黑土区田块土壤有机质空间分异及分布研究

Spatial Variability and Distribution of Soil Organic Matter in Black Soil Area at the Field Scale

本文选取东北典型黑土区田块为研究区,实测获取土壤样点数据,基于遥感影像和地形数据,分别利用单一地统计、混合地统计和遥感反演方法预测土壤有机质(SOM)空间分布。结果表明:研究区SOM含量变异系数为31.897%呈中等程度变异,且存在强烈空间自相关性;对光谱反射率进行数学运算得到的光谱指数"Tan345"(Landsat8影像345波段夹角正切值)与SOM极显著相关,相关系数最高达0.570;以光谱指数"Tan345"与地形因子"G"(高程)为输入量、利用回归克里格法预测的SOM精度最高;研究区SOM含量西高东低,沟底和平缓的坡顶含量较高。研究结果对于促进精准农业、估算土壤碳库有着重要的意义,并为小尺度SOM预测提供借鉴。

Soil sample data were measured in the field of typical Black Soil area of Northeast China. Based on remote sensing images and measured digital elevation models, the spatial distribution of soil organic matter (SOM) was predicted by using the methods of single geostatistics, mixed geostatistics and remote sensing inversion. The coefficient of variation of SOM content in the study area was 31.897%, with moderate variation and strong spatial autocorrelation. Spectral index obtained by mathematical calculation of spectral reflectivity was significantly correlated with SOM, and their correlation coefficient was up to 0.570. When the spectral index "tangent of the angle formed by band 3, band 4 and band 5 of Landsat 8 image" and the topographic index "elevation" were taken as inputs, the content of SOM predicted by regression kriging method was the highest. Generally, SOM content in the west was higher than that in the east, and was higher in gully bottom and gentle slope. These results could be used to predict the SOM content at field scale, and provide reference for precision agriculture and the estimation of soil carbon pool.