The Experts below are selected from a list of 8640 Experts worldwide ranked by ideXlab platform
Filipe Behrends Kraemer - One of the best experts on this subject based on the ideXlab platform.
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soil stabilisation by water repellency under no till management for soils with contrasting mineralogy and carbon quality
Geoderma, 2019Co-Authors: Filipe Behrends Kraemer, Paul D Hallett, Hector Jose Maria Morras, Lucas A Garibaldi, Diego Cosentino, Matias Ezequiel DuvalAbstract:Abstract No-till soil management is common around the globe, but the impacts on soil structural quality varies depending on Cropping Practice and inherent soil properties. This study explored water repellency as a driver of soil stabilization, as affected by soil mineralogy, granulometry and organic carbon quality in three Mollisols and one Vertisol under no-till management and with different levels of Cropping intensity. The studied soils were located along a west-east textural gradient in the northern part of the Pampean region of Argentina. Cropping intensity treatments evaluated in each one of the soils were: Poor Agricultural Practices (PAP) close to a monoculture, Good Agricultural Practices (GAP) involving a diverse crop rotation and more targeted inputs, and the soil in the surrounding natural environment (NE) as a reference. NE had the greatest aggregate stability (MWD) of all Cropping intensities, with GAP being more stable than PAP for Mollisols and PAP being greater than GAP for the Vertisol. This trend matched the Repellency Index (Rindex), with greater Rindex associated with greater MWD, including the difference between the Mollisols and Vertisol. However, the persistence of water repellency, measured by the Water Drop Penetration Time (WDPT) test followed the trend NE > GAP>PAP regardless of soil type. The increases in Rindex and MWD were related to higher intensification as measured by the Crop Sequence Index, and decreased with greater soybean occurrence in the sequence. Both WDPT and Rindex were closely related to aggregate stability, particularly for Mollisols. These results highlight the importance of considering the inherent soil characteristics texture and mineralogy to understand aggregate stabilization mediated by water repellency. Good correlations between soil water repellency, organic carbon fractions and aggregate stability were found. Under no-till, crop rotations can be altered to increase soil stability by inducing greater water repellency in the soils. The findings suggest that water repellency is a major property influencing soil structure stabilization, thus providing a useful quality indicator.
Haijun Liu - One of the best experts on this subject based on the ideXlab platform.
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an assessment of irrigation Practices sprinkler irrigation of winter wheat in the north china plain
Agricultural Water Management, 2015Co-Authors: Xiangping Wang, Guanhua Huang, Jingsong Yang, Quanzhong Huang, Haijun LiuAbstract:Winter wheat production in the North China Plain (NCP) relies mainly on irrigation. To assess the effect irrigation management Practices on crop production, the HYDRUS-1D model was modified by incorporating the crop growth module adopted from the EPIC model. The modified HYDRUS-1D model was calibrated and validated by using data collected from 2006/2007 and 2007/2008 winter wheat growing seasons in Beijing area. The predicted values for soil water content, soil nitrate concentration, crop growth, yield, and evapotranspiration showed good agreements with the measured values. The calibrated model was then used to evaluate the yield and water use efficiency (WUE) under different hydrologic years. The WUE for different irrigation depth was considered as the criterion for investigating the appropriate irrigation management Practices. Results showed that the appropriate irrigation depth per application could be determined as 62.5% of the difference between 20cmpan evaporation and precipitation for hydrologic years with 75%, 50% and 25% probability of rainfall occurrence, respectively, under the recommended nitrogen application rate in Beijing area. And the corresponding total irrigation amount was 244.7, 213.8 and 192.5mm. The results of this study provide scientific implications for water management of winter wheat under sprinkler irrigation in the NCP and those areas with similar climatic and Cropping Practice conditions.
Xiangping Wang - One of the best experts on this subject based on the ideXlab platform.
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an assessment of irrigation Practices sprinkler irrigation of winter wheat in the north china plain
Agricultural Water Management, 2015Co-Authors: Xiangping Wang, Guanhua Huang, Jingsong Yang, Quanzhong Huang, Haijun LiuAbstract:Winter wheat production in the North China Plain (NCP) relies mainly on irrigation. To assess the effect irrigation management Practices on crop production, the HYDRUS-1D model was modified by incorporating the crop growth module adopted from the EPIC model. The modified HYDRUS-1D model was calibrated and validated by using data collected from 2006/2007 and 2007/2008 winter wheat growing seasons in Beijing area. The predicted values for soil water content, soil nitrate concentration, crop growth, yield, and evapotranspiration showed good agreements with the measured values. The calibrated model was then used to evaluate the yield and water use efficiency (WUE) under different hydrologic years. The WUE for different irrigation depth was considered as the criterion for investigating the appropriate irrigation management Practices. Results showed that the appropriate irrigation depth per application could be determined as 62.5% of the difference between 20cmpan evaporation and precipitation for hydrologic years with 75%, 50% and 25% probability of rainfall occurrence, respectively, under the recommended nitrogen application rate in Beijing area. And the corresponding total irrigation amount was 244.7, 213.8 and 192.5mm. The results of this study provide scientific implications for water management of winter wheat under sprinkler irrigation in the NCP and those areas with similar climatic and Cropping Practice conditions.
Robert L. Mcgraw - One of the best experts on this subject based on the ideXlab platform.
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Yield, maturation, and forage quality of alfalfa in a black walnut alley-Cropping Practice
Agroforestry Systems, 2008Co-Authors: Robert L. Mcgraw, James H. Houx, W. Terrell Stamps, Marc J. LinitAbstract:There is interest in producing alfalfa as an alley crop because alfalfa ( Medicago sativa L.) is the most profitable hay crop in the USA. Field experiments were conducted near Stockton, MO in 2003 and 2004. Treatments consisted of alfalfa grown in open plots and in plots that were alley cropped between 20-year-old black walnut trees ( Juglans nigra L.) planted in rows 24.4- and 12.2-m apart. Alfalfa was sampled for three harvest cycles each year. In the alley-Cropping plots, samples were taken beneath the canopy (2.5 m from the tree row) and in the center of the alleys. Data were taken on dry-matter yield, maturity, and forage quality. At all harvest dates over both years, yields from beneath the canopy of both alleys and the narrow alley centers were less than yields from the wide alley centers and open plots. Yield from the wide alley centers was similar to that in open plots in every harvest but the final harvest of 2004. Transects across the plots indicated that yields increased linearly from the tree row to the center of both alleys. Alfalfa tended to mature faster in the open and wide alley centers compared to beneath the canopy of both alleys and the narrow alley centers. Forage quality differences were inconsistent across treatments. Alfalfa yield was significantly reduced and maturity was delayed by the narrow 12.2 m tree spacing, but yield was not reduced in the centers of the wider 24.4 m alleyways.
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green mulch decomposition and nitrogen release from leaves of two inga spp in an organic alley Cropping Practice in the humid tropics
Soil Biology & Biochemistry, 2006Co-Authors: Humberto A Leblanc, Pekka Nygren, Robert L. McgrawAbstract:Inga edulis Mart and Inga samanensis Uribe are promising yet little studied legume trees for use in agroforestry on acidic soils. The objective of this study was to analyze the decomposition and N release processes of green mulch from these species. Litterbags filled with leaves from each species were placed on the ground in an organic maize (Zea mays L.) alley-Cropping experiment at the time of maize sowing and collected every 2 weeks over a 20 week period, and measured for dry matter, N, hemicellulose, cellulose, and lignin content. Three types of models were applied to the data, according to the characteristics of each component, to analyze the decomposition dynamics of whole leaves and leaf components: a negative exponential decay function, an inverted Michaelis‐Menten function, and a linear regression. Initial decay of I. samanensis mulch was faster than I. edulis mulch. However, the recalcitrant fraction was about half of the initial litter mass in both Inga spp. Hemicellulose disappeared almost completely from the litter during the 20week incubation period, while no significant lignin decay occurred. After a slow start, cellulose partially decayed following linear kinetics. The half-life of labile N, estimated as a Michaelis‐Menten parameter, was 10 weeks in I. samanensis and ca. 24 weeks in I. edulis litter. Polyphenol content was significantly higher in I. edulis. Litter of I. edulis and I. samanensis may be classified as ‘lowquality’ and ‘medium-quality’ mulch, respectively. Due to the relatively large recalcitrant mulch fraction, both Inga spp. may promote C sequestration and long-term N accumulation in soil. q 2005 Elsevier Ltd. All rights reserved.
Matias Ezequiel Duval - One of the best experts on this subject based on the ideXlab platform.
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soil stabilisation by water repellency under no till management for soils with contrasting mineralogy and carbon quality
Geoderma, 2019Co-Authors: Filipe Behrends Kraemer, Paul D Hallett, Hector Jose Maria Morras, Lucas A Garibaldi, Diego Cosentino, Matias Ezequiel DuvalAbstract:Abstract No-till soil management is common around the globe, but the impacts on soil structural quality varies depending on Cropping Practice and inherent soil properties. This study explored water repellency as a driver of soil stabilization, as affected by soil mineralogy, granulometry and organic carbon quality in three Mollisols and one Vertisol under no-till management and with different levels of Cropping intensity. The studied soils were located along a west-east textural gradient in the northern part of the Pampean region of Argentina. Cropping intensity treatments evaluated in each one of the soils were: Poor Agricultural Practices (PAP) close to a monoculture, Good Agricultural Practices (GAP) involving a diverse crop rotation and more targeted inputs, and the soil in the surrounding natural environment (NE) as a reference. NE had the greatest aggregate stability (MWD) of all Cropping intensities, with GAP being more stable than PAP for Mollisols and PAP being greater than GAP for the Vertisol. This trend matched the Repellency Index (Rindex), with greater Rindex associated with greater MWD, including the difference between the Mollisols and Vertisol. However, the persistence of water repellency, measured by the Water Drop Penetration Time (WDPT) test followed the trend NE > GAP>PAP regardless of soil type. The increases in Rindex and MWD were related to higher intensification as measured by the Crop Sequence Index, and decreased with greater soybean occurrence in the sequence. Both WDPT and Rindex were closely related to aggregate stability, particularly for Mollisols. These results highlight the importance of considering the inherent soil characteristics texture and mineralogy to understand aggregate stabilization mediated by water repellency. Good correlations between soil water repellency, organic carbon fractions and aggregate stability were found. Under no-till, crop rotations can be altered to increase soil stability by inducing greater water repellency in the soils. The findings suggest that water repellency is a major property influencing soil structure stabilization, thus providing a useful quality indicator.