盐胁迫下甲维盐·毒死蜱对菜田土壤微生物生态效应研究

采用实验室盆栽方法,运用正交试验探究盐与复配农药甲维盐·毒死蜱的复合污染对菜地土壤中酶活性与微生物数量的影响.结果表明:盐胁迫和甲维盐·毒死蜱分别作用下土壤中的脲酶、蔗糖酶、脱氢酶和过氧化氢酶活性均受到不同程度的抑制作用,且随着盐分水平和甲维盐·毒死蜱浓度的升高呈显著下降趋势;土壤细菌、真菌和放线菌数量亦随土壤盐分和甲维盐·毒死蜱浓度的增加而减少.随着时间的延长,农药在土壤中不断被降解而减少,对微生物的毒害性也就随着减弱,并最终恢复到与对照组相一致的水平.但是在与高盐复合胁迫时,土壤微生物数量与土壤酶活性始终处于被抑制状态,由此可以说明盐胁迫是抑制土壤微生物数量和酶活性的主导因素.

Effects of Salt and Emamectin Benzoate-Chlorpyrifos Mix on Ecological Characteristics of Microorganisms in Vegetable Soil

Soil microorganisms and enzyme activities are important indicators of soil ecosystem responses to environmental stresses. The impacts of salt and emamectin benzoate-chlorpyrifos mix on soil enzyme activities and microorganism population in a vegetable soil was examined using the orthogonal experimental design and pot culture. Results showed that the activities of soil urease, sucrase, dehydrogenase and catalase were inhibited in varying degrees by salt and emamectin benzoate-chlorpyrifos mix in a dose-effect mode. Similarly, the populations of soil bacteria, fungi, and actinomycetes decreased with increasing stresses. As time passed, the pesticide degraded gradually, thus reducing its toxicity and restoring the soil microbes to the control level. However, soil enzyme activities and microorganism quantities were inhibited all the time under co-existence of salt and pesticide. These results suggest that salt stress is the controlling factor of soil enzyme activity and microorganism inhibition by pesticides.