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ThesisItem Open Access Effect of abiotic factors and soil moisture status on Bt cotton (Gossypium hirsutum) production using simulation and statistical relations(Punjab Agricultural University, Ludhiana, 2021) Aulakh, Sandeep Singh; Raj Kumar PalA field experiment entitled “Effect of abiotic factors and soil moisture status on Bt cotton production using simulation and statistical relations” was conducted at Punjab Agricultural University, Regional Research Station, Bathinda during kharif 2019. The experimental field was laid out in the split-plot design with three replications. The main plot treatments included three dates of sowing i.e. 30th April (D1), 15th May (D2) and 30th May (D3) and four sub-plot treatments of irrigation schedules viz. 60% of ETC (I1), 80% of ETC (I2), 100% of ETC (I3) and 120% of ETC (I4). The first irrigation applied to the crop was common to all the treatments, which was given after the recommended time of 30 DAS. Results revealed that, number of days taken to achieve various phenophases from emergence to maturity as well as yield contributing characters were recorded significantly higher under 30th April sowing followed by 15th May and 30th May sown crop. Similarly, higher values of phenology and yield attributes were recorded under more number of irrigation level (120% ETC) and decreased with decrease in irrigation frequency. Seed cotton yield was found to be decreased by 20.4% and 19.4%, with 15 days delayed in sowing from 30th April to 15th May and 15th May to 30th May, respectively, while, decreased by 35.88% with 30 days delayed in sowing from 30th April to 30th May. Similarly, the percent reduction in seed cotton yield was attributed by 1.74%, 8.74% and 4.96% due to decrease in irrigation frequency from I1 to I2, I2 to I3 and I3 to I4 respectively. Among dates of sowing and irrigation levels, crop water use efficiency-CWUE (kg ha-1 mm-1) and apparent water use efficiency-AWUE (kg ha-1 m-3) indicated significant results. Moreover, higher value of CWUE was recorded with more number of irrigations (120% ETC) and decreased with decrease in irrigation frequency. While, AWUE indicated increasing trend with decreasing number of irrigation applied. Among the sowing environments, during the crop growing period of the crop, due to minimal or lesser scarcity of soil moisture with optimum irrigation frequency under 120% to 100% ETC level, seed cotton yield was found higher. CROPGRO-Cotton model showed 0 - 12.9%, 0.7 – 4.28%, 0.14 - 7.82% deviation in simulated values in terms of anthesis, physiological maturity and seed cotton yield, respectively over observed data. Moreover, % deviation in simulated values over observed showed almost increasing trend with delayed sowing and decreased irrigation frequency in respect of phenology and seed cotton yield. Among the crop characters used for sensitivity analysis of model, higher deviation in simulated value over observed was found with incremented/decremented mean temperature (±1 to ±3ºC) than rainfall (±10 to ±30%) and solar radiation (±1 to ±3MJ m-1 d-1).
