Phenophasic model of mango using weather variables and remote sensing 

Abstract

Mango (Mangifera indica L.) is of great economic importance, especially in India, where diverse agroclimatic conditions support the cultivation of numerous varieties, solidifying the nation's leading position in the global market. In Muthalamada, Kerala, unique geographic and climatic factors enable early mango production, offering a market edge. However, in recent years, due to climate variability, a change in mango phenology has been observed in this region, which has affected yield and reduced market price. This study investigated the phenology of mango plants in 35 orchards in Muthalamada, Kerala, during the 2023–2024 season. Four major commercial varieties, namely, Alphonso, Sindhooram, Banganpalli, and Totapuri, were analyzed during key stages such as leaf bud development, inflorescence emergence, flowering, and fruit development through the pea, marble, and maturity stages until harvest. Weather variables—maximum temperature (Tmax), minimum temperature (Tmin), rainfall (RF), mean relative humidity (RH), wind speed (WS), bright sunshine hours (BSS)—and remote sensing indices—Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST)—were used to assess their influence on mango phenophases. The variation in NDVI values across different phenological stages for all farms was analyzed using single-factor Analysis of Variance (ANOVA). The analysis showed that higher minimum temperatures (Tmin) can reduce the number of days to inflorescence emergence in Banganpalli, Alphonso, and Totapuri, while increased maximum temperatures (Tmax) can delay peak flowering in Banganpalli, Alphonso, and Sindhooram. Bright sunshine hours (BSS) can increase duration, whereas rainfall (RF) and relative humidity (RH) shorten the time to pea-size stage and marble stage. Increases in Tmax, Tmin, and BSS can delay the duration of maturity and harvest. Higher Land Surface Temperature (LST) can increase vegetative growth and delay flowering. Lower NDVI values indicate shorter phenophase durations, while higher NDVI values indicate extended phenological durations. The ANOVA results (F = 156.16, P < 0.001) indicate significant variation in NDVI across phenological stages. The results showed that the study can be used for phenophasic assessment of mango.