Labile factions of soil organic matter and microbial characteristics of soil under organic and conventional crop management systems

摘要

The aim of this study was to compare contents of labile fraction of soil organic matter and microbial parameters in soil under winter wheat and spring wheat grown according to organic, without animal manure application, and conventional crop management systems. Particulate organic matter fraction in the organically managed soil was significantly higher by 26% than that in the soil under the conventional farming system. Culturable colony forming units of bacteria and fungi, dehydrogenase and alkaline phosphatase activities, as well as C contents in microbial biomass and in hot water extracts (HWE) were significantly higher for the organic soil than for the conventional system. HWE prepared from both soils contained almost the same amounts of total N, but microbial biomass-N was higher in the organic soil. These results indicate that organically managed soils can maintain a high biological activity and substantial pools of readily available nitrogen even without application of animal manures.