Influence of erosion on soil microbial biomass,abundance and community diversity

This study aimed to determine microbial biomass carbon and microbial abundance immediately after, and two years after, forest soil erosion, so as to estimate the degree of damage, including the rate of recovery of microorganisms, in each area. It also aimed to determine the community diversity, and to establish relationships between microbial biomass, microbial abundance and the physico‐chemical properties of the soil. Three different study areas in Hiroshima Prefecture, Japan, were used. One undisturbed area and two eroded areas (one immediately after and one two years after erosion). The analysis of variance showed a highly significant difference in microbial biomass carbon and abundance between the study areas. The undisturbed area showed the highest value, followed by the area eroded two years ago, then lastly the area studied immediately after the erosion. The biomass carbon was highly correlated with gram positive bacteria with r² = 0·983, p < 0·01. The biomass carbon and microbial population were shown to be significantly correlated to the soil's physico‐chemical properties, such as pH, moisture content, water‐holding capacity and CN ratio. However, CN ratio proved to be closely correlated to biomass carbon with r² = −0·978, p < 0·01, to Gram‐positive bacteria with r² = −0·977, p < 0·01, to Gram‐negative bacteria with r² = −0·989, p < 0·01 and to fungi with r² = −0·977, p < 0·01. The undisturbed area showed a highly diverse community in both of the restriction enzymes used, followed by the area affected by erosion two years ago, then the area immediately after erosion. Copyright © 2004 John Wiley & Sons, Ltd.