LIGHT ENVIRONMENT AND LAI MONITORING IN RICE COMMUNITY BY GROUND- AND UAV-BASED REMOTE SENSING

Abstract. Cultivation management adapted to various environmental changes has been required under changing climate, hence it is necessary to monitor the growth status efficiently. Photosynthesis in crop production is the essential process in crop growth model for forecasting the yield. In this study, we focused on light environment and LAI as important factors in photosynthesis, and conducted the observations to obtain time-series RGB images taken by digital cameras fixed on tower and mounted on UAV in the paddy field and to measure PPFDs at the top (I₀) and the bottom (I) of rice canopy during planted period. Three kinds of vegetation color indices (CIs), vegetation coverage (VC) and plant height (PH) derived by processing RGB images were compared with relative PPFD (I/I₀) and LAI calculated from relative PPFD. As the results, CIs and VC were basically expressed linear relations with relative PPFD and PH showed the exponential relation with relative PPFD and the linear relation with LAI respectively. Through this study, we clarified that VC and PH would be effective parameters for spatio-temporal monitoring of light environment and LAI.