Optimisation of cropping pattern considering stomatal response to elevated CO2 emission and climate change

The current article seeks to explore the function of elevated CO2 emission on the variations of reference evapotranspiration (ET0) for optimising cropping pattern in 18 Iranian regions. Accordingly, meteorological data and agricultural information were collected since 1961 to 2010 and 2002 to 2013, respectively. A trend-free pre-whitening (TFPW) approach was applied to modify Mann-Kendall test to determine the ET0 trend based on the Food and Agriculture Organization of the United Nation (FAO)-Penman-Monteith (FPM) method. Then, the function of stomatal response was investigated as an assimilation coefficient to adjust the ET0 since 2050 to 2100. In the next step, the anomalies of the ET0 were calculated in both monthly and annual scales with respect to the significant trends of the meteorological parameters and stomatal response via three different schemes. Finally, to optimise cropping pattern, two indicators namely total virtual water (TVW) and unit blue water value (UBWV) were employed.