ESTIMATION OF CROP WATER REQUIREMENT OF SWEET POTATO (IPOMOEA BATATAS (L.) USING CROPWAT 8.0 MODEL IN AWKA, A HUMID FOREST AREA OF SOUTH EASTERNNIGERA

Ike, C.R., Orakwe, L.C, Okore, I.K

DOI: 10.26480/bda.02.2026.37.42

ABSTRACT
Annual fluctuation in climatic variable due to climate change phenomenon has resulted to unpredictable gap between crops actual and potential yields, in recent years. This study estimated the crop water requirement (CWR) of sweet potato (Ipomoea batata.) in Awka, a humid forest area of South Eastern Nigeria, using the CROPWAT 8.0 model. In determining the optimal irrigation schedules for sustainable water resource management, ten years (2014-2023) meteorological data consisting of temperature, relative humidity, wind speed, and sunshine hours, were utilized to calculate reference evapo-transpiration (ETo) using the FAO Penman-Monteith method. Some relevant soil data (field capacity, permanent wilting point, and infiltration rates) were integrated into the model for accurate estimations. The results indicated that the CWR of the crop was 588.6 mm/decade over its life cycle for the area, with the highest water demand (36.4 mm/decade) occurring in the month of July (mid-season stage), which coincided with the period the crop had its maximum canopy coverage and evapotranspiration. Rainfall contribution was 1020 mm from planting to harvest period, with only 237.1 mm being effective, necessitating supplementary irrigation for optimum growth and yield performance. Total gross irrigation was calculated at 212.5 mm, with an efficiency of 70%. This suggests that strategic irrigation scheduling, based on the CWR and climatic conditions, could optimize water use, reduce losses, and enhance the crop productivity. The findings further provide valuable insights for farmers and agricultural planners, enabling efficient water management and sustainable cultivation practices in the Area

KEYWORDS
Crop Water Requirement (CWR); Potato, CROPWAT 8.0; Irrigation Scheduling; Reference Evapotranspiration (ETo) ; Sustainable Water Management