土壤呼吸是碳循环中的1个重要过程,土壤呼吸作用的过程及其影响因子对理解陆地碳循环极为关键.本文对迄今为止国内外关于土壤呼吸时空变异性影响因素的一些研究进行综述,分析了气候、植被、土壤因素对土壤呼吸变异性的影响规律.以往的研究表明,气候因素中对土壤呼吸具有重要影响的因子为气温和降水,植被因素中对土壤呼吸具有重要影响的因子为叶面积指数、凋落物质量、细根生物量,而土壤因素中的有机碳含量、质地对土壤呼吸具有影响.气候、植被、土壤因素对土壤呼吸的影响往往表现为综合作用.温度、降水一方面直接影响土壤中根系和微生物的呼吸速率,另一方面通过影响植物、微生物生长以及土壤条件从而间接影响土壤呼吸.要更深入地了解土壤呼吸时空变异性的影响因素,须解决4个方面的主要问题,分别为:定量区分土壤呼吸中自养和异养组分,土壤呼吸观测方法及时间尺度统一,土壤呼吸与环境因子的同步观测,加强对湿地生态系统土壤呼吸的观测.
Soil respiration is an important process in carbon cycling.Understanding the processes and controlling factors of soil respiration are crucial in investigating the terrestrial carbon cycling.This article reviews the investigations about the factors controlling the temporal and spatial variability of soil respiration.The temporal and spatial variability in soil respiration is linked with climate,vegetation and soil factors.Air temperature and precipitation generally contribute great to the variability of soil respiration.Leaf area index(LAI),litter fall and fine root biomass are three plant-related factors that can be employed to explained the variability of soil respiration,while soil carbon content and texture are two soil factors responsible for the variability of soil respiration.Generally,climate,vegetation and soil factors contribute collectively to the temporal and spatial variability of terrestrial soil respiration.Temperature and precipitation,on the one hand,directly affect the root and microbial respiration rates.On the other hand,temperature and precipitation indirectly affect soil respiration by influencing the plant and microbial growth and soil conditions.In order to understand the controlling factors of the temporal and spatial variability of soil respiration,there are four main issues need to be addressed.The issues include quantitatively partitioning the autotrophic and heterotrophic components of soil respiration,standardizing the method and scale of measuring soil respiration,coupling measurements of soil respiration with environmental factors and performing more measurements of soil respiration in wetland ecosystems.