Use of ERA5-L reanalysis datasets to derive heat units and predict the maturity period of wheat crop in central Punjab

The ERA5-L reanalysis dataset, produced by ECMWF is the latest and most advanced global climate reanalysis datasets available with high spatial and temporal resolution. To assess the applicability of ERA5-L reanalysis data, a field experiment was conducted to predict the onset of maturity period of wheat crop based on heat units derived by ERA5-L data at the University research farm in Ludhiana. The wheat variety Unnat PBW-550 was sown under two dates of sowing (D1: 27th October and D2: 17th November) during three consecutive seasons (2020–21, 2021–22, and 2022–23). The phenological observations revealed that the October sown wheat took a greater number of days (153-154 days) to attain maturity as compared to November sown (139-142 days) crop. When heat units were derived from ERA5-L dataset, accumulated GDD (R2:0.95) and accumulated PTU (R2:0.95) displayed higher maturity prediction accuracy compared to HTU (R2:0.32) in all three rabi seasons. Ground observed and ERA5-L information were employed to estimate the beginning of maturity for wheat. For this, the accumulated heat units were calculated from sowing to booting stage of wheat crop. Our findings provided intriguing prospects for using ERA5-L reanalysis data as a different data source to predict crop phenology far in advance.