## 2 Materials and Methods
### Green Water Footprint  
The Penman-Monteith equation [33; 34; 35; 36] was utilized to determine the reference evapotranspiration (ETo), a method endorsed by the Food and Agriculture Organization (FAO) [37] and proven effective by [38; 39]. This equation is widely preferred for assessing water footprints [40]. The ETo calculator software ([[http://www.fao.org/land-water/databases-and-software/eto-calculator/en/](http://www.fao.org/land-water/databases-and-software/eto-calculator/en/)]([http://www.fao.org/land-water/databases-and-software/eto-calculator/en/](http://www.fao.org/land-water/databases-and-software/eto-calculator/en/)), version 3.2, September 2012, accessed on 15 April 2022) was employed along with meteorological data to compute the ETo. The computation of the green water footprint adhered to the guidelines outlined in FAO Irrigation and Drainage Paper No. 56 [41], involving the determination of daily crop evapotranspiration (ETc, mm) and effective precipitation (Pe\({}_{\text{eff}}\), mm) throughout the growing season.  
\[\text{ET}_{\text{C}}=\text{K}_{\text{c}}\times\text{ET}_{\text{O}} \tag{5}\]  
Reference evapotranspiration (ET\({}_{\text{O}}\)) is calculated in mm d\({}^{-1}\), with the adjusted crop coefficient denoted as K\({}_{\text{C}}\). ET\({}_{\text{O}}\) is estimated using the Penman-Monteith equation through the ET\({}_{\text{O}}\) calculator software. Additional information on data and calculations for ET\({}_{\text{O}}\) can be found in Mokhtar, He [34]. Adjustments to K\({}_{\text{C}}\) are made based on FAO guidelines when RH\({}_{\text{min}}\) deviates from 45% or when U\({}_{2}\) exceeds or falls below 2.0 m s\({}^{-1}\).  
\[\text{K}_{\text{c adjusted}}=\text{K}_{\text{c reference}}+[0.04(\text{U}_{2}-2 )-0.004(\text{RH}_{\text{min}}-45)]\bigg{(}\frac{\text{h}}{3}\bigg{)}^{0.3} \tag{6}\]  
Pe is the effective precipitation (mm) over the growing season, and it was calculated using the following equation:  
\[\text{P}_{\text{e}}=\left\{\begin{array}{ll}\frac{\text{P}(4.17-0.2\text{P} )}{4.17},&P<8.3\\ 4.17+0.1\text{P},&P\geq 8.3\end{array}\right\} \tag{7}\]  
where P and Pe are the monthly precipitation and effective precipitation [20], respectively [42; 43]. Effective precipitation (Pe) over the growing period was calculated using the following formula. The water footprint (WF) is categorized into green water footprint classifications [40]. As per [PERSON] [4] terminology, the water footprint of the crop season (WFc) is the summation of the green components (WFgreen) and is typically expressed in m\({}^{3}\) ton\({}^{-1}\), equivalent to L Kg\({}^{-1}\).  
\[\text{The green Water Footprint}\left(\text{WF}_{\text{green}} \right)=\frac{\text{CWR}_{\text{green}}}{\text{Y}}=10\times\frac{\text{ET}_{ \text{green}}}{\text{Y}} \tag{8}\] \[\text{The green water footprint}\left(\text{WF}_{\text{green}} \right)=\text{Max}(0,\text{ETc}-\text{pe})\] (9) \[\text{The green water footprint}\left(\text{WF}_{\text{green}} \right)=\text{Min}(0,\text{ETc}-\text{pe}) \tag{10}\]  
WFgreen denotes the green water footprint, Y represents crop yield (ton ha\({}^{-1}\)), and CWRgreen signifies green water utilization (m\({}^{3}\) ha\({}^{-1}\)); ETgreen and ETgreen denote green (effective precipitation) and green (evapotranspiration) water, respectively. ET stands for crop evapotranspiration during the growing season [44].  
\[\text{CWR}_{\text{green}}=10\text{$\sum$ET}_{\text{green}} \tag{11}\]