Drip irrigation, also known as trickle irrigation or micro irrigation or localized irrigation, is an irrigation method that saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and drippers (emitters). It is done through narrow tubes that deliver water directly to the base of the plant.
Drippers come in two basic styles: pressure compensating (PC) and non-compensating.
Pressure compensating (PC) drippers will give the same amount of water flow within a range of pressure. A dripper will be rated something like this: will give 1 GPH between 15 and 55 PSI. Pressure compensating (PC) drippers are made in a way that they can automatically flush themselves out during start-up and shutdown, to a certain degree of course. This equates to a longer lifespan and more constant flow during the lifetime of the dripper. These drippers should be used on larger systems where the goal is to maximize the amount of poly tube length and total drippers on a single line while maintaining a very close flow from each dripper. They are also better if slight elevation differences occur in the system. These drippers are more expensive than other types.
Non-compensating drippers will give the same amount of flow depending upon the pressure at each dripper. In other words the higher the pressure the more flow the dripper will give. The lower the pressure the less flow the dripper will give. These drippers cannot self-flush and need very good filtration to work well over a longer period of time. The life span is less than the compensating drippers and elevation differences cause pressure differences that will cause drippers to give slightly different flows. These drippers work well for smaller systems where water quality is good and no elevation differences occur.