The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Søren B. Hansen - One of the best experts on this subject based on the ideXlab platform.
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Tillage Effects on topsoil structural quality assessed using X-ray CT, soil cores and visual soil evaluation
Soil & Tillage Research, 2013Co-Authors: Amin Garbout, Lars J. Munkholm, Søren B. HansenAbstract:Abstract Soil structure plays a key role in the ability of soil to fulfil essential functions and services in relation to, e.g., root growth, gas and water transport and organic matter turnover. The objective of this paper was: (1) To quantify Tillage Effects on soil structural quality in the entire topsoil layer (0–20 cm) using X-ray CT, visual evaluation and traditional core methods; and (2) To correlate pore network characteristics from X-ray CT imaging with the results from the visual evaluation and the core method. Samples were taken in May 2009 from a long-term rotation and Tillage field experiment on a Danish sandy loam. The Tillage treatments were direct drilling (D) and ploughing (P). For X-ray CT scanning, we sampled large soil cores ( O = 20 cm, height = 20 cm) from the top layer. Small 100 cm 3 samples were taken from the 4–8 and 12–16 cm layers for water content and bulk density measurements. Visual soil structure evaluation was carried out in the field at the same time as sampling. CT images (0.39 × 0.39 × 0.6 mm 3 voxels) were produced using a medical X-ray CT scanner. The visual assessment showed a good structural quality in the top 5–8 cm for both treatments (Sq −3 , respectively), whereas relatively high bulk density values were observed for both treatments in the 12–16 cm layers (1.50 and 1.56 g cm −3 , respectively). The X-ray CT image analysis showed that the P soil had more networks, branches and junctions but a lower degree of anisotropy and shorter average branch length than the D soil. The image data also confirmed a clear stratification of the 0–20 cm topsoil layer for both Tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary Tillage and natural consolidation, and aggravated by a poor structural stability due to a low organic matter content. The visual soil evaluation scores were negatively correlated to soil porosity and number of pore networks estimated from X-ray CT imaging and positively correlated to the macropore characteristics of branch length and pore thickness.
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Tillage Effects on topsoil structural quality assessed using x ray ct soil cores and visual soil evaluation
Soil & Tillage Research, 2013Co-Authors: Amin Garbout, Lars J. Munkholm, Søren B. HansenAbstract:Soil structure plays a key role in the ability of soil to fulfil essential functions and services in relation to, e.g., root growth, gas and water transport and organic matter turnover. The objective of this paper was: (1) To quantify Tillage Effects on soil structural quality in the entire topsoil layer (0–20 cm) using X-ray CT, visual evaluation and traditional core methods; and (2) To correlate pore network characteristics from X-ray CT imaging with the results from the visual evaluation and the core method. Samples were taken in May 2009 from a long-term rotation and Tillage field experiment on a Danish sandy loam. The Tillage treatments were direct drilling (D) and ploughing (P). For X-ray CT scanning, we sampled large soil cores (O = 20 cm, height = 20 cm) from the top layer. Small 100 cm3 samples were taken from the 4–8 and 12–16 cm layers for water content and bulk density measurements. Visual soil structure evaluation was carried out in the field at the same time as sampling. CT images (0.39 × 0.39 × 0.6 mm3 voxels) were produced using a medical X-ray CT scanner. The visual assessment showed a good structural quality in the top 5–8 cm for both treatments (Sq < 2). A poorer soil structure was observed in lower part or the topsoil where a firm structure (Sq = 2.9) was observed for D and relatively friable structure (Sq = 2.2) for P. Lower bulk density was found for P than for D in the 4–8 cm layer (1.34 and 1.52 g cm−3, respectively), whereas relatively high bulk density values were observed for both treatments in the 12–16 cm layers (1.50 and 1.56 g cm−3, respectively). The X-ray CT image analysis showed that the P soil had more networks, branches and junctions but a lower degree of anisotropy and shorter average branch length than the D soil. The image data also confirmed a clear stratification of the 0–20 cm topsoil layer for both Tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary Tillage and natural consolidation, and aggravated by a poor structural stability due to a low organic matter content. The visual soil evaluation scores were negatively correlated to soil porosity and number of pore networks estimated from X-ray CT imaging and positively correlated to the macropore characteristics of branch length and pore thickness.
Christoph Müller - One of the best experts on this subject based on the ideXlab platform.
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The importance of management information and soil moisture representation for simulating Tillage Effects on N 2 O emissions in LPJmL5.0-Tillage
Geoscientific Model Development Discussions, 2020Co-Authors: Femke Lutz, Stephen J. Delgrosso, Stephen M. Ogle, Stephen Alaric Williams, Sara Minoli, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Christoph MüllerAbstract:Abstract. No-Tillage is often suggested as a strategy to reduce greenhouse gas emissions. Modeling Tillage Effects on nitrous oxide (N2O) emissions is challenging and subject to large uncertainties, as the processes producing the emissions are complex and strongly non-linear. Previous findings have shown deviations between the LPJmL5.0-Tillage model and results from meta-analysis on global estimates of Tillage Effects on N2O emissions. Here we tested LPJmL5.0-Tillage at four different experimental sites across Europe and the USA, to verify whether deviations in N2O emissions under different Tillage regimes result from a lack of detailed information on agricultural management and/or the representation of soil water dynamics. Model results were compared to observational data and outputs from field-scale DayCent simulations. DayCent has been successfully applied for the simulation of N2O emissions and provides a richer data base for comparison than non-continuous measurements at the experimental sites. We found that adding information on agricultural management improved the simulation of Tillage Effects on N2O emissions in LPJmL. We also found that LPJmL overestimated N2O emissions as well as the Effects of no-Tillage on N2O emissions, whereas DayCent tended to underestimate the emissions of no-Tillage treatments. LPJmL showed a general bias to over-estimate soil moisture content. Modifications of hydraulic properties in LPJmL in order to match properties assumed in DayCent, as well as of the parameters related to residue cover, improved the overall simulation of soil water as well as the N2O emissions simulated under Tillage and no-Tillage separately. However, the Effects of no-Tillage (shifting from Tillage to no-Tillage) did not improve. Advancing the current state of information on agricultural management as well as improvements in soil moisture highlight the potential to improve LPJmL5.0-Tillage and global estimates of Tillage Effects on N2O emissions.
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Simulating the effect of Tillage practices with the global ecosystem model LPJmL (version 5.0-Tillage)
Geoscientific Model Development, 2019Co-Authors: Femke Lutz, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Christoph MüllerAbstract:Abstract. The Effects of Tillage on soil properties, crop productivity, and global greenhouse gas emissions have been discussed in the last decades. Global ecosystem models have limited capacity to simulate the various Effects of Tillage. With respect to the decomposition of soil organic matter, they either assume a constant increase due to Tillage or they ignore the Effects of Tillage. Hence, they do not allow for analysing the Effects of Tillage and cannot evaluate, for example, reduced Tillage or no Tillage (referred to here as “no-till”) practises as mitigation practices for climate change. In this paper, we describe the implementation of Tillage-related practices in the global ecosystem model LPJmL. The extended model is evaluated against reported differences between Tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analyses on Tillage Effects. In general, the model is able to reproduce observed Tillage Effects on global, as well as regional, patterns of carbon and water fluxes. However, modelled N fluxes deviate from the literature values and need further study. The addition of the Tillage module to LPJmL5 opens up opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions, and other environmental indicators.
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Simulating the effect of Tillage practices with the global ecosystem model LPJmL (version 5.0-Tillage)
2018Co-Authors: Femke Lutz, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Christoph MüllerAbstract:<p><strong>Abstract.</strong> The Effects of Tillage on soil properties (e.g. soil carbon and nitrogen), crop productivity, and global greenhouse gas emissions have been discussed in the last decades. Global ecosystem models are limited in simulating Tillage. Hence, they do not allow for analyzing the Effects of Tillage and cannot evaluate, for example, reduced-Tillage or no-till as mitigation practices for climate change. In this paper, we describe the implementation of Tillage related practices in the global ecosystem model LPJmL. The model is subsequently evaluated against reported differences between Tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analysis on Tillage Effects. In general, the model is able to reproduce observed Tillage Effects on global, as well as regional patterns of carbon and water fluxes. However, modeled N-fluxes deviate from the literature and need further study. The addition of the Tillage module to LPJmL 5.0 opens opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions and other environmental indicators.</p>
Amin Garbout - One of the best experts on this subject based on the ideXlab platform.
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Tillage Effects on topsoil structural quality assessed using X-ray CT, soil cores and visual soil evaluation
Soil & Tillage Research, 2013Co-Authors: Amin Garbout, Lars J. Munkholm, Søren B. HansenAbstract:Abstract Soil structure plays a key role in the ability of soil to fulfil essential functions and services in relation to, e.g., root growth, gas and water transport and organic matter turnover. The objective of this paper was: (1) To quantify Tillage Effects on soil structural quality in the entire topsoil layer (0–20 cm) using X-ray CT, visual evaluation and traditional core methods; and (2) To correlate pore network characteristics from X-ray CT imaging with the results from the visual evaluation and the core method. Samples were taken in May 2009 from a long-term rotation and Tillage field experiment on a Danish sandy loam. The Tillage treatments were direct drilling (D) and ploughing (P). For X-ray CT scanning, we sampled large soil cores ( O = 20 cm, height = 20 cm) from the top layer. Small 100 cm 3 samples were taken from the 4–8 and 12–16 cm layers for water content and bulk density measurements. Visual soil structure evaluation was carried out in the field at the same time as sampling. CT images (0.39 × 0.39 × 0.6 mm 3 voxels) were produced using a medical X-ray CT scanner. The visual assessment showed a good structural quality in the top 5–8 cm for both treatments (Sq −3 , respectively), whereas relatively high bulk density values were observed for both treatments in the 12–16 cm layers (1.50 and 1.56 g cm −3 , respectively). The X-ray CT image analysis showed that the P soil had more networks, branches and junctions but a lower degree of anisotropy and shorter average branch length than the D soil. The image data also confirmed a clear stratification of the 0–20 cm topsoil layer for both Tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary Tillage and natural consolidation, and aggravated by a poor structural stability due to a low organic matter content. The visual soil evaluation scores were negatively correlated to soil porosity and number of pore networks estimated from X-ray CT imaging and positively correlated to the macropore characteristics of branch length and pore thickness.
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Tillage Effects on topsoil structural quality assessed using x ray ct soil cores and visual soil evaluation
Soil & Tillage Research, 2013Co-Authors: Amin Garbout, Lars J. Munkholm, Søren B. HansenAbstract:Soil structure plays a key role in the ability of soil to fulfil essential functions and services in relation to, e.g., root growth, gas and water transport and organic matter turnover. The objective of this paper was: (1) To quantify Tillage Effects on soil structural quality in the entire topsoil layer (0–20 cm) using X-ray CT, visual evaluation and traditional core methods; and (2) To correlate pore network characteristics from X-ray CT imaging with the results from the visual evaluation and the core method. Samples were taken in May 2009 from a long-term rotation and Tillage field experiment on a Danish sandy loam. The Tillage treatments were direct drilling (D) and ploughing (P). For X-ray CT scanning, we sampled large soil cores (O = 20 cm, height = 20 cm) from the top layer. Small 100 cm3 samples were taken from the 4–8 and 12–16 cm layers for water content and bulk density measurements. Visual soil structure evaluation was carried out in the field at the same time as sampling. CT images (0.39 × 0.39 × 0.6 mm3 voxels) were produced using a medical X-ray CT scanner. The visual assessment showed a good structural quality in the top 5–8 cm for both treatments (Sq < 2). A poorer soil structure was observed in lower part or the topsoil where a firm structure (Sq = 2.9) was observed for D and relatively friable structure (Sq = 2.2) for P. Lower bulk density was found for P than for D in the 4–8 cm layer (1.34 and 1.52 g cm−3, respectively), whereas relatively high bulk density values were observed for both treatments in the 12–16 cm layers (1.50 and 1.56 g cm−3, respectively). The X-ray CT image analysis showed that the P soil had more networks, branches and junctions but a lower degree of anisotropy and shorter average branch length than the D soil. The image data also confirmed a clear stratification of the 0–20 cm topsoil layer for both Tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary Tillage and natural consolidation, and aggravated by a poor structural stability due to a low organic matter content. The visual soil evaluation scores were negatively correlated to soil porosity and number of pore networks estimated from X-ray CT imaging and positively correlated to the macropore characteristics of branch length and pore thickness.
Femke Lutz - One of the best experts on this subject based on the ideXlab platform.
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The importance of management information and soil moisture representation for simulating Tillage Effects on N 2 O emissions in LPJmL5.0-Tillage
Geoscientific Model Development Discussions, 2020Co-Authors: Femke Lutz, Stephen J. Delgrosso, Stephen M. Ogle, Stephen Alaric Williams, Sara Minoli, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Christoph MüllerAbstract:Abstract. No-Tillage is often suggested as a strategy to reduce greenhouse gas emissions. Modeling Tillage Effects on nitrous oxide (N2O) emissions is challenging and subject to large uncertainties, as the processes producing the emissions are complex and strongly non-linear. Previous findings have shown deviations between the LPJmL5.0-Tillage model and results from meta-analysis on global estimates of Tillage Effects on N2O emissions. Here we tested LPJmL5.0-Tillage at four different experimental sites across Europe and the USA, to verify whether deviations in N2O emissions under different Tillage regimes result from a lack of detailed information on agricultural management and/or the representation of soil water dynamics. Model results were compared to observational data and outputs from field-scale DayCent simulations. DayCent has been successfully applied for the simulation of N2O emissions and provides a richer data base for comparison than non-continuous measurements at the experimental sites. We found that adding information on agricultural management improved the simulation of Tillage Effects on N2O emissions in LPJmL. We also found that LPJmL overestimated N2O emissions as well as the Effects of no-Tillage on N2O emissions, whereas DayCent tended to underestimate the emissions of no-Tillage treatments. LPJmL showed a general bias to over-estimate soil moisture content. Modifications of hydraulic properties in LPJmL in order to match properties assumed in DayCent, as well as of the parameters related to residue cover, improved the overall simulation of soil water as well as the N2O emissions simulated under Tillage and no-Tillage separately. However, the Effects of no-Tillage (shifting from Tillage to no-Tillage) did not improve. Advancing the current state of information on agricultural management as well as improvements in soil moisture highlight the potential to improve LPJmL5.0-Tillage and global estimates of Tillage Effects on N2O emissions.
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Simulating the effect of Tillage practices with the global ecosystem model LPJmL (version 5.0-Tillage)
Geoscientific Model Development, 2019Co-Authors: Femke Lutz, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Christoph MüllerAbstract:Abstract. The Effects of Tillage on soil properties, crop productivity, and global greenhouse gas emissions have been discussed in the last decades. Global ecosystem models have limited capacity to simulate the various Effects of Tillage. With respect to the decomposition of soil organic matter, they either assume a constant increase due to Tillage or they ignore the Effects of Tillage. Hence, they do not allow for analysing the Effects of Tillage and cannot evaluate, for example, reduced Tillage or no Tillage (referred to here as “no-till”) practises as mitigation practices for climate change. In this paper, we describe the implementation of Tillage-related practices in the global ecosystem model LPJmL. The extended model is evaluated against reported differences between Tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analyses on Tillage Effects. In general, the model is able to reproduce observed Tillage Effects on global, as well as regional, patterns of carbon and water fluxes. However, modelled N fluxes deviate from the literature values and need further study. The addition of the Tillage module to LPJmL5 opens up opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions, and other environmental indicators.
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Simulating the effect of Tillage practices with the global ecosystem model LPJmL (version 5.0-Tillage)
2018Co-Authors: Femke Lutz, Susanne Rolinski, Jens Heinke, Jetse J. Stoorvogel, Tobias Herzfeld, Sibyll Schaphoff, Werner Von Bloh, Christoph MüllerAbstract:<p><strong>Abstract.</strong> The Effects of Tillage on soil properties (e.g. soil carbon and nitrogen), crop productivity, and global greenhouse gas emissions have been discussed in the last decades. Global ecosystem models are limited in simulating Tillage. Hence, they do not allow for analyzing the Effects of Tillage and cannot evaluate, for example, reduced-Tillage or no-till as mitigation practices for climate change. In this paper, we describe the implementation of Tillage related practices in the global ecosystem model LPJmL. The model is subsequently evaluated against reported differences between Tillage and no-till management on several soil properties. To this end, simulation results are compared with published meta-analysis on Tillage Effects. In general, the model is able to reproduce observed Tillage Effects on global, as well as regional patterns of carbon and water fluxes. However, modeled N-fluxes deviate from the literature and need further study. The addition of the Tillage module to LPJmL 5.0 opens opportunities to assess the impact of agricultural soil management practices under different scenarios with implications for agricultural productivity, carbon sequestration, greenhouse gas emissions and other environmental indicators.</p>
Kripal Singh - One of the best experts on this subject based on the ideXlab platform.
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Tillage Effects on crop yield and physicochemical properties of sodic soils
Land Degradation & Development, 2016Co-Authors: Kripal Singh, Ashish K Mishra, Bajrang Singh, Rana Pratap Singh, D D PatraAbstract:Tillage modifies soil structure and has been suggested as a practice to improve physical, hydrological and chemical properties of compacted soils. But little is known about effect of long-term Tillage on physicochemical soil properties and crop yield on sodic soils in India. Our objective was to investigate the effect of different Tillage regimes on crop yield (wheat and paddy rice) and physicochemical properties of sodic soils. Two sodic sites under conventional Tillage for 5 (5-YT; 5-year Tillage) and 9 (9-YT; 9-year Tillage) years were selected for this study. Changes in crop yield and physicochemical soil properties were compared with a control, sodic land without any till history, that is, 0-year Tillage/untilled (0-YT). Five replicated samples at 0- to 10-cm and 10- to 20-cm soils depths were analysed from each site. In the top, 0- to 10-cm soil depth 5-YT and 9-YT sites had higher particle density (Pd), porosity, water holding capacity, hydraulic conductivity, organic carbon, total nitrogen (Nt), available nitrogen (Navail), phosphorus (Pavail) and exchangeable calcium (Exch. Ca++) than 0-YT, whereas bulk density (Bd), C : N ratio and CaCO3 were significantly lower. Bd, pH, EC and CaCO3 increased significantly with depth in all the lands, whereas Pd, porosity, water holding capacity, hydraulic conductivity, organic carbon, Nt, Navail, Pavail and Exch. Ca++ decreased. We conclude that continuous Tillage and cropping can be useful for physical and chemical restoration of sodic soils. Copyright © 2013 John Wiley & Sons, Ltd.