三峡库区兰陵溪小流域3种林型土壤呼吸组分的量化

Soil Respiration and Its Components Partitioning of Three Types of Forests in Lanlingxi Small Watershed of Three Gorges Reservoir Area

采用壕沟法和红外气体分析法测定了三峡库区兰陵溪小流域针叶林、阔叶林、针阔混交林的土壤总呼吸（Rt）、根系呼吸（Rr）、地上凋落物分解（Rl）及土壤有机质分解（Rs）的呼吸速率，量化了土壤呼吸各组分对土壤总呼吸的贡献率。结果表明：3种森林类型的土壤总呼吸及组分的呼吸速率均呈现出明显的季节变化．夏秋季最高，冬季最低；Rr在春季和秋季的贡献率较高，蜀在秋季对R．的贡献最高，而段在春季和夏季的贡献率较高；针叶林、阔叶林、针阔混交林三种林型，置的年均值分别为1．61、1．47、2．04μmol·m-2·S-1、Rr的年均值分别为0．47、0．35、0．76μmol·m-2·S-1，Rl的年均值分别为0．38、0．16、0．48μmol·m-2·S-1，Rs的年均值分别为0．76、0．96、0．80μmol·m-2·S-1。在3种类型森林中，对土壤总呼吸Rt年贡献率最大的是Rr（39％～65％），其次是足（24％～37％），最小的为Rl（11％～24％）。

Trenching plot approach and infrared gas exchange analyzer were used to determine the soil respiration and its components for the coniferous forest, broad-leaved forest and conifer-broadleaved forest in Lanlingxi small watershed of Three Gorges Reservoir Area. The soil respiration （Rt） includes root respiration （Rr ）, aboveground litter decomposition （Rl ） and belowground soil organic matter decomposition （Rs ）. The respiration rates of Rs, Rr, Rl and Rs are higher in summer and autumn than those in winter. Rr is higher in spring and autumn, Rt in autumn was biggest, while Rs is higher in spring and summer. The mean annual rates of Rt, Rr, Rl and Rs of coniferous forest, broad-leaved forest, conifer-broadleaved forest are 1.61, 1.47, 2.04 μmol·m-2·S-1, 0.47, 0.35, 0.76μmol·m-2·S-1 , 0.38, 0. 16, 0.48μmol·m-2·S-1, and 0.76, 0.96, 0.80μmol·m-2·S-1 , respectively. The highest annual rate is Rs of 39% -65% followed by Rr of 24%-37% , and the lowest is Rl of 11%-24%.