Increasing the productivity of water in agriculture will play a vital role in easing competition for scarce resources, prevention of environment degradation and provision of food security. The argument for this statement is simple, by growing more food with the less water; more water will be available for other natural and human uses. Increasing agricultural productivity of water is particularly important in arid and semiarid areas like Iran, where water is a scarce resource and more food is high due to high population rate. The advanced irrigation methods like various type of sprinkle and drip irrigation methods have many and in some cases unique advantages from viewpoint of agronomy, land and water conservation and economic issues. Sprinkle and trickle irrigation represent the board class of "pressurized" irrigation methods, in which water is carried through a pipe system to a point near where it will be consumed. This is in contrast to surface irrigation methods, in which water must travel over the soil surface for rather long distances. Thus, surface irrigation methods depend on critical uncertainties associated with the water infiltration into the soil while being conveyed. Understanding basic soil-water-plant relations under different situation of field, crop, soil, climate, water quality, as well as socioeconomics are central to the ability to design and manage of sprinkler and trickle irrigation systems. Accordingly the Pressurized Irrigation Engineering Research Department (PIERD) as a sub-division of Irrigation & Drainage Division has conducted research since 1993 to answer main issues related to pressurized irrigation systems design and management.