The Study On The Soil Erosion Prediction Model And Nutrient Loss On Different Ecological Controls Of Red-soil Slope Land In Jiangxi Province

Red soil is the main regional in Jiangxi province. Serious soil and water loss, caused by climate and unreasonable use, has induced degeneration of the eco-environment and soil fertility, seriously restricted the sustainable development of agriculture and social economy. Together with the characteristic of red-soil in Jiangxi province, the principle contents of this paper are as follows:(1) The research development of soil erosion models at home and abroad was systematically analyzed. Based on international widely used RUSLE model, together with the eco-environment characteristic of red-soil slope land in Jiangxi province, the erosion factors were revised by least square method, and the prediction model of annual soil erosion model on different ecological controls was established. Rainfall erosivity, the key factor of soil loss model, was specially studied. The characteristics of natural rainfall were researched. Critical precipitation rainfall and rainfall intensity of erosive rainfall in red-soil slope land were 12.2mm and 0.762 mm·h^-1.ΣE₆₀·I₃₀ was the best combination of rainfall erosivity, and the best raindrop kinetic energy was chosen, then distribution of rainfall erosivity was researched. The other factors of soil erosion model were quantitatively studied.(2) The red-soil slope land nutrient loss regulation under natural rainfall on different ecological controls was tentatively studied in Jiangxi province. Analyzing nutrient concentration removed with runoff process, it had a generally downtrend along with runoff, tending to stable at final phase, and nutrient concentrations removed with runoff on different ecological controls were all lower than bare soil (CK). Results showed that the majority of soil nutrient was removed with sediment under high rainfall intensity, and nutrient loss gathered largely at the beginning of runoff gene-rated, stably in the later stage. The total nitrogen loss was the most severely among total nitrogen, total phosphorus and total potassium. The sediment nutrient was enriched, and different ecological controls had a good effect on reducing nutrient loss of red-soil slope land, which worked well in preventing eutrophication of water. The terrace with sod grass on its wall, mound before its platform ditch behind its platform of all ecological controls, was the most effective method to prevent soil nutrient loss.