Water balance components in any agro-ecological system are indispensible for most physical and physiological processes within the soil-plant-atmosphere system, especially in arid and semi-arid regions. Quantitative water balance information is required for the development of efficient method of soil water management (Odofin, et al., 2012). The knowledge of the circulation of water in and out of the soil mass and especially in a cropped field is very crucial in the planning and operation of various soil and water management strategies. A good understanding of all the aspect of soil hydrological balance (soil water balance), that is, rainfall and or irrigation, water stored in the soil, and water losses from cropped soil due to evapotranspiration, deep percolation and runoff is of importance to appreciate the role of various soil and water management strategies in solving environmental problems and increasing agricultural production. It is a very vital tool in estimating the water need of crops (Zoabeida, 2012; Federer, 1996), irrigation scheduling by soil water accounting under different scenario (Crookston, 2011; Igbadun, 2008). Besides planning of irrigation systems, knowledge of soil water balance and hence crop water use is required when planning the various soil and water management structures such as: erosion control structures, planning and design of water harvesting structures and other soil moisture conservation techniques both during rainy and dry seasons.

Soil water balance (accounting) can be likened to a financial statement of income and expenditure. It is an account of all quantities of water added to ― a control volume of soil‖ through rainfall, irrigation or capillary rise from shallow ground water, and expended.