Sensitivity of Multi-Temporal L-Band Radar Backscattering Power to Soil Moisture for Two Crops with Contrasting Features

CARLOS LOPEZ-MARTINEZ; MATIAS BARBER; FRANCISCO GRINGS

Valencia

Congreso; IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium; 2019

IEEE

Microwaves are expected to retrieve soil conditions in agricultural lands when an overlying crop canopy is presented. Since crop plants involve dielectric elements of complex shapes, sizes and orientations, a number of scattering mechanisms combine together to yield the microwave backscatter response. This paper aims at assessing soil moisture variations through a canopy imaged by an airborne Synthetic Aperture Radar (SAR). Multi-temporal co-polarized and cross-polarized response is compared to volumetric insitu soil moisture for two crops with contrasting biomass and plant height, namely soybean and corn. The considered dataset is comprised by several soybean and corn fields, whose response to microwaves is averaged leading to an overall assessment for each crop. For canopies with large stalks such as corn, observations suggest an important contribution of the double bounce mechanism when soil surface is wet. For drier conditions, response is insensitive to moisture variations in accordance to backscattering from plant elements. Results might be useful for crops with similar features such as wheat and rapeseed.