基于TM遥感影像的玛多县草地土壤有机质的时空格局反演

Spatial pattern of grassland soil organic matter based on TM image in the Maduo County

土壤有机质是土壤的重要组成部分,同时也是土壤肥力的核心指标之一。本研究利用玛多县地面采样数据与TM遥感影像各波段DN值进行相关分析,筛选出与表层土壤有机质含量相关的TM波段,同时建立玛多县表层土壤有机质遥感反演模型。结果表明,研究区表层土壤有机质含量与TM3、TM5波段的DN值呈极显著的负相关关系(r分别为-0.670和-0.675),与TM3、TM5波段的DN值满足三次多项式回归关系(R2=0.815,P<0.001);反演模型对玛多县表层土壤有机质空间格局模拟效果较好;玛多县表层土壤有机质含量整体水平较低,北部明显低于南部。15年来,玛多县大范围土壤有机质含量已经增加,但是在交通要道沿线以及靠近居民点等人类活动较为频繁区域仍有较为严重的减少现象。

Soil organic matter is not only an important part of the soil,but also is one of the core indices of soil fertility.The proper bands of the TM image correlating with the content of surface soil organic matter were selected by analyzing the quantitative relationship between field data and the digital number（DN） values of the bands of TM image,and then a remote sensing retrieval model was established to simulate the surface soil organic matter in the Maduo County.The results of this study showed that surface soil organic matter had a significant negative correlation with the DN values of TM3 and TM4（r=-0.670 and-0.675）,and an inverse cubic order polynomial regression with the DN values of TM3 and TM5（R2=0.813,P0.001）.Remote sensing retrieval model could make a reliable prediction of the spatial distribution pattern of surface soil organic matter in the Maduo County.Across the Maduo County,the surface soil organic matter content was low,in which the north was significant lower than that the southern.During the past 15 years,the surface soil organic matter content increased in the most part of Maduo County.But the surface soil organic matter degradation was severe especially in the areas along traffic artery and close to settlement with frequent human activities.