Impacts of organic materials returning on redistribution of soil labile organic carbon fractions in a Chinese Mollisols

摘要

Labile organic carbon is the most active part of soil organic matter. Because of their dynamic nature, labile fractions of organic carbon such as microbial biomass organic C (MBC), light fraction organic C ( LFOC) and water -soluble organic C ( WSOC) pools can respond rapidly to the changes in C supply. Such components have therefore been suggested as early indicators of the effects of soil management on soil organic matter quality, even soil quality (Gregorich et al. 1994; Haynes et al. 1996). Owing to long -term inappropriate farming practice, Mollisols (black soils) tend to degrade over time in Northeast China, and chemical fertilizers and different kinds of organic materials were applied to improve soil fertility. This paper described how soil organic matter quality, as estimated using labile organic matter fractions ( LFOC, MBC and WSOC), is influenced by various organic materials returning systems in a Mollisols.