ABSTRACT
A major part of it is used for irrigation. However, due to increasing population and multifarious use, per capita availability and shared of water for irrigation is decreasing day by day. The pore space or porosity is that proportion of the total soil volume which is occupied by air and/or water. It is generally expressed in percentage. It may also be expressed as the total volume of pores per unit volume of soil. The chapter discusses the moisture content of soil in percentage, it has to be converted to depth, as irrigation recommendations are generally given in terms of depth, e.g. 4 cm irrigation, 5 cm irrigation, 6 cm irrigation etc. When irrigation water is applied in a particular crop field, it is finally converted to volume.
