Use of different temporal scales to monitor phenology and its relationship with temporal evolution of normalized difference vegetation index in wheat

摘要

We propose the use of temporal series of remote-sensing images (RS) for the characterization of the dynamics of the crop canopy throughout the growing and development cycle. Crop phenology, meteorological data, and normalized difference vegetation index (NDVI) were obtained during the period 2008 to 2016 for commercial fields planted with wheat. Three temporal scales based on the number of days, the growing degree-days (GDD), and the reference evapotranspiration (ETo) were analyzed for the intercomparison of the growing cycles. The use of the accumulated value of ETo as the reference scale for the temporal evolution of NDVI allowed for a better analysis of the differences among the fields. This scale also improves the estimation of the duration of the cycles and the prediction of flowering and physiological maturity. The analysis of the accumulated NDVI indicated that flowering occurs during the middle of the growing cycle and that the accumulated NDVI in the vegetative and reproductive phases is similar if the growing cycle is analyzed in terms of ETo or GDD. In addition, the estimation of the green-up based on RS data allows for the definition of the beginning of the growing period for this crop even in the absence of planting dates data. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)