The Grain for Green Project(GGP) is an important measure for the prevention of sloping farmland and the restoration of natural vegetation.This project has been critical to the restoration of ecological environments in...The Grain for Green Project(GGP) is an important measure for the prevention of sloping farmland and the restoration of natural vegetation.This project has been critical to the restoration of ecological environments in western China. However,the effect of the GGP on freshwater ecosystem services under extreme climates remains unclear. Thus, taking the middle and upper reaches of the Wujiang River Basin in western China as an example, this study assessed the variation of three freshwater ecosystem services(e.g., water yield, soil retention and nutrient retention) impacted by the GGP under drought stress by employing the Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST) model. In addition,the trade-off/synergistic relationship between three freshwater ecosystem services was analyzed based on the Pearson correlation coefficient. As revealed from the results, the effect of the GGP on the water yield and nutrient retention under drought stress was significantly higher than that on the soil retention.With the increase in the drought degree, the variation rate of the water yield and nutrient retention impacted by the GGP increased, whereas that of the soil retention decreased. The GGP in droughts of different seasons resulted in a significant heterogeneity in the changes of three freshwater ecosystem services. The correlation coefficients between the water yield and soil retention as well as that between the water yield and the nutrient retention increased, and the correlation coefficients declined between soil and nutrient retention under different drought degrees following the GGP. Unlike for the summer drought case, there were no significant changes in the correlation coefficients between three freshwater ecosystem services in spring, autumn and winter droughts. The results suggest that the amount of farmland converted to shrubland should be regulated to reduce the trade-off intensity between freshwater ecosystem services. In addition, food security and ecological environment protection should be balanced during the implementation of the GGP, and the most concentrated distribution region of farmland-to-forest conversion will be the key area of ecological management in the future.展开更多
Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program(GGP), which was launched in 1999, aims to reduce soil...Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program(GGP), which was launched in 1999, aims to reduce soil and water loss and alleviate the ecological environment problem in western China. Two typical counties in western China, the Zhongxian(in Chongqing Municipality) and Ansai(in Shaanxi Province) were chosen to evaluate the dynamic changes of land use and agricultural production structure before and after the implementation of the Program in this paper. The results showed that the cultivated land area was reduced by 7.08% from 1989 to 2003. The cultivated land per person was decreased by 8.42% during 1999-2003. Moreover, the stability index of the secondary sector of the economy was increased from 0.91 in the period 1990-1999 to 0.94 in the following ten years. In addition, the stability index of tertiary economic sector increased from 0.88 to 0.92 in Zhongxian county. Meanwhile, the cultivated land area was reduced by 15.48% from 1990 to 1999. The soil erosion modulus was decreased by 33.33% from 1999 to 2006. Also, the stability index of secondary and tertiary economic sectors was 0.86 in the period 1998-2002. However, it decreased by 77% during 2002 to 2007 in Ansai County. These results imply that the Grain for Green Program had different impact on the two regions. Several effective strategies of soil and water conservation have been carried out to ameliorate the sustainable development of ecological environment and economy in these two counties of western China.展开更多
基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、...基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、恢复时间和气候等数据735条,旨在探究我国退耕还草工程对土壤有机碳含量的影响及其主导因素。结果表明:1)农田恢复为草地后,土壤有机碳含量呈先下降后上升趋势(时间拐点约为第6年),整体上退耕还草工程使土壤有机碳含量提高了19.8%。2)土壤有机碳的正响应随土壤深度增加而减弱,且深度超过1 m时其正响应不明显。3)土壤有效氮是影响土壤有机碳恢复的主要因素,而土壤有效磷和植物功能群对其影响不大。4)沿着增加的水分梯度,土壤有机碳的恢复效果由负变正,转变阈值为25.15 (干旱指数)。总体而言,我国退耕还草工程对土壤有机碳含量的影响为正效应,此效应受环境梯度和恢复时间的共同影响。本研究能够为我国土地利用变化背景下土壤碳库管理的相关决策提供科学依据。展开更多
Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and...Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.展开更多
实施退耕还林,是控制中国水土流失、改善生态环境的有效途径。如何制定最具成本-效益的退耕还林方案,以平衡生态、经济和粮食安全之间的矛盾,是保证退耕还林工程可持续发展的关键。该研究以淮河上游的息县流域为研究区,在土地利用现状...实施退耕还林,是控制中国水土流失、改善生态环境的有效途径。如何制定最具成本-效益的退耕还林方案,以平衡生态、经济和粮食安全之间的矛盾,是保证退耕还林工程可持续发展的关键。该研究以淮河上游的息县流域为研究区,在土地利用现状的基础上,一方面通过建立分布式水文模型SWAT(soil and water assessment tool)依次模拟各子流域的退耕还林操作得到泥沙削减系数,另一方面通过GDP(gross domestic product)与土地利用现状的空间叠置分析得到各子流域进行退耕还林的GDP损失系数,据此分别构成退耕还林的减沙效益目标和经济效益目标,采用多目标遗传算法NSGA-II优化求解子流域尺度的退耕还林方案。研究结果表明:1)建立的SWAT模型对研究区径流和泥沙的模拟精度较高,Nash系数分别在0.90和0.70以上,决定系数均大于0.80,且百分比偏差均控制在-20%~20%以内,可认为SWAT模型能够用于评估退耕还林的泥沙削减效果;2)子流域泥沙削减系数范围为26.70~2675.85 t/km^(2),并表现出从上游到下游逐渐减小的趋势,说明在流域上游的河源区实施单位面积的退耕还林能够取得更好的泥沙控制效果;3)子流域GDP损失系数在空间上呈现出较大的差异性,既有子流域出现了GDP的增加也有子流域出现了GDP的减小,对比发现在行政市或县主要居民点所在的子流域进行退耕还林需要付出更大的经济代价;4)多目标优化求解得到的退耕还林方案集将人均耕地面积维持在1.04×10^(−3)~1.54×10^(−3) km^(2),明显高于粮食安全的警戒水平,同时该方案集能够在仅损失30.13%~37.67%经济产值的同时将泥沙产量削减53.54%~69.86%,并达到区域可持续发展的土壤侵蚀水平。该研究提出的基于生态减沙效益和经济效益的子流域尺度退耕还林优化方法可为流域水土保持、退耕还林工程的科学规划提供借鉴和指导。展开更多
基金supported by the Science and Technology Foundation of Guizhou Province (No. [2020]1Y152)the Guizhou Education Department Project (No. KY[2021]075)。
文摘The Grain for Green Project(GGP) is an important measure for the prevention of sloping farmland and the restoration of natural vegetation.This project has been critical to the restoration of ecological environments in western China. However,the effect of the GGP on freshwater ecosystem services under extreme climates remains unclear. Thus, taking the middle and upper reaches of the Wujiang River Basin in western China as an example, this study assessed the variation of three freshwater ecosystem services(e.g., water yield, soil retention and nutrient retention) impacted by the GGP under drought stress by employing the Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST) model. In addition,the trade-off/synergistic relationship between three freshwater ecosystem services was analyzed based on the Pearson correlation coefficient. As revealed from the results, the effect of the GGP on the water yield and nutrient retention under drought stress was significantly higher than that on the soil retention.With the increase in the drought degree, the variation rate of the water yield and nutrient retention impacted by the GGP increased, whereas that of the soil retention decreased. The GGP in droughts of different seasons resulted in a significant heterogeneity in the changes of three freshwater ecosystem services. The correlation coefficients between the water yield and soil retention as well as that between the water yield and the nutrient retention increased, and the correlation coefficients declined between soil and nutrient retention under different drought degrees following the GGP. Unlike for the summer drought case, there were no significant changes in the correlation coefficients between three freshwater ecosystem services in spring, autumn and winter droughts. The results suggest that the amount of farmland converted to shrubland should be regulated to reduce the trade-off intensity between freshwater ecosystem services. In addition, food security and ecological environment protection should be balanced during the implementation of the GGP, and the most concentrated distribution region of farmland-to-forest conversion will be the key area of ecological management in the future.
基金the Foundation of National Key Science and Technology Program (2011BAD31B03)the National Natural Science Foundation of China (41001163)+1 种基金Western Light Western Doctor of CAS, the international cooperation program of Sichuan province (2013HH0016)CAS West Action: Experimental and Demonstrational study on soil and water losses and non-point pollution in the Three Gorges (KZCX2-XB3-09)
文摘Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program(GGP), which was launched in 1999, aims to reduce soil and water loss and alleviate the ecological environment problem in western China. Two typical counties in western China, the Zhongxian(in Chongqing Municipality) and Ansai(in Shaanxi Province) were chosen to evaluate the dynamic changes of land use and agricultural production structure before and after the implementation of the Program in this paper. The results showed that the cultivated land area was reduced by 7.08% from 1989 to 2003. The cultivated land per person was decreased by 8.42% during 1999-2003. Moreover, the stability index of the secondary sector of the economy was increased from 0.91 in the period 1990-1999 to 0.94 in the following ten years. In addition, the stability index of tertiary economic sector increased from 0.88 to 0.92 in Zhongxian county. Meanwhile, the cultivated land area was reduced by 15.48% from 1990 to 1999. The soil erosion modulus was decreased by 33.33% from 1999 to 2006. Also, the stability index of secondary and tertiary economic sectors was 0.86 in the period 1998-2002. However, it decreased by 77% during 2002 to 2007 in Ansai County. These results imply that the Grain for Green Program had different impact on the two regions. Several effective strategies of soil and water conservation have been carried out to ameliorate the sustainable development of ecological environment and economy in these two counties of western China.
基金partly funded by the National Key Research and Development Program of China(NK2023190801)the National Foreign Experts Program of China(G2023041024L)the Key Scientific Research Program of Shaanxi Provincial Education Department,China(21JT028)。
文摘Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB.
文摘实施退耕还林,是控制中国水土流失、改善生态环境的有效途径。如何制定最具成本-效益的退耕还林方案,以平衡生态、经济和粮食安全之间的矛盾,是保证退耕还林工程可持续发展的关键。该研究以淮河上游的息县流域为研究区,在土地利用现状的基础上,一方面通过建立分布式水文模型SWAT(soil and water assessment tool)依次模拟各子流域的退耕还林操作得到泥沙削减系数,另一方面通过GDP(gross domestic product)与土地利用现状的空间叠置分析得到各子流域进行退耕还林的GDP损失系数,据此分别构成退耕还林的减沙效益目标和经济效益目标,采用多目标遗传算法NSGA-II优化求解子流域尺度的退耕还林方案。研究结果表明:1)建立的SWAT模型对研究区径流和泥沙的模拟精度较高,Nash系数分别在0.90和0.70以上,决定系数均大于0.80,且百分比偏差均控制在-20%~20%以内,可认为SWAT模型能够用于评估退耕还林的泥沙削减效果;2)子流域泥沙削减系数范围为26.70~2675.85 t/km^(2),并表现出从上游到下游逐渐减小的趋势,说明在流域上游的河源区实施单位面积的退耕还林能够取得更好的泥沙控制效果;3)子流域GDP损失系数在空间上呈现出较大的差异性,既有子流域出现了GDP的增加也有子流域出现了GDP的减小,对比发现在行政市或县主要居民点所在的子流域进行退耕还林需要付出更大的经济代价;4)多目标优化求解得到的退耕还林方案集将人均耕地面积维持在1.04×10^(−3)~1.54×10^(−3) km^(2),明显高于粮食安全的警戒水平,同时该方案集能够在仅损失30.13%~37.67%经济产值的同时将泥沙产量削减53.54%~69.86%,并达到区域可持续发展的土壤侵蚀水平。该研究提出的基于生态减沙效益和经济效益的子流域尺度退耕还林优化方法可为流域水土保持、退耕还林工程的科学规划提供借鉴和指导。
