ABSTRACT
The drip irrigation method has now gained worldwide popularity particularly in water scarce regions, undulating hilly areas and saline soils. It is an appropriate water saving and production augmenting technique for wide spaced orchard and plantation crops. It is also used for commercial crops like cotton, tobacco, sugarcane and also for vegetables. Typically, it has decreased wetted volume thus requiring more frequent irrigations. An irrigation regime with an excessively high irrigation frequency can cause the soil surface to remain wet and the evaporation process persists most of the time, resulting in substantial loss of water. This is one of the disadvantages of the drip irrigation system. The wetted area beneath the emitters particularly in arid and semiarid regions is susceptible to high evaporation. On soils having low infiltration rate, surface application of water by drip irrigation may result in significant surface wetting and ponding, which suffer from high evaporative demand and thereby decreasing the water use efficiency [3]. Advent of subsurface drip irrigation is in fact an approach to curb enhances this efficiency. However, subsurface drip irrigation may suffer from clogging of emitters and microtubes. An alternative approach to the clogging problem is to increase the size of the emitters and microtubes. However, this may increase the discharge of the microtubes and emitters and change the pattern of wetting in the soil thus affecting the water availability to the plants.
