Litter decomposition in China.xlsx

The feedback between litter and climate is partly determined by litter turnover time (LTT) that is affected by climate, litter and soil properties. However, the earth system models that simulate C-climate feedbacks are largely untested with respect to LTT and the interplay between these variables and LTT are rarely quantified. To investigate the direct and indirect effects of climate variables, litter quality, and soil properties on LTT, we obtained 1378 LTTs and their respective environmental variables from 246 published papers, which spanned forest, grassland, and cropland ecosystems. We analyzed the spatial pattern of LTT and investigated the direct and indirect effects of these variables on LTT. The mean LTT was longest in forest ecosystems, followed by grassland and cropland ecosystems. LLT varied significantly according to litter tissues (root, stem, and leaf), litter species, and climate zones. Mean annual temperature (MAT) and precipitation (MAP) best predicted LTT when we used negative exponential equations. Among these variables, the most influential variable on LTT was MAT for the forest litter and cropland litter, and MAP for grassland litter. Climate (MAT and MAP) accounted for more than half of the relative influence on LTT, followed by litter quality (litter tissues, carbon to nitrogen ratio of litter, and lignin content), and soil properties (soil organic carbon and sand content). Path analysis identified MAT negatively affected LTT both directly and indirectly through decreasing litter quality and soil properties. MAP negatively affected LTT by decreasing lignin content. Lignin content positively affected LTT both directly and indirectly through increasing soil organic carbon. <i>Synthesis</i>. Our results suggest that climate variables has contrasting effects on LTT and could mediate litter quality and soil properties to control LTT. These results highlight important implications for climate-smart soil management and aid the reliable model predictions.