Abstract:

The objectives are to overcome the limitation that optical satellite remote sensing can only obtain the surface soil spectral information and can not be used to directly estimate the soil water content of the cultivated layer, and establish an indirect estimation model of the cultivated layer soil water content based on the surface soil spectral information. According to the soil water content and hyperspectral data of 85 tidal soil samples in Jiyang, Shandong, and the intrinsic relationship between the soil water content of the surface layer and the cultivated layer, an indirect spectral estimation model of soil water in the cultivated layer was established. The results showed that the logarithmic transformation effect of spectral reflectance of surface soil was better. With the logarithmic transformation values of 1339 nm, 1457 nm, 1745 nm, 1969 nm and 1996 nm bands as estimation factors, the determinant coefficient R ² of the surface water content estimation model established by multiple linear regression model was 0.8911 and the average relative error was 13.67%. There was a significant correlation in soil moisture content between the surface layer and the cultivated layer, and the determinant coefficient R ² between them was 0.8131. The accuracy of the indirect spectrum estimation model of soil water content in the cultivated layer was higher, the model’s determinant coefficient R ² was 0.8138 and the average relative error was 9.66%. The results indicate that there is a significant correlation between the surface and the cultivated soil water content of the tidal soil in Jiyang, Shandong, and it is feasible and effective to estimate the soil water content of the cultivated layer by using the surface soil spectrum.

Key words: the cultivated layer, soil water content, hyperspectral remote sensing, indirect estimation, estimation model