南水北调中线水源区土地利用变化对土壤有机碳的影响

A Study on Soil Organic Carbon Based on Land Use Change at Water Source Area of the Middle Line of Project of Transferring Water from South to North

以宁陕县寨沟流域不同退耕年限地为研究对象,并以坡耕地作为对照,分层采集土样,测定土壤有机碳(SOC)含量、pH值、全氮(TN)含量、容重。借助spss软件和统计分析技术,探讨了土地利用方式改变后SOC的分布规律及其与pH值、TN、容重的相关关系。研究结果表明:随着退耕年限的增长,SOC和TN含量不断增大,且在垂直剖面上变化趋势基本一致,二者呈显著的正相关,相关系数均(r2)在0.867以上;退耕地SOC含量与pH值呈负相关,而坡耕地SOC与pH值呈正相关。

Taking rehabilitation land in Zhaigou drainage area of Ningshan county for example, this paper compared it with sloping farm land. Soil samples were collected according to profile layers, and the contents of SOC, pH, TN and soil bulk density were determined under different modes of land use. Furthermore, the relationship among the SOC distribution, pH were value, TN and bulk density. As a result, the longer the rehabilitation land had, the more the content of SOC and TN were in it. Meover, contents of SOC and TN had the same transformation trended in vertical profile in that they had close correlation coefficient （≥0.867）. There was a significant negative correlation between SOC content of rehabilitation land and pH value, whereas SOC content of sloping farming land had a positive correlation with pH value.