Long-term cattle manure application in soil. II. Effect on soil microbial populations and community structure

Studies were conducted to evaluate microbial populations and community structures in soils under different management systems in a long-term continuous winter wheat experiment. These soils had been treated with cattle manure for over a century, and P, NP, NPK, or NPK plus lime for over 70 years. Cattle manure application promoted the growth of bacteria, but not fungi, when compared with the control soil. Application of chemical fertilizers enriched the K-strategist bacterial community, while application of manure enriched both r- and K-strategists. DNA recovered was most abundant in the manure-treated soil. Effects on bacterial species richness and evenness following long-term soil treatments were also demonstrated by analyzing bacterial community DNA using amplified ribosomal DNA restriction analysis and repetitive extragenic palindromic-polymerase chain reaction fingerprinting. The richness and evenness of the bacterial community were enhanced by manure treatment and treatments that included N and P, which were positively correlated with soil productivity.