Submitted to: Encyclopedia of Agricultural, Food, and Biological Engineering
Publication Type: Book / Chapter
Publication Acceptance Date: June 3, 2009
Publication Date: N/A
Interpretive Summary: Irrigation provides approximately 40% of the world food supply on 20% of the arable land using approximately 70 – 80% of the developed fresh water supply. To maintain this use and productivity in the face of competing demands from municipal, industrial and environmental sectors, the irrigation community will have to be good stewards of land and water resources. This manuscript describes the various numerical methods that are used to characterize the efficiency of water use in irrigation, the losses in irrigation and the uniformity of application of the major system types e.g. surface, sprinkler and microirrigation. Management considerations related to matching water quality, soil types, and cropping are discussed for each of the principal irrigation system types. An overview of the operational characteristics is provided for surface, sprinkler, and microirrigation systems.
Technical Abstract: Effective operation of an irrigation system requires matching the operational characteristics of a system to the soil, crop, field, and water supply. Each of these components will affect the quality of the irrigation system performance. The performance measures used to characterize the irrigation system operation include the irrigation and applied efficiency which describe the beneficial use of water for meeting crop water requirements and maintaining soil productivity. The deep percolation ratio, leaching requirement and water tailwater ratio are used to describe the loss of water from the field. The system uniformity is described using distribution uniformity, emission uniformity and Christensen’s Uniformity Coefficient. The equations and applications for each of the aforementioned coefficients are described. Management considerations related to matching water quality, soil types, and cropping are discussed for each of the principal irrigation system types. An overview of the operation characteristics is provided for surface, sprinkler, and microirrigation systems.