三峡库区马尾松林土壤呼吸的空间变异特征

基于对三峡库区秭归县典型马尾松林样地土壤呼吸速率的测定,采用传统统计方法与地统计学方法,对样地尺度下土壤呼吸空间变异特征进行研究,并分析研究地土壤理化性质、微生物量、细根生物量等因子对土壤呼吸的空间异质性的影响。结果表明:三峡库区马尾松林土壤呼吸时间异质性明显,土壤温度是导致季节动态的主要因子。各季节土壤呼吸空间变异系数在32.6%~46.3%之间,属于中等变异。不同季节土壤呼吸均具有良好的空间自相关特征,并表现出明显的斑块分布格局,可由球状模型和指数模型拟合。在样地水平上,土壤速效氮含量、土壤孔隙度和细根生物量是导致土壤呼吸空间异质性的主导因子。

Spatial variability characteristics of soil respiration of Pinus massoniana forest in Three Gorges Reservoir Area

Based on the continuous measurement of the soil respiration of typical Pinus massoniana forest in Zigui County of Three Gorges Reservoir Area,the spatial variation characteristics of soil respiration in sample scale was studied. The effects of factors including physical and chemical properties of soil,microbial biomass and fine root biomass on spatial heterogeneity of soil respiration were analyzed using geostatistics combining with the classic statistics. The results showed that soil respiration had an obvious seasonal dynamics due to the changes of soil temperature among different seasons. Soil respiration had a moderate variation in each season with a coefficient of variation between 32.6% and 46.3%. Soil respiration had a spatial autocorrelation characteristic and a clear patchy distribution,and could be described well by spherical model or exponential model. Spatial variation of soil respiration in the forest stand was controlled by the biomass of fine root,the porosity of the surface layer soil and the soil available nitrogen.