SIMULATION OF CROP WATER PRODUCTIVITY AND YIELD RESPONSE OF POTATOES UNDER SUBSURFACE DRIP IRRIGATION SYSTEM USING THE AQUACROP MODEL | Journal of Engineering in Agriculture and the Environment

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2023-05-20

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Journal of Engineering In Agriculture And The Environment

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The need for increased food production by applying low water quantity is pausing more challenges to farmers. The production of Irish Potatoes in Kenya in arid and semi-arid areas is challenging for most farmers due to low yields. A field experiment was conducted at Egerton University during the 2021-2022 dry season. The effect of deficit subsurface drip Irrigation allied with superabsorbent polymer soil amendment on growth parameters and yield of potatoes was evaluated. Twelve treatments composed of three water application levels 70%IL, 85%IL,100%IL and four super absorbent polymer (SAP) application rates No SAP, 6 kg/ha, 10 kg/ha, and 14kg/ha laid in factorial experimental design were applied in December 2021 to May 202 season. Irrigation was undertaken when the allowable water depletion reached 50%. The AquaCrop model was applied to predict soil water content, biomass, canopy cover, dry yield, and water productivity (WP). The 100% water application level with 0kg/ha SAP was used in model calibration, whereas the remaining was used to validate the model. The model simulated compared with observed canopy cover, biomass and WP produced a good performance with R2 range of 0.86 to 0.98, root mean square error (RMSE) of 10.6%, NSE of 0.9, and Wilmot's degree of agreement of 0.98. However, the model underestimated the water content due to the application of SAP in the soil. The findings indicated that the combined effect of SAP and subsurface drip resulted in increased yield in deficit water application. The calibrated model was successfully applied in simulating WP and yield response of the three water treatments for No SAP, 6 kg/ha SAP, 10 kg/ha SAP, and 14 kg/ha SAP. 

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