Surface soil moisture modeling using C-band SAR observations at different stages of agricultural crops

Abstract

Surface soil moisture (SSM) can be helpful in irrigation monitoring, water conservation, and a variety of other hydrological modeling applications. The majority of previous researches concentrated on the applicability or development of soil moisture models at only one stage of agricultural crop. The goal of this research is to model SSM of agricultural crops at different crop stages using C-band SAR data. The SSM of agricultural crops modeled include Paddy, Tomato, Sugarcane, and Maize fields. The whole crop cycle of these crops are divided into vegetative, maturity and yield stage. Field data like soil moisture, roughness, and Vegetation Water Content (VWC) were gathered in synchronization with the satellite pass over the study area. SEM’s for each crop stage is developed and compared to existing models like Oh 2004 and WCM. From the study, it is observed temporal variation of SSM is almost uniform for the whole crop cycle of sugarcane (~ 5%). But in case of other crops, SSM is high during the seedling/vegetative stage and comparatively less during the yield stage. Developed SSM models using SAR data is performing well in vegetative and maturity stage of all crops whereas in yield formation stage of maize and paddy error is comparatively high. On the hand, both developed and existing models did not perform well in case of sugarcane crop at maturity and yield stage. To the best of our knowledge, this is the only study that deals with surface soil moisture modeling of different crops and their stages at the plot scale in the semi-arid tropics. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.