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为了探讨土地利用方式对土壤有机碳固定的影响,论文以乔木、灌木、草地和农田等不同植被类型,纯林和混交两种栽培模式的黄土台塬为研究对象,进行了土壤有机碳(SOC)和颗粒有机碳(POC)分析。结果表明:不同土地利用方式土壤SOC和POC在0~100 cm土体中均存在差异,尤以0~40 cm深度突出,其中灌木林地和天然草地在整个剖面上可积累更多的SOC和POC;不同土地利用方式土壤细颗粒有机碳(FPOC)含量、分配比例及其在剖面上的分布变化均小于粗颗粒有机碳(CPOC),在0~100 cm土体中,CPOC敏感性指标分别为SOC、FPOC和POC总量的2.66~13.56、3.75~5.99和2.58~4.17倍;不同土地利用方式土壤SOC与POC极显著相关,耕地SOC与POC相关性相对较小,乔灌混交林地和乔木林地最大。因此,CPOC和FPOC均可作为衡量土地利用方式转变对于土壤影响的评价指标之一。
In order to explore the effect of land use on soil organic carbon fixation, the paper studied the relationship between soil organic carbon (SOC) and soil organic carbon (SOC) under different vegetation types such as arbor, shrub, grassland and farmland, ) And particulate organic carbon (POC) analysis. The results showed that soil SOC and POC in different land use patterns differed in 0 ~ 100 cm soil layer, especially in 0 ~ 40 cm depth, in which shrub and natural grassland could accumulate more SOC and POC (P <0.05). The contents of FPOC and the distribution of soil FPOC in different land use patterns were all less than those of coarse-grained organic carbon (CPOC). The indices of soil CPOC sensitivity in 0-100 cm soil were SOC, POCOC and POC were 2.66 ~ 13.56, 3.75 ~ 5.99 and 2.58 ~ 4.17 times respectively. Soil SOC and POC were significantly correlated with different land use patterns. SOC and POC had a relatively low correlation with cultivated land, maximum. Therefore, both CPOC and FPOC can be used as a measure of the impact of land-use change on soil.