Evaluating the climate change impact on water use efficiency of cotton-wheat in semi-arid conditions using DSSAT model
Abstract Water is the most important limiting factor of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) cropping systems in semi-arid conditions of Southern Punjab. A two-year field experiment (comprising of cotton-wheat cropping) was conducted in Vehari (Southern Punjab) to calibrate and validate a DSSAT model in the climatic conditions of 1 × CO2 concentration (conc.) (current). The model simulation during calibration was good with errors up to 4.7, 4.4, 10.1, 6.4 and −5.4% for days to anthesis, days to maturity, total dry matter, yield and HI, respectively for the cotton-wheat cropping system. During model validation, the error percentages were also under reasonable limits. So, the model was run under 2 × CO2 conc. (future) conditions and it showed a difference of −7.3 to 19.7% anthesis days, maturity days, total dry matter, grain yield, crop ET and WUEGY with respect to current CO2 concentration. Simulation by DSSAT showed that the cotton cultivar MNH-886 and wheat cultivar Lassani-2008 were better utilizers of limited water resources under changed climatic conditions in semi-arid conditions of Vehari, which was due to their better water use efficiency. Wheat and cotton cultivars with high water use efficiency would enable crop growth to maintain high crop yields under increased CO2 and its associated consequences in future.
