The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during Nov...The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.展开更多
Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studie...Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.展开更多
Land use patterns(LUPs)are the form in which various land use types are combined spatially,evidently impacting soil water.However,the influence mechanism by which LUPs form remains unclear.In this study,the soil water...Land use patterns(LUPs)are the form in which various land use types are combined spatially,evidently impacting soil water.However,the influence mechanism by which LUPs form remains unclear.In this study,the soil water content(SWC)in the 0–160-cm soil depth was observed in shrubland(SL),mature forestland(MF),grassland(GL)and young forestland(YF)sites on four slopes with different LUPs in the Yangjuangou catchment of the Chinese Loess Plateau.The SWC in SL-YF-SL(13.28%)was significantly greater than that in YF-MF(9.93%),MF-GL-YF(10.38%)and SL-MF(10.83%)and was temporally stable during the study period.The spatial distribution of SWC along the slope differed among the four LUPs.Vegetation characteristics and soil texture mainly determined the spatial variations in SWC in the shallow soil layers(0–40 cm),while topographic factors were the determinants in the deep soil layers(60–160 cm)as well as in the entire soil profile(0–160 cm).The significance of SWC differences among the various land use patterns increased with decreasing precipitation during the growing seasons.YF-MF(77.8 mm)and SL-YF-GL(73.9 mm)required more rainwater than SL-MF(68.2 mm)and MF-GL-MF(67.5 mm)to compensate for the loss of soil water on the monthly scale during the rainy season.Therefore,vegetation restoration should consider land use patterns on hillslopes for soil water conservation.展开更多
The Soil and Water Assessment Tool(SWAT)is widely used to relate farm management practices to their impacts on surface waters at the watershed scale,yet its smallest spatial unit is not generally defined by physically...The Soil and Water Assessment Tool(SWAT)is widely used to relate farm management practices to their impacts on surface waters at the watershed scale,yet its smallest spatial unit is not generally defined by physically meaningful boundaries.The hydrologic response unit(HRU)is the smallest spatial unit of the model,and the standard HRU definition approach lumps all similar land uses,soils,and slopes within a subbasin based upon user-defined thresholds.This standard method provides an efficient way to discretize large watersheds where simulation at the field scale may not be computationally feasible.In relatively smaller watersheds,however,defining HRUs to specific spatial locations bounded by property lines or field borders would often be advantageous,yet this is not currently possible within the ArcSWAT interface.In this study,a simple approach is demonstrated that defines HRUs by field boundaries through addition of uniquely named soils to the SWAT user soil database and creation of a field boundary layer with majority land use and soil attributes.Predictions of nitrogen,phosphorus,and sediment losses were compared in a case study watershed where SWAT was set up using both the standard HRU definition and field boundary approach.Watershed-scale results were reasonable and similar for both methods,but aggregating fields by majority soil type masked extremely high soil erosion predicted for a few soils.Results from field-based HRU delineation may be quite different from the standard approach due to choosing a majority soil type in each farm field.This approach is flexible such that any land use and soil data prepared for SWAT can be used and any shapefile boundary can divide HRUs.展开更多
总结国内外土壤水盐运移研究领域的主要研究内容,并探索其发展前景。基于CNKI与WOS核心数据库,统计2000-2020年中关于土壤水盐运移的文献,利用VOSviewer可视化分析软件并结合CNKI和WOS中可视化分析功能,对国内外近21 a土壤水盐运移领域...总结国内外土壤水盐运移研究领域的主要研究内容,并探索其发展前景。基于CNKI与WOS核心数据库,统计2000-2020年中关于土壤水盐运移的文献,利用VOSviewer可视化分析软件并结合CNKI和WOS中可视化分析功能,对国内外近21 a土壤水盐运移领域文献的发文量、关键词共现、作者合作等进行可视化分析。结果表明:2000-2020年,在土壤水盐运移领域的发文量总体呈攀升态势;该领域核心期刊刊出论文较多的主要期刊有《AGRICULTURAL WATER MANAGEMENT》、《灌溉排水学报》、《节水灌溉》等;该领域的发文国家数量较多,主要活跃在滴灌、微咸水灌溉、冻融等条件下的实验研究和数值模型的模拟,我国在该领域的高影响力发文机构也位于世界前列;未来关于土壤水盐运移的研究将主要集中在土壤结构、种植耕作与管理方式、模型预测、滨海盐碱地、耐盐性植被的盐分适应性等几个方面。近年来土壤水盐运移规律的研究将是治理土壤盐渍化的重要理论依据,不同耦合条件下的土壤水盐运移规律研究及模拟预测对于我国土壤盐渍化治理具有重要意义。展开更多
文摘The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.
基金funded by the Knowledge Innovation Program of Chinese Academy of Sciences(KZCX2-SW-415,KZCX3-SW-426).
文摘Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.
基金National Key Research and Development Program of China,No.2017YFC0504701,No.2016YFC0501602Natural Science Basic Research Plan in Shaanxi Province of China,No.2019JQ-767Doctoral Foundation of Tianjin Normal University,No.52XB1910。
文摘Land use patterns(LUPs)are the form in which various land use types are combined spatially,evidently impacting soil water.However,the influence mechanism by which LUPs form remains unclear.In this study,the soil water content(SWC)in the 0–160-cm soil depth was observed in shrubland(SL),mature forestland(MF),grassland(GL)and young forestland(YF)sites on four slopes with different LUPs in the Yangjuangou catchment of the Chinese Loess Plateau.The SWC in SL-YF-SL(13.28%)was significantly greater than that in YF-MF(9.93%),MF-GL-YF(10.38%)and SL-MF(10.83%)and was temporally stable during the study period.The spatial distribution of SWC along the slope differed among the four LUPs.Vegetation characteristics and soil texture mainly determined the spatial variations in SWC in the shallow soil layers(0–40 cm),while topographic factors were the determinants in the deep soil layers(60–160 cm)as well as in the entire soil profile(0–160 cm).The significance of SWC differences among the various land use patterns increased with decreasing precipitation during the growing seasons.YF-MF(77.8 mm)and SL-YF-GL(73.9 mm)required more rainwater than SL-MF(68.2 mm)and MF-GL-MF(67.5 mm)to compensate for the loss of soil water on the monthly scale during the rainy season.Therefore,vegetation restoration should consider land use patterns on hillslopes for soil water conservation.
基金Primary funding for this work came from a USDA NRCS Conservation Innovation GrantThis work was also partially funded by the University of Michigan Graham Sustainability Instituteby the Great Lakes Restoration Initiative(administered by USEPA)through a NOAA-GLERL SOAR project.
文摘The Soil and Water Assessment Tool(SWAT)is widely used to relate farm management practices to their impacts on surface waters at the watershed scale,yet its smallest spatial unit is not generally defined by physically meaningful boundaries.The hydrologic response unit(HRU)is the smallest spatial unit of the model,and the standard HRU definition approach lumps all similar land uses,soils,and slopes within a subbasin based upon user-defined thresholds.This standard method provides an efficient way to discretize large watersheds where simulation at the field scale may not be computationally feasible.In relatively smaller watersheds,however,defining HRUs to specific spatial locations bounded by property lines or field borders would often be advantageous,yet this is not currently possible within the ArcSWAT interface.In this study,a simple approach is demonstrated that defines HRUs by field boundaries through addition of uniquely named soils to the SWAT user soil database and creation of a field boundary layer with majority land use and soil attributes.Predictions of nitrogen,phosphorus,and sediment losses were compared in a case study watershed where SWAT was set up using both the standard HRU definition and field boundary approach.Watershed-scale results were reasonable and similar for both methods,but aggregating fields by majority soil type masked extremely high soil erosion predicted for a few soils.Results from field-based HRU delineation may be quite different from the standard approach due to choosing a majority soil type in each farm field.This approach is flexible such that any land use and soil data prepared for SWAT can be used and any shapefile boundary can divide HRUs.
文摘总结国内外土壤水盐运移研究领域的主要研究内容,并探索其发展前景。基于CNKI与WOS核心数据库,统计2000-2020年中关于土壤水盐运移的文献,利用VOSviewer可视化分析软件并结合CNKI和WOS中可视化分析功能,对国内外近21 a土壤水盐运移领域文献的发文量、关键词共现、作者合作等进行可视化分析。结果表明:2000-2020年,在土壤水盐运移领域的发文量总体呈攀升态势;该领域核心期刊刊出论文较多的主要期刊有《AGRICULTURAL WATER MANAGEMENT》、《灌溉排水学报》、《节水灌溉》等;该领域的发文国家数量较多,主要活跃在滴灌、微咸水灌溉、冻融等条件下的实验研究和数值模型的模拟,我国在该领域的高影响力发文机构也位于世界前列;未来关于土壤水盐运移的研究将主要集中在土壤结构、种植耕作与管理方式、模型预测、滨海盐碱地、耐盐性植被的盐分适应性等几个方面。近年来土壤水盐运移规律的研究将是治理土壤盐渍化的重要理论依据,不同耦合条件下的土壤水盐运移规律研究及模拟预测对于我国土壤盐渍化治理具有重要意义。
