[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns （corn field, cherry tree land, wood land） were selected from Hongta District, Yuxi City, and under these three patterns, soil microbial quantity and activity were studied. [Result] Under the three land use patterns, soil microorganisms were domi- nated by bacteria; soil microbial quantity ranked as wood land＇s〉cheery tree land＇s〉 corn field＇s; and total microbial activity, catalase activity and urease activity all ranked as cherry tree land＇s〉wood land＇s〉corn field＇s. [Conclusion] Soil microbial activity and functions are related to farmland management measures, as well as land use pattern and soil nutrients.
Using traditional microbiological culture method,under laboratory conditions,different concentrations of Cr6＋ were selected for stress culture on Pistia stratiote,Sagittaria sagittifolia and Myriophyllum spicatum.Through determination of the rhizosphere microorganism and the nitrogen cycle bacteria change of three kinds of aquatic macrophytes,the tolerance of rhizosphere microorganism to Cr6＋ was studied.The results showed that the sensitivity of microorganisms could be summarized as：actinomycete bacteria fungi,it has no obvious regularity about tolerance of 3 microorganisms;while the effects demonstrated their specificity on ammonification bacteria,nitrifying bacteria,nitrosococcus bacteria and denitrifying bacteria.
