Post-evaluation Of Effects Of Pesticides Application On Ecosystem Of Rice-paddy Field

As the impeller of agricultural production,pesticides are increasingly used in producing crops,especially grain products human beings live on such as cereals,beans and tubers.In planting these products,a great amount of pesticides have been used.The rice is typical grain cereal,with its output accounting for relatively high proportion in the world.However,in planting the rice,the use frequency of pesticides is surprising.The use of a great amount of pesticides causes a series of environmental problems,including water body pollution,soil pollution and air pollution.Biologies living in the environment have direct influence in terms of pollution.Food chain cycle and the effect of biological concentration make human beings the final victims.Only by properly managing and using pesticides can the safety of ecological environment and human beings be guaranteed.In foreign countries,there has been pesticide post-evaluation in pesticide management.In China,there is only pesticide management before registration without properly implementing pesticide management after using.Hence,this study will,combining with the basic situation of using pesticides in the rice fields,carry out studies on post-evaluation technologies to influence of pesticides on ecological system in the rice fields.The main contents and results of studies are as follows:(1)Based on literature reference and preliminary study,select the index system of post-evaluation of pesticides’ influence on ecological system in the rice field,use soil biodiversity,soil enzyme activity,phytoplankton diversity,zooplankton diversity as well as concentration of pesticide residue in water body and in the soil as evaluation indexes,and soil microbial activity as alternative index.(2)Select typical pesticide of Chlorpyrifos and conventional pesticides,according to basic requirements on filed management and prevention and control of diseases and pests,use actually separately and in combination in the rice and make comprehensive evaluation to the influence on ecological system.By analyzing diversity of soil organism,phytoplankton and zooplankton,the results show that there is no obvious influence on diversity of soil animals in rice growing period while certain influence on phytoplankton and zooplankton.Under different situations of pesticide application,the soil enzyme activity can obviously reflect the influence of pesticide application.In the meantime during different sampling period,the residue of pesticides in water body and soil change obviously.(3)By comprehensively evaluating the influence of typical pesticide(Chlorpyrifos)on ecological system,using this typical pesticide in the rice field has risks,and it shall pay high attention to its actual using situation.