侵蚀环境退耕撂荒地土壤活性有机碳与碳库管理指数演变

Active Organic Matter and Carbon Pool Management Index of Soil at the Abandoned Cropland in Erosion Environment

采用时空互代法,以典型侵蚀环境纸坊沟流域生态恢复过程中不同年限的撂荒地为研究对象,选取坡耕地和天然侧柏林为对照,分析了植被恢复过程中土壤有机碳(TOC)、活性有机碳(LOC)、非活性有机碳(NLOC)及碳库管理指数的演变特征。结果表明:侵蚀环境的坡耕地土壤碳库各组分含量较低,土壤碳库处于高速低效率运转;撂荒后可以显著增加土壤碳库各组分含量,并随恢复年限呈显著线性关系,50 a时,TOC、LOC和NLOC分别较坡耕地增加169%、144%和201%,为侧柏林的35%、39%和33%;碳库指数和碳库管理指数较坡耕地明显增加,增幅分别达到169%和117%,仅为侧柏林的35%和42%。表明坡耕地撂荒后,土壤碳库转化效率逐步提高,土壤管理经营更趋于健康科学,但相对于破坏前天然林水平还有很大的差距。有机碳、活性有机碳、非活性有机碳、碳库指数、碳库管理指数与土壤主要肥力因子密切相关,可以作为反映生态恢复过程土壤质量演变的指标。

With Zhifanggou watershed under typical erosion environment as study plot,the abandoned in different time as subjects,and slope cropland and natural Chinese arborvitae stand as CK,the substitution method of space for time was applied to analyze organic carbon(OC),active organic carbon(AOC),non active organic carbon(NAOC) and evolvement of carbon pool management index in the period of ecological restoration.The result showed that the content of soil carbon indices on slope cropland were lower and increased dramatically in linear pattern after the cropland were abandoned for some time.50 years after abandonment,OC,AOC and NAOC would increase by 169%,144%and 210%respectively,compared to the slope cropland and would be 35%,39% and 33% respectively,of the natural Chinese arborvitae stand.The carbon pool index and carbon pool management index would sharply increased by 169% and 117%,comapared to the slope cropland would increase by 35% and 42% respectively,compared to natural Chinese arborvitae stand.The result indicated that conversion rate of soil carbon of cropland would increase after abandonment and the soil management was improved,though still far from the standards of natural forest before devastation.Correlation analysis showed that soil fertility was closely related to OC,AOC,NAOC,carbon index and carbon management index.The five indices could be regarded as the indicators reflecting the evolvement of soil quality in the period of ecology restoration.