IRRIGATION WATER REQUIREMENTS

Authors: Barnes, Edward; Hunsaker, Douglas - Doug

Submitted to: Encyclopedia of Agricultural, Food, and Biological Engineering
Publication Type: Book / Chapter
Publication Acceptance Date: 8/23/2001
Publication Date: 9/25/2003
Citation: Barnes, E.M., Hunsaker, D.J. 2003. Irrigation water requirements. Encyclopedia of Agricultural, Food, and Biological Engineering. pp. 549-551

Interpretive Summary: It is important to know the total amount of water that an irrigation system will need to deliver, both for a single irrigation event and for the entire season. Without this information, the system may not be properly designed to meet all the irrigation needs. Typically, irrigation requirements are thought of as the amount of water needed to supplement natural precipitation so crops do not experience excessive stress resulting in yield loss or crop quality degradation. Additionally, irrigation is used to insure adequate seed germination, prevent heat stress or freezing, apply chemicals, suppress dust, and prevent excessive salt development in the root zone. The amount of irrigation required for any of the previously mentioned applications must include the water needed to meet the management objective and account for any inefficiencies or losses in the system. Therefore, consideration must be given to the boundaries of the system for which the requirements are defined. For example, irrigation requirements can be defined for the growing season over an entire watershed, or defined for a particular field and single irrigation event. This paper reviews the basic elements that must be considered in determining irrigation requirements and is part of a larger document dealing with all aspects of irrigation systems. This information will be of use to engineers involved in the design of irrigation equipment and agricultural producers in irrigated regions.

Technical Abstract: Irrigation requirements can be loosely defined as the amount of water needed to supplement natural precipitation so crops do not experience excessive stress that would result in yield loss or crop quality degradation. Additionally, irrigation water can be used to insure adequate seed germination, prevent heat stress or freezing, apply chemicals, suppress dust, and prevent excessive salt development in the root zone. The total amount of irrigation required for the previously mentioned applications includes the water needed to meet the management objective and account for any inefficiencies or losses in the system. Therefore, consideration must be given to the boundaries of the system for which the requirements are defined. For example, irrigation requirements can be defined for the growing season over an entire watershed, or defined for a particular field and single irrigation event. This article provides an overview of items that must be considered when determining irrigation requirements and is part of a larger work on irrigation systems.