Abstract: This paper summarized the effects of herbicides and germicides on the farmland ecosystem. The herbicides had influence on various plants, animals and microorganisms (including fungi).The germicides influenced mainly on bacteria and fungi, caused the change of the composition of microbiological populations.The durability and selectivity of agricultural chemicals should be controlled and regulated for reducing the unfavorable consequences of their application to the farmland ecosystem.

Key words: Biomarkers, ChE, GST, Gammarus pulex L