ABSTRACT
Drip irrigation provides water with uniform rate, precisely controls the amount of water, increases crop yield, reduces evapotranspiration and deep percolation, and decreases dangers of soil degradation and salinity.1-3 Well-aerated conditions (appropriate proportion of soil and water) can also be maintained. In addition, drip irrigation can supply water at low discharge rates and high frequencies over an extended period and minimize salinity levels in the soil water by leaching the salts.4 Because of point-source characteristics of drip irrigation, salts will be pushed toward the fringe of the wetting area along with water and can form a desalinization zone at its center, in close proximity to the emitter.5,6 Many studies have shown that drip irrigation on saline soil is an important method for improving saline land.7-9
Drip irrigation system applies precise amount of water to the crop at the right time and ensures its uniform distribution in the field. Although it is the most efficient method, the suspended salts and solids in groundwater (GW) can lead to a high risk of system failure due to clogging of the drippers and difficulties in filtering. In drip irrigation system, quality of water, emitter characteristics, and filter efficacy play key roles to minimize clogging. However, other factors being the same, the most important feature for success is good filtration system.10,11
In India, gravel media filters, screen filters, and disk filters are commonly used to remove sediments from water for drip irrigation. According to Capra and Scicolone,12 screen filters are not suitable for use with wastewater, the exception being diluted and settled wastewater. They also observed almost similar performance by disk and gravel media filters with treated municipal wastewater. Besides, many researchers have conducted studies with freshwater and wastewater using drip irrigation mostly by surface placement of laterals and also under laboratory conditions.12-15 Subsurface drip irrigation (SDI) has not been evaluated to use GW. Thus, there is a need to develop a methodology for utilizing GW through drip irrigation on sustainable basis.
