CHANGES OF SOIL MICROBIAL PROPERTIES AFFECTED BY DIFFERENT LONG-TERM FERTILIZATION REGIMES

Aims Soil health is important for sustainable development of terrestrial ecosystems. We studied soil microbial properties such as microbial biomass, functional diversity of microbial communi-ties and soil enzyme activities in order to illustrate the function of soil microbial properties as bio-indicators of soil health. Methods A 15-year fertilizer experiment on Fluvo-aquic soil in Changping County, Beijing, China, was established in a wheat-maize rotation in 1991 to explore long-term impact of four different fertili-zation regimes: no fertilizer (CK), mineral fertilizers (NPK), mineral fertilizers plus swine manure (NPKM) and mineral fertilizers with maize straw incorporated (NPKS). We used BIOLOG ECO mi-cro-plate analysis to study the functional diversity of microbial communities. Important findings Long-term fertilization regimes had clear effects on soil microbial properties compared to CK. Soil microbial biomass C N, urease activity, soil organic matter, soil total nitrogen, and soil total phosphorus increased more with NPKM and NPKS than with NPK and CK. The utiliza-tion ability of microbial communities for carbon and functional diversity of microbial communities in-creased to some extent with NPKM and NPKS, but had no significant differences with CK. NPKM and NPKS could significantly decrease soil pH and C/N. The utilization ability of microbial communitiesfor carbon and the functional diversity of microbial communities under CK were much higher than those under NPK since the other soil microbial properties were higher under NPK treatment. Catalase activity had no obvious differences among the four treatments. Principal component analysis of carbon utilization for soil microbial communities indicated there were different carbon substrate utilization patterns among the fertilization treatments.