| Global hydrological cycle changed with global climate change, resulted in frequent occurrence of drying-rewetting of soil and influenced the decomposition of soil organic matter. Carbon reserve in wetland occupied more than25%of terrestrial carbon reserve. So it was important to do study the effect of drying-rewetting on decomposition of wetland soil carbon. In order to understand what the effect of drying-rewetting on litter and soil organic matter decomposition in wetland, the dynamic change of soil organic carbon and litter decomposition in three types of soil in Zoige Wetland were analyzed:wet soil (100%of water holding capacity), dry soil (60%of water holding capacity) and drying-rewetting soil. Results showed that:1. Compared with wet soil, drying-rewetting could promote the litter decomposition. Rate of litter decomposition decreased with time.2. Drying-rewetting had a significant impact on soil CO2emission, and the emission rate decreased with time. In wet soil, CH4emission rate increased first and then decreased. In drying-rewetting soil, CH4emission rate increased and the cumulant enhanced by litter input. In this study, soil N2O emission had no responses to litter input. N2O emission rate fluctuated widely during incubation.3. Soil microbial biomass carbon (MBC) and dissolved organic carbon (DOC) decreased with time, which were significantly influenced by litter、time and moisture. There were interactions during the factors.4. The size and direction of priming effect changed with time. At the end of incubation, the priming effect caused by litter input of wet soil was higher than drying-rewetting soil and dry soil. At the early stage, there was negative priming effect. Then it turned to positive and reached the maximum. In a word, drying-rewetting would promote the litter decomposition, increase the emission of CO2and N2O, inhibit the emission of CH4and show significant priming effect of soil organic matter, compared with wet soil. |
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