Chemical properties of experiment field soil.

Field experiment on sowing dates was carried out with BARI Mung-6 during pre-monsoon (kharif-I) season of 2021 for the evaluation of Agricultural Production Systems Simulator (APSIM) crop model. The APSIM model was parameterized using data from March 10 sowing, while validation was done with other sowing dates and data from literatures. Simulation was done with elevated temperatures (1-, 2- and 3-°C) to find out the adaptation option against future temperature stress situations. The model was run for different sowing dates using long-term (1981–2021) historical weather data. The evaluations showed that the model performance was satisfactory in predicting crop phenology, total biomass and grain yields of BARI Mung-6. Simulated grain yields during March 10 to March 25 sowings were very similar to attainable grain yields while, very early or late sowing gave comparatively lower grain yields. The best simulated planting window was from 15 to 25 March having the highest mean grain yields with less variability over the years. Increase in temperature by 1°C increase exhibited no significant influence on grain yields across the sowing dates, but significant yield reductions were observed with the rise of temperatures by 2 and 3°C on March 20, March 30 and April 10 sowings. Elevated temperatures showed positive impact on grain yield of March 10 sowing only. Results revealed that optimum sowing window for mungbean is from 15 to 25 March with existing weather conditions. In future temperature rises situations, sowing of seeds by the first week of March would be one of the options to combat climate change impact on mungbean grain yield in Bangladesh.