University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 50 6 2019 10 23 Optimization of Cropping Pattern and Water Resources at Different Levels of Irrigation for Hot and Dry Areas (Case study: Dehloran Plains, Ilam Province) Optimization of Cropping Pattern and Water Resources at Different Levels of Irrigation for Hot and Dry Areas (Case study: Dehloran Plains, Ilam Province) 1351 1361 73208 10.22059/ijswr.2019.267849.668036 FA Mohsen Najarchi Assistant Professor ,Department of Water Engineering, Arak Branch, Islamic Azad University, Arak,Iran Hamidreza Shekari Graduated PhD of Department of Water Engineering, Arak Branch, Islamic Azad University, Arak,Iran Reza Jafarinia Assistant Professor ,Department of Water Engineering, Arak Branch, Islamic Azad University, Arak,Iran Shahroo Mokhtari Assistant Professor ,Department of Water Engineering, Arak Branch, Islamic Azad University, Arak,Iran Hamzehali Alizadeh Assistant Professor, Department of Water and Soil Engineering, Faculty of Agriculture, University of Ilam,Iran Journal Article 2018 10 28 The objective of this research was to save water resources, using nonlinear programming model to optimize the crop pattern under full and deficit irrigation techniques in eight observation fields for eleven predominant irrigated crops, including winter wheat, barley, rapeseed, autumn sugar beet, corn, sorghum, tomato, onion and potatoes, bean and autumn watermelon in the downstream lands of Doyraj Dehloran reservoir located in the southwest of Iran. The yield reduction and net income of each crop were calculated for 50, 60, 70, 80, 90 and 100% of water requirements during the growing season. The objective function for maximizing net profit with different constraints including constant cultivated area was determined for the existing cropping pattern, the policies of the Ministry of Agriculture Jihad and the proposed pattern. In the case of full irrigation, the results showed that the net profit of the Ministry of Agriculture Jihad cropping pattern was increased 1.33, 1.19 and 1.05% for 100, 90 and 80% of water requirement, respectively. Under deficit irrigation conditions (90 and 80%), water resources are saved 18 and 34%, respectively. The proposed cropping pattern, including four crops of wheat, canola, autumn sugar beet and grain corn increased the net profit of 60, 70, 80 and 90% of the crop water requirement treatments by 14.4, 33.6, 54 and 74.7%, respectively, as compared to the existing cropping pattern. In the proposed deficit irrigation treatments, the water resources were saved 60%, 49%, 35% and 19%, respectively. The results of nonlinear programing model showed that the optimization of cropping pattern with deficit irrigation technique, not only increases the net profits, but also it can be effective in conserving surface and ground water resources. The objective of this research was to save water resources, using nonlinear programming model to optimize the crop pattern under full and deficit irrigation techniques in eight observation fields for eleven predominant irrigated crops, including winter wheat, barley, rapeseed, autumn sugar beet, corn, sorghum, tomato, onion and potatoes, bean and autumn watermelon in the downstream lands of Doyraj Dehloran reservoir located in the southwest of Iran. The yield reduction and net income of each crop were calculated for 50, 60, 70, 80, 90 and 100% of water requirements during the growing season. The objective function for maximizing net profit with different constraints including constant cultivated area was determined for the existing cropping pattern, the policies of the Ministry of Agriculture Jihad and the proposed pattern. In the case of full irrigation, the results showed that the net profit of the Ministry of Agriculture Jihad cropping pattern was increased 1.33, 1.19 and 1.05% for 100, 90 and 80% of water requirement, respectively. Under deficit irrigation conditions (90 and 80%), water resources are saved 18 and 34%, respectively. The proposed cropping pattern, including four crops of wheat, canola, autumn sugar beet and grain corn increased the net profit of 60, 70, 80 and 90% of the crop water requirement treatments by 14.4, 33.6, 54 and 74.7%, respectively, as compared to the existing cropping pattern. In the proposed deficit irrigation treatments, the water resources were saved 60%, 49%, 35% and 19%, respectively. The results of nonlinear programing model showed that the optimization of cropping pattern with deficit irrigation technique, not only increases the net profits, but also it can be effective in conserving surface and ground water resources. https://ijswr.ut.ac.ir/article_73208_c9175d89bc581520126b4e58945a7155.pdf