Effect Of Selenium Added Into The Soil On The Antagonistic Metal Of Soybean

Selenium(Se) is an essential nutrient element for human, animal and plant, and it is a component of glutathione peroxidase in animals and human body. Modern medical research shows that selenium can prevent Keshan disease, Kashin Beck disease, tumor, cancer and oxidation, improve the immunity of human and animal, and delay senescence. With the development of industry, the soil environment pollution seriously affects the sustainable development of economy and human health. However, it shows that Se has strong antagonistic effect on heavy metals, and can improve the Se content of agricultural products and reduce the content of heavy metals in order to maintain normal physiological activities.Something have been studied such as Se-rich ability of different parts of soybean, the speciation changes of heavy metals in soil and the accumulation of heavy metals in different parts of soybean after the addition of different concentrations of Se, as well as the antagonistic effect of Se on heavy metals in soybean, by soybean pot experiment which was applied Se in soil. The results show that:(1) The total contents of heavy metals had not been changed with the increasement of Se added into the soil, but the speciation such as As, Cu, Cd, which had been deactivated by Se.The speciation of Cd was mainly ion exchange and water soluble, so that Cd was easy to migrate in soil and to be absorbed by plants. Other heavy metals were mainly in the form of humic acid binding state or residue. It was thought that the treatment should be given priority to Cd on soil remediation.(2) By adding with Na2SeO3 in soil, the speciation of Se was essentially changed from ion to humic acid and strong organic after aging, which proved that the organic matter had a strong fixed effect on Se, and the soil with high organic matter content was beneficial to the enrichment of Se.Increase the content of soil organic matter, which can be a way to get Selenium rich soil.(3) The soybean biomass was the lowest under the more serious heavy metal stress, when the Se content was 2.56mg/kg in soil, but other contents not. It was suggested that the amount of Se should be controlled in a suitable range, otherwise it could be possible to activate the heavy metals and damage the crops.(4) The Se-rich ability of soybean was in accordance with the order of the "fruits > leaf > stem > shell" by adding with different concentrations of Se, which showed that beans had the strongest accumulation of Se, and the soybean had the development prospect as Se-rich food.The heavy metals content in soybean were decreased in different degrees, particularly Cd, with the increasement of Se in soil, which showed the antagonistic effect of Se.It was suggested that there were not suitable to grow soybeans in Ni, Cu, Zn, Cr contaminated soil, because soybean had strong accumulation of Ni, Cu, Zn, and Cr.