Comparative and Diurnal Analysis of Sun-Induced Fluorescence as a Water Stress Indicator in Arable Crops

By Mehala Koneru

Abstract
Detection of stress effects in crops is crucial for sustainable agricultural practices. Sun-induced fluorescence is a promising tool for monitoring the photosynthetic activity of plants and crop health and has advantages over traditional vegetation indices to be sensitive to plant changes. In this study, we use high-resolution spectral data from the Hyplant airborne sensor to detect water stress in arable crops and compare SIF over the vegetation indices - NDVI and PRI to determine sensitivity to changes in plant environmental conditions. We analyzed SIF variations across different crop varieties and treatments spatially and diurnally to detect water stress among plots. We observed higher SIF values in the summer wheat crop compared to winter wheat and beans wheat mixture, indicating better crop health and photosynthetic activity. Lower SIF values are associated with stress conditions. Diurnal analysis of SIF showed that the peak values are at midday relating to light intensity and rising temperature and decreasing in the afternoon. Comparing SIF with NDVI and PRI showed that SIF is more sensitive to plant responses than vegetation indices. This study highlights the potential of using SIF as a tool for the detection of water stress. In future research, integrating validation data to characterize stress in plants would be more effective in monitoring and management in agriculture.