Soil erosion and nutrient loss due to erosion are world-wide problems. Similar to soil loss by erosion, soil nitrogen (N) loss by erosion in small catchments is affected by vegetation coverage. The practice of compreh...Soil erosion and nutrient loss due to erosion are world-wide problems. Similar to soil loss by erosion, soil nitrogen (N) loss by erosion in small catchments is affected by vegetation coverage. The practice of comprehensive management for catchments mainly by adjusting cropland, grassland and woodland areas was widely adopted to reduce soil and water loss in catchments of the Chinese Loess Plateau. Three experiments under natural and artificial rainfall conditions on N loss by erosion for a model catchment and for an actual catchment in Zhifanggou of Ansai County in China was performed to determine the relationships between comprehensive management and N loss by runoff in small catchments. The results for vegetation coverage of 60%, 40%, 20% and 0 show that runoff loss of ammonium, nitrate, and total N were 87.08, 44.31, 25.16, 13.71 kg/km(2); 85.50, 74.06, 63.95, 56.23 kg/km(2); and 0.18, 1.18, 1.98, 7.51 t/ km(2), respectively. Due to reduction in the size of cropped area on steeply sloping land, soil N loss by erosion in the catchments was decreased by 15.8% as compared with that in 1992, i.e., from 8 758.5 kg in 1992 to 7 562.2 kg in 1998. Whereas, catchments act as a filter for ammonium and nitrate in rain, the catchment filtering effects on nitrate is remarkably higher than that on ammonium. The enrichment of < 20 mum aggregate in sediment results in the enrichment of organic matter and total N in flood sediment. Greater vegetation coverage can effectively decrease soil erosion and total N loss. However, soil mineral N loss increased as vegetation coverage increased.展开更多
Soil erosion represents one of the most important destructive phenomenon of the soil, through surface and depth erosion. The activity of water erosion in Albania is favoured from some factors like relief, geological s...Soil erosion represents one of the most important destructive phenomenon of the soil, through surface and depth erosion. The activity of water erosion in Albania is favoured from some factors like relief, geological structure, slope, soil, etc. Erosion depth growth is closely related with the vegetal cover ravage high rate and in the first instance that of woodland flora in sloping ground. The degradation of the flora or total destruction of it is defined from many factors, but in notably from social-economical system of every country. It can be also seen some special areas in our country were the results of the human negative impacts in natural environment. The erosion phenomenon is more problematic, especially during intensive raining time.展开更多
Land erosion is an increasing problem that is seriously affecting our country in recent years. In many areas of our country, mountainous and hilly territories suffer major erosion in both surface and depth, where the ...Land erosion is an increasing problem that is seriously affecting our country in recent years. In many areas of our country, mountainous and hilly territories suffer major erosion in both surface and depth, where the solids are deposited in the flat parts of the country, thus leading to a higher content of gravel in agricultural land and filling of the sewage networks. The phenomenon of erosion is greater in the vicinity of residential areas where damages are larger and more sensitive. One of the most vulnerable in our country in terms of soil erosion is the district of Tirana. This study had the main goal to define and categorise of erosion rates in natural environments of the forest economies of the Tirana, the rate of recovery of vegetation, slope and rainfall index, which will serve as information and guidance on the land use by farmers, communes and the state regulatory officials, depending on the ownership of these woodland surfaces.展开更多
The paper analyzes the sediment source of watershed by means of studying watershed in westernShanxi of the Losses Plateau. On the basis of watersheds classification, 7 typical watersheds were chosen andobserved for 11...The paper analyzes the sediment source of watershed by means of studying watershed in westernShanxi of the Losses Plateau. On the basis of watersheds classification, 7 typical watersheds were chosen andobserved for 11 years. The result shows that the sediment at the small watershed mainly comes from gullies,which is 60% of the total sediment. Erosion modulus of valley (including gully head, gully bed, valley side)is 1.28~2.48 times as that of the area between channels(including hill slope and mound of the Loess Plateau).The main sediment source of slope erosion is cultivated land on slope without water and soil conservationmeasures.展开更多
文摘Soil erosion and nutrient loss due to erosion are world-wide problems. Similar to soil loss by erosion, soil nitrogen (N) loss by erosion in small catchments is affected by vegetation coverage. The practice of comprehensive management for catchments mainly by adjusting cropland, grassland and woodland areas was widely adopted to reduce soil and water loss in catchments of the Chinese Loess Plateau. Three experiments under natural and artificial rainfall conditions on N loss by erosion for a model catchment and for an actual catchment in Zhifanggou of Ansai County in China was performed to determine the relationships between comprehensive management and N loss by runoff in small catchments. The results for vegetation coverage of 60%, 40%, 20% and 0 show that runoff loss of ammonium, nitrate, and total N were 87.08, 44.31, 25.16, 13.71 kg/km(2); 85.50, 74.06, 63.95, 56.23 kg/km(2); and 0.18, 1.18, 1.98, 7.51 t/ km(2), respectively. Due to reduction in the size of cropped area on steeply sloping land, soil N loss by erosion in the catchments was decreased by 15.8% as compared with that in 1992, i.e., from 8 758.5 kg in 1992 to 7 562.2 kg in 1998. Whereas, catchments act as a filter for ammonium and nitrate in rain, the catchment filtering effects on nitrate is remarkably higher than that on ammonium. The enrichment of < 20 mum aggregate in sediment results in the enrichment of organic matter and total N in flood sediment. Greater vegetation coverage can effectively decrease soil erosion and total N loss. However, soil mineral N loss increased as vegetation coverage increased.
文摘Soil erosion represents one of the most important destructive phenomenon of the soil, through surface and depth erosion. The activity of water erosion in Albania is favoured from some factors like relief, geological structure, slope, soil, etc. Erosion depth growth is closely related with the vegetal cover ravage high rate and in the first instance that of woodland flora in sloping ground. The degradation of the flora or total destruction of it is defined from many factors, but in notably from social-economical system of every country. It can be also seen some special areas in our country were the results of the human negative impacts in natural environment. The erosion phenomenon is more problematic, especially during intensive raining time.
文摘Land erosion is an increasing problem that is seriously affecting our country in recent years. In many areas of our country, mountainous and hilly territories suffer major erosion in both surface and depth, where the solids are deposited in the flat parts of the country, thus leading to a higher content of gravel in agricultural land and filling of the sewage networks. The phenomenon of erosion is greater in the vicinity of residential areas where damages are larger and more sensitive. One of the most vulnerable in our country in terms of soil erosion is the district of Tirana. This study had the main goal to define and categorise of erosion rates in natural environments of the forest economies of the Tirana, the rate of recovery of vegetation, slope and rainfall index, which will serve as information and guidance on the land use by farmers, communes and the state regulatory officials, depending on the ownership of these woodland surfaces.
文摘The paper analyzes the sediment source of watershed by means of studying watershed in westernShanxi of the Losses Plateau. On the basis of watersheds classification, 7 typical watersheds were chosen andobserved for 11 years. The result shows that the sediment at the small watershed mainly comes from gullies,which is 60% of the total sediment. Erosion modulus of valley (including gully head, gully bed, valley side)is 1.28~2.48 times as that of the area between channels(including hill slope and mound of the Loess Plateau).The main sediment source of slope erosion is cultivated land on slope without water and soil conservationmeasures.
