红壤侵蚀地马尾松林恢复后土壤有机碳库动态

运用RothC(version 26.3)模型,并结合“时空代换法”对长汀河田红壤侵蚀退化地马尾松人工恢复后林地表层(0-20cm)土壤有机碳库的动态变化进行了反演和预测,研究结果表明:RothC 26.3模型的模拟结果能够较好地反映红壤侵蚀地植被恢复过程中土壤有机碳的变化趋势；RothC 26.3模型适用于中亚热带季风气候条件下马尾松林地土壤碳库的动态模拟；侵蚀退化地在马尾松林建植后,林地表层土壤碳吸存速率以非线性的形式上升,并在15-25a时间内达到最大,马尾松恢复后前30a林地土壤平均碳吸存速率约为0.385 tC·hm-2· a-1,自马尾松建植后演替至当地顶级群落(次生林)全过程中平均碳吸存速率约0.156 tC·hm-2·a-1；根据模拟结果得到的拟合方程,计算得到研究区红壤侵蚀退化地的碳饱和容量约为36.85 tC/hm2,固碳潜力约为33.26 tC/hm2.

Dynamic of soil organic carbon pool after restoration of Pinus massoniana in eroded red soil area

Afforestation in degraded area is thought to be an efficient way commonly adopted all over the word to prevent soil degradation, and plays an important role in alleviating the CO₂ concentration in the atmosphere, which is of great significance to mitigate global climate change. Many studies about the effects of land use change on soil organic carbon have been widely carried out in China, including many aspects such asdynamics of soil organic carbon pool induced by the conversions among natural forests, grassland, plantations and cropland, while the study of dynamics of soil organic carbon pool in the eroded land after vegetation restoration, is still scarce. In this study, we chose several Pinus massoniana plantation plots at different stand ages located in Hetian, Changting, as research objects. Combining with space-time replacement method, RothC(version 26.3)model was used to retrieve and predict the dynamics of soil organic carbon in topsoil(0-20cm)after the restoration of Pinus massoniana in eroded red soil. The result showed that RothC(version 26.3)model played well in inversion and prediction of soil organic carbon in topsoil during the restoration of Pinus massoniana, and the simulations of soil carbon changes given by RothC model could perfectly reflect the change trend of soil organic carbon in the process of vegetation recovery in southern eroded red soil region. Analysis revealed strong correlations between the simulated and measured values (r>0.9, P<0.01), which suggests that RothC 26.3 model is a feasible tool to assess the dynamic of soil organic carbon pool of Pinus massoniana woodland in southern eroded red soil region, under the condition of mid-subtropical monsoon climate. After the plantation of Pinus massoniana, the carbon sequestration rate of topsoil(0-20cm)in eroded land increases gradually in a nonlinear way, which will reach the utmost in 15 to 25 years, and the average rate of soil carbon sequestration in the first 30 years (after masson pine recovery) is about 0.385 tC·hm^-2·a^-1, and the average rate of carbon sequestration during the succession to the local climax community is about 0.156 tC·hm^-2·a^-1. Calculated by stimulation fitting equation,the saturated carbon capacity of eroded red soil land is about 36.85 tC/hm² and carbon sequestration potential is 33.26 tC/hm² in study area.