Research on spectral index of soil organic matter in black soil for collaborative monitoring of multi-source hyperspectral data

The successive launches of hyperspectral satellites have provided a rich data source for soil quality monitoring. Soil Organic Matter (SOM) is an essential soil quality indicator. How to use multi-source hyperspectral data for cooperative monitoring to obtain SOM content is an important issue in black soil surveys. In this paper, a spectral index of SOM applicable to collaborative monitoring with multi-source hyperspectral data is developed for the black soil region. First, a series of spectral indices were constructed by combining spectral transformations (such as reciprocal and square root) and dual-band index formulas (such as ratio and difference), respectively. Then, the Pearson’s correlation coefficient (ρ) of SOM and all the spectral indices were calculated for each dataset. Finally, the optimal spectral index of SOM was determined based on the ρ of different datasets. The results show that the optimal spectral index of SOM is DIOR (560,600). The R2 of the exponential fit reaches 0.54, indicating that DIOR (560,600) can effectively characterize the soil organic matter content. Also, DIOR (560,600) is stable and simple to calculate, showing great potential in SOM estimation of black soil using multi-source satellite hyperspectral data.