Effects of Cattle Manure and Green Manure on the Microbial Community Structure in Upland Soil Determined by Denaturing Gradient Gel Electrophoresis

Abstract

Fungal and bacterial communities were investigated by denaturing gradient gel electrophoresis (DGGE) and a pattern-based analysis after the application of two types of organic fertilizer (cattle manure and green manure). Crops were not cultivated in the experimental plots in order to minimize the effects of plants on the microbial communities. Unexpectedly, the microbial populations and DGGE profiles in the soils treated with cattle manure did not differ significantly from the controls. Although the microbial populations in the soils amended with green manure were significantly higher throughout the two-year experiment, differences in the DGGE band profiles were minor. A principal component analysis (PCA) demonstrated a succession of differences in the DGGE profiles, as the application of green manure slightly affected the fungal community. Principal component and sequence analyses for characteristic DGGE bands identified close relatives of Chaetomium globosum, Fusarium oxysporum, and Mortierella alpina which appeared to be involved with the decomposition of green manure. These results suggested that the application of green manure was more effective at increasing microbial populations than that of cattle manure, and activated several characteristic fungi which should be considered to play a significant role in the decomposition of green manure.