Microbial biomass carbon, nitrogen and phosphorus in the soil profiles of different vegetation covers established for soil rehabilitation in a red soil region of southeastern China

This study investigated the distribution of microbial biomass carbon ( MB- C ), nitrogen ( MB- N ) and phosphorus ( MB- P ) in the soil profiles of five different vegetation systems including bare area ( Br ), Bamboo ( Bmb ), Chinese Fir ( CF ), Citrus Orchard ( Ctr ) and Rice field ( Rf ). The MB- C levels in the Bmb system were higher than those in the other systems, and it decreased with increasing soil depth in all vegetation systems except the Bmb. The highest MB- N was detected in the top 20 cm of soil for the Bmb and in the 20 similar to 40 cm soil layer for the other vegetation systems such as Ctr, CF and Rf. The order of soil MB- P levels from highest to lowest was as follows: Bmb > CF > Ctr > Rf > Br. In all vegetation systems the level of MB- P decreased with increasing soil depth. Experimental results showed that the ratio of MB- C to TOC ranged from 0.75 similar to 2.7%, agreeing well with ranges previously reported by many others. Results also indicate that vegetation covers and management practices have a strong impact on the development and distribution of soil microbial properties in the soil profile.