Studies on Plant and Soil Water Relationship : Availability Of Soil Water To Plants Under Different Levels Of Soil Water Potential

The subject of soil water availability to plants has long been investigated. Recently. it has been recognized that soil water availability depends upon the balance between the supply and demand tor water to the plant. Water moves trom the soil towards the roots following the water potential gradient. The rate ot water uptake depends upon the evapotranspirative demand of the air and the status and mobility of soil water, as well as an the root density. habit and distribution. Soil water management requires a relaible estimate of soil water properties for effective prediction and control of the dynamics of water in the soil as related to water status in plant. including the spatial variability of soil physical properties dominated by texture and related characteristics. and the root extraction patterns. However, for the purposes of experimental and applied irrigation, soil water potential is an intrinsic property of the film water and its records provide a means of evaluating or prescribing irrigation practices without reference to soi1 moisture content, but plant parameters must be involved specially those concerned with potential and water forms. Therefore, the present investigation was conducted to study plant -soil- water relationship with regard to the availsbility of soil water plants underv different levels of soil water petential, and its effect on differrent water forms in various plants.