Chemigation is the use of agricultural chemicals (fertilizer, fungicides, herbicides, nematodes, soil improvement remedies, growth regulators, sewage and manure water), in an effective and economic way, by means of an irrigation system. Chemigation can be applied by means of any type of irrigation system, although some flood irrigation systems may not be apt for the application of certain types of chemicals, because of poor application uniformity. The careless use of chemicals and over-irrigation must also be prevented, because it can lead to pollution of soil and water sources.