黄土丘陵区不同农田类型土壤碳库管理指数分异研究

Characteristics of Soil Carbon Management Index of Different Farmland Types in Hilly Loess Plateau

以纸坊沟流域不同农田类型土壤为研究对象,分析土壤有机碳、活性有机碳、非活性有机碳及碳库管理指数的演变特征。结果表明,黄土丘陵区不同农田类型土壤碳库各组分含量差异较大,其中活性有机碳是总有机碳的主要部分,占总有机碳的58.0%～79.6%,是碳库变化的主要因素。不同农田类型土壤有机碳、活性有机碳、非活性有机碳含量变化规律一致,大棚菜地最高,其次是川地、梯田和坝地、沟台地,坡耕地最小。不同农田类型土壤碳库活度、活度指数、碳库指数和碳库管理指数差异明显,变化规律相似,相对于坡耕地,各指数增加明显,其中大棚菜地增幅最大,其后从大到小依次是川地、梯田、坝地、沟台地,表明其他几种农田类型经营管理较坡耕地更为科学。相关分析表明,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相关性密切,可以作为该地区农田类型土壤肥力的监测指标因子。

The soil samples of different farmland types in the typical erosion environment of Zhifanggou small watershed were regarded as study objects,and organic carbon,labile organic carbon,non-labile organic carbon and carbon management index were evaluated.The results showed that fraction of soil organic carbon in the different farmland types differed significantly.Labile organic carbon was the major part of the total organic carbon,accounting for 58.0%-79.6%.Organic carbon,labile organic carbon and non-labile organic carbon behaved similarly,the highest observation was in the greenhouse vegetable land,followed by plain field,terrace,dam land and gully land,and the lowest was the slope cropland.Soil carbon pool activity,activity index,carbon pool index and carbon management index in the different farmland types differed significantly and behaved similarly.Compared with the slope cropland,all the indexes increased drastically,the increase extent was the highest in greenhouse vegetable land,followed by plain field,terrace,dam land and gully land.The results suggested that compared to the slope cropland,other farmland types were managed more scientifically.Correlation analysis showed that soil organic carbon,labile organic carbon,non-labile organic carbon,carbon pool index,and carbon management index were significantly correlated with the fertility factors,they could be considered as the indicators for monitoring the soil fertility of the local farmlands.