Study On The Effects Of Soil And Water Conservation By Different Agricultural Measures In Danjiangkou Reservoir Area

As the water source of the middle route line of South-to-North Water Transfer Project, the water quality of Danjiangkou reservoir area is important to accomplish this project. But according to some date, the ecological condition of the reservoir area is bad, the vegetation coverage is low, soil and water loss is serious. The nutrient of the slope fields, which losses with runoff and erosion soil have effected the water quality.For research the rules of soil and water loss in the slope fields, and provide reference for land use and soil and water conservation, I designed several experiments. One is planting different crop species (include Dioscorea ZingiBerensis C.H.Wright, sweet potato, sesame, maize), another is about soil and water loss under different farming measures (the treatments is no-tillage, no-tillage with straw mulch, conventional tillage, conventional tillage with straw mulch, mulching with plastic film, contour ridge planting). I have observed and recorded the process of soil and water loss, analysed its loss rule and crop production efficiency. The experiments conclude as follows.(1)Sweet potato and sesame compare to the other crop have more efficient in soil and water conservation. According to the date, these tow crops can improve the vegetation coverage, reduce the rainfall and runoff energy, control the ground runoff flow and soil erosion. Compare to Dioscorea ZingiBerensis C.H.Wright, sweet potato reduce 79.60% ground runoff flow and 39.52% sediment erosion. Compares with maize, the sweet potato nutrient element loss accounted for only 1/10, and increase income 6,300 yuan per hectare. Sweet potato reduce the runoff and erosion soil flowing to reservoir area, help relieve the flood control pressure. And these tow crops can also reduce the loss of nitrogen and phosphorus in slop cultivated land, that can help control the eutrophicated water and non-point source pollution. These suggest that sweet potato can protect the water quality of in reservoir area, and make sure this great project has a successful conclusion. Sweet potato is a crop species suitable for local popularization.(2) Different tillage methods have different ground runoff flow and soil erosion at early and late stage. At early stage, different tillage methods have more ground runoff flow and soil erosion than its at late stage. Compare with non-tillage and conventional tillage, non-tillage with straw mulch and conventional tillage with straw mulch less income 1700 and 3300 yuan per hectare. Mulching with plastic film have the least sediment erosion, is only 6.89 kg/hm2, but the ground runoff is the largest. Conventional tillage with straw mulch soil and water erosion and nutrient loss are at a lower level. Compared with conservation tillage, conventional tillage with straw mulch can reduce 58.7% of ground runoff and 64.24% of sediment erosion.(3) Compare with conventional tillage and conventional tillage with straw mulch, treating with mulching with plastic film and contour ridge planting's maize has a shorter growth stage, its about a week earlier, and that help crop avoid water stress during high-temperature, less rainfall period. When it comes to non-tillage and non-tillage with straw mulch, its about 8 days later. Treating with mulching with plastic film's sloping farmland has a better water circumstances, and a higher yield than the other treatment. Treating with on-tillage with straw mulch and conventional tillage with straw mulch's crop showed production decline, and the crop treating with contour ridge planting has the lowest output. So according to efficiency of agricultural investment, high income, and reduce soil erosion effect conventional tillage with straw mulch is a suitable tillage methods for reservoir area.