四种常见农药对土壤呼吸作用的影响及其危害性评价

【作者】 王占华；

【导师】 袁星；

【作者基本信息】 东北师范大学 ， 环境科学， 2004， 硕士

【摘要】 长期以来，人们把测定土壤呼吸作用强度看作是衡量土壤微生物总的活性或作为评价土壤肥力的指标之一。随着农药种类和用量日益增多，在新农药开发和使用中，研究农药对土壤微生物呼吸作用强度的影响，已成为不少国家评价农药生态环境安全性的一个重要指标。目前，对大田和大棚蔬菜生产过程中农药污染的差别及农药对土壤呼吸作用的影响尚不十分清楚，开展此方面的研究更有实际意义。因此，本论文选取多菌灵、百菌清、吡虫啉、万灵为受试农药，用密闭直接吸收法测定了农药对三种土壤（农田土、大棚土和校园土）呼吸作用的影响；讨论了农药种类、浓度、土壤条件的改变引起的土壤呼吸作用强度的变化及土壤呼吸量与土壤中细菌数量变化的关系；确定了农药的毒性等级和危害系数，为农药使用的环境安全性评价提供科学依据。实验结果表明：多菌灵对农田土、大棚土和校园土土壤呼吸均有激活作用；百菌清、吡虫啉和万灵对农田土和大棚土的土壤呼吸有激活作用，而对校园土的土壤呼吸有抑制作用。在实验浓度范围内，农药对农田土壤呼吸激活作用的顺序为百菌清＞多菌灵＞万灵＞吡虫啉。浓度为1mg/kg和10mg/kg的农药对大棚土壤呼吸激活作用的顺序分别为多菌灵＞万灵＞吡虫啉＞百菌清、多菌灵＞吡虫啉＞百菌清＞万灵；除百菌清外，浓度为100mg/kg的农药对大棚土壤呼吸激活作用的顺序为多菌灵＞万灵＞吡虫啉。农药对校园土壤呼吸的抑制作用顺序分别为：万灵＞吡虫啉＞百菌清（1mg/kg）；百菌清＞吡虫啉＞万灵（10mg/kg）；万灵＞百菌清＞吡虫啉（100mg/kg）。多菌灵和百菌清对土壤细菌数量的影响与对土壤呼吸作用的影响趋势基本一致；吡虫啉和万灵对土壤细菌生长起激活作用，对土壤呼<WP=4>吸的抑制可能是抑制了其他菌群的生长所致。通过毒性评价，四种常见农药对土壤微生物均属低毒或无实际危害级农药。更多还原

【Abstract】 For a long time, soil respiration strength was considered as one of the guide lines for soil microorganism activity or soil fertility. Following the increasing of pesticides’ sorts and quantity, during the development and using of new pesticides, it has been one important criterion of evaluating pesticides’ environment safety for many countries that researching the soil respiration strength under pesticide action.Now, it is not very clarity that the difference of pesticide pollutions and the soil respiration under pesticide action during the production of field and shed vegetables. It has more practical significance to carry such researching. This paper chose Carbendazim, Daconil, Imidacloprid and Methomyl as experiment objects, determined their influence to soil respiration of field, shed and school using obturate direct absorb method; discussed not only the variety of soil respiration under different pesticide’s sorts, concentration and soil conditions but also the relationship between soil respiration and the variety of bacteria number in soil; confirmed the toxicity grade and dangerous index; provided an scientific basis for environment safety evaluation of pesticide’s using.The experimental results indicate:Carbendazim can activate the soil respiration of field, shed and school; Daconil, Imidacloprid and Methomyl can active the soil respiration of field and shed, while have prohibitive effection to school soil.Under the experimental concentrations, the order of pesticide that can activate the soil respiration of field was: Daconil > Carbendazim > Methomyl > Imidacloprid.When the concentrate was 1mg/kg and 10mg/kg, the order of pesticides that can activate the soil respiration of shed respectively was: <WP=6>Carbendazim >Methomyl >Imidacloprid >Daconil, Carbendazim > Imidacloprid > Daconil > Methomyl; when the concentrate was 100mg/kg, the pesticides’ order was Carbendazim > Methomyl > Imidacloprid except Daconil.The order of pesticides that restrain school soil’s respiration respectively was: Methomyl > Imidacloprid > Daconil (1mg/kg); Daconil > Imidacloprid > Methomyl (10mg/kg); Methomyl > Daconil > Imidacloprid (100mg/kg).Carbendazim and Daconil have the almost same influence to soil bacteria’s number and soil respiration; Imidacloprid and Methomyl can activate the growth of soil bacteria, the restrain to soil respiration maybe caused by inhibiting the growth of others bacteria groups.Through the toxicity evaluation, these 4 kinds of pesticides in common used were all to be the low toxicity or no toxicity grade to soil microorganisms.更多还原