English

Abstract

The effects of three years continuous application of different rates of bio-organic fertilizer (BOF) were evaluated on three kinds of the counts of soil microbes, microbial metabolic activity and disease index of Verticillium wilt through greenhouse pot experiments. The results showed that, the BOF not only reduced the occurrence of verticillium wilt in cotton and decreased the counts of V. dahliae, but also improved the number of fungi, bacteria, actinomycetes, and microbial activity. The number of V. dahliae reduced gradually and fungi, bacteria, actinomycetes and average well color development (AWCD) firstly increased and then decreased with increasing the amount of fertilization in different organic matter content of soil. The number of V. dahliae was significantly increased by three years of fertilization. It showed that application of bio-organic fertilizer only delays the growth in the number of pathogen in soil within a certain time. The numbers of bacteria, actinomycetes were increased and the number of fungi was slightly reduced with increase of fertilization period. Application of bio-organic fertilizer made AWCD significantly higher than no fertilization (CK). By cluster analysis and principal component analysis, the results showed that the classification similar to disease index of various treatments, and it coincided with the number of microorganisms and AWCD values. BOF not only can control and improve the metabolic characteristics of soil microbial communities, but also maintain a high soil biological activity.© 2016 Friends Science Publishers Keyword: BOF; BIOLOG; Cotton verticillium wilt; V. dahliae; Principal component analysis