Plant growth is influenced by a wide range of physical, climatic, and biological factors. In dry areas, however, water shortage may be the principal limiting factor on crop production. Some understanding of soil-water-plant relations is necessary for design and management of water harvesting interventions. This includes an understanding of the significance of water to plants and the way in which the plants obtain and lose water in the atmosphere-soil-plant system (Berliner, 2005; Barrow, 1999). Almost every process occurring in plants is affected by water, but the links are complex. The plant-water relationship varies with plant characteristics, stage of development, soil, and climatic conditions. In simple terms, water is absorbed by the plant roots and lost by transpiration. About 95% of water taken in by plants is transpired, while 5% or less used in plant growth. If water cannot be absorbed by the roots to compensate for transpiration loss, then a water deficit develops in the plants, and plants may wilt. Water shortage has a significant impact on plant growth and production, but the impact magnitude may vary depending upon plant type and stage of development.