Abstract: Litter decomposition provides nutrients for soil and is a major contributor to soil organic matter formation. In this paper， 189 sets of valid data were collected from 30 literatures published in grassland ecosystems， and the effects of warming on litter decomposition in terrestrial ecosystems were studied by meta-analysis. The results showed that decomposition rate of litter was significantly increased when the temperature range was less than 1℃ （P<0.05）， but decreased when the temperature range was more than 1℃. Annual mean precipitation （MAP） could regulate the effects of warming on litter decomposition， and low annual mean precipitation （≤300 mm） could promote litter decomposition under warming， high annual precipitation （≥600 mm） inhibited litter decomposition. In addition， soil organisms and litter mass also had different effects on litter decomposition. The appropriate soil organisms （0.5-1 mm） could promote litter decomposition， and the higher the litter matrix quality was， the higher the litter mass was the faster the litter decomposition rate. The above results indicated that temperature increase would significantly affect litter decomposition， and the magnitude and direction of the influence were related to the average annual precipitation， soil biology and litter quality.

Key words: Warming, Grassland, Litter decomposition, Influencing factors

摘要： 凋落物分解能够为土壤提供养分，是土壤有机质形成的主要贡献者。为探究增温对草地生态系统凋落物分解的影响及主要影响因素，筛选国内外已发表的30篇相关文献，共收集到189组有效数据，然后进行Meta分析。结果表明：增温幅度是影响凋落物分解的主要因子，增温幅度<1℃时，凋落物分解速率显著（P<0.05）增加，而增温幅度>1℃时，凋落物分解速率则会降低。年平均降水量（Mean annual precipitation，MAP）会调节增温对凋落物分解的效应；MAP≤300 mm时，增温会促进凋落物分解，MAP>600 mm时，增温有抑制凋落物分解的作用。此外，土壤生物和凋落物质量也会对凋落物分解产生不同的影响效应，中型土壤生物（0.5~1 mm）增强了增温对凋落物分解的效应，增温加速了高木质素含量凋落物的分解。以上结果表明增温会显著影响凋落物的分解，影响大小和方向与MAP、土壤生物和凋落物质量有关。

关键词: 增温, 草地, 凋落物分解, 影响因素