| Mechanisms of forest vegetation of controlling on slope water erosion include hydraulics, forest hydrology, soil science, hydraulics, and other disciplines of knowledge, needing to be resolved interdisciplinarily. This study was conducted in Dongtaigou watershed, Huairou District, Beijing to set standards for different site conditions and different runoff plots. Under precipitation conditions in the field to research the variation of rainfall, runoff response process, with hydraulics, soil erosion and other scientific theories to deeply reveal the influence and impact of different vegetation patterns and slope erosion factors on hillslope runoff and sediment. Also simulating the process of the dynamics of vegetation controlling and emphasizing the function of vegetation in prentection water ersoin via hydrologic model water erosion mechanism for Beijing to control water erosion in the mountains provide a basis for scientific theory. The main conclusions are as follows:(1) From 1980 to 2009, the total rainfall was 11817.4 mm in study area, mena annual rainfall was 393.9mm, and the overall rainfall was low. In the rainy season from May to October, the range of the average monthly rainfall was 354.1 mm, and dry season rainfall was 39.8 mm; during 2000 to 2009, the average rainfall for each month and the monthly average number of days was familiar. The dry season and wet season were obvious, from November to next April, the total number of average rainy days was 9.6d, while the average rainfall from May to October the total number of days was 32.4d. From 2001 to 2008, March to October of the monthly average rainfall intensity presented a single peak curve shape, similar with distribution of rainfall; the rainfall screenings of 4 class sessions(0-1 mm/h,1-5 mm/h,5-10mm/h,>10mm/h) respectively were 93,147,29,34, the screenings of seven stages (rainfall duration< 30 min, 30-60 min,60-90 min,90-150 min,150-300 min,300-600min and>600 min) respectively were 44,41,20,43,49,62 and 44. Light rains were 213 times, accounting for 70.3% and the vast majority. Moderate rains were 70 times, accounting for 23.1%. The proportion of light rain and moderate rainfall in the local account for the composition of the vast majority was 93.4%.(2) The runoff coefficient of runoff plots without vegetation cover was significantly greater than it runoff with vegetation cover, indicating the formation of vegetation for is obvious that appropriate vegetation cover and soil and water conservationmeasures will help reduce runoff and prevent soil erosion.There was no significant linear relationship between runoff and rainfall as a single factor, indicating that runoff generation mechanism is very complicated which is not only affected by rainfall.(3) Sediment yield of bare area was significantly higher than area with measures, campared with area with high coverage, sediment yield of bare area canbe as 1,000 times moreas other areas; Vegetation coverage is a significant factor on sediment yield in area without stirring. In 2004 and 2007,vegetation coverage of area 19is above 75%, while the 18 area is under 30%Both in this twoyear, differences of sediment yield in the these two areas is significant; A-type rain and B-type rain are the mainly produced rain in the Huairou district which has been as much as 90%.; The functional relation between sediment yield and its impact factors are most of power function, there are few S function; The functional relation between sediment yield and vegetation coveris obviously, with the function expressed as:y=1.0461n(x)+4.3986, R2 is 0.5705.(4) Locust maximum water holding capacity is higher, at 25.93 t·hm-2, and maximum water holding capacity of Rhus is smaller, only 8.54 t·hm-2, but its water holding capacity is relatively higher; the maximum water holding properties of litter of Locust and Rhus were 556.64% and 333.03%, Locust> Rhus, similar with the maximum water holding capacity. A covered litter runoff plots, runoff less Locust< Rhu |
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