Diurnal Pattern of Sun-Induced Chlorophyll Fluorescence as Reliable Indicators of Crop Water Stress

Sun-induced chlorophyll fluorescence (SIF) is a promising remote sensing signal for early stress detection due to its close link with photosynthesis. Canopy SIF signals are controlled by leaf physiology, canopy structure, radiation intensity and sun-observer geometry. Variations in observations affected variations these controlling factors besides water stress. Mitigating the interference of non-drought on accurately evaluate drought degree still challenging. In this study, we explore response apparent yield (SIFy) progressive maize. With experimental evidence, show that difference between noon morning SIFy was better indicator than mono-temporal measurements. We proposed noon-to-morning ratio (NMR) characterize diurnal dynamics assess severity drought. The results midday measurements were most stress, least. NMR successfully revealed tracking timing transition from light-limited water-limited conditions within day. Hence, NMRs considerably more sensitive their values, traditional vegetation indices, especially during phase This demonstrates use multi-temporal or reliable detection.