Current and potential capabilities of UAS for crop water productivity in precision agriculture

In order to feed growing populations under scare water resources, a suitable technology that improves crop water productivity (CWP) is crucial. Precision agriculture that utilizes digital techniques such as unmanned aerial systems (UAS) can play a significant role in improving CWP. CWP is an important indicator that quantifies the effect of agricultural water management. To improve CWP, implementation of suitable methods for early detection of crop water stress before irreversible damage on crops occurs, is vital. Conventionally, farmers have relied on in situ measurements of soil moisture and weather variables for detecting crop water status for irrigation scheduling. This method is time consuming and does not account for spatial and temporal variability associated with crop water status. Hence, the aim of this study is to give an overview of the current and potential capabilities of UAS for crop water productivity in precision agriculture. Identified in this study are the factors as well as the technology that can improve CWP. UAS thermal remote sensing is found to be the most suitable technology for monitoring and assessing crop water status using certain indices. Determining a crop water stress index (CWSI) from thermal imagery has the potential to detect instantaneous variations of water status. CWSI obtained from UAS thermal imaging camera can be adapted for real-time irrigation scheduling for maximum crop water productivity.