The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixin...The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.展开更多
Soil erosion is a major issue in Ethiopia,prompting ongoing watershed development campaigns.This study contributes to exploring Best Soil Conservation practices(BSCPs)to reduce erosion rates to/or below Tolerable Soil...Soil erosion is a major issue in Ethiopia,prompting ongoing watershed development campaigns.This study contributes to exploring Best Soil Conservation practices(BSCPs)to reduce erosion rates to/or below Tolerable Soil Loss Limits(TSLLs).To achieve these the study used the SWAT model,coupled with the SWAT Calibration and Uncertainty Procedures(SWAT-CUP),for simulation,sensitivity analysis,calibration,and validation using streamflow and sediment yield data.The calibrated SWAT model was used to assess soil erosion hotspot areas and evaluate the effectiveness of the selected BSCPs:Soil and/or Stone Bund(SSB),Grass strip(GT),reforestation(RF),Soil and/or Stone Bund and grass strip(SSB and GT)and Soil and/or Stone Bund and Reforestation(SSB and RF).The results revealed that 22.9%of the area showed soil loss rates below the TSLL.Furthermore,varying degrees of erosion above the TSLL was observed,with sub-watershed SW-12 experiencing the highest erosion rate(47 t ha^(-1)yr^(-1))and sub-watershed SW-2 experiencing the lowest(7.8 t ha^(-1)yr^(-1)).Among the evaluated BSCPs,SSB+RF demonstrated the greatest erosion reduction effectiveness at 76.6%,followed by SSB+GT,SSB,RF,and GT,with erosion reduction effectiveness values of 61.7%,60.0%,43.3%,and 13.9%,respectively.Based on these findings,SSB+RF is recommended for erosion reduction to or below the TSLL,with imple-mentation priority given to sub-watersheds SW-12,SW-10,SW-3,SW-2,and SW-5,ranked in descending order of erosion rate severity.During implementation,emphasis should be placed on reforestation of plant species of high ecological importance.展开更多
Critical source areas （CSAs）, characterized by severe soil erosion and high sediment yield, are considered to have a high priority for conservation. How to identify CSAs and assess the effectiveness of conservation ...Critical source areas （CSAs）, characterized by severe soil erosion and high sediment yield, are considered to have a high priority for conservation. How to identify CSAs and assess the effectiveness of conservation practices is a key issue in site-specific watershed management. The Soil and Water Assessment Tool （SWAT） model is a useful tool for site-specific conservation practices design and several studies have attempted to identify CSAs based on watershed models. However, limited research has reported about the effectiveness of conservation practices targeting CSAs. The aim of this study was to assess the effectiveness of conservation pracrices targeted on CSAs using the SWAT model. CSA was firstly identified based on the 4-year average yearly erosion of each HRU. Appropriate soil conservation practices were then designed for the CSAs. A scenario with conservation practices for the whole watershed was also established as the contrasting counter parts scheme and then compared to the outcome of CSA-targeted conservation practices. The result shows that SWAT can accurately simulate sediment yield in the study area. CSAs were mainly located in slope farmland areas and steep gullies, coinciding with the distribution of land use and slope. The identified CSA covered 20% of the HRUs and contributed on average 44% of sediment yield. Conservation practices targeting CSAs had higher sediment reduction effectiveness （24 115 t km-2 y-1） than conservation practice covering the whole watershed （20 290 t km-2 y-1）. Thus conservation practices targeting CSAs are more effective than broad conservation practices. We conclude that soil conservation practices focusing on CSAs do increase sediment reduction effectiveness. Targeting the placement of soil conservation practices based on the CSAs concept will assist water quality control in watersheds.展开更多
基金Under the auspices of Foundation of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(No.10501-1210)National Natural Science Foundation of China(No.31101606)+1 种基金Basic Scientific Research Operating Expenses of Jilin University(No.200903377)National Key Projects in National Science&Technology Program during the 12th Five-Year Plan Period of China(No.2011BAD16B10-3,2012BAD04B02-3)
文摘The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.
文摘Soil erosion is a major issue in Ethiopia,prompting ongoing watershed development campaigns.This study contributes to exploring Best Soil Conservation practices(BSCPs)to reduce erosion rates to/or below Tolerable Soil Loss Limits(TSLLs).To achieve these the study used the SWAT model,coupled with the SWAT Calibration and Uncertainty Procedures(SWAT-CUP),for simulation,sensitivity analysis,calibration,and validation using streamflow and sediment yield data.The calibrated SWAT model was used to assess soil erosion hotspot areas and evaluate the effectiveness of the selected BSCPs:Soil and/or Stone Bund(SSB),Grass strip(GT),reforestation(RF),Soil and/or Stone Bund and grass strip(SSB and GT)and Soil and/or Stone Bund and Reforestation(SSB and RF).The results revealed that 22.9%of the area showed soil loss rates below the TSLL.Furthermore,varying degrees of erosion above the TSLL was observed,with sub-watershed SW-12 experiencing the highest erosion rate(47 t ha^(-1)yr^(-1))and sub-watershed SW-2 experiencing the lowest(7.8 t ha^(-1)yr^(-1)).Among the evaluated BSCPs,SSB+RF demonstrated the greatest erosion reduction effectiveness at 76.6%,followed by SSB+GT,SSB,RF,and GT,with erosion reduction effectiveness values of 61.7%,60.0%,43.3%,and 13.9%,respectively.Based on these findings,SSB+RF is recommended for erosion reduction to or below the TSLL,with imple-mentation priority given to sub-watersheds SW-12,SW-10,SW-3,SW-2,and SW-5,ranked in descending order of erosion rate severity.During implementation,emphasis should be placed on reforestation of plant species of high ecological importance.
基金the Knowledge Innovation Program,Chinese Academy of Sciences (KZCX2-YW-442)National Basic Research Program of China (2007CB407207)National Natural Science Foundation (40971236)
文摘Critical source areas （CSAs）, characterized by severe soil erosion and high sediment yield, are considered to have a high priority for conservation. How to identify CSAs and assess the effectiveness of conservation practices is a key issue in site-specific watershed management. The Soil and Water Assessment Tool （SWAT） model is a useful tool for site-specific conservation practices design and several studies have attempted to identify CSAs based on watershed models. However, limited research has reported about the effectiveness of conservation practices targeting CSAs. The aim of this study was to assess the effectiveness of conservation pracrices targeted on CSAs using the SWAT model. CSA was firstly identified based on the 4-year average yearly erosion of each HRU. Appropriate soil conservation practices were then designed for the CSAs. A scenario with conservation practices for the whole watershed was also established as the contrasting counter parts scheme and then compared to the outcome of CSA-targeted conservation practices. The result shows that SWAT can accurately simulate sediment yield in the study area. CSAs were mainly located in slope farmland areas and steep gullies, coinciding with the distribution of land use and slope. The identified CSA covered 20% of the HRUs and contributed on average 44% of sediment yield. Conservation practices targeting CSAs had higher sediment reduction effectiveness （24 115 t km-2 y-1） than conservation practice covering the whole watershed （20 290 t km-2 y-1）. Thus conservation practices targeting CSAs are more effective than broad conservation practices. We conclude that soil conservation practices focusing on CSAs do increase sediment reduction effectiveness. Targeting the placement of soil conservation practices based on the CSAs concept will assist water quality control in watersheds.
