Dr. LIU Lei and ZHANG Tao from South China Botanical Garden investigated the responses of soil microbial biomass and community composition to phosphorus (P) addition in three tropical forests. They found that addition of P significantly altered the microbial community composition and increased soil respiration in old-growth forest, which was nitrogen (N) saturation. In contrast, P addition had no (or few) effects on the microbial biomass and community composition in both disturbed forests, which were still N-limited. This work was guided by Prof. MO Jiangming from ecosystem management group of South China Botanical Garden and Prof. Per Gundersen from University of Copenhagen.

It is widely believed that tropical forest ecosystems were P limited due to long-term of weathering and leaching. High N deposition originated from human activities would stimulate P limitation in tropical forests. The results of this study indicate the importance of available P in tropical/subtropical forest soils and the possibility of decreased available P due to N deposition which would limit decomposition of organic matter. The investigation is important for explaining the possible mechanism of accumulation of carbon from old-growth forest soils.

This study was founded by National Key Basic Research 973 Program, National Natural Science Foundation of China, and Natural Science Foundation of Guangdong Province, China. This paper has been published online on Soil Biology & Biochemistry (http://www.sciencedirect.com/science/article/pii/S0038071711003233).

secondary forest - coniferous and broad-leaved mixed forest site