Optimization of crop cultivation area using Grasshopper algorithm with virtual water perspectives

Agriculture sector is the largest water consumer among all known demands for water. Having measured the direct water consumption is only one indicator of water supplied to this sector, while the virtual water used during the production process can also stand for a large share of water being indirectly used. Therefore, considering the virtual water consumption can be a defining factor to optimize crop cultivation accordingly. To this end, this research is structured to practice optimizing crop cultivation area in Golestan province of Iran, with the objectives of maximizing green water use and conservation of water resources while maintaining the farmers’ profit through the virtual water trade approach using the Grasshopper optimization algorithm. The crop water demand (CWD), blue virtual water (BVW), green virtual water (GVW), and total virtual water (TVW) of 21 agricultural products were calculated in Seven categories including cereals, industrial products, beans, vegetable, cucurbits, feed plants, and rice for 13 major counties of the Golestan province for the period of 2008–2016. The optimization model was implemented for the 2015 data. Results showed that in most counties the area under cereals cultivation was declined sharply after the optimization and other products such as bean, feed plants and vegetables, etc. replaced it. In addition, in the whole province, the area under cultivation of cereal crops and rice decreased by 93% and 36%, respectively; while the area under bean and vegetables cultivation increased by 949.22% and 111.1%, respectively. The optimization process increased the farmers’ profit by 46.15%, while decreasing the export of blue virtual water by 323.76 mm³ (81.6%). Results, proved the effectiveness of the Grasshopper optimization algorithm in this application and its strength in dealing with multi-objective models especially in water resources engineering. It is also concluded that the virtual water trade, being a key factor in the plant factories profitability, can be optimized effectively to benefit farmers through managing the crop cultivation theme according to the regional status of water-food-energy nexus.