subsurface irrigation system usually provides a continious and homogeneous humid zone at root zone depth and keeps it at unsaturated status. This system with the use of new applicator (Porous pipes made mostly of’ rubber) diffuses water like a natural membrane over its total surface and over its total length. The selection of the proper depth and space between
Pipes depends on the physical and hydraulic characteristics of the soil and plants root system as well.To study the effects of the different pressures and pipe lengths on moisture and salt distribution, an experiment was statistically designed with three replications of each combination of three pressures (0.5. 1.0. and 1.5 bar) and three pipe lengths (0.0. 25.0. and 50 meter). This study was conducted in a vineyard in Karaj. Iran. in which the pipes were spaced 60 cm apart and buried at a depth of 40 cm having 50 meter length.The statisitical analysis of the data obtaind from these experiments showed that the movement of water through the soil is a function of pressure. that is, the positive pressure increased moisture gradients from the water source. The tests on the salt movement also indicated the in crease of’ the salt gradients from the water source toward surface. The application efficiency and yield under this system were about 50 and 41 percent more than the surface irrigation system. respectively.
)