAKT(SK) 185/99; Slovak Scientific Grant Agency VEGA(SK) 1/0619/03; Slovak Scientific Grant Agency VEGA(SK) 2/3032/23 Institutional research plan: CEZ:AV0Z20600510 Keywords : Danubian Lowland * Macropore flow * Field soil * Cadmium * Adsorption Subject RIV: GD - Fertilization, Irrigation, Soil Processing Impact factor: 1.619, year: 2006

Soil-to-crop transfer factors of radium in Japanese agricultural fields

International Nuclear Information System (INIS)

Uchida, S.; Tagami, K.

2007-01-01

The concentrations of 226 Ra in upland field crops (e.g., cabbage, leek, onion, potato, and so on) and associated soils collected from 45 locations throughout Japan were determined in order to obtain soil-to-crop transfer factors (TFs). Concentrations of 226 Ra in the soils collected in southwestern Japan were higher than those in northeastern Japan; however, no correlations between 226 Ra concentrations in crops and soils were observed. The TFs ranged from -3 to 5.8 x 10 -2 with a geometric mean of 6.4 x 10 -3 . These data were within the 95% confidential range of TF-Ra for several crops as reported in the IAEA Technical Reports Series No.364. Among the alkaline earth metals. TF-Ba was similar to TF-Ra. (author)

A drill-soil system modelization for future Mars exploration

Science.gov (United States)

Finzi, A. E.; Lavagna, M.; Rocchitelli, G.

2004-01-01

This paper presents a first approach to the problem of modeling a drilling process to be carried on in the space environment by a dedicated payload. Systems devoted to work in space present very strict requirements in many different fields such as thermal response, electric power demand, reliability and so on. Thus, models devoted to the operational behaviour simulation represent a fundamental help in the design phase and give a great improvement in the final product quality. As the required power is the crucial constraint within drilling devices, the tool-soil interaction modelization and simulation are finalized to the computation of the power demand as a function of both the drill and the soil parameters. An accurate study of the tool and the soil separately has been firstly carried on and, secondly their interaction has been analyzed. The Dee-Dri system, designed by Tecnospazio and to be part of the lander components in the NASA's Mars Sample Return Mission, has been taken as the tool reference. The Deep-Drill system is a complex rotary tool devoted to the soil perforation and sample collection; it has to operate in a Martian zone made of rocks similar to the terrestrial basalt, then the modelization is restricted to the interaction analysis between the tool and materials belonging to the rock set. The tool geometric modelization has been faced by a finite element approach with a Langrangian formulation: for the static analysis a refined model is assumed considering both the actual geometry of the head and the rod screws; a simplified model has been used to deal with the dynamic analysis. The soil representation is based on the Mohr-Coulomb crack criterion and an Eulerian approach has been selected to model it. However, software limitations in dealing with the tool-soil interface definition required assuming a Langrangian formulation for the soil too. The interaction between the soil and the tool has been modeled by extending the two-dimensional Nishimatsu

Identification of qSOR1, a major rice QTL involved in soil-surface rooting in paddy fields.

Science.gov (United States)

Uga, Yusaku; Hanzawa, Eiko; Nagai, Shinsei; Sasaki, Kazuhiro; Yano, Masahiro; Sato, Tadashi

2012-01-01

Specific Indonesian lowland rice (Oryza sativa L.) cultivars elongate thick primary roots on the soil surface of paddy fields. To clarify the genetic factors controlling soil-surface rooting, we performed quantitative trait locus (QTL) analyses using 124 recombinant inbred lines (RILs) derived from a cross between Gemdjah Beton, an Indonesian lowland rice cultivar with soil-surface roots, and Sasanishiki, a Japanese lowland rice cultivar without soil-surface roots. These cultivars and the RILs were tested for soil-surface rooting in a paddy field. We identified four regions of chromosomes 3, 4, 6, and 7 that were associated with soil-surface rooting in the field. Among them, one major QTL was located on the long arm of chromosome 7. This QTL explained 32.5-53.6% of the total phenotypic variance across three field evaluations. To perform fine mapping of this QTL, we measured the basal root growth angle of crown roots at the seedling stage in seven BC(2)F(3) recombinant lines grown in small cups in a greenhouse. The QTL was mapped between markers RM21941 and RM21976, which delimit an 812-kb interval in the reference cultivar Nipponbare. We have designated this QTL qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1).

The Role of Soil Biological Function in Regulating Agroecosystem Services and Sustainability in the Quesungual Agroforestry System

Science.gov (United States)

Fonte, S.; Pauli, N.; Rousseau, L.; SIX, J. W. U. A.; Barrios, E.

2014-12-01

The Quesungual agroforestry system from western Honduras has been increasingly promoted as a promising alternative to traditional slash-and-burn agriculture in tropical dry forest regions of the Americas. Improved residue management and the lack of burning in this system can greatly impact soil biological functioning and a number of key soil-based ecosystem services, yet our understanding of these processes has not been thoroughly integrated to understand system functionality as a whole that can guide improved management. To address this gap, we present a synthesis of various field studies conducted in Central America aimed at: 1) quantifying the influence of the Quesungual agroforestry practices on soil macrofauna abundance and diversity, and 2) understanding how these organisms influence key soil-based ecosystem services that ultimately drive the success of this system. A first set of studies examined the impact of agroecosystem management on soil macrofauna populations, soil fertility and key soil processes. Results suggest that residue inputs (derived from tree biomass pruning), a lack of burning, and high tree densities, lead to conditions that support abundant, diverse soil macrofauna communities under agroforestry, with soil organic carbon content comparable to adjacent forest. Additionally, there is great potential in working with farmers to develop refined soil quality indicators for improved land management. A second line of research explored interactions between residue management and earthworms in the regulation of soil-based ecosystem services. Earthworms are the most prominent ecosystem engineers in these soils. We found that earthworms are key drivers of soil structure maintenance and the stabilization of soil organic matter within soil aggregates, and also had notable impacts on soil nutrient dynamics. However, the impact of earthworms appears to depend on residue management practices, thus indicating the need for an integrated approach for

An automatic time domain reflectometry device to measure and store soil water contents for stand-alone field use

NARCIS (Netherlands)

Elsen, van den H.G.M.; Kokot, J.; Skierucha, W.; Halbertsma, J.M.

1995-01-01

A field set-up was developed to measure soil moisture content on ten different positions using the time domain reflectometry (TDR) technique. The set-up works on a 12 V battery or solar panel system, independent of an external power source, has low power consumption, and compact dimensions. The

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce.

Science.gov (United States)

Schreiter, Susanne; Ding, Guo-Chun; Heuer, Holger; Neumann, Günter; Sandmann, Martin; Grosch, Rita; Kropf, Siegfried; Smalla, Kornelia

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years under the same agricultural management to reveal differences directly linked to the soil type and not influenced by other factors such as climate or cropping history. Bulk soil and rhizosphere samples were collected 3 and 7 weeks after planting. The analysis of 16S rRNA gene fragments amplified from total community DNA by denaturing gradient gel electrophoresis and pyrosequencing revealed soil type dependent differences in the bacterial community structure of the bulk soils and the corresponding rhizospheres. The rhizosphere effect differed depending on the soil type and the plant growth developmental stage. Despite the soil type dependent differences in the bacterial community composition several genera such as Sphingomonas, Rhizobium, Pseudomonas, and Variovorax were significantly increased in the rhizosphere of lettuce grown in all three soils. The number of rhizosphere responders was highest 3 weeks after planting. Interestingly, in the soil with the highest numbers of responders the highest shoot dry weights were observed. Heatmap analysis revealed that many dominant operational taxonomic units were shared among rhizosphere samples of lettuce grown in diluvial sand, alluvial loam, and loess loam and that only a subset was increased in relative abundance in the rhizosphere compared to the corresponding bulk soil. The findings of the study provide insights into the effect of soil types on the rhizosphere microbiome of lettuce.

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

Directory of Open Access Journals (Sweden)

Susanne eSchreiter

2014-04-01

Full Text Available The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for ten years under the same agricultural management to reveal differences directly linked to the soil type and not influenced by other factors such as climate or cropping history. Bulk soil and rhizosphere samples were collected three and seven weeks after planting. The analysis of 16S rRNA gene fragments amplified from total community DNA by denaturing gradient gel electrophoresis and pyrosequencing revealed soil type-dependent differences in the bacterial community structure of the bulk soils and the corresponding rhizospheres. The rhizosphere effect differed depending on the soil type and the plant growth developmental stage. Despite the soil type-dependent differences in the bacterial community composition several genera such as Sphingomonas, Rhizobium, Pseudomonas and Variovorax were significantly increased in the rhizosphere of lettuce grown in all three different soils. The number of rhizosphere responders was highest three weeks after planting. Interestingly, in the soil with the highest numbers of responders the highest shoot dry weights were observed. Heatmap analysis revealed that many dominant operational taxonomic units were shared among rhizosphere samples of lettuce grown in diluvial sand, alluvial loam, and loess loam and that only a subset was increased in relative abundance in the rhizosphere compared to the corresponding bulk soil. The findings of the study provide insights into the effect of soil types on the rhizosphere microbiome of lettuce.

Different farming and water regimes in Italian rice fields affect arbuscular mycorrhizal fungal soil communities.

Science.gov (United States)

Lumini, Erica; Vallino, Marta; Alguacil, Maria M; Romani, Marco; Bianciotto, Valeria

2011-07-01

Arbuscular mycorrhizal fungi (AMF) comprise one of the main components of soil microbiota in most agroecosystems. These obligate mutualistic symbionts colonize the roots of most plants, including crop plants. Many papers have indicated that different crop management practices could affect AMF communities and their root colonization. However, there is little knowledge available on the influence of conventional and low-input agriculture on root colonization and AMF molecular diversity in rice fields. Two different agroecosystems (continuous conventional high-input rice monocropping and organic farming with a five-year crop rotation) and two different water management regimes have been considered in this study. Both morphological and molecular analyses were performed. The soil mycorrhizal potential, estimated using clover trap cultures, was high and similar in the two agroecosystems. The diversity of the AMF community in the soil, calculated by means of PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and 18S rDNA sequencing on clover trap cultures roots, was higher for the organic cultivation. The rice roots cultivated in the conventional agrosystem or under permanent flooding showed no AMF colonization, while the rice plants grown under the organic agriculture system showed typical mycorrhization patterns. Considered together, our data suggest that a high-input cropping system and conventional flooding depress AMF colonization in rice roots and that organic managements could help maintain a higher diversity of AMF communities in soil.

Biochar Improves Soil Aggregate Stability and Water Availability in a Mollisol after Three Years of Field Application

Science.gov (United States)

Zhang, Yulan; Yang, Lijie; Yu, Chunxiao; Yin, Guanghua; Doane, Timothy A.; Wu, Zhijie; Zhu, Ping; Ma, Xingzhu

2016-01-01

A field experiment was carried out to evaluate the effect of organic amendments on soil organic carbon, total nitrogen, bulk density, aggregate stability, field capacity and plant available water in a representative Chinese Mollisol. Four treatments were as follows: no fertilization (CK), application of inorganic fertilizer (NPK), combined application of inorganic fertilizer with maize straw (NPK+S) and addition of biochar with inorganic fertilizer (NPK+B). Our results showed that after three consecutive years of application, the values of soil bulk density were significantly lower in both organic amendment-treated plots than in unamended (CK and NPK) plots. Compared with NPK, NPK+B more effectively increased the contents of soil organic carbon, improved the relative proportion of soil macro-aggregates and mean weight diameter, and enhanced field capacity as well as plant available water. Organic amendments had no obvious effect on soil C/N ratio or wilting coefficient. The results of linear regression indicated that the improvement in soil water retention could be attributed to the increases in soil organic carbon and aggregate stability. PMID:27191160

Biochar Improves Soil Aggregate Stability and Water Availability in a Mollisol after Three Years of Field Application.

Science.gov (United States)

Ma, Ningning; Zhang, Lili; Zhang, Yulan; Yang, Lijie; Yu, Chunxiao; Yin, Guanghua; Doane, Timothy A; Wu, Zhijie; Zhu, Ping; Ma, Xingzhu

2016-01-01

A field experiment was carried out to evaluate the effect of organic amendments on soil organic carbon, total nitrogen, bulk density, aggregate stability, field capacity and plant available water in a representative Chinese Mollisol. Four treatments were as follows: no fertilization (CK), application of inorganic fertilizer (NPK), combined application of inorganic fertilizer with maize straw (NPK+S) and addition of biochar with inorganic fertilizer (NPK+B). Our results showed that after three consecutive years of application, the values of soil bulk density were significantly lower in both organic amendment-treated plots than in unamended (CK and NPK) plots. Compared with NPK, NPK+B more effectively increased the contents of soil organic carbon, improved the relative proportion of soil macro-aggregates and mean weight diameter, and enhanced field capacity as well as plant available water. Organic amendments had no obvious effect on soil C/N ratio or wilting coefficient. The results of linear regression indicated that the improvement in soil water retention could be attributed to the increases in soil organic carbon and aggregate stability.

Biochar Improves Soil Aggregate Stability and Water Availability in a Mollisol after Three Years of Field Application.

Directory of Open Access Journals (Sweden)

Ningning Ma

Full Text Available A field experiment was carried out to evaluate the effect of organic amendments on soil organic carbon, total nitrogen, bulk density, aggregate stability, field capacity and plant available water in a representative Chinese Mollisol. Four treatments were as follows: no fertilization (CK, application of inorganic fertilizer (NPK, combined application of inorganic fertilizer with maize straw (NPK+S and addition of biochar with inorganic fertilizer (NPK+B. Our results showed that after three consecutive years of application, the values of soil bulk density were significantly lower in both organic amendment-treated plots than in unamended (CK and NPK plots. Compared with NPK, NPK+B more effectively increased the contents of soil organic carbon, improved the relative proportion of soil macro-aggregates and mean weight diameter, and enhanced field capacity as well as plant available water. Organic amendments had no obvious effect on soil C/N ratio or wilting coefficient. The results of linear regression indicated that the improvement in soil water retention could be attributed to the increases in soil organic carbon and aggregate stability.

Soil surface roughness decay in contrasting climates, tillage types and management systems

Science.gov (United States)

Vidal Vázquez, Eva; Bertol, Ildegardis; Tondello Barbosa, Fabricio; Paz-Ferreiro, Jorge

2014-05-01

Soil surface roughness describes the variations in the elevation of the soil surface. Such variations define the soil surface microrelief, which is characterized by a high spatial variability. Soil surface roughness is a property affecting many processes such as depression storage, infiltration, sediment generation, storage and transport and runoff routing. Therefore the soil surface microrelief is a key element in hydrology and soil erosion processes at different spatial scales as for example at the plot, field or catchment scale. In agricultural land soil surface roughness is mainly created by tillage operations, which promote to different extent the formation of microdepressions and microelevations and increase infiltration and temporal retention of water. The decay of soil surface roughness has been demonstrated to be mainly driven by rain height and rain intensity, and to depend also on runoff, aggregate stability, soil reface porosity and soil surface density. Soil roughness formation and decay may be also influenced by antecedent soil moisture (either before tillage or rain), quantity and type of plant residues over the soil surface and soil composition. Characterization of the rate and intensity of soil surface roughness decay provides valuable information about the degradation of the upper most soil surface layer before soil erosion has been initiated or at the very beginning of soil runoff and erosion processes. We analyzed the rate of decay of soil surface roughness from several experiments conducted in two regions under temperate and subtropical climate and with contrasting land use systems. The data sets studied were obtained both under natural and simulated rainfall for various soil tillage and management types. Soil surface roughness decay was characterized bay several parameters, including classic and single parameters such as the random roughness or the tortuosity and parameters based on advanced geostatistical methods or on the fractal theory. Our

Behaviour of transuranic radionuclides in soils, plants and soil-plant system

International Nuclear Information System (INIS)

Vyas, B.N.; Mistry, K.B.

1996-01-01

The present paper reviews the investigations undertaken to elucidate the physicochemical, edaphic and physiological aspects of the behaviour of long-lived transuranic radionuclides 239 Pu and 241 Am in typical Indian soils and soil-plant systems. 23 refs

Nitrogen Fertilization Increases Cottonwood Growth on Old-Field Soil

Science.gov (United States)

B. G. Blackmon; E. H. White

1972-01-01

Nitrogen (150 lb ./acre as NH4N03 ) applied to a 6-year-old eastern cottonwood plantation in an old field on Commerce silt loam soil increased diameter, basal area, and volume growth by 200 percent over untreated controls. The plantation did not respond to 100 pounds P per acre from concentrated superphosphate.

Tetracyclines and tetracycline resistance in agricultural soils: microcosm and field studies.

OpenAIRE

Schmitt, Heike; Stoob, Krispin; Hamscher, Gerd; Smit, Eric; Seinen, Willem

2006-01-01

The influence of the use of antibiotics on the prevalence of resistance genes in the environment is still poorly understood. We studied the diversity of tetracycline and sulfonamide resistance genes as influenced by fertilization with pig manure in soil microcosms and at two field locations. Manure contained a high diversity of resistance genes, regardless of whether it stemmed from a farm operation with low or regular use of antibiotics. In the microcosm soils, the influence of fertilization...

Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil

Directory of Open Access Journals (Sweden)

Yun Zhang

2014-01-01

Full Text Available A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP and 2-methylphosphinico-acetic acid (MPA, in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg. Soil samples were extracted with ammonium hydroxide solution 5% (v/v, concentrated, and reacted with trimethyl orthoacetate (TMOA in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC using a flame photometric detector (FPD. The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.

Field dissipation and storage stability of glufosinate ammonium and its metabolites in soil.

Science.gov (United States)

Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan

2014-01-01

A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2-95.5%, 98.3-100.3%, and 99.3-99.6% with relative standard deviations (RSD) of 1.8-4.1%, 0.4-1.4%, and 1.3-2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30-2.93 days in an open field. In soil samples stored at -20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.

Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil

Science.gov (United States)

Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan

2014-01-01

A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD) of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment. PMID:25374604

Adaptation of ammonia-oxidizing microorganisms to environment shift of paddy field soil.

Science.gov (United States)

Ke, Xiubin; Lu, Yahai

2012-04-01

Adaptation of microorganisms to the environment is a central theme in microbial ecology. The objective of this study was to investigate the response of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) to a soil medium shift. We employed two rice field soils collected from Beijing and Hangzhou, China. These soils contained distinct AOB communities dominated by Nitrosomonas in Beijing rice soil and Nitrosospira in Hangzhou rice soil. Three mixtures were generated by mixing equal quantities of Beijing soil and Hangzhou soil (BH), Beijing soil with sterilized Hangzhou soil (BSH), and Hangzhou soil with sterilized Beijing soil (HSB). Pure and mixed soils were permanently flooded, and the surface-layer soil where ammonia oxidation occurred was collected to determine the response of AOB and AOA to the soil medium shift. AOB populations increased during the incubation, and the rates were initially faster in Beijing soil than in Hangzhou soil. Nitrosospira (cluster 3a) and Nitrosomonas (communis cluster) increased with time in correspondence with ammonia oxidation in the Hangzhou and Beijing soils, respectively. The 'BH' mixture exhibited a shift from Nitrosomonas at day 0 to Nitrosospira at days 21 and 60 when ammonia oxidation became most active. In 'HSB' and 'BSH' mixtures, Nitrosospira showed greater stimulation than Nitrosomonas, both with and without N amendment. These results suggest that Nitrosospira spp. were better adapted to soil environment shifts than Nitrosomonas. Analysis of the AOA community revealed that the composition of AOA community was not responsive to the soil environment shifts or to nitrogen amendment. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Investigating microbial transformations of soil organic matter: synthesizing knowledge from disparate fields to guide new experimentation

Science.gov (United States)

Billings, S. A.; Tiemann, L. K.; Ballantyne, F., IV; Lehmeier, C. A.; Min, K.

2015-04-01

Discerning why some soil organic matter (SOM) leaves soil profiles relatively quickly while other compounds, especially at depth, can be retained for decades to millennia is challenging for a multitude of reasons. Simultaneous with soil-specific advances, multiple other disciplines have enhanced their knowledge bases in ways potentially useful for future investigations of SOM decay. In this article, we highlight observations highly relevant for those investigating SOM decay and retention but often emanating from disparate fields and residing in literature seldom cited in SOM research. We focus on recent work in two key areas. First, we turn to experimental approaches using natural and artificial aquatic environments to investigate patterns of microbially mediated OM transformations as environmental conditions change, and highlight how aquatic microbial responses to environmental change can reveal processes likely important to OM decay and retention in soils. Second, we emphasize the importance of establishing intrinsic patterns of decay kinetics for purified substrates commonly found in soils to develop baseline rates. These decay kinetics - which represent the upper limit of the reaction rates - can then be compared to substrate decay kinetics observed in natural samples, which integrate intrinsic decay reaction rates and edaphic factors essential to the site under study but absent in purified systems. That comparison permits the site-specific factors to be parsed from the fundamental decay kinetics, an important advance in our understanding of SOM decay (and thus persistence) in natural systems. We then suggest ways in which empirical observations from aquatic systems and purified substrate-enzyme reaction kinetics can be used to advance recent theoretical efforts in SOM-focused research. Finally, we suggest how the observations in aquatic and purified substrate-enzyme systems could be used to help unravel the puzzles presented by oft-observed patterns of SOM

Sampling soils for 137Cs using various field-sampling volumes

International Nuclear Information System (INIS)

Nyhan, J.W.; Schofield, T.G.; White, G.C.; Trujillo, G.

1981-10-01

The sediments from a liquid effluent receiving area at the Los Alamos National Laboratory and soils from intensive study area in the fallout pathway of Trinity were sampled for 137 Cs using 25-, 500-, 2500-, and 12 500-cm 3 field sampling volumes. A highly replicated sampling program was used to determine mean concentrations and inventories of 137 Cs at each site, as well as estimates of spatial, aliquoting, and counting variance components of the radionuclide data. The sampling methods were also analyzed as a function of soil size fractions collected in each field sampling volume and of the total cost of the program for a given variation in the radionuclide survey results. Coefficients of variation (CV) of 137 Cs inventory estimates ranged from 0.063 to 0.14 for Mortandad Canyon sediments, where CV values for Trinity soils were observed from 0.38 to 0.57. Spatial variance components of 137 Cs concentration data were usually found to be larger than either the aliquoting or counting variance estimates and were inversely related to field sampling volume at the Trinity intensive site. Subsequent optimization studies of the sampling schemes demonstrated that each aliquot should be counted once, and that only 2 to 4 aliquots out of an many as 30 collected need be assayed for 137 Cs. The optimization studies showed that as sample costs increased to 45 man-hours of labor per sample, the variance of the mean 137 Cs concentration decreased dramatically, but decreased very little with additional labor

Kinetic and dynamic aspects of soil-plant-snail transfer of cadmium in the field

International Nuclear Information System (INIS)

Gimbert, Frederic; Mench, Michel; Coeurdassier, Michael; Badot, Pierre-Marie; Vaufleury, Annette de

2008-01-01

The proper use of bioaccumulation in the assessment of environmental quality involves accounting for chemical fluxes in organisms. Cadmium (Cd) accumulation kinetics in a soil-plant-snail food chain were therefore investigated in the field under different soil contamination (from 0 to 40 mg kg -1 ), soil pH (6 and 7) and season. Allowing for an accurate and sensitive assessment of Cd transfer to snails, toxicokinetics appears an interesting tool in the improvement of risk assessment procedures and a way to quantify metal bioavailability for a defined target. On the basis of uptake fluxes, snails proved to be sensitive enough to distinguish moderate soil contaminations. The soil pH did not appear, in the range studied, as a modulating parameter of the Cd transfer from soil to snail whereas the season, by influencing the snail mass, may modify the internal concentrations. The present data specifying a time integrated assessment of environmental factors on metal bioavailability and transfer to terrestrial snails should ensure their rational use in environmental biomonitoring. - Toxicokinetics and uptake fluxes can be used to describe the environment contamination by Cd, its bioavailability and transfer to Helix aspersa snails in the field

Recommendations to the NRC for soil cover systems over uranium mill tailings and low-level radioactive wastes

International Nuclear Information System (INIS)

Bennett, R.D.; Kimbrell, A.F.

1991-02-01

The US Army Engineer Waterways Experiment Station (WES) has provided recommendations to the US Nuclear Regulatory Commission (NRC) for the selection placement, compaction, testing, and acceptance of soils proposed to be placed in cover systems over uranium mill tailings and low-level radioactive wastes. The recommendations from WES are contained in three volumes of NUREG/CR-5432. Volume 1 identifies the various soil types and engineering properties that are needed to fulfill important soil cover functions. The identified soils are then ranked according to their capability to perform the low-permeability and filter and drainage functions. Volume 2 provides recommendations for conducting pertinent laboratory and field tests to ensure acceptable soil cover performance. Volume 3 covers recommendations from WES on proper field construction methods including guidance on quality control testing and inspections. Recommendations are given for sealing penetrations (e.g., observation wells) that are required to penetrate covers for environmental monitoring of disposal facility performance. 30 refs., 6 figs., 9 tabs

Field controlled experiments of mercury accumulation in crops from air and soil

Energy Technology Data Exchange (ETDEWEB)

Niu Zhenchuan [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Zhang Xiaoshan, E-mail: zhangxsh@rcees.ac.cn [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Zhangwei, E-mail: wangzhw@rcees.ac.cn [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Ci Zhijia [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)

2011-10-15

Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation. - Highlights: > Hg accumulation in crop organs was studied by OTCs and soil Hg enriched experiments. > Hg accumulation in foliages and roots was mainly from air and soil, respectively. > Air Hg had stronger influence than soil Hg on stem Hg accumulation. > Foliar Hg concentrations showed the trend of increase over growth stages. - Capsule Mercury accumulated in the aboveground organs of crop was mainly from the air.

Soil Respiration Controls Ionic Nutrient Concentration In Percolating Water In Rice Fields

Science.gov (United States)

Kimura, M.

2004-12-01

Soil water in the plow layer in rice fields contains various kinds of cations and anions, and they are lost from the plow layer by water percolation. Some portions of CO2 produced by respirations of rice roots and soil microorganisms are also leached by water percolation to the subsoil layer as HCO3-. As the electrical neutrality of inorganic substances in percolating water is maintained when they are assumed to be in the form of simple cations and anions, soil respiration accelerates the leaching of ionic nutrients from the plow layer by water percolation. The proportion of inorganic carbon (Σ CO2) originated from photosynthates in the total Σ CO2 in soil solution in the plow layer was from 28 to 36 % in the rice straw amended soil and from 16 to 31 % in the soil without rice straw amendment in a soil pot experiment with rice plant after the maximum tillering stage. Most of Σ CO2 in percolating water from the plow layer accumulates in the subsoil layer. Periodical measurement of Σ CO2 in percolating water at 13 and 40 cm soil depths indicated that 10 % of total soil organic C in the plow layer was leached down from the plow layer (13 cm), and that about 90 % of it was retained in the subsoil layer to the depth of 40 cm. Water soluble organic materials are also leached from the plow layer by water percolation, and the leaching is accelerated by soil reduction. Soil reduction decreased the content of organic materials that were bound with ferric iron in soil (extractable by 0.1M Na4P2O7 + NaBH4) and increased the content of organic materials that were extractable by the neutral chelating solution (0.1M Na4P2O7). In addition, water percolation transformed the latter organic materials to those that were extractable by water and a neutral salt. Considerable portions of organic materials in percolating water are adsorbed in the subsoil layer, and then partially decomposed and polymerized to specific soil organic materials in the subsoil. Organic materials that were

Mercury contamination in soil, tailing and plants on agricultural fields near closed gold mine in Buru Island, Maluku

Directory of Open Access Journals (Sweden)

Reginawanti Hindersah

2018-01-01

Full Text Available Agricultural productivity in Buru Island, Maluku is threatened by tailings which are generated from formerly gold mine in Botak Mountain in Wamsait Village. Gold that extracted by using mercury was carried out in mining area as well agricultural field.  High content of mercury in tailings and agricultural field pose a serious problem of food production and quality; and further endangers human health. The purpose of this research was to determine the contaminant level of mercury in tailing, soil and its accumulation in edible part of some food crops. Soil, tailing and plant samples for Hg testing were taken by purposive method based on mining activities in Waelata, Waeapo and Namlea sub district. Six soil samples had been analyzed for their chemical properties. Total mercury levels in tailings and plants were measured by Atomic Adsorption Spectrophotometer. This study showed that agricultural field where tailings were deposited contained Hg above the threshold but agricultural area which is far from hot spot did not. Most edible parts of food crops accumulated mercury more than Indonesian threshold for mercury content in food. This evidence explained that tailings deposited on the surface of agricultural field had an impact on soil quality and crop quality. Tailing accumulated on soil will decreased soil quality since naturally soil fertility in agricultural field in Buru is low.

Remediation of a radioactively contaminated soil using a mobile soil-washing system

International Nuclear Information System (INIS)

Grant, D.C.; Lahoda, E.J.; Dietrich, A.J.; Weigle, D.H.; Keegan, C.P.; Sachse, J.D.

1993-01-01

In order to obtain free-release of a former uranium mining site in Texas, it was required that the surface soil meet specific radiological guidelines. The soil has been contaminated with uranium and radium as a result of the spillage of well-drilling material, process solutions, and ion exchange resins during mining. To meet the required guidelines, the contaminated soil had to be either removed and disposed of off-site or remediated. For economic and long-term liability reasons, remediation of the soil by soil washing was performed. The remediation of this site utilizing the Scientific Ecology Group's soil washing system is discussed in this paper

Effects of soil moisture on the diurnal pattern of pesticide emission: Comparison of simulations with field measurements

Science.gov (United States)

Reichman, Rivka; Yates, Scott R.; Skaggs, Todd H.; Rolston, Dennis E.

2013-02-01

Pesticide volatilization from agricultural soils is one of the main pathways in which pesticides are dispersed in the environment and affects ecosystems including human welfare. Thus, it is necessary to have accurate knowledge of the various physical and chemical mechanisms that affect volatilization rates from field soils. A verification of the influence of soil moisture modeling on the simulated volatilization rate, soil temperature and soil-water content is presented. Model simulations are compared with data collected in a field study that measured the effect of soil moisture on diazinon volatilization. These data included diurnal changes in volatilization rate, soil-water content, and soil temperature measured at two depths. The simulations were performed using a comprehensive non-isothermal model, two water retention functions, and two soil surface resistance functions, resulting in four tested models. Results show that the degree of similarity between volatilization curves simulated using the four models depended on the initial water content. Under fairly wet conditions, the simulated curves mainly differ in the magnitude of their deviation from the measured values. However, under intermediate and low moisture conditions, the simulated curves also differed in their pattern (shape). The model prediction accuracy depended on soil moisture. Under normal practices, where initial soil moisture is about field capacity or higher, a combination of Brooks and Corey water retention and the van de Grind and Owe soil surface resistance functions led to the most accurate predictions. However, under extremely dry conditions, when soil-water content in the top 1 cm is below the volumetric threshold value, the use of a full-range water retention function increased prediction accuracy. The different models did not affect the soil temperature predictions, and had a minor effect on the predicted soil-water content of Yolo silty clay soil.

Extensive management of field margins enhances their potential for off-site soil erosion mitigation.

Science.gov (United States)

Ali, Hamada E; Reineking, Björn

2016-03-15

Soil erosion is a widespread problem in agricultural landscapes, particularly in regions with strong rainfall events. Vegetated field margins can mitigate negative impacts of soil erosion off-site by trapping eroded material. Here we analyse how local management affects the trapping capacity of field margins in a monsoon region of South Korea, contrasting intensively and extensively managed field margins on both steep and shallow slopes. Prior to the beginning of monsoon season, we equipped a total of 12 sites representing three replicates for each of four different types of field margins ("intensive managed flat", "intensive managed steep", "extensive managed flat" and "extensive managed steep") with Astroturf mats. The mats (n = 15/site) were placed before, within and after the field margin. Sediment was collected after each rain event until the end of the monsoon season. The effect of management and slope on sediment trapping was analysed using linear mixed effects models, using as response variable either the sediment collected within the field margin or the difference in sediment collected after and before the field margin. There was no difference in the amount of sediment reaching the different field margin types. In contrast, extensively managed field margins showed a large reduction in collected sediment before and after the field margins. This effect was pronounced in steep field margins, and increased with the size of rainfall events. We conclude that a field margin management promoting a dense vegetation cover is a key to mitigating negative off-site effects of soil erosion in monsoon regions, particularly in field margins with steep slopes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of fomesafen on the soil microbial communities in soybean fields in Northeastern China.

Science.gov (United States)

Wu, Xiao-Hu; Zhang, Ying; Du, Peng-Qiang; Xu, Jun; Dong, Feng-Shou; Liu, Xin-Gang; Zheng, Yong-Quan

2018-02-01

Fomesafen, a widely adopted residual herbicide, is used throughout the soybean region of northern China for the spring planting. However, the ecological risks of using fomesafen in soil remain unknown. The aim of this work was to evaluate the impact of fomesafen on the microbial community structure of soil using laboratory and field experiments. Under laboratory conditions, the application of fomesafen at concentrations of 3.75 and 37.5mg/kg decreased the basal respiration (R B ) and microbial biomass carbon (MBC). In contrast, treatment with 375mg/kg of fomesafen resulted in a significant decrease in the R B , MBC, abundance of both Gram+ and Gram- bacteria, and fungal biomass. Analysis of variance showed that the treatment accounted for most of the variance (38.3%) observed in the soil microbial communities. Furthermore, the field experiment showed that long-term fomesafen application in continuously cropped soybean fields affected the soil bacterial community composition by increasing the relative average abundance of Proteobacteria and Actinobacteria species and decreasing the abundance of Verrucomicrobia species. In addition, Acidobacteria and Chloroflexi species showed a pattern of activation-inhibition. Taken together, our results suggest that the application of fomesafen can affect the community structure of soil bacteria in the spring planting soybean region of northern China. Copyright © 2017 Elsevier Inc. All rights reserved.

Soil Erodibility Parameters Under Various Cropping Systems of Maize

Science.gov (United States)

van Dijk, P. M.; van der Zijp, M.; Kwaad, F. J. P. M.

1996-08-01

For four years, runoff and soil loss from seven cropping systems of fodder maize have been measured on experimental plots under natural and simulated rainfall. Besides runoff and soil loss, several variables have also been measured, including rainfall kinetic energy, degree of slaking, surface roughness, aggregate stability, soil moisture content, crop cover, shear strength and topsoil porosity. These variables explain a large part of the variance in measured runoff, soil loss and splash erosion under the various cropping systems. The following conclusions were drawn from the erosion measurements on the experimental plots (these conclusions apply to the spatial level at which the measurements were carried out). (1) Soil tillage after maize harvest strongly reduced surface runoff and soil loss during the winter; sowing of winter rye further reduced winter erosion, though the difference with a merely tilled soil is small. (2) During spring and the growing season, soil loss is reduced strongly if the soil surface is partly covered by plant residues; the presence of plant residue on the surface appeared to be essential in achieving erosion reduction in summer. (3) Soil loss reductions were much higher than runoff reductions; significant runoff reduction is only achieved by the straw system having flat-lying, non-fixed plant residue on the soil surface; the other systems, though effective in reducing soil loss, were not effective in reducing runoff.

Phosphorus cycling in natural and low input soil/plant systems: the role of soil microorganisms

Science.gov (United States)

Tamburini, F.; Bünemann, E. K.; Oberson, A.; Bernasconi, S. M.; Frossard, E.

2011-12-01

was faster in the P-free treatment. Laboratory incubation also showed a more rapid P uptake by microbial biomass in the NK than in the NPK treatment (37% and 6% of added 33P recovered in microbial P after 100 minutes in NK and NPK, respectively). The seasonal microbial P flux in both treatments was 1.5-4 times larger than the annual plant P uptake. In field studies carried out on highly weathered low P soils in Colombia, the comparison between grass-legume and grass-only pastures showed that the presence of legumes had an impact on the overall biological activity. In fact, microbial biomass and phosphatase activity were significantly larger in grass-legume pastures than in the legume-free experiments. Larger release of Pi from the organic P pool improved P availability to plants and pointed at a modified C:N:P stoichiometry along pathways of the nutrient cycle in the soil/plant system. All these data are evidence of a highly dynamic microbial P pool, which controls Pi concentration and, hence, availability for plants in natural and low input agricultural ecosystems.

Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

Energy Technology Data Exchange (ETDEWEB)

Tao Yuqiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)], E-mail: szzhang@rcees.ac.cn; Wang Zijian [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Christie, Peter [Queen' s University Belfast, Agricultural and Environmental Science Department, Newforge Lane, Belfast BT9 5PX (United Kingdom)

2009-02-15

Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C{sub TECAM}) correlated well with the concentrations in soils (r{sup 2} = 0.693-0.962, p < 0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C{sub TECAM} and the partition coefficient between TECAM and water (K{sub TECAM-w}). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r{sup 2} = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils. - Triolein embedded cellulose acetate membranes can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.

A Portable, Low-Power Analyzer and Automated Soil Flux Chamber System for Measuring Wetland GHG Emissions

Science.gov (United States)

Nickerson, Nick; Kim-Hak, David; McArthur, Gordon

2017-04-01

Preservation and restoration of wetlands has the potential to help sequester large amounts of carbon due to the naturally high primary productivity and slow turnover of stored soil carbon. However, the anoxic environmental conditions present in wetland soils are also the largest natural contributor to global methane emissions. While it is well known that wetlands are net carbon sinks over long time scales, given the high global warming potential of methane, the short-term balances between C uptake and storage and loss as CO2 and CH4 need to be carefully considered when evaluating the climate effects of land-use change. It is relatively difficult to measure methane emissions from wetlands with currently available techniques given the temporally and spatially sporadic nature of the processes involved (methanogenesis, methane oxidation, ebullition, etc.). For example, using manual soil flux chambers can often only capture a portion of either the spatial or temporal variability, and often have other disadvantages associated with soil atmosphere disturbance during deployment in these relatively compressible wetland soils. Automated chamber systems offer the advantage of collecting high-resolution time series of gaseous fluxes while reducing some human and method induced biases. Additionally, new laser-based analyzers that can be used in situ alongside automated chambers offer a greater minimum detectable flux than can be achieved using alternative methods such as Gas Chromatography. Until recently these types of automated measurements were limited to areas that had good power coverage, as laser based systems were power intensive and could not easily be supplemented with power from field-available sources such as solar. Recent advances in laser technology has reduced the power needed and made these systems less power intensive and more field portable in the process. Here we present data using an automated chamber system coupled to a portable laser based greenhouse gas

Assessment of soil moisture dynamics on an irrigated maize field using cosmic ray neutron sensing

Science.gov (United States)

Scheiffele, Lena Maria; Baroni, Gabriele; Oswald, Sascha E.

2015-04-01

In recent years cosmic ray neutron sensing (CRS) developed as a valuable, indirect and non-invasive method to estimate soil moisture at a scale of tens of hectares, covering the gap between point scale measurements and large scale remote sensing techniques. The method is particularly promising in cropped and irrigated fields where invasive installation of belowground measurement devices could conflict with the agricultural management. However, CRS is affected by all hydrogen pools in the measurement footprint and a fast growing biomass provides some challenges for the interpretation of the signal and application of the method for detecting soil moisture. For this aim, in this study a cosmic ray probe was installed on a field near Braunschweig (Germany) during one maize growing season (2014). The field was irrigated in stripes of 50 m width using sprinkler devices for a total of seven events. Three soil sampling campaigns were conducted throughout the growing season to assess the effect of different hydrogen pools on calibration results. Additionally, leaf area index and biomass measurements were collected to provide the relative contribution of the biomass on the CRS signal. Calibration results obtained with the different soil sampling campaigns showed some discrepancy well correlated with the biomass growth. However, after the calibration function was adjusted to account also for lattice water and soil organic carbon, thus representing an equivalent water content of the soil, the differences decreased. Soil moisture estimated with CRS responded well to precipitation and irrigation events, confirming also the effective footprint of the method (i.e., radius 300 m) and showing occurring water stress for the crop. Thus, the dynamics are in agreement with the soil moisture determined with point scale measurements but they are less affected by the heterogeneous moisture conditions within the field. For this reason, by applying a detailed calibration, CRS proves to be a

Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

Directory of Open Access Journals (Sweden)

Ni Huang

Full Text Available To examine the method for estimating the spatial patterns of soil respiration (Rs in agricultural ecosystems using remote sensing and geographical information system (GIS, Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI, canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m(-2 s(-1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China.

Soil-ecological risks for soil degradation estimation

Science.gov (United States)

Trifonova, Tatiana; Shirkin, Leonid; Kust, German; Andreeva, Olga

2016-04-01

Soil degradation includes the processes of soil properties and quality worsening, primarily from the point of view of their productivity and decrease of ecosystem services quality. Complete soil cover destruction and/or functioning termination of soil forms of organic life are considered as extreme stages of soil degradation, and for the fragile ecosystems they are normally considered in the network of their desertification, land degradation and droughts /DLDD/ concept. Block-model of ecotoxic effects, generating soil and ecosystem degradation, has been developed as a result of the long-term field and laboratory research of sod-podzol soils, contaminated with waste, containing heavy metals. The model highlights soil degradation mechanisms, caused by direct and indirect impact of ecotoxicants on "phytocenosis- soil" system and their combination, frequently causing synergistic effect. The sequence of occurring changes here can be formalized as a theory of change (succession of interrelated events). Several stages are distinguished here - from heavy metals leaching (releasing) in waste and their migration downward the soil profile to phytoproductivity decrease and certain phytocenosis composition changes. Phytoproductivity decrease leads to the reduction of cellulose content introduced into the soil. The described feedback mechanism acts as a factor of sod-podzolic soil self-purification and stability. It has been shown, that using phytomass productivity index, integrally reflecting the worsening of soil properties complex, it is possible to solve the problems dealing with the dose-reflecting reactions creation and determination of critical levels of load for phytocenosis and corresponding soil-ecological risks. Soil-ecological risk in "phytocenosis- soil" system means probable negative changes and the loss of some ecosystem functions during the transformation process of dead organic substance energy for the new biomass composition. Soil-ecological risks estimation is

[Dynamics of soil water reservoir of wheat field in rain-fed area of the Loess Tableland, China].

Science.gov (United States)

Li, Peng Zhan; Wang, Li; Wang, Di

2017-11-01

Soil reservoir is the basis of stable grain production and sustainable development in dry farming area. Based on the long-term field experiment, this paper investigated the changes of soil moisture in wheat field located in the rain-fed Changwu Tableland, and analyzed the interannual and annual variation characteristics and dynamics trends of soil reservoir from 2012 to 2015. The results showed that the vertical distribution curves of average soil water content were double peaks and double valleys: first peak and valley occurred in the 10-20 and 50 cm soil layer, respectively, while for the second peak and valley, the corresponding soil layer was the 100 and 280 cm soil layer. Soil reservoir did not coincide with precipitation for all yearly precipitation patterns but lagged behind. Yearly precipitation patterns had a great influence on the interannual and annual dynamic changes of soil reservoir. Compared with rainy year, the depth of soil moisture consumption decreased and supplementary effect of precipitation on soil moisture became obvious under effects of drought year and normal year. In rainy year, soil reservoir had a large surplus (84.2 mm), water balance was compensated; in normal year, it had a slight surplus (9.5 mm), water balance was compensated; while in drought year, it was slightly deficient (1.5 mm), water balance was negatively compensated. The dynamics of soil water in winter wheat field in the rain-fed Changwu Tableland could be divided into four periods: seedling period, slow consumption period, large consumption period, and harvest period, the order of evapotranspiration was large consumption period> seedling period> harvest period> slow consumption period.

Soil organic phosphorus in soils under different land use systems in northeast Germany

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Slazak, Anna; Freese, Dirk; Hüttl, Reinhard F.

2010-05-01

Phosphorus (P) is commonly known as a major plant nutrient, which can act as a limiting factor for plant growth in many ecosystems, including different land use systems. Organic P (Po), transformations in soil are important in determining the overall biological availability of P and additionally Po depletion is caused by land cultivation. It is expected that changes of land use modifies the distribution of soil P among the various P-pools (Ptotal, Plabile, Po), where the Plabile forms are considered to be readily available to plants and Po plays an important role with P nutrition supply for plants. The aim of the study was to measure the different soil P pools under different land use systems. The study was carried out in northeast of Brandenburg in Germany. Different land use systems were studied: i) different in age pine-oak mixed forest stands, ii) silvopastoral land, iii) arable lands. Samples were taken from two mineral soil layers: 0-10 and 10-20 cm. Recently, a variety of analytical methods are available to determine specific Po compounds in soils. The different P forms in the soil were obtained by a sequential P fractionation by using acid and alkaline extractants, which mean that single samples were subjected to increasingly stronger extractants, consequently separating the soil P into fractions based on P solubility. The soil Ptotal for the forest stands ranged from 100 to 183 mg kg -1 whereas Po from 77 to 148 mg kg -1. The Po and Plabile in both soil layers increased significantly with increase of age-old oak trees. The most available-P fraction was Plabile predominate in the oldest pine-oak forest stand, accounting for 29% of soil Ptotal. For the silvopasture and arable study sites the Ptotal content was comparable. However, the highest value of Ptotal was measured in the 30 years old silvopastoral system with 685 mg kg-1 and 728 mg kg-1 at 0-10 cm and 10-20 cm depth, respectively than in arable lands. The results have shown that the 30 years old

Effect of soil moisture, over field capacity, on growth of beans plants (phaseolus vulgaris L.)

International Nuclear Information System (INIS)

Ballesteros, M.; Mazon, M. P.

1985-01-01

The effect of soil moisture, over field capacity, on growth and photosynthesis of three moisture levels (20,30 and 40 %) was studied.The first moisture level was near field capacity while the others exceeded. Weekly dry weight of different plant parts, chlorophyll content, net CO 2 exchange rate in light and darkness, 14 C O 2 assimilated rate and stomatal aperture were determined. Results show a positive effect of soil moisture over field capacity on growth, photosynthate and transpiration of beans during the first growing month. (Author) 76 refs

SoilEffects - start characterization of the experimental soil

DEFF Research Database (Denmark)

Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun

-14). The aim of the SoilEffects project is to identify potential risks and benefits for soil fertility when animal manure is anaerobically digested for biogas production. The field experiment was established on Tingvoll research farm in 2011. A biogas plant was built at this farm in 2010, to digest the manure...... in spring, no legumes are grown, and aboveground plant material is removed at harvest. This practice is intended to stress the maintenance of soil organic matter in the arable system, to possibly reveal clearer effects of the experimental treatments. Within each cropping system, five experimental treatments...... by ignition loss was 11.3 % in the grass and 6.6 % in the arable system. Analyzed by total-C measurements, the corresponding SOM values were 11.03 % and 5.97 %. In Norwegian soil, SOM values between 3 and 6 % are regarded as high humus contents (“moldrik”), whereas values between 6 and 12 % are regarded...

Field Research in the Teaching of Undergraduate Soil Science

Science.gov (United States)

Brevik, Eric C.; Senturklu, Songul; Landblom, Douglas

2015-04-01

Several studies have demonstrated that undergraduate students benefit from research experiences. Benefits of undergraduate research include 1) personal and intellectual development, 2) more and closer contact with faculty, 3) the use of active learning techniques, 4) creation of high expectations, 5) development of creative and problem-solving skills, 6) greater independence and intrinsic motivation to learn, and 7) exposure to practical skills. The scientific discipline also benefits, as studies have shown that undergraduates who engage in research experiences are more likely to remain science majors and finish their degree program (Lopatto, 2007). Research experiences come as close as possible to allowing undergraduates to experience what it is like to be an academic or research member of their profession working to advance their discipline. Soils form in the field, therefore, field experiences are very important in developing a complete and holistic understanding of soil science. Combining undergraduate research with field experiences can provide extremely beneficial outcomes to the undergraduate student, including increased understanding of and appreciation for detailed descriptions and data analysis as well as an enhanced ability to see how various parts of their undergraduate education come together to understand a complex problem. The experiences of the authors in working with undergraduate students on field-based research projects will be discussed, along with examples of some of the undergraduate research projects that have been undertaken. In addition, student impressions of their research experiences will be presented. Reference Lopatto, D. 2007. Undergraduate research experiences support science career decisions and active learning. CBE -- Life Sciences Education 6:297-306.

Organic fertilizer application increases the soil respiration and net ecosystem carbon dioxide absorption of paddy fields under water-saving irrigation.

Science.gov (United States)

Yang, Shihong; Xiao, Ya Nan; Xu, Junzeng

2018-04-01

Quantifying carbon sequestration in paddy soil is necessary to understand the effect of agricultural practices on carbon cycles. The objective of this study was to assess the effect of organic fertilizer addition (MF) on the soil respiration and net ecosystem carbon dioxide (CO 2 ) absorption of paddy fields under water-saving irrigation (CI) in the Taihu Lake Region of China during the 2014 and 2015 rice-growing seasons. Compared with the traditional fertilizer and water management (FC), the joint regulation of CI and MF (CM) significantly increased the rice yields and irrigation water use efficiencies of paddy fields by 4.02~5.08 and 83.54~109.97% (p < 0.05). The effects of organic fertilizer addition on soil respiration and net ecosystem CO 2 absorption rates showed inter-annual differences. CM paddy fields showed a higher soil respiration and net CO 2 absorption rates during some periods of the rice growth stage in the first year and during most periods of the rice growth stage in the second year. These fields also had significantly higher total CO 2 emission through soil respiration (total R soil ) and total net CO 2 absorption compared with FC paddy fields (p < 0.05). The total R soil and net ecosystem CO 2 absorption of CM paddy fields were 67.39~91.55 and 129.41~113.75 mol m -2 , which were 27.66~135.52 and 12.96~31.66% higher than those of FC paddy fields. The interaction between water and fertilizer management had significant effects on total net ecosystem CO 2 absorption. The frequent alternate wet-dry cycles of CI paddy fields increased the soil respiration and reduced the net CO 2 absorption. Organic fertilizer promoted the soil respiration of paddy soil but also increased its net CO 2 absorption and organic carbon content. Therefore, the joint regulation of water-saving irrigation and organic fertilizer is an effective measure for maintaining yield, increasing irrigation water use efficiency, mitigating CO 2 emission, and promoting paddy

A mobile automatic gas chromatograph system to measure CO2, CH4 and N2O fluxes from soil in the field

International Nuclear Information System (INIS)

Silvola, J.; Martikainen, P.; Nykaenen, H.

1992-01-01

A caravan has been converted into mobile laboratory for measuring fluxes of CO 2 , CH 4 and N 2 O from the soil in the field. The caravan was equipped with a gas chromatograph fitted with TC-, FI- and EC-detectors, and a PC controlled data logger. The gas collecting chambers can be used up to 50 m from the caravan. The closing and opening of the chambers, as well as the flows of sample gases from chambers to the gas chromatograph. is pneumatically regulated. Simultaneous recordings of temperature, light intensity and the depth of water table are made. The system has been used for two months in 1992, and some preliminary results are presented

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

Science.gov (United States)

Koestel, J. K.; Norgaard, T.; Luong, N. M.; Vendelboe, A. L.; Moldrup, P.; Jarvis, N. J.; Lamandé, M.; Iversen, B. V.; Wollesen de Jonge, L.

2013-02-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field site in Silstrup (Denmark) at a sampling distance of approximately 15 m (with a few exceptions), covering an area of approximately 1 ha (60 m × 165 m). For 64 of the 65 investigated soil columns, we observed BTC shapes indicating a strong preferential transport. The strength of preferential transport was positively correlated with the bulk density and the degree of water saturation. The latter suggests that preferential macropore transport was the dominating transport process. Increased bulk densities were presumably related with a decrease in near-saturated hydraulic conductivities and as a consequence to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column scale have to be upscaled when applied to the field scale or larger.

A new method of fully three dimensional analysis of stress field in the soil layer of a soil-mantled hillslope

Science.gov (United States)

Wu, Y. H.; Nakakita, E.

2017-12-01

Hillslope stability is highly related to stress equilibrium near the top surface of soil-mantled hillslopes. Stress field in a hillslope can also be significantly altered by variable groundwater motion under the rainfall influence as well as by different vegetation above and below the slope. The topographic irregularity, biological effects from vegetation and variable rainfall patterns couple with others to make the prediction of shallow landslide complicated and difficult. In an increasing tendency of extreme rainfall, the mountainous area in Japan has suffered more and more shallow landslides. To better assess shallow landslide hazards, we would like to develop a new mechanically-based method to estimate the fully three-dimensional stress field in hillslopes. The surface soil-layer of hillslope is modelled as a poroelastic medium, and the tree surcharge on the slope surface is considered as a boundary input of stress forcing. The modelling of groundwater motion is involved to alter effective stress state in the soil layer, and the tree root-reinforcement estimated by allometric equations is taken into account for influencing the soil strength. The Mohr-Coulomb failure theory is then used for locating possible yielding surfaces, or says for identifying failure zones. This model is implemented by using the finite element method. Finally, we performed a case study of the real event of massive shallow landslides occurred in Hiroshima in August, 2014. The result shows good agreement with the field condition.

Crop diversification, tillage, and management system influences on spring wheat yield and soil water use

Science.gov (United States)

Depleted soil quality, decreased water availability, and increased weed competition constrain spring wheat production in the northern Great Plains. Integrated crop management systems are necessary for improved crop productivity. We conducted a field experiment from 2004-2010 comparing productivity...

The Influence of Ecological and Conventional Plant Production Systems on Soil Microbial Quality under Hops (Humulus lupulus)

Science.gov (United States)

Oszust, Karolina; Frąc, Magdalena; Gryta, Agata; Bilińska, Nina

2014-01-01

The knowledge about microorganisms—activity and diversity under hop production is still limited. We assumed that, different systems of hop production (within the same soil and climatic conditions) significantly influence on the composition of soil microbial populations and its functional activity (metabolic potential). Therefore, we compared a set of soil microbial properties in the field experiment of two hop production systems (a) ecological based on the use of probiotic preparations and organic fertilization (b) conventional—with the use of chemical pesticides and mineral fertilizers. Soil analyses included following microbial properties: The total number microorganisms, a bunch of soil enzyme activities, the catabolic potential was also assessed following Biolog EcoPlates®. Moreover, the abundance of ammonia-oxidizing archaea (AOA) was characterized by terminal restriction fragment length polymorphism analysis (T-RFLP) of PCR ammonia monooxygenase α-subunit (amoA) gene products. Conventional and ecological systems of hop production were able to affect soil microbial state in different seasonal manner. Favorable effect on soil microbial activity met under ecological, was more probably due to livestock-based manure and fermented plant extracts application. No negative influence on conventional hopyard soil was revealed. Both type of production fulfilled fertilizing demands. Under ecological production it was due to livestock-based manure fertilizers and fermented plant extracts application. PMID:24897025

The Influence of Ecological and Conventional Plant Production Systems on Soil Microbial Quality under Hops (Humulus lupulus

Directory of Open Access Journals (Sweden)

Karolina Oszust

2014-06-01

Full Text Available The knowledge about microorganisms—activity and diversity under hop production is still limited. We assumed that, different systems of hop production (within the same soil and climatic conditions significantly influence on the composition of soil microbial populations and its functional activity (metabolic potential. Therefore, we compared a set of soil microbial properties in the field experiment of two hop production systems (a ecological based on the use of probiotic preparations and organic fertilization (b conventional—with the use of chemical pesticides and mineral fertilizers. Soil analyses included following microbial properties: The total number microorganisms, a bunch of soil enzyme activities, the catabolic potential was also assessed following Biolog EcoPlates®. Moreover, the abundance of ammonia-oxidizing archaea (AOA was characterized by terminal restriction fragment length polymorphism analysis (T-RFLP of PCR ammonia monooxygenase α-subunit (amoA gene products. Conventional and ecological systems of hop production were able to affect soil microbial state in different seasonal manner. Favorable effect on soil microbial activity met under ecological, was more probably due to livestock-based manure and fermented plant extracts application. No negative influence on conventional hopyard soil was revealed. Both type of production fulfilled fertilizing demands. Under ecological production it was due to livestock-based manure fertilizers and fermented plant extracts application.

Soil erosion and mitigation measures on rented and owned fields in Uruguay: the impact of transgenic soya and foreign investors

Science.gov (United States)

Caon, Lucrezia; Kessler, Aad; Keesstra, Saskia; Cruze, Rick

2014-05-01

Governments, companies and individuals with financial capital to invest, are worldwide buying or renting land in developing or third world countries. Uruguay is a developing country whose economy is mainly based on agriculture. Since 2000 many foreigners started to invest in the Uruguayan agricultural sector and to practice intensive large-scale agriculture. The significant presence of foreigners in the country is proven by the fact that almost 360 000 ha out of the 500 000 ha forming the study area were managed by foreigners in 2012. Nowadays farmers have abandoned the traditional crop rotation plan that included pasture to produce grain for export, and transgenic soya (soya RR) became the main crop planted by both foreigners and locals. Besides the high soil erosion rates related to having soya as main crop, planting soya implies the use of glyphosate, a broad-spectrum systemic herbicide leading to important environmental impacts. It is commonly said that foreigners investing in poor countries are exploiting the local natural resources aiming to get the highest possible profit from them. Is this a valid assumption in Uruguay? The purpose of this study was to compare the land management style of foreign and local farmers and to relate it to the soil erosion occurring in the study area. The land tenure (rented or owned fields) and the type of farmer interviewed ("individual farmer" equivalent to L.L.C. or "anonymous society" equivalent to P.L.C.) were taken into consideration during the analysis. Based on what stated by the farmers interviewed, the soil erosion simulations considered the seven most popular crop rotation plans on rented and owned fields, three ideals crop rotation plans, the application of no mitigation measures, and the construction of terraces and conservation buffers. Depending on the crop rotation plan, soils characterized by slope gradients higher than 2 resulted in soil erosion rates higher than the 7 ton/ha/year allowed by law. The highest

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions.

Science.gov (United States)

DeJong, Jason T; Soga, Kenichi; Banwart, Steven A; Whalley, W Richard; Ginn, Timothy R; Nelson, Douglas C; Mortensen, Brina M; Martinez, Brian C; Barkouki, Tammer

2011-01-06

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming-these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that 'soil engineering in vivo', wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon-effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized.

Soil engineering in vivo: harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions

Science.gov (United States)

DeJong, Jason T.; Soga, Kenichi; Banwart, Steven A.; Whalley, W. Richard; Ginn, Timothy R.; Nelson, Douglas C.; Mortensen, Brina M.; Martinez, Brian C.; Barkouki, Tammer

2011-01-01

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming—these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that ‘soil engineering in vivo’, wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon—effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized. PMID:20829246

Norm in soil and sludge samples in Dukhan oil Field, Qatar state

Energy Technology Data Exchange (ETDEWEB)

Al-Kinani, A.T.; Hushari, M.; Al-Sulaiti, Huda; Alsadig, I.A., E-mail: mmhushari@moe.gov.qa [Radiation and Chemical Protection Department, Ministry of Environment, Doha (Qatar)

2015-07-01

The main objective of this work is to measure the activity concentrations of Naturally Occurring radioactive Materials (NORM) produced as a buy products in oil production. The analyses of NORM give available information for guidelines concerning radiation protection. Recently NORM subjected to restricted regulation issued by high legal authority at Qatar state. Twenty five samples of soil from Dukhan onshore oil field and 10 sludge samples collected from 2 offshore fields at Qatar state. High resolution low-level gamma-ray spectrometry used to measure gamma emitters of NORM. The activity concentrations of natural radionuclide in 22 samples from Dukhan oil field, were with average worldwide values . Only three soil samples have high activity concentration of Ra-226 which is more than 185 Bq/kg the exempted level for NORM in the Quatrain regulation. The natural radionuclide activity concentrations of 10 sludge samples from offshore oil fields was greater than 1100Bq/kg the exempted values of NORM set by Quatrain regulation so the sludge need special treatments. The average hazards indices (H{sub ex} , D , and Ra{sub eq}), for the 22 samples were below the word permissible values .This means that the human exposure to such material not impose any radiation risk. The average hazards indices (H{sub ex} , D , and Ra{sub eq}), for 3 soil samples and sludge samples are higher than the published maximal permissible. Thus human exposure to such material impose radiation risk. (author)

Norm in soil and sludge samples in Dukhan oil Field, Qatar state

International Nuclear Information System (INIS)

Al-Kinani, A.T.; Hushari, M.; Al-Sulaiti, Huda; Alsadig, I.A.

2015-01-01

The main objective of this work is to measure the activity concentrations of Naturally Occurring radioactive Materials (NORM) produced as a buy products in oil production. The analyses of NORM give available information for guidelines concerning radiation protection. Recently NORM subjected to restricted regulation issued by high legal authority at Qatar state. Twenty five samples of soil from Dukhan onshore oil field and 10 sludge samples collected from 2 offshore fields at Qatar state. High resolution low-level gamma-ray spectrometry used to measure gamma emitters of NORM. The activity concentrations of natural radionuclide in 22 samples from Dukhan oil field, were with average worldwide values . Only three soil samples have high activity concentration of Ra-226 which is more than 185 Bq/kg the exempted level for NORM in the Quatrain regulation. The natural radionuclide activity concentrations of 10 sludge samples from offshore oil fields was greater than 1100Bq/kg the exempted values of NORM set by Quatrain regulation so the sludge need special treatments. The average hazards indices (H ex , D , and Ra eq ), for the 22 samples were below the word permissible values .This means that the human exposure to such material not impose any radiation risk. The average hazards indices (H ex , D , and Ra eq ), for 3 soil samples and sludge samples are higher than the published maximal permissible. Thus human exposure to such material impose radiation risk. (author)

Field controlled experiments of mercury accumulation in crops from air and soil

International Nuclear Information System (INIS)

Niu Zhenchuan; Zhang Xiaoshan; Wang Zhangwei; Ci Zhijia

2011-01-01

Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation. - Highlights: → Hg accumulation in crop organs was studied by OTCs and soil Hg enriched experiments. → Hg accumulation in foliages and roots was mainly from air and soil, respectively. → Air Hg had stronger influence than soil Hg on stem Hg accumulation. → Foliar Hg concentrations showed the trend of increase over growth stages. - Capsule Mercury accumulated in the aboveground organs of crop was mainly from the air.

Effect of Soil Fumigation on Degradation of Pendimethalin and Oxyfluorfen in Laboratory and Ginger Field Studies.

Science.gov (United States)

Huang, Bin; Li, Jun; Fang, Wensheng; Liu, Pengfei; Guo, Meixia; Yan, Dongdong; Wang, Qiuxia; Cao, Aocheng

2016-11-23

Herbicides are usually applied to agricultural fields following soil fumigation to provide effective weed control in high-value cash crops. However, phytotoxicity has been observed in ginger seedlings following the application of herbicides in fumigated fields. This study tested a mixture of herbicides (pendimethalin and oxyfluorfen) and several fumigant treatments in laboratory and field studies to determine their effect on the growth of ginger. The results showed that soil fumigation significantly (P oxyfluorfen was extended by an average of about 1.19 times in the field and 1.32 times in the laboratory. Moreover, the extended period of herbicide degradation in the fumigant and nonfumigant treatments significantly reduced ginger plant height, leaf number, stem diameter, and the chlorophyll content. The study concluded that applying a dose below the recommended rate of these herbicides in chloropicrin (CP) or CP + 1,3-dichloropropene fumigated ginger fields is appropriate, as application of the recommended herbicide dose in fumigated soil may be phytotoxic to ginger.

Impact of Cropping Systems, Soil Inoculum, and Plant Species Identity on Soil Bacterial Community Structure.

Science.gov (United States)

Ishaq, Suzanne L; Johnson, Stephen P; Miller, Zach J; Lehnhoff, Erik A; Olivo, Sarah; Yeoman, Carl J; Menalled, Fabian D

2017-02-01

Farming practices affect the soil microbial community, which in turn impacts crop growth and crop-weed interactions. This study assessed the modification of soil bacterial community structure by organic or conventional cropping systems, weed species identity [Amaranthus retroflexus L. (redroot pigweed) or Avena fatua L. (wild oat)], and living or sterilized inoculum. Soil from eight paired USDA-certified organic and conventional farms in north-central Montana was used as living or autoclave-sterilized inoculant into steam-pasteurized potting soil, planted with Am. retroflexus or Av. fatua and grown for two consecutive 8-week periods to condition soil nutrients and biota. Subsequently, the V3-V4 regions of the microbial 16S rRNA gene were sequenced by Illumina MiSeq. Treatments clustered significantly, with living or sterilized inoculum being the strongest delineating factor, followed by organic or conventional cropping system, then individual farm. Living inoculum-treated soil had greater species richness and was more diverse than sterile inoculum-treated soil (observed OTUs, Chao, inverse Simpson, Shannon, P soil contained more Chloroflexi and Acidobacteria, while the sterile inoculum soil had more Bacteroidetes, Firmicutes, Gemmatimonadetes, and Verrucomicrobia. Organically farmed inoculum-treated soil had greater species richness, more diversity (observed OTUs, Chao, Shannon, P soil. Cyanobacteria were higher in pots growing Am. retroflexus, regardless of inoculum type, for three of the four organic farms. Results highlight the potential of cropping systems and species identity to modify soil bacterial communities, subsequently modifying plant growth and crop-weed competition.

Field-scale apparent soil electrical conductivity

Science.gov (United States)

Soils are notoriously spatially heterogeneous and many soil properties (e.g., salinity, water content, trace element concentration, etc.) are temporally variable, making soil a complex media. Spatial variability of soil properties has a profound influence on agricultural and environmental processes ...

Soil carbon pools in different pasture systems

Directory of Open Access Journals (Sweden)

Francisco M. Cardozo, Jr.

2016-03-01

Full Text Available The aim of this study was to assess the carbon pools of a tropical soil where the native forest was replaced with different pasture systems. We studied five pasture production systems, including four monoculture systems with forage grasses such as Andropogon, Brachiaria, Panicum, and Cynodon, and an agroforestry system as well as a native vegetation plot. Greater availability of fulvic acid was detected in the agroforestry system as compared with that in the other systems. Higher lability of C was detected in the Andropogon system during the dry and rainy seasons and during the dry season in Cynodon. During the dry season, all pastures systems showed deficits in the net removal of atmospheric CO2. The structure and practices of the agroforestry system enables more carbon to be sequestered in the soil as compared with the monoculture pasture, suggesting that it is an important practice to mitigate climatic change and to improve soil quality.

Field sampling of soil pore water to evaluate trace element mobility and associated environmental risk

Energy Technology Data Exchange (ETDEWEB)

Moreno-Jimenez, Eduardo, E-mail: eduardo.moreno@uam.es [Departamento de Quimica Agricola, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Beesley, Luke [James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom); Lepp, Nicholas W. [35, Victoria Road, Formby, Liverpool L37 7DH (United Kingdom); Dickinson, Nicholas M. [Department of Ecology, Lincoln University, Lincoln 7647, PO Box 84 (New Zealand); Hartley, William [School of Computing, Science and Engineering, University of Salford, Cockcroft Building, Salford, M5 4WT (United Kingdom); Clemente, Rafael [Dep. of Soil and Water Conservation and Organic Waste Management, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30100 Espinardo, Murcia (Spain)

2011-10-15

Monitoring soil pollution is a key aspect in sustainable management of contaminated land but there is often debate over what should be monitored to assess ecological risk. Soil pore water, containing the most labile pollutant fraction in soils, can be easily collected in situ offering a routine way to monitor this risk. We present a compilation of data on concentration of trace elements (As, Cd, Cu, Pb, and Zn) in soil pore water collected in field conditions from a range of polluted and non-polluted soils in Spain and the UK during single and repeated monitoring, and propose a simple eco-toxicity test using this media. Sufficient pore water could be extracted for analysis both under semi-arid and temperate conditions, and eco-toxicity comparisons could be effectively made between polluted and non-polluted soils. We propose that in-situ pore water extraction could enhance the realism of risk assessment at some contaminated sites. - Highlights: > In situ pore water sampling successfully evaluates trace elements mobility in soils. > Field sampling proved robust for different soils, sites and climatic regimes. > Measurements may be directly related to ecotoxicological assays. > Both short and long-term monitoring of polluted lands may be achieved. > This method complements other widely used assays for environmental risk assessment. - In situ pore water sampling from a wide variety of soils proves to be a beneficial application to monitor the stability of pollutants in soils and subsequent risk through mobility.

Dissipation and leaching of acephate, chlorpyrifos, and their main metabolites in field soils of Malaysia.

Science.gov (United States)

Chai, L K; Mohd-Tahir, N; Hansen, S; Hansen, H C B

2009-01-01

Preventive treatment with insecticides at high dosing rates before planting of a new crop- soil drenching- is a common practice in some tropical intensive cropping systems, which may increase the risk of leaching, soil functioning, and pesticide uptake in the next crop. The degradation rates and migration of acephate and chlorpyrifos and their primary metabolites, methamidophos and 3,5,6-trichloropyridinol (TCP), have been studied in clayey red yellow podzolic (Typic Paleudults), alluvial (Typic Udorthents), and red yellow podzolic soils (Typic Kandiudults) of Malaysia under field conditions. The initial concentrations of acephate and chlorpyrifos in topsoils were found to strongly depend on solar radiation. Both pesticides and their metabolites were detected in subsoils at the deepest sampling depth monitored (50 cm) and with maximum concentrations up to 2.3 mg kg(-1) at soil depths of 10 to 20 cm. Extraordinary high dissipation rates for weakly sorbed acephate was in part attributed to preferential flow which was activated due to the high moisture content of the soils, high precipitation and the presence of conducting macropores running from below the A horizons to at least 1 m, as seen from a dye tracer experiment. Transport of chlorpyrifos and TCP which both sorb strongly to soil organic matter was attributed to macropore transport with soil particles. The half-lives for acephate in topsoils were 0.4 to 2.6 d while substantially longer half-lives of between 12.6 and 19.8 d were observed for chlorpyrifos. The transport through preferential flow of strongly sorbed pesticides is of concern in the tropics.

Phytoremediation of contaminated soils and groundwater: lessons from the field

Energy Technology Data Exchange (ETDEWEB)

Vangronsveld, J.; van der Lelie, D.; Herzig, R.; Weyens, N.; Boulet, J.; Adriaensen, K.; Ruttens, A.; Thewys, T.; Vassilev, A.; Meers, E.; Nehnevajova, E.; Mench, M.

2009-11-01

The use of plants and associated microorganisms to remove, contain, inactivate, or degrade harmful environmental contaminants (generally termed phytoremediation) and to revitalize contaminated sites is gaining more and more attention. In this review, prerequisites for a successful remediation will be discussed. The performance of phytoremediation as an environmental remediation technology indeed depends on several factors including the extent of soil contamination, the availability and accessibility of contaminants for rhizosphere microorganisms and uptake into roots (bioavailability), and the ability of the plant and its associated microorganisms to intercept, absorb, accumulate, and/or degrade the contaminants. The main aim is to provide an overview of existing field experience in Europe concerning the use of plants and their associated microorganisms whether or not combined with amendments for the revitalization or remediation of contaminated soils and undeep groundwater. Contaminations with trace elements (except radionuclides) and organics will be considered. Because remediation with transgenic organisms is largely untested in the field, this topic is not covered in this review. Brief attention will be paid to the economical aspects, use, and processing of the biomass. It is clear that in spite of a growing public and commercial interest and the success of several pilot studies and field scale applications more fundamental research still is needed to better exploit the metabolic diversity of the plants themselves, but also to better understand the complex interactions between contaminants, soil, plant roots, and microorganisms (bacteria and mycorrhiza) in the rhizosphere. Further, more data are still needed to quantify the underlying economics, as a support for public acceptance and last but not least to convince policy makers and stakeholders (who are not very familiar with such techniques).

Compartmental model for tritium persistence in the soil-plant system

International Nuclear Information System (INIS)

Iyengar, T.S.; Sadarangani, S.H.; Vaze, P.K.; Soman, S.D.

1977-01-01

A three-component computer model for tritium persistence in the soil-plant system, on the basis of an exponential polynomial is attempted. A series of field experiments with four species of trees, viz. Cardia sebastina, Terminalia catappa, Aracaria bidwilli and Mangifera indica, were carried out to generate data for testing the model. It is observed that there are two short-term components and one long-term component for tritium mean residence time, corresponding to the three phases of tritium in the system, viz. Tissue-Free-Water-Tritium, labile component of Tissue-Bound-Tritium and non-labile component of Tissue-Bound-Tritium. (author)

Field Phenotyping and Long-Term Platforms to Characterise How Crop Genotypes Interact with Soil Processes and the Environment

Directory of Open Access Journals (Sweden)

Timothy S. George

2014-05-01

Full Text Available Unsustainable agronomic practices and environmental change necessitate a revolution in agricultural production to ensure food security. A new generation of crops that yield more with fewer inputs and are adapted to more variable environments is needed. However, major changes in breeding programmes may be required to achieve this goal. By using the genetic variation in crop yield in specific target environments that vary in soil type, soil management, nutrient inputs and environmental stresses, robust traits suited to specific conditions can be identified. It is here that long-term experimental platforms and field phenotyping have an important role to play. In this review, we will provide information about some of the field-based platforms available and the cutting edge phenotyping systems at our disposal. We will also identify gaps in our field phenotyping resources that should be filled. We will go on to review the challenges in producing crop ideotypes for the dominant management systems for which we need sustainable solutions, and we discuss the potential impact of three-way interactions between genetics, environment and management. Finally, we will discuss the role that modelling can play in allowing us to fast-track some of these processes to allow us to make rapid gains in agricultural sustainability.

Organic vs. organic - soil arthropods as bioindicators of ecological sustainability in greenhouse system experiment under Mediterranean conditions.

Science.gov (United States)

Madzaric, Suzana; Ceglie, F G; Depalo, L; Al Bitar, L; Mimiola, G; Tittarelli, F; Burgio, G

2017-11-23

Organic greenhouse (OGH) production is characterized by different systems and agricultural practices with diverse environmental impact. Soil arthropods are widely used as bioindicators of ecological sustainability in open field studies, while there is a lack of research on organic production for protected systems. This study assessed the soil arthropod abundance and diversity over a 2-year crop rotation in three systems of OGH production in the Mediterranean. The systems under assessment differed in soil fertility management: SUBST - a simplified system of organic production, based on an input substitution approach (use of guano and organic liquid fertilizers), AGROCOM - soil fertility mainly based on compost application and agroecological services crops (ASC) cultivation (tailored use of cover crops) as part of crop rotation, and AGROMAN - animal manure and ASC cultivation as part of crop rotation. Monitoring of soil fauna was performed by using pitfall traps and seven taxa were considered: Carabidae, Staphylinidae, Araneae, Opiliones, Isopoda, Myriapoda, and Collembola. Results demonstrated high potential of ASC cultivation as a technique for beneficial soil arthropod conservation in OGH conditions. SUBST system was dominated by Collembola in all crops, while AGROMAN and AGROCOM had more balanced relative abundance of Isopoda, Staphylinidae, and Aranea. Opiliones and Myriapoda were more affected by season, while Carabidae were poorly represented in the whole monitoring period. Despite the fact that all three production systems are in accordance with the European Union regulation on organic farming, findings of this study displayed significant differences among them and confirmed the suitability of soil arthropods as bioindicators in protected systems of organic farming.

The Development of a Sub-Surface Monitoring System for Organic Contamination in Soils and Groundwater

Directory of Open Access Journals (Sweden)

Sharon L. Huntley

2002-01-01

Full Text Available A major problem when dealing with environmental contamination is the early detection and subsequent surveillance of the contamination. This paper describes the potential of sub-surface sensor technology for the early detection of organic contaminants in contaminated soils, sediments, and landfill sites. Rugged, low-power hydrocarbon sensors have been developed, along with a data-logging system, for the early detection of phase hydrocarbons in soil. Through laboratory-based evaluation, the ability of this system to monitor organic contamination in water-based systems is being evaluated. When used in conjunction with specific immunoassays, this can provide a sensitive and low-cost solution for long-term monitoring and analysis, applicable to a wide range of field applications.

Effects of irrigation strategies and soils on field grown potatoes

DEFF Research Database (Denmark)

Ahmadi, Seyed Hamid; Plauborg, Finn; Andersen, Mathias Neumann

2011-01-01

Root distribution of field grown potatoes (cv. Folva) was studied in 4.32m2 lysimeters and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. Drip irrigation was applied for all irrigations. Irrigations were run in three different soils: coarse sand......, loamy sand, and sandy loam. Irrigation treatments started after tuber bulking and lasted until final harvest with PRD and DI receiving 65% of FI. Potatoes irrigated with water-saving irrigation techniques (PRD and DI) did not show statistically different dry root mass and root length density (RLD, cm...... density in the furrow. Most roots accumulated in the surface layers of coarse sand as compared to the other soil types. In the deep soil profile (30–70 cm) a higher root density was found in loamy sand compared with the sandy loam and coarse sand. Approximately twice the amounts of roots were found below...

Sustainable Soil Management

DEFF Research Database (Denmark)

Green, Ole; Evgrafova, Alevtina; Kirkegaard Nielsen, Søren

Linket til højre henviser til rapporten i trykt format til download. This report provides an overview on new technologies for integrate sustainable and resilient management practices in arable ecosystems for advanced farmers, consultants, NGOs and policy makers. By following sustainable soil...... and soil quality in short- and long-terms. This report also illustrates the importance to combine a system approach for plant production by assessing field readiness, managing in-field traffic management, implementing the sitespecific controlled as well as sensor-controlled seedbed preparation, seeding...

Highly Diverse Endophytic and Soil Fusarium oxysporum Populations Associated with Field-Grown Tomato Plants

Science.gov (United States)

Demers, Jill E.; Gugino, Beth K.

2014-01-01

The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants. Included in this total were 112 isolates from the stems of all 32 plants, a niche that has not been previously included in F. oxysporum population genetics studies. Isolates were characterized using the DNA sequence of the translation elongation factor 1α gene. A diverse population of 26 sequence types was found, although two sequence types represented nearly two-thirds of the isolates studied. The sequence types were placed in different phylogenetic clades within F. oxysporum, and endophytic isolates were not monophyletic. Multiple sequence types were found in all plants, with an average of 4.2 per plant. The population compositions differed between the two fields but not between soil samples within each field. A certain degree of differentiation was observed between populations associated with different tomato cultivars, suggesting that the host genotype may affect the composition of plant-associated F. oxysporum populations. No clear patterns of genetic differentiation were observed between endophyte populations and soil populations, suggesting a lack of specialization of endophytic isolates. PMID:25304514

Soil nitrous oxide and methane fluxes in integrated crop-livestock systems in subtropics

International Nuclear Information System (INIS)

Dieckow, Jeferson; Pergher, Maico; Moraes, Anibal de; Piva, Jonatas Thiago; Bayer, Cimélio; Sakadevan, Karuppan

2015-01-01

Integrated crop-livestock (ICL) system is an agricultural practice in which crop-pasture rotation is carried out in the same field over time. In Brasil, ICL associated with no-tillage farming is increasingly gaining importance as a soil use strategy that improves food production (grain, milk and beef) and economic returns to farmers. Integrated crop-livestock-forestry (ICLF) is a recent modification of ICL in Brazil, with the inclusion of trees cultivation aiming at additional wood production and offering thermal comfort to livestock (Porfírio-da-Silva & Moraes, 2010). However, despite the increasing importance of ICL, little information is available on how this system may affect soil-atmosphere exchange of nitrous oxide (N 2 O) and methane (CH 4 )

Site Study Plan for soils, Deaf Smith County site, Texas: Environmental Field Program: Preliminary draft

International Nuclear Information System (INIS)

1987-06-01

The Soils Site Study Plan describes a field program consisting of a soil characterization survey, impact monitoring of soils, predisturbance soil salinity survey, and a reclamation suitability study. This information will be used to plan for soil stripping, stockpiling, and replacement; reclamation of soils; determining predisturbance chemical and physical characteristics of the soils; including salinity levels; and monitoring for changes in chemical and physical characteristics of the soil. The SSP describes for each study the need for the study, the study design, data management and use, schedule of proposed activities, and the quality assurance program. These studies will provide data needed to satisfy requirements contained in, or derived from, the Salt Repository Project Requirements Document. 75 refs., 10 figs., 5 tabs

Behavior of iodine in the atmosphere-soil-plant system

International Nuclear Information System (INIS)

Muramatsu, Yasuyuki; Yoshida, Satoshi; Uchida, Shigeo

1996-01-01

Levels and behavior of radioactive and stable iodine in the environment have been studied to obtain parameter values for the assessment of 129 I released from nuclear facilities. The deposition velocity (V D ) of gaseous iodine from the atmosphere to rice grains (rough rice) was 0.00048 cm 3 g -1 s -1 for CH 3 I and 0.15 cm 3 g -1 s -1 for I 2 . The ratio of the iodine distribution in a grain exposed to CH 3 I was as follows, rough rice : brown rice (hulled rice) : polished rice = 1.0 : 0.49 : 0.38. The distribution ratio in polished rice for CH 3 I was about 20 times higher than that for I 2 . The soil-solution distribution coefficient (K d ) for both I - and IO 3 - varied very widely, i.e. -1 . High values were found in soils having high concentrations of total organic carbon, active-Al and active-Fe (Al and Fe extracted by a mixture of oxalic acid and ammonium oxalate). Andosol, one of the most typical Japanese soils derived from deposits of volcanic ash, showed specifically high K d values. The soil-to-plant transfer factors (or concentration ratio) in the edible parts of crops were in the range 0.0002-0.016. The transfer factors for tomato, sweet potato, carrot, soybeans and rice were significantly lower than their leaf values. The value for rice (polished) was 0.002. Iodine was found to be evaporated from the soil-plant system as CH 3 I. The emission of CH 3 I from rice plants grown on flooded soil was much higher than that from oat plants grown on unflooded soil. The 129 I levels in environmental samples collected in and around Tokai-mura, where a spent nuclear fuel reprocessing plant is located, have been determined by neutron activation analysis. The concentrations of 129 I in surface soils ranged from -1 . The 129 I concentrations in forest soil tended to be higher than those in field soils. Most of the 129 I was retained in the first 10 cm of the surface soil collected from forests in Tokai-mura. (author)

Operable Unit 3-13, Group 3, Other Surface Soils (Phase II) Field Sampling Plan

Energy Technology Data Exchange (ETDEWEB)

G. L. Schwendiman

2006-07-27

This Field Sampling Plan describes the Operable Unit 3-13, Group 3, Other Surface Soils, Phase II remediation field sampling activities to be performed at the Idaho Nuclear Technology and Engineering Center located within the Idaho National Laboratory Site. Sampling activities described in this plan support characterization sampling of new sites, real-time soil spectroscopy during excavation, and confirmation sampling that verifies that the remedial action objectives and remediation goals presented in the Final Record of Decision for Idaho Nuclear Technology and Engineering Center, Operable Unit 3-13 have been met.

Microbial Indicators of Soil Quality under Different Land Use Systems in Subtropical Soils

Science.gov (United States)

Maharjan, M.

2016-12-01

Land-use change from native forest to intensive agricultural systems can negatively impact numerous soil parameters. Understanding the effects of forest ecosystem transformations on markers of long-term soil health is particularly important in rapidly developing regions such as Nepal, where unprecedented levels of agriculturally-driven deforestation have occurred in recent decades. However, the effects of widespread land use changes on soil quality in this region have yet to be properly characterized. Microbial indicators (soil microbial biomass, metabolic quotient and enzymes activities) are particularly suited to assessing the consequences of such ecosystem disturbances, as microbial communities are especially sensitive to environmental change. Thus, the aim of this study was to assess the effect of land use system; i.e. forest, organic and conventional farming, on soil quality in Chitwan, Nepal using markers of microbial community size and activity. Total organic C and N contents were higher in organic farming compared with conventional farming and forest, suggesting higher nutrient retention and soil preservation with organic farming practices compared to conventional. These differences in soil composition were reflected in the health of the soil microbial communities: Organic farm soil exhibited higher microbial biomass C, elevated β-glucosidase and chitinase activities, and a lower metabolic quotient relative to other soils, indicating a larger, more active, and less stressed microbial community, respectively. These results collectively demonstrate that application of organic fertilizers and organic residues positively influence nutrient availability, with subsequent improvements in soil quality and productivity. Furthermore, the sensitivity of microbial indicators to different management practices demonstrated in this study supports their use as effective markers of ecosystem disturbance in subtropical soils.

Improving Simulated Soil Moisture Fields Through Assimilation of AMSR-E Soil Moisture Retrievals with an Ensemble Kalman Filter and a Mass Conservation Constraint

Science.gov (United States)

Li, Bailing; Toll, David; Zhan, Xiwu; Cosgrove, Brian

2011-01-01

Model simulated soil moisture fields are often biased due to errors in input parameters and deficiencies in model physics. Satellite derived soil moisture estimates, if retrieved appropriately, represent the spatial mean of soil moisture in a footprint area, and can be used to reduce model bias (at locations near the surface) through data assimilation techniques. While assimilating the retrievals can reduce model bias, it can also destroy the mass balance enforced by the model governing equation because water is removed from or added to the soil by the assimilation algorithm. In addition, studies have shown that assimilation of surface observations can adversely impact soil moisture estimates in the lower soil layers due to imperfect model physics, even though the bias near the surface is decreased. In this study, an ensemble Kalman filter (EnKF) with a mass conservation updating scheme was developed to assimilate the actual value of Advanced Microwave Scanning Radiometer (AMSR-E) soil moisture retrievals to improve the mean of simulated soil moisture fields by the Noah land surface model. Assimilation results using the conventional and the mass conservation updating scheme in the Little Washita watershed of Oklahoma showed that, while both updating schemes reduced the bias in the shallow root zone, the mass conservation scheme provided better estimates in the deeper profile. The mass conservation scheme also yielded physically consistent estimates of fluxes and maintained the water budget. Impacts of model physics on the assimilation results are discussed.

Effect of soil moisture on the temperature sensitivity of Northern soils

Science.gov (United States)

Minions, C.; Natali, S.; Ludwig, S.; Risk, D.; Macintyre, C. M.

2017-12-01

Arctic and boreal ecosystems are vast reservoirs of carbon and are particularly sensitive to climate warming. Changes in the temperature and precipitation regimes of these regions could significantly alter soil respiration rates, impacting atmospheric concentrations and affecting climate change feedbacks. Many incubation studies have shown that both temperature and soil moisture are important environmental drivers of soil respiration; this relationship, however, has rarely been demonstrated with in situ data. Here we present the results of a study at six field sites in Alaska from 2016 to 2017. Low-power automated soil gas systems were used to measure soil surface CO2 flux from three forced diffusion chambers and soil profile concentrations from three soil depth chambers at hourly intervals at each site. HOBO Onset dataloggers were used to monitor soil moisture and temperature profiles. Temperature sensitivity (Q10) was determined at each site using inversion analysis applied over different time periods. With highly resolved data sets, we were able to observe the changes in soil respiration in response to changes in temperature and soil moisture. Through regression analysis we confirmed that temperature is the primary driver in soil respiration, but soil moisture becomes dominant beyond a certain threshold, suppressing CO2 flux in soils with high moisture content. This field study supports the conclusions made from previous soil incubation studies and provides valuable insights into the impact of both temperature and soil moisture changes on soil respiration.

Determination of plant species for the phytoremediation of carbofuran residue in rice field soils

Directory of Open Access Journals (Sweden)

Alissara Reungsang

2005-09-01

Full Text Available This study searched for plant species suitable for accumulating carbofuran residue in rice field soil. Three groups of plant, i.e. grass crops, upland crops, and vegetable crops, were grown in 8 inches diameter plastic pots filled with soil containing 5 mg/kg carbofuran. Parts of plants (stems and leaves, roots, fruits were harvested at day 120 and analyzed for carbofuran residue using HPLC. The results indicated that Helianthus annuus L. (sunflower was the most suitable species for phytoremediation of carbofuran residue in rice field soil because it highly accumulated carbofuran up to 93.4 μg/kg dry weight in its stems and leaves. In addition, H. annuus L. (sunflower could tolerate carbofuran since it showed similar physical appearance (circumference and height to control not receiving carbofuran.