Monitoring crop phenology is required for understanding intra- and interannual variations of agroecosystems, as well as for improving yield prediction models. The objective of this paper is to remotely evaluate the phenological development of maize (Zea mays L.) in terms of both biomass accumulation and reproductive organ appearance. Maize phenology was monitored by means of the recently developed visible atmospherically resistant indices, derived from spectral reflectance data. Visible atmospherically resistant indices provided significant information for crop phenology monitoring as they allowed us to detect: (i) changes due to biomass accumulation, (ii) changes induced by the appearance and development of reproductive organs, and (iii) the onset of senescence, earlier than widely used vegetation indices. Visible atmospherically resistant indices allowed the identification of the timing of phenological transitions that are related to the maize physiological development. They also allowed identification of the onset of the grain-fill period, which is important since maximum yield potential of maize plants depends on optimal environmental conditions during this period.
