CROPGRO-Cotton Model Application for Predicting Cotton Sowing Time in Nagarkurnool District of Telangana State, India

Aims: A study was carried out to find out the optimum sowing time with the validated CROPGRO-Cotton model using DSSAT v 4.7 seasonal analysis tool under rainfed situation at mandal level in Nagarkurnool district of Telangana state, India.Study Design: CROPGRO-Cotton model using DSSAT v 4.7 seasonal analysis tool.Place and Duration of Study: Nagarkurnool district, 2023.Methodology: Cotton production was affected with changing climate in several ways and its impact on rainfed agriculture was higher and influences the Indian economy. The prevailing weather conditions during different phenophases of the crop influences the seed cotton yield. There is a need to optimize the sowing time so that the timing of critical growth stages to minimize stresses and enhance resource utilization. The adjusting of sowing environment proved to be an adaptation management technique for realising higher seed cotton yield.A well calibrated and validated model was used for long term simulations using DSSAT seasonal analysis tool programme with Mallika Bt as test variety for 100 different scenarios (20 mandals × 5 sowing dates) using 32 years historical daily weather data from 1991 to 2022 starting sowing time from 1st June to 1st August at 15 days interval in twenty mandals of the district.Results: The simulation results showed, significantly higher seed cotton yield (1505 kg ha-1) was predicted with crop sown on 1st June followed by 1st July sown crop (1337 kg/ha) which was comparable with 16th June (1324 kg/ha) and significantly differed with delayed sowings of 16th July sown crop (1203 kg/ha) and 1st August sown crop (1192 kg/ha). Among the different mandals of the district, the model simulated higher seed cotton yield (2136-2530 kg/ha) in Amrabad mandal and lower yields in Thimmajipet mandal (596-997 kg/ha) under different sowing environments. Conclusion: Based on simulation scenarios, higher seed cotton yield can be obtained when crop sown between 1st June to 1st July in different mandals of the Nagarkurnool district of Telangana State. The mandals which have less yield potential and realising poor yields by the farmers can be advocated with location specific alternate best management practices to get the higher cotton yield.