Influence of Freshwater Marsh Tillage on Microbial Biomass and Dissolved Organic Carbon and Nitrogen
湿地垦殖对土壤微生物量及土壤溶解有机碳、氮的影响

The changes in microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) were examined in order to assess the effect of surface layer soil (0 - 10 cm) under different land-use types after freshwater marshes tillage in the Sanjiang Plain Northeast China. Land uses were Deyeuxia angustifolia freshwater marshes ((DAM), cultivated land (CL), recovery freshwater marsh (RFM), constructed woodland (CW). After DAM soil tillage, MBC, MBN, DOC and DON declined strongly in agricultural surface soil layer, decreased 63.8%-80.5% (MBC), 56.3%-67.1% (MBN), 43.1%-44.3% (DOC) and 25.2%-56.1% (DON) respectively. In contrast, these C, N fraction had significant recovered in RFM and CW surface soil, increased 36.1%-59.9% (MBC), 46.7%-65.9% (MBN), 67.0%-69.3% (DOC)and 81.2%-88.3% (DON) respectively. Cultivation and land-use affected soil MBC, MBN, DOC and DON intensely. Therefore these labile C, N fractions have the significant relative under different land-use types. However DOC was more obvious controlled than DON by the land-use types. The relative between DOC and MBC, MBN have much difference than DON, the main reason of this distinction is the diverse source in available carbon and nitrogen that taken by microbial property under different land uses.