An Assessment of Water Budget of Ibadan, Nigeria

Abstract

The influence of climatic conditions of precipitation and evapotranspiration exercise great control on soil water budget. This is fundamental to crop production and hydrological processes. This study assessed the temporal variability of soil moisture condition of Ibadan, Nigeria using the water budget approach. Specifically the study analyzed the climatic variables of monthly rainfall and means monthly air temperature, computed the mean monthly evapotranspiration values, plots the water budget graph, and discussed the implications of the observed seasonal trend in water budget condition on agricultural activities and hydrological processes. Monthly rainfall and mean monthly air temperature data used were collected from the archives of the Nigeria meteorological agency for the period 2008-2020. Monthly potential evapotranspiration data used in the study was estimated from the mean monthly air temperature data. The monthly rainfall data and the monthly evapotranspiration data were used to plot the water budget graph. Results revealed temporal variability in soil moisture condition. Water deficit condition was observed between November and April while water surplus condition was observed between May and October. The highest water surplus condition was observed in September (111.9mm) while the highest deficit condition (-125.64mm) was observed in December. The month of October recorded the lowest water surplus condition (41.30mm) while the month of April recorded the lowest water deficit condition (-10.10mm). The implications of the observed seasonal variation in soil moisture status on agricultural activities and hydrological processes were discussed.