不同植被恢复阶段土壤温室气体排放对干湿交替的响应

The Characteristics of Soil Greenhouse Gases Emission at Different Vegetation Restoration Stages and Its Responses to Wetting and Drying Alternation

我国已普遍开展南方红壤退化问题的恢复工作,因治理时间的差异形成了不同的植被恢复阶段。通过室内培养实验探讨不同恢复阶段土壤温室气体排放特征及对干湿交替的响应。研究选取了裸地、10年恢复林、20年恢复林、30年恢复林及天然林为研究对象。结果表明:(1)随着恢复年限提高,CO_2的排放量逐渐升高,干湿交替显著增加了裸地CO_2排放量,却降低了其它4种林分土壤排放量;(2)除30年恢复林,其它4林分土壤累积CH_4通量在实验最后都表现出净吸收,干湿交替对裸地、10年恢复林土壤CH_4的吸收影响不大,促使天然林与20年恢复林土壤CH_4由吸收转为排放,30年林由排放转为吸收;(3)实验中只有天然林土壤的N_2O表现出净排放,其它均为净吸收,而干湿交替处理中林分土壤都表现为净吸收。本研究结果为精确科学地评价南方红壤区水土流失区恢复的生态效应、森林土壤碳通量模型估算提供很好的数据支撑。

Restoration of degenerated red soil has been carried out in southern China,because of the time difference in management,several vegetation restoration stages are formed in this area.In this study,a laboratory incubation experiment was conducted to find out the characteristics of soil greenhouse gases emission at different vegetation restoration stages and its responses to wetting and drying alternation.Bare land,10-year restoration forest,20-year restoration forest,30-year restoration forest,and natural forest were selected as the study subjects.The results indicated that the CO2emission rate rose with rehabilitation age,and the treatment of wetting and drying increased the CO2emission in bare land,on the other hand,decreased CO2 emission in the other forests;except for the30-year restoration forest,the cumulative CH4 emission of the other forests showed a net absorption at the end of the experiment;the treatment of wetting and drying had no effects on CH4emission of the bare land and the 10-year restoration forest,while there was a positive effect on the 20-year restoration forest and the natural forest and a negative effect on the30-year restoration forest;the natural forest soil N2O showed net emission,while that in the others showed net absorption;all the forest soils showed a net N2O absorption in the treatment of wetting and drying.These results can provide data support to accurate and scientifical evaluation of ecological effects of degenerated red soil restoration and estimation of carbon flux model of forest soil.