Estimation of Water Needs of Sweet Potato (Ipomea batata) Using the Penman-Monteith Model in Abeokuta, South-western Nigeria
Adequate knowledge of crop water needs is required for effective water management and application in Abeokuta, a typical sub humid part of southwestern Nigeria. This research was carried out to determine the crop water requirements, rainfall intensity and irrigation water requirements of sweet potato for agricultural activities in Abeokuta. The estimation of water needs of sweet potato was based on twenty-one years meteorological data. The meteorological data collected were used for the estimation of reference evapotranspiration (ETo) using Penman – Monteith model. The results obtained showed that the Monthly reference evapotranspiration (ETo) varied from 96.90 to 165.23 mm/month with a mean of 131.58 mm/month. The seasonal crop evapotranspiration (ETc) values for early and late season sweet potato are 338.37 mm and 468.03 mm respectively. The rainfall intensity of the study area varied from 0.20 – 8.56 mm/hr with mean of 4.22 mm/hr. The study showed that the study area has low rainfall intensity values. However, this will promote steady infiltration of rainwater into the soil hereby giving the soil adequate moisture content needed by the crop to attain its optimum growth yield. The Irrigation water requirement was 22.80 mm and 473.87 mm for early and late season respectively. To achieve optimum crop performance and production of quality yield sweet potato in Abeokuta, supplementary irrigation is necessary during the early and late growing seasons of the crop.