Spatial Assessment of Heat Stress Impact on Rice Production in Two Districts of Andhra Pradesh, India

Physiological studies have provided clear evidence of heat-induced spikelet sterility in rice, which can cause significant yield reductions. However, it is rather difficult to evaluate such yield losses in real world situations in farmers’ fields, especially across large areas. State-of-the-art technologies, such as remote sensing and crop modeling, can offer solutions for evaluating the heat-induced yield penalty in rice across a spatial area. Remote-sensing technologies, especially Synthetic Aperture Radar (SAR), can provide spatial detection of the start of the rice-growing season. This information, combined with time-series temperature data, can be assimilated into a crop simulation model, which can provide a thorough assessment of any heat-induced yield penalty over a specific geographic region. In this paper, we demonstrate how SAR can be used to assess the effects of heat stress in rice in two districts of Andhra Pradesh, India, during the 2017 rabi (dry) season. The accumulated data suggest that 53,623 and 21,436 ha of rice fields in Nellore and West Godavari districts, respectively, had yield losses due to heat stress. Rice fields in Nellore suffered higher yield and production losses due to heat stress because of steeper trend of increasing temperatures during the rice plants’ reproductive stage.