| Three Gorges Reservoir has large sloping land area. At the same time, the soil is barren, 55.1% of arable land in Three Gorges Reservoir Area, which is the main reason of sloping land in the Three Gorges Reservoir. According to statistics, the total soil erosion in Three Gorges Reservoir area of 6.13 million hm2, Annual sediment yield in the reservoir area has reached 157 million tons, including soil erosion in sloping land amounted to 94.5 million t, annual sediment storage capacity 18.9 million t. Soil erosion is not only a direct result of soil nutrient loss.At the same time, land degradation, decreased productivity, will be accompanied by sediment and nutrient runoff reservoirs and river siltation loss, and ultimately subject to eutrophication of receiving waters. Three Gorges reservoir area ecological security barrier as the Yangtze River, water environment safety Gorges reservoir area is directly related to water security and the Yangtze River city group and economic and social development, closely related to the overall sustainable development of China. Currently, soil erosion and agricultural pollution has an impact on the ecological environment of the Three Gorges reservoir area and the number one key factor in the Three Gorges Reservoir environmental issues seriously restricted the sustainable economic and social development of the reservoir area, so finding effective ways prevention and control in the Three Gorges Reservoir soil erosion is essential.In this paper, the author take Three Gorges Reservoir Wangjiagou watershed as research subjects. By field experiments and laboratory analysis method, the 18 runoff plots Wangjiagou basin different fertilizer and vegetation cover(T1: 100% conventional corn fertilization +, T2: incremental fertilizer + 120% corn, T3: 80% reduction + fertilizing corn, T4: conventional fertilization + ryegrass, T5: conventional fertilization + Mexican corn grass, T6: conventional fertilization + Hercules sweet sorghum) under water and soil erosion and nutrient loss from observation, comparative analysis of fertilization and vegetation cover on soil erosion and nutrient loss in sloping land.In order to choose the right farming methods, from the source point source pollution control in the Three Gorges reservoir area to provide a theoretical basis. The main conclusions are as follows:(1) Effect of fertilizer nutrients on sloping land of loss: From time rainfall runoff and sediment volume terms, increasing the amount of fertilizer can be reduced surface runoff and sediment loss; but after the maize harvest, the case exposed surface, different fertilization treatment(T1, T2, T3) of runoff and sediment loss were increased, but no significant difference between treatments. After the end of the entire trial monitoring period, the total maximum runoff T1 treatment(85.51 L / m2), followed by T3(84.77 L / m2) and T2(77.19 L / m2), the total sediment loss expressed as T3(262.87 t /km2)>T1(256.84 t / km2)> T2(237.76 t / km2). Overall, incremental fertilization can significantly reduce the amount of runoff and sediment loss; however, reductions compared to conventional fertilization fertilization effect is not significant.On the terms of rainfall, runoff and sediment loss volume TN TN loss volume, the amount of loss of total phosphorus runoff and sediment total phosphorus loss volume presents with increasing fertilizer increasing trend. TN runoff loss amounts under different treatments only to 20.51% ~ 21.98% of the total nitrogen loss volume, total phosphorus runoff loss accounted for 16.10% ~ 17.13% total phosphorus loss volume, indicating dry slopes nitrogen and phosphorus loss of key to carry sediment loss mainly visible control runoff and sediment loss in sloping land is nitrogen, phosphorus key nutrient loss is reduced.(2) The effect of vegetation cover on nutrient loss in sloping land: under different vegetation cover total size runoff showed T6(90.98 L / m2)> T1(85.51 L / m2)> T4(84.85 L / m2)> T5(82.53 L / m2), the total sediment loss size T1(256.84 t / km2)> T6(239.44 t / km2)> T4(243.17 t / km2)> T5(221.49 t / km2), visible Mexican corn grass mulching T5 in reducing runoff and sediment loss and a good performance in terms of results. On time in terms of rainfall, runoff under different vegetation cover processing nitrogen, total phosphorus and sediment total nitrogen, total phosphorus loss volume, both showed T1> T6> T4> T5, T4, T5, T6 treatment Total Nitrogen loss of 72.56% ~ 84.23% T1 treatment, the total amount of phosphorus loss was 54.36% ~ 63.70% T1 treatment, compared with conventional maize visible cover, grass cover is more effective in reducing runoff and sediment loss, especially Mexican corn straw mulching.(3) The effect of fertilization on crop yield and quality: different ground fresh corn fertilization is under significant small T2(2043.89 kg / mu)> T1(1767.46 kg / mu)> T3(1635.41 kg / acre); dry matter accumulation an amount of 653.51 ~ 744.10 kg / mu, and fertilizer had a significant positive correlation. Visible increase fertilizer can significantly improve the yield and dry matter accumulation of corn, reducing fertilizer on corn ground fresh weight is not obvious. Corn different organs to dry grain dry matter distribution ratio highest, up to 47.84% ~ 48.04%, the impact on the various organs dry fertilizer distribution ratio was not significant. With the increase of the amount of fertilizer, dry matter, crude protein of corn on the ground part of the blade, stem, bud axis, crude fat content were decreased, but grain crude protein, crude fat content increased.(4) The effect of vegetation cover on crop yield and quality: fresh weight of grass coverage process reached 6672.33 ~ 8648.43 kg / acre, corn mulching 3.78 ~ 4.89 times T1, the dry matter accumulation was 902.93 ~ 1140.33 kg / mu, 1.21 ~ 1.53 times the T1 treatment. Wherein the leaf dry matter forage mulching distribution ratio up to 69.40% ~ 74.44%, indicating that three species of pastures dry matter accumulation of dry matter accumulation in leaves are based.Under T4, T5, T6 treatment, crude protein,crude fat, crude fiber, crude ash accumulation were maize mulching 1.60 to 3.21 times T1 and 1.02 to 1.52 times, 1.16 and 1.56 times, 2.41 and 4.71 times. Dry matter crude protein content of T4 treatment(19.58%) the highest; crude fiber content of T4 treatment(20.89%) the lowest low of 6.55%- 9.57% more than other treatments; crude ash content expressed as T4> T6> T5> T1 three forage crude ash content was higher than corn. At the same time, different vegetation cover treatment T1, T2, T3, T4, the amount of nitrogen resulting in increased soil nitrogen is 2.04 ~ 3.98 kg / mu, where Mexican corn grass cover of nitrogen increased the minimum amount due. |
