Distribution And Control Of Chemicals In Soils In Chongqing Vegetable Base

At present, the quality and safety issues of agricultural products are increasingly causing concern of the whole society, soil pollution of agricultural farmland is the unsafe source. Due to pollution, soil nutrient function, purification, buffering capability and the support function of organism are being lost. Therefore, it’s essential to governance soil pollution of vegetable land and improves soil environmental quality.This study was on the basis of a comprehensive survey of damage and extent of chemical substances such as mineral salts, heavy metals, pesticides and root exudates of vegetable bases in Chongqing, through trial and hydroponics pot experiment of Chinese cabbage, investigated the effects of hazardous substances in soil for vegetable seeding growth and development, identified the critical threshold of vegetable by the chemical factors of heavy metals, mineral salts, pesticides and root exudates. By cell experiment studied about in situ remediation of hazardous substances of vegetable soils in Chongqing.Test main results are as follows:(1) The survey tests show that the main chemical substances in vegetable soil are heavy metals Cd, Pb, followed by root exudates. The serious heavy metal pollutants in vegetable soil are Cd and Pb. The heavy pollutants in vegetables are Pb、Gr、As. The main root exudates are Benzoic acid, Vanillin and Hydroxybenzoic acid.(2) The barrier effect tests show that heavy metal Cd has very strong influence on the vegetables. Adding lmg/kg Cd can produce serious pollution on soil and vegetables. In root exudates, Benzonic acid can produce serous harm to plants. Water and pot culture experiments have demonstrated acid test was applied to reduce the root activity of plants, reducing the plants yields.(3) Situ distribution tests show that for the repair of heavy metal Cd,13.33～26.67kg per acre of humic distribution works best. Considering the effects of heavy metal distribution and vegetable production,13.33～26.67kg per acre of humic acid can improve vegetable production and significantly reduce the heavy metal content of vegetables as well.13.33～26.67kg per acre of reduced iron can improve vegetable production and promote the degradation of root exudates and other organic matter in soil.