A missing sink in forest ecosystems, the effect of dwarf bamboo understory on soil carbon sequestration

为评价矮竹林下植被对森林生态系统土壤固碳的影响，比较了两个相邻落叶阔叶林样地表层矿物层土壤碳含量和溶解有机碳（DOC）通量。由于凋落物的存在，Sasa站有机层DOC通量比非Sasa站高20%。我们还应用Rothamsted碳（Roth C）模型估计了林下Sasa森林土壤中有机质的碳固存。模拟了15年的三种情景：A（地上树木凋落物产生），B（地上树木和莎莎凋落物产生），C（地上和地下树木和莎莎凋落物产生）。在情况C（ca. 0.7tC ha ~（-1）yr ~（-1））高于方案A和B。这些结果表明，Sasa通过增加DOC的吸附量对土壤碳的固定具有积极的启动作用，Sasa的凋落物（尤其是地下凋落物）的产生对落叶阔叶林SOC的固定具有重要作用。

To evaluate the effect of dwarf bamboo (Sasa senanensis) understory on soil carbon sequestration in forest ecosystems, we compared the soil carbon content and the dissolved organic carbon (DOC) flux for a surface mineral horizon between two adjacent deciduous broad-leaved forest sites. The DOC flux of the organic horizon at the Sasa site was 20% higher than that at the non-Sasa site because of a presence of Sasa litterfall. We also estimated the carbon sequestration of organic matter in forested soil with understory Sasa by applying the Rothamsted carbon (Roth C) model. A 15-year simulation was run three scenarios: A (aboveground tree litter production), B (aboveground tree and Sasa litter production), C (above- and belowground litter production of trees and Sasa). The annual SOC accumulation in case C (ca. 0.7tC ha-1 yr-1) was higher than that of case A and B. These results suggest that Sasa exerts a positive priming effect on soil carbon sequestration by increasing the amount of DOC sorption, and that litter production (especially for belowground) of Sasa are important to SOC sequestration in deciduous broad-leaved forestecosystems.