A soil texture categorization mapping from empirical and semi-empirical modelling of target parameters of synthetic aperture radar

Abstract

The present study investigates the potential of synthetic aperture radar in demonstrating the relative percentage of sand, silt and clay content in the soil. The contribution of vegetation and topography in the backscattering coefficient has been significantly reduced by employing the terrain correction model, dual polarized SAR vegetation index and water cloud model. The target parameters namely ‘Soil Roughness (h_rms-soil)’ and ‘Dielectric Constant’ (${\epsilon }_{\mathit{vv}-\mathrm{soil} }^{\prime }$) has arrived from cross-polarization ratio and modified Dubois model. The extracted target parameters are sufficiently correlated with in situ sand (R² = 0.81) and clay measurements (R² = 0.78). The relative percentage of silt was mapped by the novel idea of performing the correlation analysis between h_rms-soil and ${\epsilon }_{\mathit{vv}-\mathrm{soil} }^{\prime }$ and thus represented the percentage of silt with reasonable accuracy (R² = 0.77). From the soil triangle formed with three estimated target parameters, we found that the clay category has shared around 35% of the total area followed by sandy loam (23%).

Keywords:

• Soil texture
• soil roughness
• dielectric constant
• correlation coefficient
• soil triangle

Acknowledgements

We express our sincere thanks to the SRM Institute of Science and Technology for encouraging and providing us with sufficient time and excellent lab facilities to carry out the research work. We thank European Space Agency (ESA) for providing free and open Sentinel 1 and 2 data access.

Disclosure statement

No potential conflict of interest was reported by the authors.