In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information syst...In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information system(GIS),multi-temporal digital elevation models(DEM) were constructed from the data collected by GPS and used for further analysis.Based on the analysis of multi-temporal DEM,we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed.The results are:(1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m,gully area extended 170-400 m2,net gully eroded volume 220-320 m3,and gully erosion modulus 2200-4800 t?km?2?a?1.(2) Compared with the mature gully the initial gully grows rapidly,and its erosion parameters are relatively large.The erosion parameters have not only to do with flow energy,but also with the growth phase.(3) There are significant seasonal differences in gully erosion parameters.The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season.(4) It is remarkable for freeze-thaw erosion in the black soil area of NE China.The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004,and the distance of gully head retreated maximally 6.4 m.(5) Due to freeze-thaw action and snowmelt,gully is primarily in the interior adjustment process in winter and early spring.There are much more depositions compared with that during rainy season,which can almost happen throughout the gully,while erosion mostly occurs near head,esp.for gullies having a relatively long history of development.On the other hand,the process of energy exchange with exterior dominates in rainy season.It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.展开更多
In order to evaluate the soil erosion rate for different land uses and make recommendations on land-use alternatives for erosion control in hilly and mountain areas on a Purplish soil (Regosols in FAO taxonomy), exper...In order to evaluate the soil erosion rate for different land uses and make recommendations on land-use alternatives for erosion control in hilly and mountain areas on a Purplish soil (Regosols in FAO taxonomy), experimental data were obtained from three continuously monitored sites located at Yanting, Nanbu and Pengxi of Sichuan province. The data showed that the rank of erosion rate is farmland > unfenced grassland > fenced grassland > forestland. The erosion rate of farmland was more than 3 times higher than that of forestland and fenced grassland, indicating that restricting human activity is crucial for over-erosion. The erodibility was higher at the initial period of rainy season for all the three types of land use. The erosion rates of fenced grassland and mature afforestation land were not proportional to rainfall intensity because these land uses changed impact energy of the rainfall. This research showed that restricting human activity, intensifying the management of initial period of rainy season, and increasing the cover rate of land surface are the three major measures for soil erosion prevention. It is recommended that farmers should cease cultivation on farmland at the top of hills and steep slope land return those lands back to grassland or forestland.展开更多
1. General Situation of Soil Erosion The loessial hilly area of southern Ningxia, Situated at the south of Ningxia Hui Au-tonomous Region, middle-upper reaches of the Yellow River, part of Chinese Loess Pla-teau, cove...1. General Situation of Soil Erosion The loessial hilly area of southern Ningxia, Situated at the south of Ningxia Hui Au-tonomous Region, middle-upper reaches of the Yellow River, part of Chinese Loess Pla-teau, covers an area of 1500 square kilometers with an annual mean temperature of 5-8℃,a precipitation of 300-500mm of which 70% taking place concentratively during the peri-od between June and September in form of rainstorm, The annual evaporation展开更多
The investigation was conducted on the spatial and temporal distributions of soil organic mater （SOM） in the mixed plantations of alder （Aluns crernastogyne） and cypress （Cupressus funebris ） （MPAC）, which dis...The investigation was conducted on the spatial and temporal distributions of soil organic mater （SOM） in the mixed plantations of alder （Aluns crernastogyne） and cypress （Cupressus funebris ） （MPAC）, which distributed in the hilly areas of central Sichuan Basin （HACSB）. The results show that： （1） the spatial distribution of SOM among different sites at the same age are not significant before 15-year-old, but significant at 20-year-old, and not significant again after 25-year-old; （2） the SOM contents in 0-15 cm and 15-30 cm layers increase sharply from 10- to 15-year-old, and decline gradually from 15- to 30- year-old; the SOM contents of the 30-year-old PCP were 80. 38% and 78.42% higher than that of the 10-year-old, but 29.16% and 53.37% lower than that of 15-year-old in the 0-15 cm and 15-30 cm layers, respectively. The decrease of SOM contents would lead to the degradation of soil fertility and the decline of forest productivity.展开更多
The irrational land use is one of the main reasons for the soil erosion and nutrient loss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in ...The irrational land use is one of the main reasons for the soil erosion and nutrient loss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in the loess hill slope are selected to study the effect of land use structure on the distribution of soil nutrients. From hill bottom to hill top, the patterns of land use types are:, grassland-slope farmland-forest, slope farmland-grassland-forest, terrace-grassland-forest and slope farmland-forest-grassland. By measuring the contents of the total N, total P, available N, available P and organic matter of soils, the results show that the land use structure types of slope farmland-grassland-forest and terrace-grassland-forest have a better capacity to maintain the soil nutrients.展开更多
Soil quality assessment is valuable for agricultural production. In this research, 155 soil samples at two soil depths were collected from four land use types in an agricultural area of the A Luoi district in the Cent...Soil quality assessment is valuable for agricultural production. In this research, 155 soil samples at two soil depths were collected from four land use types in an agricultural area of the A Luoi district in the Central Vietnam. Differences of soil organic carbon, total nitrogen in soil and soil pH under different land use types and topographic aspects were compared. Soil organic carbon contents in arable land and plantation forest are higher than those in natural forest and grassland (p < 0.05). Conversely, the total nitrogen in natural forest was significantly lesser in comparison to other land use types. Meanwhile there were no significant differences of the total nitrogen content (p < 0.05) among arable land, plantation forest, and grassland. The soil of grassland, natural and plantation forests land use types were more significantly acidic than those of the soils of the arable land use type. Soil organic carbon and total nitrogen showed a decreasing trend while soil depth increased in all land use types. The soil pH in plantation forest and arable land use types showed no significant change in relation to soil depth. Significant differences were not found in topographic aspects and soil organic carbon content;however, the different changing trends of soil organic carbon content between land use types and aspects were found. The impact of slope, elevation, farming system or soil texture accounted for the differences in these soil indicators under different land use types in the A Luoi district.展开更多
为了更全面地评价WEPP模型在我国的适用性,该文通过建立模型数据库,利用WEPP分别模拟了坡长为10、20、30和40 m的径流量和土壤侵蚀量,并用实测径流和侵蚀资料进行对比分析。结果表明,在10、20、30和40 m 4个坡长条件下,WEPP模型对降雨...为了更全面地评价WEPP模型在我国的适用性,该文通过建立模型数据库,利用WEPP分别模拟了坡长为10、20、30和40 m的径流量和土壤侵蚀量,并用实测径流和侵蚀资料进行对比分析。结果表明,在10、20、30和40 m 4个坡长条件下,WEPP模型对降雨、每年和多年平均径流量模拟的Nash-Sutcliffe有效性(ME)分别为0.915、0.879和-0.056,对单场降雨、每年和多年平均土壤侵蚀量模拟的ME分别为0.853、0.758和-0.456,多年平均的ME为负值可能是由小样本计算造成的。WEPP模型对单场降雨和每年径流量和侵蚀量模拟效果较好。尽管WEPP模型对多年平均径流量和土壤侵蚀量模拟效果较差,但模型模拟的多年径流量和土壤侵蚀量与实测值的多年径流量和土壤侵蚀量的最大相对误差分别为7.90%和29.20%,表明WEPP模型对多年径流量和侵蚀量的模拟可满足要求。径流量模拟值随坡长增加的变化和实测值相比不够敏感;而土壤侵蚀量模拟值随坡长增加的变化和实测值相比过于敏感。展开更多
基金Key Project for National Natural Science Foundation of China,No.40235056The Ph.D. Programs Foundation of Ministry of Education of China, No.20030027015+3 种基金China Postdoctoral Science Foundation,No.20070410482Doctoral Foundation of University of Jinan,No.B0620National Natural Science Foundation of China,No.40672158Key Subject Foundation Supported by Shandong Province
文摘In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information system(GIS),multi-temporal digital elevation models(DEM) were constructed from the data collected by GPS and used for further analysis.Based on the analysis of multi-temporal DEM,we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed.The results are:(1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m,gully area extended 170-400 m2,net gully eroded volume 220-320 m3,and gully erosion modulus 2200-4800 t?km?2?a?1.(2) Compared with the mature gully the initial gully grows rapidly,and its erosion parameters are relatively large.The erosion parameters have not only to do with flow energy,but also with the growth phase.(3) There are significant seasonal differences in gully erosion parameters.The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season.(4) It is remarkable for freeze-thaw erosion in the black soil area of NE China.The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004,and the distance of gully head retreated maximally 6.4 m.(5) Due to freeze-thaw action and snowmelt,gully is primarily in the interior adjustment process in winter and early spring.There are much more depositions compared with that during rainy season,which can almost happen throughout the gully,while erosion mostly occurs near head,esp.for gullies having a relatively long history of development.On the other hand,the process of energy exchange with exterior dominates in rainy season.It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.
基金supported by project of national tackle key problem“Integrated techniques and implement practices of countermeasures for soil and water losses in hilly area of Sichuan Basin”“National Nature Science Youth Foundation(NO.40201029).
文摘In order to evaluate the soil erosion rate for different land uses and make recommendations on land-use alternatives for erosion control in hilly and mountain areas on a Purplish soil (Regosols in FAO taxonomy), experimental data were obtained from three continuously monitored sites located at Yanting, Nanbu and Pengxi of Sichuan province. The data showed that the rank of erosion rate is farmland > unfenced grassland > fenced grassland > forestland. The erosion rate of farmland was more than 3 times higher than that of forestland and fenced grassland, indicating that restricting human activity is crucial for over-erosion. The erodibility was higher at the initial period of rainy season for all the three types of land use. The erosion rates of fenced grassland and mature afforestation land were not proportional to rainfall intensity because these land uses changed impact energy of the rainfall. This research showed that restricting human activity, intensifying the management of initial period of rainy season, and increasing the cover rate of land surface are the three major measures for soil erosion prevention. It is recommended that farmers should cease cultivation on farmland at the top of hills and steep slope land return those lands back to grassland or forestland.
文摘1. General Situation of Soil Erosion The loessial hilly area of southern Ningxia, Situated at the south of Ningxia Hui Au-tonomous Region, middle-upper reaches of the Yellow River, part of Chinese Loess Pla-teau, covers an area of 1500 square kilometers with an annual mean temperature of 5-8℃,a precipitation of 300-500mm of which 70% taking place concentratively during the peri-od between June and September in form of rainstorm, The annual evaporation
文摘The investigation was conducted on the spatial and temporal distributions of soil organic mater （SOM） in the mixed plantations of alder （Aluns crernastogyne） and cypress （Cupressus funebris ） （MPAC）, which distributed in the hilly areas of central Sichuan Basin （HACSB）. The results show that： （1） the spatial distribution of SOM among different sites at the same age are not significant before 15-year-old, but significant at 20-year-old, and not significant again after 25-year-old; （2） the SOM contents in 0-15 cm and 15-30 cm layers increase sharply from 10- to 15-year-old, and decline gradually from 15- to 30- year-old; the SOM contents of the 30-year-old PCP were 80. 38% and 78.42% higher than that of the 10-year-old, but 29.16% and 53.37% lower than that of 15-year-old in the 0-15 cm and 15-30 cm layers, respectively. The decrease of SOM contents would lead to the degradation of soil fertility and the decline of forest productivity.
文摘The irrational land use is one of the main reasons for the soil erosion and nutrient loss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in the loess hill slope are selected to study the effect of land use structure on the distribution of soil nutrients. From hill bottom to hill top, the patterns of land use types are:, grassland-slope farmland-forest, slope farmland-grassland-forest, terrace-grassland-forest and slope farmland-forest-grassland. By measuring the contents of the total N, total P, available N, available P and organic matter of soils, the results show that the land use structure types of slope farmland-grassland-forest and terrace-grassland-forest have a better capacity to maintain the soil nutrients.
文摘Soil quality assessment is valuable for agricultural production. In this research, 155 soil samples at two soil depths were collected from four land use types in an agricultural area of the A Luoi district in the Central Vietnam. Differences of soil organic carbon, total nitrogen in soil and soil pH under different land use types and topographic aspects were compared. Soil organic carbon contents in arable land and plantation forest are higher than those in natural forest and grassland (p < 0.05). Conversely, the total nitrogen in natural forest was significantly lesser in comparison to other land use types. Meanwhile there were no significant differences of the total nitrogen content (p < 0.05) among arable land, plantation forest, and grassland. The soil of grassland, natural and plantation forests land use types were more significantly acidic than those of the soils of the arable land use type. Soil organic carbon and total nitrogen showed a decreasing trend while soil depth increased in all land use types. The soil pH in plantation forest and arable land use types showed no significant change in relation to soil depth. Significant differences were not found in topographic aspects and soil organic carbon content;however, the different changing trends of soil organic carbon content between land use types and aspects were found. The impact of slope, elevation, farming system or soil texture accounted for the differences in these soil indicators under different land use types in the A Luoi district.
文摘为了更全面地评价WEPP模型在我国的适用性,该文通过建立模型数据库,利用WEPP分别模拟了坡长为10、20、30和40 m的径流量和土壤侵蚀量,并用实测径流和侵蚀资料进行对比分析。结果表明,在10、20、30和40 m 4个坡长条件下,WEPP模型对降雨、每年和多年平均径流量模拟的Nash-Sutcliffe有效性(ME)分别为0.915、0.879和-0.056,对单场降雨、每年和多年平均土壤侵蚀量模拟的ME分别为0.853、0.758和-0.456,多年平均的ME为负值可能是由小样本计算造成的。WEPP模型对单场降雨和每年径流量和侵蚀量模拟效果较好。尽管WEPP模型对多年平均径流量和土壤侵蚀量模拟效果较差,但模型模拟的多年径流量和土壤侵蚀量与实测值的多年径流量和土壤侵蚀量的最大相对误差分别为7.90%和29.20%,表明WEPP模型对多年径流量和侵蚀量的模拟可满足要求。径流量模拟值随坡长增加的变化和实测值相比不够敏感;而土壤侵蚀量模拟值随坡长增加的变化和实测值相比过于敏感。
