Study On Migration Activity And Control Technology Of Cu、Zn In Paddy Soil

Rice occupies a very important position in Chinese food crops, A quarter of the country’s arable land area of rice farming,rice solved the problem of food and clothing for most people in our country. So we can say, the status of rice production in China’s food security is play adecisive role, paddy soil heavy metals pollution problem has become particularly important. Heavy metal pollution in soil not only affects the yield and quality of agricultural products, also will affect the water environment and atmospheric environment quality. Therefore, it can be said that heavy metal pollution is extremely serious. Heavy metal pollution can produce great damage to the ecological environment, severely restricting our country’s economy, hinder the sustainable development of economy. Therefore, the heavy metal pollution prevention and control has become the environmental protection work of top priority.Leaching experiment of existing mostly in the field sampling, sampling to the laboratory after packed column leaching, the structure of the experimental method will change the soil, thus it is very difficult to clarify the real situation of the migration of contaminants in the soil. At the same time to carry out the undisturbed soil leaching experiment is relatively less. Heavy metal control technology of high cost in paddy field, at present almost no practical application, so there search of control technology be imperative.Research on the adsorption and desorption behavior characteristics of copper, zinc using batch equilibrium method. By adding urea and ammonium sulfate fertilizer(nitrogen content of differe forms of the same), change the content of exogenous heavy metal pH value of the solution and the change of soil organic matter to study the effect of paddy soil on copper, zinc adsorption desorption behavior; The preliminary research on the control technology is by means of adding organic fertilizer and soil anti-seepage agents, thus to leaching of undisturbed soil, in order to observe the law of two kinds of heavy metal elements copper, zinc leaching effect.The research results show that: the adsorption kinetics of copper, zinc, adsorption of two heavy metals copper, zinc of the soil have experienced 3 stages, namely, fast adsorptionstage, slow adsorption stage and the equilibrium adsorption stage.The adsorption equilibrium time of two elements for 8h. In the paddy soil, adsorption of copper, zinc in tested soil isspontaneous, endothermic and entropy increase process. So high temperature is good for paddy soil adsorption of copper and zinc. Application of nitrogen fertilizer in the same but different forms of urine and ammonium sulfate, the effects of urea on the test for copper,zinc in soil of the two types of heavy metal elements than ammonium sulphate, urea can promote the adsorption of two kinds of heavy metals copper, zinc, heavy metals can be fixed,to prevent the excessive migration and transformation. There was a positive correlation between adsorption quantity and soil pH value of copper, zinc. With the decrease of pH value,adsorption of Cu, Zn to reduce, increase of pH promote the adsorption of copper, zinc of the soil, adsorption ability strong. The removal of organic matter in soils after adsorption capacityfor copper, zinc is abate, adsorption amount are reduced. Organic matter is the main factor affecting the adsorption of copper and zinc in soil.In the process of desorption, desorption of copper, zinc also experienced 3 stages of rapiddesorption, desorption and equilibrium desorption speed reducer.The increase of temperature desorption behavior of the copper, zinc is advantageous, decrease desorption temperature would inhibit the copper, zinc, copper, zinc and reduce the migration activity, reduce the harm of heavy metals in soil. Applying urea and ammonium sulfate in the soil(the nitrogen content of the same), urea is more advantageous for desorption of copper, zinc in the soil, the transformation has a stronger effect on promoting the migration of heavy metal. Under acidic conditions, copper, zinc desorption was negatively correlated with pH value. With the continuous increase of the solution pH, two kinds of heavy metal elements Cu,Zn desorption decreases. With the solution pH value becomes larger, reduce biological activity and chemical activity of copper, zinc, thus weakening the migration ability of copper, zinc, desorption decreases. The amount and the content of soil organic matter were negatively related to copper, zinc solution. Soil organic matter is inhibited in the presence of copper, zincon desorption in paddy soil. The contents of soil organic matter significantly affect thedesorption of copper, zinc.In undisturbed soil leaching test, soil extract can inhibit the leaching of copper, zinc and other organic pollutants, soil extract the soil adsorption capacity of copper, zinc, zinc enhanced, copper leaching amount decrease. With the leaching solution pH value decreased, the leaching amount increased significantly, especially the leaching solution pH value from 8.9 to 4.2, copper, zinc leaching increase respectively 19.33% and 39.25%. Therefore, pH is one of the important elements affecting the activity of heavy metals in soil. In the process of continuous leaching, the leaching of copper, zinc amount greater than that of intermittent leaching leaching amount, good for desorption of copper and zinc. Intermittent leaching soil adsorption ability enhancement of copper and zinc. That continuous precipitation can aggravate the soil heavy metal pollution. Organic matter content is the important factors influencing the copper, zinc leaching. Organic adsorption has a promoting effect of copper, zinc, inhibit the leaching of copper and zinc. Under the condition of the soil organic matter content is higher, copper and zinc is not easy to transfer, the higher organic matter content, the worse the migration characteristics.In a preliminary study on the control technology, add organic matter content and add more high, the adsorption capacity of copper, zinc, copper, the stronger the zinc leaching performance is small. The content of soil organic matter, soil particle composition alsoincludes the main factors affecting the leaching performance.Compared with not addingspecial anti-seepage agent paddy soil, adding anti-seepage agent for copper, zinc leaching solution volume was significantly smaller. The addition of anti-seepage agent can make the soil water retention capacity increased, improve soil structure, increase the water temperature, soil temperature, soil to create good conditions for rice. Add the anti-seepage agent can reduce the paddy special copper zinc leaching amount. Therefore, the addition of anti-seepage agent can reduce the pollution of heavy metals in paddy soil in a certain extent.