Microbial Ecological Characteristics And Biological Indexes In Paddy Soils Polluted By Cr(Ⅵ) Ion

Heavy metals are very important kinds of contaminations in soil, so building a system of alarming and evaluating for soil repairing is becoming more and more scorching in the study of soil environment. However, prevenient scholars were rarely studied the influence between periods of rice and indexes. In this paper, microbial characteristics and biochemical indicators were studied in paddy soils which were simulative conducted by different concentration of Cr(â…¥). Through studying, We try to explore what on earth indexes are the most sensitive, what's the relationship between periods of rice and the indexes, and what's the effect of Si on the soil contaminations. The main results of this study are presented:1, There were significant negative relationships among soil microbial biomass carbon, microbial biomass nitrogen, basal respiration, urease activity, ammonification activity and denitration activity and the availability of Cr(â…¥), by contraries, the contaminative soil had a positive relationship or close positive relationship between soil microbial biomass C/N and soil catalase activity and the availability of Cr(â…¥).2, Obvious differences were found among indexes, In this paper, soil microbial biomass carbon, microbial biomass nitrogen, C/N and urease activity were the most sensitive indexes.3, The amounts of soil bacteria were activated by low concentration Cr(â…¥), however, the high concentration Cr(â…¥) played the adverse role, There were significant negative relationships among the amounts of soil fungi, actinomycetes and potassium solubilizing bacteria, however, the amounts of soil phosphate solubilizing bacteria were significant in paddy soils.4, The sensitive degree of each index were dissimilar in different periods of rice, but the indexes were hardly disturbed by heavy metals.