Research On The Migration Of Soil Zinc And The Influencing Factors For It

Nutrient migration and loss of nutrients in soil on a slope during rainfall are the research focus and research hotspot in soil science, ecology, hydrology, environmental science and other field of science.Zinc is a necessary trace element for plant growth and development. In massive of trace element, Zinc has close relation with production and life activities of human.In Loess Plateau Region, the phennmenon of Zinc trace is very serious.Loss of Zinc on a slope has a closer relationship with soil degradation process under soil erosion conditions.So development of the research on slope nutrient transport—A case study of soil Zinc is of important theoretical value and productive value to exploring mechanisms of soil quality degradation, improving perdiction ability of nutrient loss, making optimum agricultural management of slope farmland, improving ecological environment and improving productivity of dry farming.Selecting Zinc as materials of study, this paper has discussed the effect of water retaining agent and vegetation coverage on Zinc transport, explored the mecharnism of Zinc transport flowing with sediment in rainfall and analysed the law of zinc transport and loss by the methods of laboratory analysis and simulated rainfall in the filed plots. This paper has an important part in making management measures of agricultural production and improving water environment.The main conclusions are as follows:1 PAM can improve the content of soil surface moisture, inhibit water evaporation,increase soil water retention,decrease soil bulk density and increase saturated hydraulic conductivity.When the application dosage is 2.0 g/m~2,there ia a inflection point in PAM'utility.PAM can shorten emergence flow time in rainfall.The bigger the application dosage is, the shorter emergence flow time will.The rate of runoff yield and runoff volume are increasing with the application dosage increasing.The sediment concentration and silt loss are reducing with application dosage increasing. Zn concentration and enrichment ratio in sediment is increasing when application dosage is smaller than 2.0 g/m~2,it is reducing when application dosage is smaller than 2.0 g/m~2.But the loss quantity of Zinc is reducing.The enrichment rate of Zinc in sediment is reducing with application dosage increasing..2 Vegetation coverage can reduce soil bulk density and increase saturated hydraulic conductivity. Vegetation coverage can increase emergence flow time in rainfall.the bigger the vegetation coverage is, the longer emergence flow time will. The rate of runoff yield,runoff volume, sediment concentration and silt loss are reducing with vegetation coverage increasing.Zinc of sediment is reducing in the rainfall process. Zn concentration and enrichment ratio in sediment is increasing with vegetation coverage increasing, but the loss quantity of Zinc is reducing.The enrichment rate of Zinc in sediment is increasing with vegetation coverage increasing.3 The germination of alfalfa and the length of radical are improved than control by effect of PAM. The bigger the application dosage is, the bigger the germination and length of radical will.PAM can increase biomass of alfalfa and increase absorpyion and accumulation of Zinc in inside plant.4 Vegetation coverage and PAM can reduce runoff yield, sediment yield and nutrient loss.we call this synergistic effect.