scholarly journals EFFECTS OF SOIL WATER AVAILABILITY AND ORGANIC MATTER CONTENT ON FRUIT YIELD AND SEED OIL CONTENT OF CASTOR BEAN1

2020 ◽  
Vol 40 (6) ◽  
pp. 703-710
Author(s):  
Rogério D. de Lacerda ◽  
Larissa C. Almeida ◽  
Hugo O. C. Guerra ◽  
José E. B. da Silva
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Water Availability ◽  
Oil Content ◽  
Seed Oil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Fruit Yield ◽  
Soil Water Availability ◽  
Seed Oil Content

Soil–air partitioning of volatile organic compounds into soils with high water content

2020 ◽  
Vol 17 (8) ◽  
pp. 545
Author(s):  
Jeonghyeon Ahn ◽  
Guiying Rao ◽  
Mustafa Mamun ◽  
Eric P. Vejerano
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Exposure Limits ◽  
Case Scenario ◽  
Worst Case ◽  
Water Saturated ◽  
Water Contents

Environmental contextAssessing environmental and human health impacts of chemical spills relies on information about how chemicals move across multiple environments. We measured volatile contaminants in the air above soil saturated with water to provide estimates of air concentrations of selected chemicals released to soil from an oil refinery in Texas during Hurricane Harvey. Estimated concentrations were below recommended exposure limits, even in a worst-case scenario. AbstractThe emission of volatile organic compounds (VOCs) from soil into air is affected by soil moisture dynamics, soil temperature, solar irradiance and carbon availability. The high amount of water in soil can modify its properties, which changes how VOCs interact. We conducted a comprehensive measurement of the soil–air partition coefficient (KSA) of VOCs into water-saturated soil with both low and high water contents for polar, weakly polar and nonpolar VOCs into a mineral soil (S-clay) and soil containing a high amount of organic matter (S-om) under a water-saturated condition. Partitioning of non-polar substituted aromatics (1,2-dichlorobenzene and toluene) was sensitive to the organic matter content in water-saturated soil. 1,2-Dichlorobenzene and toluene had higher affinities to S-om than to S-clay at all investigated water contents because of their strong interaction with the organic matter in soil. KSA decreased with elevated water content only for non-polar substituted aromatic VOCs. Less hydrophobic VOCs (benzene and trichloroethylene) exhibited similar partitioning into both soils by sorbing onto the air-water interface and dissolving in soil water, while the organic matter did not affect partitioning. The weakly polar and polar VOCs (methyl tert-butyl ether and 1-butanol) showed similar partitioning into both soils by dissolving in soil water while sorption to the organic matter was significant only at high soil water contents. KSA of VOCs on soil with high organic matter content correlated strongly with psat and Koa, but not on mineral soil. Estimates of the air concentrations for a subset of VOCs released from one refinery during Hurricane Harvey in 2017 in Harris County, Texas were lower than the recommended exposure limits, even under a worst-case scenario.

scholarly journals Evaluation of Improved Model to Accurately Monitor Soil Water Content

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3441
Author(s):  
Jingyu Ji ◽  
Junzeng Xu ◽  
Yixin Xiao ◽  
Yajun Luan
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Irrigation Management ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Matter Content ◽  
Improved Model

The accurate monitoring of soil water content during the growth of crops is of great importance to improve agricultural water use efficiency. The Campbell model is one of the most widely used models for monitoring soil moisture content from soil thermal conductivities in farmland, which always needs to be calibrated due to the lack of adequate original data and the limitation of measurement methods. To precisely predict the water content of complex soils using the Campbell model, this model was evaluated by investigating several factors, including soil texture, bulk density and organic matter. The comparison of the R2 and the reduced Chi-Sqr values, which were calculated by Origin, was conducted to calibrate the Campbell model calculated. In addition, combining factors of parameters, a new parameter named m related to soil texture and the organic matter was firstly introduced and the original fitting parameter, E, was improved to an expression related to clay fraction and the organic matter content in the improved model. The soil data collected from both the laboratory and the previous literature were used to assess the revised model. The results show that most of the R2 values of the improved model are >0.95, and the reduced Chi-Sqr values are <0.01, which presents a better matching performance compared to the original. It is concluded that the improved model provides more accurate monitoring of soil water content for water irrigation management.

scholarly journals Water retention and availability in soils of the State of Santa Catarina-Brazil: effect of textural classes, soil classes and lithology

2013 ◽  
Vol 37 (6) ◽  
pp. 1535-1548 ◽  
Author(s):  
André da Costa ◽  
Jackson Adriano Albuquerque ◽  
Adriano da Costa ◽  
Patricia Pértile ◽  
Franciani Rodrigues da Silva
Keyword(s):  
Organic Matter ◽  
Cover Crops ◽  
Water Availability ◽  
Water Retention ◽  
Mixed Model ◽  
Organic Matter Content ◽  
Matter Content ◽  
The State ◽  
Santa Catarina ◽  
Alluvial Deposits

The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may be concluded that water retention is greater in silty or clayey soils and that the organic matter content is higher, especially in Humic Cambisols, Nitisols and Ferralsol developed from igneous or sedimentary rocks. Water availability is greater in loam-textured soils, with high organic matter content, especially in soils of humic character. It is lower in the sandy texture class, especially in Arenosols formed from recent alluvial deposits or in gravelly soils derived from granite. The greater water availability in the surface horizons, with more organic matter than in the subsurface layers, illustrates the importance of organic matter for water retention and availability.

Adsorption and relative mobility of flumetsulam

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 573-578 ◽  
Author(s):  
David R. Shaw ◽  
Glen P. Murphy
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Soil Ph ◽  
Adsorption Mechanism ◽  
Organic Matter Content ◽  
Matter Content ◽  
Accurate Assessment ◽  
Relative Mobility ◽  
Laboratory Studies ◽  
Soil Columns

Laboratory studies were conducted to evaluate flumetsulam adsorption and mobility in seven Mississippi soils of different organic matter content, pH, and texture. Adsorption isotherms were determined for all soils using a 1:1 (soil: water) technique. In six of seven soils, Freundlichnconstants were close to unity, suggesting a partitioning-like adsorption mechanism for flumetsulam. Mobility was examined using packed soil columns.14C-flumetsulam recoveries in leachate ranged from 1 to 70% and were influenced by both organic matter content and soil pH. However, the effects of organic matter content and soil pH were not independent. Consequently, clear relationships between flumetsulam mobility and either organic matter content or soil pH were not established across all soils. However, among soils of similar pH (7.5 ± 0.3), mobility decreased linearly (R2= 0.75) as organic matter content increased from 0.7 to 3.6%. Across soils with similar organic matter content (3.9 ± 0.3%), mobility increased linearly (R2= 0.98) as soil pH increased from 5.3 to 7.2. Net adsorption constants (Kd) provided a more accurate assessment of flumetsulam mobility across all soils thanKoc.

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