土壤有机碳和氮分解对温度变化的响应机制

Response mechanisms of soil carbon and nitrogen decomposition to temperature change

土壤碳和氮分解对温度变化响应过程是气候变化对陆地生态系统碳汇影响的关键。本文针对土壤有机碳和氮分解对温度变化响应机制和假说进行了概括分析。土壤碳和氮分解对温度变化的响应机制主要包括:土壤有机质的稳定性、质量及有效性,微生物生物量和活性及群落结构或多样性,土壤湿度,以及植被生产力、凋落物和pH等因素的作用。对这些机制还存在很大不确定性,需要考虑土壤有机质组分或微生物属性,同时需要考虑土壤有机质组分与微生物属性间的相互作用,以及土壤碳和氮分解对温度变化短期和长期响应过程的差异。土壤碳和氮分解对温度变化的响应机制的3个假说包括有机质分解质量-温度假说、有机质物理化学过程假说和功能移动假说,这些假说还需要验证和补充完善。

The response of soil carbon and nitrogen decomposition to temperature change is crucial for the impact of climate change on terrestrial ecosystem carbon sink. In this paper, the mechanisms and hypotheses about the effects of temperature change on the decomposition of soil carbon and nitrogen were reviewed. The mechanisms mainly include the functions of the stability, quality, and availability of soil organic matter （SOM）, the biomass, activity, community structure, and diversity of soil microbes, the water content in soil, the productivity of vegetation and litter, and the soil pH. There are still uncertainties for the mechanisms about the effects of temperature change on the decomposition of soil carbon and nitrogen, and it is necessary to consider the SOM fractions with different stability, the features of microbes, the interactions between SOM fractions and soil microbial features, and the differences of the long-term and short-term responses of soil carbon and nitrogen decomposition to temperature change. The hypotheses about the effects of temperature change on the decomposition of soil carbon and nitrogen include carbon quality-temperature hypothesis, physical-chemical hypothesis, and functional shift hypothesis. Further researches and experiments are necessary to test and improve these hypotheses.