森林凋落物分解研究进展

森林凋落物是指森林生态系统内由生物组分产生,然后归还到林地表面的所有有机物质的总称。森林凋落物在促进森林生态系统正常的物质循环和养分平衡,维持生态系统功能中具有重要作用,其分解受多因素影响,且各因素之间相互交错。不同情况下,各因子的重要性可能不同。温度和湿度被认为是影响凋落物分解主要的气候因子。凋落物随着温度升高分解速率加快,增加土壤湿度对凋落物分解有积极作用。凋落物的化学性质中,C、N比和木质素含量被认为是最重要的指标。凋落物分解前期的分解速率受到养分含量、水溶性碳化合物和结构碳化合物含量的强烈影响,而后期则更多地受到木质素及纤维素/木质素比值的支配。土壤动物可以粉碎凋落物,土壤微生物也是促进凋落物分解的重要因素,人为活动也影响凋落物分解。N沉降、全球变暖和臭氧层破坏等全球变化对森林凋落物分解的影响已逐渐成为研究热点。未来凋落物分解的研究方向是统一研究方法,开展长期定位监测,加强对分解过程中有机碳含量和释放量的研究,以及N沉降对凋落物分解作用机理的研究。

Review on forest litter decomposition

Forest litter is defined as the organic matter produced from biological component in forest ecological systems and then returned to woodland surface. Forest litter plays a significant role in promoting the circulation of substances, nutrient balance and maintaining the functions of the forest ecosystem. Its decomposition is influenced by a variety of mixed factors. Each factor may take a different level of importance in different situations. Temperature and humidity are considered to be the major climatic factor to affect the litter decomposition. Litter decomposition is prompted by increase of temperature and soil water. In the litter's chemical properties, beth the ratio of C and N and the lignin content are regarded as the most important indexes. Litter decomposition rate is strongly affected by nutrient content, water-soluble carbon compound and structural carbon compound in early decomposition period, whereas it is mainly controlled by lignin and cellulose/lignin ratio in later decomposition period. Soil animal can break litter, soil microorganism is an important factor for litter decomposition and human activities also have influence in the litter decomposition. The influences of global climatic change on forest litter, such as N sedimentation, global warming and ozonosphere destruction, have become hot spots of scientific researches. In the future, litter decomposition research will focus on unification of study method, de-veloping long-term and location research, reinforcing studies on content and release amount of organic carbon during decomposition process and action mechanism of N sedimentation on litter decomposition.