Spatial heterogeneity of soil line parameters of black soil zone in Northeast China

Accurate soil line parameters are significant for monitoring vegetation or crop and analyzing soil properties with remote sensing images. Soil line parameters of different areas in black soil zone, Northeast China were calculated with MODIS reflectance products to analyze the spatial distribution of soil line parameters; then the vegetation indices relating to soil line were established, and the correlation coefficients between vegetation indices and crop leaf area index, the fraction of photosynthetically active radiation were analyzed. The results were as follows: the overall distribution of soil line slope in black soil zone was that from north to south, the value increased and reached maximum at south Hailun city and central Wangkui County (47°N-47.7°N), then decreased, the minimum value lay at south Dehui City and central Jiutai City. The correlation coefficients between vegetation indices relating to soil line and crop leaf area index, the fraction of photosynthetically active radiation were significantly greater than that between Normalized Difference Vegetation Index and crop physiological parameters; the most sensitive vegetation index to soil line parameters was Adjusted Transformed Soil-adjusted Vegetation Index, and the vegetation indices calculated with soil line parameters in different zones showed more significant correlation with leaf area index and the fraction of photosynthetically active radiation than that calculated with single soil line parameter. With the introduction of soil line parameters, the precision of crop physiological parameters predicted with vegetation indices is much better.