Influence Of Chlorpyrifos And Adjuvant On Soil Microbial Community Strcuture

So far,researches on pesticide give priority to the active ingredient(technical),but ignore various additives composition in pesticides.Pesticide technicals cannot be directly applied,so it must be mixed with various pesticides adjuvant to put into practice.Thus,pesticides into the soil not only include technicals,but also a variety of other chemicals,such as surfactant(e.g.,nonylphenol polyoxyethylene ether),organic solvents(such as toluene)and so on.Pesticides on soil pollution are actually a variety of material compounds,so further exploration of the mechanism,causing the pollution,has important research significance to agricultural non-point source pollution and soil ecosystem functional recovery.In this paper,throush using DGGE,BIOLOG,determination of enzyme activity and soil C/N cycle detection methods and techniques,we studied the response of soil microbial community on 480g-L-1 chlorpyrifos EC,chlorpyrifos technical and nonyl-phenol polyoxyethylene ether.Results prove that,First of all,The soil was exogenous added 480g-L-1 chlorpyrifos EC(1.25mg·kg-1?12.5mg-kg-1 and 125mg·kg-1),caused the decrease of bacterial diversity and the increased of fungal diversity.Also,chlorpyrifos content was higher,the soil microbial community structure was more single.Three concertations of chlorpyrifos all significantly inhibit urease activity.And the higher the concentration of chlorpyrifos EC,the stronger the inhibition to acid phosphatase and catalase,but all concentrations of chlorpyrifos EC didn't affect the activity of invertase.The higher the concentration of chlorpyrifos EC,the stronger the soil microbial respiration,but all does didn't affect the nitrate transformation.Secondly,The soil was exogenous added chlorpyrifos(5mg·kg-1?50mg·kg-1 and 500mg·kg-1).Results of DGGE showed that only high dose treatment significantly inhibited fungal diversity,While results of BIOLOG showed that all dose treatments inhibited soil microbial diversity significantly,and this because results of DGGE contained inanimate microorganisms.Results of soil enzyme activity showed that chlorpyrifos technical didn't affect the activity of invertase,and the higher the concentration of chlorpyrifos technical,the stronger inhibition to urea enzyme.Every dose of chlorpyrifos technical suppressed soil catalase activity before promoted,and didn't influence acid phosphatase activity.Low doses of chlorpyrifos technical restrained soil microbial respiration,but didn't affect the transformation of nitrate;middle doses of which promoted respiration,but didn't affect the transformation of nitrate either;high doses of which didn't influence respiration,but inhibited the transformation of nitrate significantly.When the concentration of chlorpyrifos technical become higher,the faster of the initial degradation.And similarly,when the concentration become lower,the slower degradation.High dose technical still had chlorpyrifos residues after 60d,but low dose was undetectable at the time of 30d When middle dose degradated completely in 60d.Thirdly,The soil was exogenous added NP10EO(80mg·kg-1?800mg·kg-1 and 8000mg·kg-1).Results of DGGE showed that all dose treatments significantly changed the community of bacterium and fungi,but didn't influence the diversity of bacteria while influence the diversity of fungi.inhibited fungal diversity,While results of BIOLOG showed that all dose treatments inhibited soil microbial diversity significantly.Results of BIOLOG showed that all dose of chlorpyrifos technical treatment group increased soil microbial diversity ultimately.The reason of their difference may be that 31 species rich carbon source of BIOLOG experiments for the development of soil microorganisms had more advantages than the soil nutrition.High dose of NP10EO neither affect sucrase,urease and catalase nor acid phosphatase activity;Low and middle concertation treatments promoted all enzymes avtivity finally.All NP10EO treatments enhance soil microbial respiration and didn't affect the transformation of nitrate,but high dose of NP10EO could significantly inhibit the conversion rate of the nitrates in the soil and promote finally.In conclusion,every added exogenous pollutants have their own characteristics,but all have no influence on intervase activity.Chlorpyrifos EC and the active ingredient(technical)all inhibit urease activity,but don't NP10EO.And three kinds of exogenous additives have different influence on other kinds of soil enzyme activity.Recommended doses of chlorpyrifos technical can inhibit soil microbial respiration,while recommended doses of chlorpyrifos EC and NP10EO promote it.And low doses of three kinds of exogenous additives don't affect soil nitrate transformation.