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对中亚热带山区天然常绿阔叶林、次生常绿阔叶林、人工林(针叶林和阔叶林)、柑橘园和坡耕地等典型土地利用方式土壤CO2排放连续3a定位观测,结果表明:天然林改为其它土地利用方式后,土壤CO2排放量显著减少32%～63%,主要原因为地上凋落物归还量减少,地下细根生物量和周转下降,频繁人为干扰和严重水土流失引起土壤有机碳库数量和质量大幅下降。本区天然林改为次生(人工)林,土壤CO2排放量减幅(32%～48%)高出热带平均水平(29%),改为农业用地,土壤CO2排放量减幅(50%～63%)高出全球平均水平(33%)。
Soil CO2 emission of typical evergreen broad-leaved forest, secondary evergreen broad-leaved forest, plantation (coniferous forest and broad-leaved forest), citrus orchard and sloping farmland in subtropical mountainous area were continuously observed for 3 years. Results The results showed that the emission of soil CO2 decreased significantly by 32% -63% after the conversion of natural forest to other land use types, mainly due to the reduction of litter return on the ground, the decrease of underground fine root biomass and turnover, frequent human disturbance and severe soil erosion Causing a substantial decline in the quantity and quality of soil organic carbon pool. The natural forest in this area was changed to secondary (artificial) forest. The reduction of soil CO2 emission (32% -48%) was higher than the average level of the tropics (29%), to agricultural land, and the reduction of soil CO2 emission (50% ~ 63%) above the global average (33%).