The arid valley region in southeastern Tibet exemplifies an ecologically vulnerable area in southwestern China,where soil erosion has intensified in recent years as a consequence of socio-economic growth and infrastru...The arid valley region in southeastern Tibet exemplifies an ecologically vulnerable area in southwestern China,where soil erosion has intensified in recent years as a consequence of socio-economic growth and infrastructure construction.This study aimed to elucidate the mechanism by which freeze-thaw cycles affect soil erosion processes on the bare slopes of this alpine arid valley region under artificial distur-bances from engineering construction.Focusing on bare slopes with inclinations of 20°and 40°,we analyzed the impact of freeze-thaw cycles on flow and sand production through indoor artificial rainfall experiments.The findings indicated an approximately threefold increase in soil splattering following the freeze-thaw cycle compared to unfrozen slopes;cumulative flow production exhibited a declining trend,decreasing by 15.99%and 37.42%after the freeze-thaw cycle at slope angles of 20°and 40°,respectively;cumulative sand production increased by 2.29%and 51.24%after the freeze-thaw cycle at slope angles of 20°and 40°,respectively.On the freeze-thaw and unfrozen slopes,the sand production rates escalated swiftly following the initiation of flow production,reaching peaks of 1.34 g m^(-2)·min^(-1)and 1.52 g m^(-2)·min^(-1)in 10 min and 12 min,respectively.Post the freeze-thaw cycle,the rates stabilized,with the sand production rates on the freeze-thaw slopes exceeding those on the unfrozen slopes.These findings will serve as a significant reference for the management of bare ground surfaces and the conservation and restoration of biological environments following construction disturbances.展开更多
This research aims to improve erosion control practice in the Loess Plateau,by studying the surface erosion processes,including splash,sheet/interrill and rill erosion in four contrasting soils under high rainfall int...This research aims to improve erosion control practice in the Loess Plateau,by studying the surface erosion processes,including splash,sheet/interrill and rill erosion in four contrasting soils under high rainfall intensity(120 mm h^(−1))with three-scale indoor artificial experiments.Four contrasting soils as sandy loam,sandy clay loam,clay loam and loamy clay were collected from different parts of the Loess Plateau.The results showed that sediment load was significantly impacted by soil properties in all three sub-processes.Splash rate(4.0-21.6 g m^(−2∙)min^(−1))was highest in sandy loam from the north part of the Loess Plateau and showed a negative power relation with the mean weight diameter of aggregates after 20 min of rainfall duration.The average sediment load by sheet/interrill erosion(6.94-42.86 g m^(−2∙)min^(−1))was highest in clay loam from middle part of the Loess Plateau,and the stable sediment load after 20 min showed a positive power relation with the silt content in soil.The average sediment load increased dramatically by rill and interrill erosion(21.03-432.16 g m^(−2∙)min^(−1)),which was highest in loamy clay from south part of the Loess Plateau.The average sediment load after the occurrence of rill showed a positive power relation with clay content and a negative power relation with soil organic matter content.The impacts of slope gradient on the runoff rate and sediment load also changed with soil properties.The critical factors varied for different processes,which were the aggregate size for splash erosion,the content of silt particles and slope gradient for sheet/interrill erosion,and the content of clay particles,soil organic matter and slope gradient for rill erosion.Based on the results of the experiments,specific erosion control practices were proposed by targeting certain erosion processes in areas with different soil texture and different distribution of slope gradient.The findings from this study should support the improvement of erosion prediction and cropland management in different regions of the Loess Plateau.展开更多
The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the cou...The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the coupling effects of surface-subsurface runoff on soil erosion are still unclear.Thus,a set of laboratory experiments were conducted to reveal impacts of tillage layer depth(10,20 and 30 cm)on surface-subsurface runoff relationships,eroded sediment processes,and soil erosion pattern evolution under the long-duration(180 min)rainfall simulation tests.A deeper TLD mitigated soil erosion.When the TLD increased from 10 to 30 cm,the average surface runoff decreased by 13%,subsurface runoff increased by 5%,and soil loss rate decreased by 19 g m^(-2)min^(-1).The interaction between surface runoff and subsurface runoff,influenced by the tillage layer depth,significantly impacts soil erosion.Both surface runoff and subsurface runoff promoted soil erosion at shallow tillage layer depths(10 and 20 cm).Conversely,at TLD 30,the diversion effect of subsurface runoff on surface runoff was enhanced,which played a role in alleviating soil erosion.With the increase of TLD,the soil erosion pattern changed from rill erosion to sheet or splash erosion.During the interill erosion stage,soil loss primarily occurred in the early stage,wherein the Variation Ratio(VR)of soil loss rate and surface runoff coefficient ranged from 2.16 to 4.99.At the rill erosion stage,the VR was approximately 1.0,and the soil loss rate was 2.7-to 6.3-fold greater than that in the interrill erosion stage.These results increase understanding of the effects of TLD on the coupling relationship of surface-subsurface runoff,which is of great significance for allevi-ating slope farmland erosion.展开更多
Dendrogeomorphological method was used to study soil erosion in two typical karst sites （Puding and Zhengfeng） in Guizhou Province, China. Eleven pairs of exposed and unexposed tree roots were measured in the field ...Dendrogeomorphological method was used to study soil erosion in two typical karst sites （Puding and Zhengfeng） in Guizhou Province, China. Eleven pairs of exposed and unexposed tree roots were measured in the field and sampled for anatomical characteristics. The results showed that the exposed roots recorded karst soil erosion. Significant changes were shown in the anatomical characteristics of the exposed tree roots when soil erosion occurred, such as suddenly narrower tree rings, smaller cells, and fewer earlywood cells. Meanwhile, the fabre lumen and vessel lumen areas markedly declined to the range of 39.20% to 70.66%, which only slightly implies soil erosion. The accurate time period during which soil erosion occurred was identified and combined with the age of the tree roots. Dynamics of soil erosion were calculated and soil erosion recorded by the exposed roots from 2002 to 2007 at an average rate of 0.484 t y^-1 at Puding, and from 2005 to 2007 at an average rate of 0.051 t y^-1 at Zhenfeng. Karst soil erosion was recorded by not only one species but by multi species of broadleaf tree roots, which can significantly enhance the study of karst soil erosion through the use of Dendrogeomorphological method. The quantity of eroded soil was found to be extremely large when records from the exposed tree roots were compared with estimates from site measurements of runoff. The major type of karst soil erosion was underground soil loss and this comprised approximately 2/3 of total erosion.展开更多
基金supported by the National Natural Science Foundation of China(No.42371291 and No.41901234)the National Key R&D Program of China(2023YFF1304204)+3 种基金the National key research and development program(No.2019YFE0116500)the Geological Survey Project of China Geological Survey“Remote Sensing Monitoring and Evaluation of Human Activities in National Nature Reserves”(No.DD20230488)the National Forestry and Grassland Administration“Remote Sensing Monitoring Project For Human Activities in Terrestrial Nature Reserves”(300012000000244068)Data supports from projects of the National Natural Science Foundation of China(No.71225005)and the Exploratory Forefront Project for the Strategic Science Plan in IGSNRR,CAS are also appreciated.
文摘The arid valley region in southeastern Tibet exemplifies an ecologically vulnerable area in southwestern China,where soil erosion has intensified in recent years as a consequence of socio-economic growth and infrastructure construction.This study aimed to elucidate the mechanism by which freeze-thaw cycles affect soil erosion processes on the bare slopes of this alpine arid valley region under artificial distur-bances from engineering construction.Focusing on bare slopes with inclinations of 20°and 40°,we analyzed the impact of freeze-thaw cycles on flow and sand production through indoor artificial rainfall experiments.The findings indicated an approximately threefold increase in soil splattering following the freeze-thaw cycle compared to unfrozen slopes;cumulative flow production exhibited a declining trend,decreasing by 15.99%and 37.42%after the freeze-thaw cycle at slope angles of 20°and 40°,respectively;cumulative sand production increased by 2.29%and 51.24%after the freeze-thaw cycle at slope angles of 20°and 40°,respectively.On the freeze-thaw and unfrozen slopes,the sand production rates escalated swiftly following the initiation of flow production,reaching peaks of 1.34 g m^(-2)·min^(-1)and 1.52 g m^(-2)·min^(-1)in 10 min and 12 min,respectively.Post the freeze-thaw cycle,the rates stabilized,with the sand production rates on the freeze-thaw slopes exceeding those on the unfrozen slopes.These findings will serve as a significant reference for the management of bare ground surfaces and the conservation and restoration of biological environments following construction disturbances.
基金Financial support was provided by the National Natural Science Foundation of China(Grant No.41977069,41771314).
文摘This research aims to improve erosion control practice in the Loess Plateau,by studying the surface erosion processes,including splash,sheet/interrill and rill erosion in four contrasting soils under high rainfall intensity(120 mm h^(−1))with three-scale indoor artificial experiments.Four contrasting soils as sandy loam,sandy clay loam,clay loam and loamy clay were collected from different parts of the Loess Plateau.The results showed that sediment load was significantly impacted by soil properties in all three sub-processes.Splash rate(4.0-21.6 g m^(−2∙)min^(−1))was highest in sandy loam from the north part of the Loess Plateau and showed a negative power relation with the mean weight diameter of aggregates after 20 min of rainfall duration.The average sediment load by sheet/interrill erosion(6.94-42.86 g m^(−2∙)min^(−1))was highest in clay loam from middle part of the Loess Plateau,and the stable sediment load after 20 min showed a positive power relation with the silt content in soil.The average sediment load increased dramatically by rill and interrill erosion(21.03-432.16 g m^(−2∙)min^(−1)),which was highest in loamy clay from south part of the Loess Plateau.The average sediment load after the occurrence of rill showed a positive power relation with clay content and a negative power relation with soil organic matter content.The impacts of slope gradient on the runoff rate and sediment load also changed with soil properties.The critical factors varied for different processes,which were the aggregate size for splash erosion,the content of silt particles and slope gradient for sheet/interrill erosion,and the content of clay particles,soil organic matter and slope gradient for rill erosion.Based on the results of the experiments,specific erosion control practices were proposed by targeting certain erosion processes in areas with different soil texture and different distribution of slope gradient.The findings from this study should support the improvement of erosion prediction and cropland management in different regions of the Loess Plateau.
基金supported by the National Natural Science Foundation of China(42377336 and U22A20611)Jiangxi Water Conservancy Science and Technology Major Project(202426ZDKT06)Hunan Students innovation and entrepreneurship training program(S202310542106).
文摘The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the coupling effects of surface-subsurface runoff on soil erosion are still unclear.Thus,a set of laboratory experiments were conducted to reveal impacts of tillage layer depth(10,20 and 30 cm)on surface-subsurface runoff relationships,eroded sediment processes,and soil erosion pattern evolution under the long-duration(180 min)rainfall simulation tests.A deeper TLD mitigated soil erosion.When the TLD increased from 10 to 30 cm,the average surface runoff decreased by 13%,subsurface runoff increased by 5%,and soil loss rate decreased by 19 g m^(-2)min^(-1).The interaction between surface runoff and subsurface runoff,influenced by the tillage layer depth,significantly impacts soil erosion.Both surface runoff and subsurface runoff promoted soil erosion at shallow tillage layer depths(10 and 20 cm).Conversely,at TLD 30,the diversion effect of subsurface runoff on surface runoff was enhanced,which played a role in alleviating soil erosion.With the increase of TLD,the soil erosion pattern changed from rill erosion to sheet or splash erosion.During the interill erosion stage,soil loss primarily occurred in the early stage,wherein the Variation Ratio(VR)of soil loss rate and surface runoff coefficient ranged from 2.16 to 4.99.At the rill erosion stage,the VR was approximately 1.0,and the soil loss rate was 2.7-to 6.3-fold greater than that in the interrill erosion stage.These results increase understanding of the effects of TLD on the coupling relationship of surface-subsurface runoff,which is of great significance for allevi-ating slope farmland erosion.
基金the National Key Basic Research Development Program(2013CB956702)Great Basic Research Fund of the Chinese Academy of Sciences(XDA05070405)+2 种基金the International Scientific Project of Guizhou(QKHWGZ-2010-7009)Great Basic Research Fund of Guizhou Province(QKH-JZ-2014-200203)100 High Level Innovating Project(QKHRC-2015-4022)
文摘Dendrogeomorphological method was used to study soil erosion in two typical karst sites （Puding and Zhengfeng） in Guizhou Province, China. Eleven pairs of exposed and unexposed tree roots were measured in the field and sampled for anatomical characteristics. The results showed that the exposed roots recorded karst soil erosion. Significant changes were shown in the anatomical characteristics of the exposed tree roots when soil erosion occurred, such as suddenly narrower tree rings, smaller cells, and fewer earlywood cells. Meanwhile, the fabre lumen and vessel lumen areas markedly declined to the range of 39.20% to 70.66%, which only slightly implies soil erosion. The accurate time period during which soil erosion occurred was identified and combined with the age of the tree roots. Dynamics of soil erosion were calculated and soil erosion recorded by the exposed roots from 2002 to 2007 at an average rate of 0.484 t y^-1 at Puding, and from 2005 to 2007 at an average rate of 0.051 t y^-1 at Zhenfeng. Karst soil erosion was recorded by not only one species but by multi species of broadleaf tree roots, which can significantly enhance the study of karst soil erosion through the use of Dendrogeomorphological method. The quantity of eroded soil was found to be extremely large when records from the exposed tree roots were compared with estimates from site measurements of runoff. The major type of karst soil erosion was underground soil loss and this comprised approximately 2/3 of total erosion.
