By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in...By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in South Chinawere analyzed on both temporal and spatial scales in soils of different parent materials, altitudes and slopes. The resultsshowed that from 1958 to 2000 severe soil erosion was coming under control with a decreasing percentage of the land undersevere erosion. It was also found that the soils developed from Quaternary red clay, granite and purple shale were moresusceptible to soil erosion and that areas sitting between 200 to 500 m in altitude with a slope less than 3° or between7° to 20° where human activities were frequent remained to be zones where soil erosion was most likely to occur. Theseareas deserve special attention in monitoring and controlling.展开更多
Collapsing gully erosion is a specific form of soil erosion types in the hilly granitic region of tropical and subtropical South China, and can result in extremely rapid water and soil loss. Knowledge of the soil phys...Collapsing gully erosion is a specific form of soil erosion types in the hilly granitic region of tropical and subtropical South China, and can result in extremely rapid water and soil loss. Knowledge of the soil physical and chemical properties of farmland influenced by collapsing gully erosion is important in understanding the development of soil quality. This study was conducted at the Wuli Watershed of the Tongcheng County, south of Hubei Province, China. The aim is to investigate soil physical and chemical properties of three soil layers （0-20, 20-40 and 40-60 cm） for two farmland types （paddy field and upland field） in three regions influenced by collapsing gully erosion. The three regions are described as follows： strongly influenced region （SIR）, weakly influenced region （WIR） and non-influenced region （NIR）. The results show that collapsing gully erosion significantly increased the soil gravel and sand content in paddy and upland fields, especially the surface soil in the SIR and WIR. In the 0-20 cm layer of the paddy field, the highest gravel content （250.94 g kg-1） was in the SIR and the lowest （78.67 g kg-1） was in the NIR, but in the upland filed, the surface soil （0-20 cm） of the SIR and the 40-60 cm soil layer for the NIR had the highest （177.13 g kg-1） and the lowest （59.96 g kg-1） values of gravel content, respectively. The distribution of gravel and sand decreased with depth in the three influenced regions, but silt and clay showed the inverse change. In the paddy field, the average of sand content decreased from 58.6 （in the SIR） to 49.0% （in the NIR）, but the silt content was in a reverse order, increasing from 27.9 to 36.9%, and the average of the clay content of three regions showed no significant variation （P〈0.05）. But in the upland filed, the sand, silt and clay fluctuated in the NIR and the WIR. Soils in the paddy and upland field were highly acidic （pH〈5.2） in the SIR and WIR; moreover lower nutrient contents （soil organic matter （SOM）, total N and available N, P, K） existed in the SIR. In the 0-20 cm soil layer of the paddy field, compared with the NIR and the WIR, collapsing gully erosion caused a very sharp decrease in the SOM and total N of the SIR （5.23 and 0.56 g kg-1, respectively）. But in the surface soil （0-20 cm） of the upland field, the highest SOM, total N, available N, available P and available K occurred in the NIR, and the lowest ones were in the SIR. Compared with the NIR, the cation exchange capacity （CEC） in the SIR and WIR was found to be relatively lower. These results suggest that collapsing gully erosion seriously affect the soil physical and chemical properties of farmland, lead to coarse particles accumulation in the field and decrease pH and nutrient levels.展开更多
The relationships between rainfall, runoff and erosion in South China granitic weathering red soil region were studied by using data collected from 7 experimental plots in Wuhua County, Guangdong Province. Results sho...The relationships between rainfall, runoff and erosion in South China granitic weathering red soil region were studied by using data collected from 7 experimental plots in Wuhua County, Guangdong Province. Results showed that when rainfall is less than 50 mm, small volumes of runoff were produced. Rainfall intensity might be the main factor in controlling runoff. When rainfall exceeds 50 mm, because of its large volume and high intensity, runoff and the produced amount of erosion increased with raimfall quickly. Analysis of the relationship bebeen runoff and erosion suggsted that runoff of 30 mm (corresponding to about 50 mm rainfall might be taken as a threshold at which wter on land surface was sufficient to start the larg amount of soil particles. Vegtation cover is very effective in protection soil from being eroded. When vegetation coverag increases from 0 to 80 percent,runoff and soil loss decrease from 179.34mm/a to 126.36mm/a and 6262.15T/a km2 to 368.02 T/a km2, respectively.展开更多
By a simulated rainfall and runoff scouring test with typical corrosive soils in main water erosion regions of China, the erosion processes of soil were analyzed from the energy point of view, and a new soil erodibili...By a simulated rainfall and runoff scouring test with typical corrosive soils in main water erosion regions of China, the erosion processes of soil were analyzed from the energy point of view, and a new soil erodibility indicator was proposed. The results show that there is a good relation- ship between the rate of sediment yield and energy consumption of slope runoff, and the erodibility coefficients of four soils are stable, being shown as follows 〉 loess 〉 black soil 〉 purple soil 〉 red soil.展开更多
基金the National Natural Science Foundation of China (No. 40471081), the Innovation Programme ofChinese Academy of Sciences (No. KZCX3-SW-422), and the Canadian International Development Agency, Canada.
文摘By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in South Chinawere analyzed on both temporal and spatial scales in soils of different parent materials, altitudes and slopes. The resultsshowed that from 1958 to 2000 severe soil erosion was coming under control with a decreasing percentage of the land undersevere erosion. It was also found that the soils developed from Quaternary red clay, granite and purple shale were moresusceptible to soil erosion and that areas sitting between 200 to 500 m in altitude with a slope less than 3° or between7° to 20° where human activities were frequent remained to be zones where soil erosion was most likely to occur. Theseareas deserve special attention in monitoring and controlling.
基金financially supported by the National Natural Science Foundation of China (41630858)
文摘Collapsing gully erosion is a specific form of soil erosion types in the hilly granitic region of tropical and subtropical South China, and can result in extremely rapid water and soil loss. Knowledge of the soil physical and chemical properties of farmland influenced by collapsing gully erosion is important in understanding the development of soil quality. This study was conducted at the Wuli Watershed of the Tongcheng County, south of Hubei Province, China. The aim is to investigate soil physical and chemical properties of three soil layers （0-20, 20-40 and 40-60 cm） for two farmland types （paddy field and upland field） in three regions influenced by collapsing gully erosion. The three regions are described as follows： strongly influenced region （SIR）, weakly influenced region （WIR） and non-influenced region （NIR）. The results show that collapsing gully erosion significantly increased the soil gravel and sand content in paddy and upland fields, especially the surface soil in the SIR and WIR. In the 0-20 cm layer of the paddy field, the highest gravel content （250.94 g kg-1） was in the SIR and the lowest （78.67 g kg-1） was in the NIR, but in the upland filed, the surface soil （0-20 cm） of the SIR and the 40-60 cm soil layer for the NIR had the highest （177.13 g kg-1） and the lowest （59.96 g kg-1） values of gravel content, respectively. The distribution of gravel and sand decreased with depth in the three influenced regions, but silt and clay showed the inverse change. In the paddy field, the average of sand content decreased from 58.6 （in the SIR） to 49.0% （in the NIR）, but the silt content was in a reverse order, increasing from 27.9 to 36.9%, and the average of the clay content of three regions showed no significant variation （P〈0.05）. But in the upland filed, the sand, silt and clay fluctuated in the NIR and the WIR. Soils in the paddy and upland field were highly acidic （pH〈5.2） in the SIR and WIR; moreover lower nutrient contents （soil organic matter （SOM）, total N and available N, P, K） existed in the SIR. In the 0-20 cm soil layer of the paddy field, compared with the NIR and the WIR, collapsing gully erosion caused a very sharp decrease in the SOM and total N of the SIR （5.23 and 0.56 g kg-1, respectively）. But in the surface soil （0-20 cm） of the upland field, the highest SOM, total N, available N, available P and available K occurred in the NIR, and the lowest ones were in the SIR. Compared with the NIR, the cation exchange capacity （CEC） in the SIR and WIR was found to be relatively lower. These results suggest that collapsing gully erosion seriously affect the soil physical and chemical properties of farmland, lead to coarse particles accumulation in the field and decrease pH and nutrient levels.
文摘The relationships between rainfall, runoff and erosion in South China granitic weathering red soil region were studied by using data collected from 7 experimental plots in Wuhua County, Guangdong Province. Results showed that when rainfall is less than 50 mm, small volumes of runoff were produced. Rainfall intensity might be the main factor in controlling runoff. When rainfall exceeds 50 mm, because of its large volume and high intensity, runoff and the produced amount of erosion increased with raimfall quickly. Analysis of the relationship bebeen runoff and erosion suggsted that runoff of 30 mm (corresponding to about 50 mm rainfall might be taken as a threshold at which wter on land surface was sufficient to start the larg amount of soil particles. Vegtation cover is very effective in protection soil from being eroded. When vegetation coverag increases from 0 to 80 percent,runoff and soil loss decrease from 179.34mm/a to 126.36mm/a and 6262.15T/a km2 to 368.02 T/a km2, respectively.
文摘By a simulated rainfall and runoff scouring test with typical corrosive soils in main water erosion regions of China, the erosion processes of soil were analyzed from the energy point of view, and a new soil erodibility indicator was proposed. The results show that there is a good relation- ship between the rate of sediment yield and energy consumption of slope runoff, and the erodibility coefficients of four soils are stable, being shown as follows 〉 loess 〉 black soil 〉 purple soil 〉 red soil.
