Application of the AquaCrop Model for Cotton Production under Water Scarce Arid Conditions

Obidjon Sindarov¹Sabirjan Isaev¹Kholmurod Khayitov¹Perizat Bulanbayeva²Shukhrat Rizaev³Sobir Sanayev³Sanoat Zakirova⁴Allamurod Khojasov⁵Feruzbek Abdulkhaqov⁶Saidakhror Isashov⁶Ulugbek Nematov⁶Bakhodir Khalikov⁷Iroda Tadjibekova⁸Botir Khaitov^8*

• ¹Tashkent Institute of Irrigation and Agricultural Mechanization Engineers National Research University, Tashkent, Uzbekistan
• ²Korkyt Ata Kyzylorda University, Kyzylorda, Kazakhstan
• ³Samarkand Agroinnovations and Research University, Samarkand, Uzbekistan
• ⁴Fergana Polytechnic Institute, Fergana, Uzbekistan
• ⁵Institute of Agriculture and Agrotechnologies of Karakalpakstan, Nukus, Uzbekistan
• ⁶Andijon qishloq xo'jalik instituti, Andijan, Uzbekistan
• ⁷Scientific Research Institute of Breeding Seed Production and Agricultural Technology of Cotton Cultivation, Tashkent, Uzbekistan
• ⁸Tashkent State Agrarian University, Tashkent, Uzbekistan

Cotton is an important fiber crop, yet traditional cultivation practices are heavily water intensive. As limited water resources increasingly constrain cotton productivity, it is important to investigate alternative irrigation strategies that can maintain stable yields under severe water scarcity conditions. Tools like the AquaCrop model play a key role in this process, allowing to simulate intricate relationships among management techniques, water use, crop development, and yield production. In this study, the model underwent calibration and validation based on three irrigation regimes (1-2-1; 1-3-1; 1-4-1) in three field capacity (FC) datasets (FC 65-65-60%, FC 70-70-65%, and FC 75-75-70%) and its effectiveness was assessed through simulations of canopy cover (CC), biomass accumulation and water productivity (WP). The results showed that the highest cotton yield was obtained under FC 70-70-65% irrigation regime (3.553 Mg ha-1 for 2022; 3.325 Mg ha-1 for 2023; 3.441 Mg ha-1 for 2024), while the simulated and measured cotton yields were consistent with a deviation < 5%. WP values were also higher with the FC 70-70-65% irrigation regime, exhibiting 0.66 kg m3 in 2024; 0.64 kg m3 in 2023 and 0.64 kg m3 in 2022. The deviations were in the range of < 2.77% to 4.89% for cotton yield, < 1.6% to 4.89% for WP, < 3.48% to 5.01% for biomass, < 1.17% to 5.17% for HI. Soil moisture content between measured and simulated values were observed with a coefficient of determination (R2) of 0.814, 0.799 and 0.604 for Fc 65–65– 60%, Fc 70–70–65% and Fc 75–75–70%, respectively. Under the optimal mode (70–70–65% of Fc) of irrigation schedule, WP increased by 13.15 to 24.13% compared other irrigation regimes. It was concluded that the digitalization of agricultural irrigation using the AquaCrop model will advance water-saving priorities, contribute to climate resilience and promote more sustainable crop production practices under the challenging water scarcity conditions of arid ecosystems.