Submitted to: Irrigation Associations Exposition and Technical Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/15/2007
Publication Date: 12/9/2007
Citation: Howell, T.A., Lamm, F. 2007. Is irrigation real or am I imagining it?. In: Proceedings of the 28th Annual International Irrigation Show, December 9-11, 2007, San Diego, California. p. 284-291. 2007 CDROM. Interpretive Summary: Several terms used to describe irrigation historically are difficult to understand and have been confusing. Artificial and supplemental add limited descriptive improvement to what irrigation is and should be discontinued in favor of just the word irrigation. Limited irrigation is a term that has been replaced by a more descriptive term, deficit irrigation, which is recommended to be used. Water use efficiency, although still a widely used term, is being replaced in recent articles by the term, water productivity. Water productivity emphasizes the crop production per unit water more clearly and does not carry the incorrect efficiency name for this bio-physical parameter. Regulated deficit irrigation (RDI) was clearly described and discussed. RDI requires a measure of plant water status not always required with deficit irrigation. Partial root zone drying was described and discussed as an irrigation management alternative. For proper communication, precise irrigation terminology and its description are important to reduce confusion and misuse.
Technical Abstract: Irrigation is an ancient practice of applying water to crops and/or plants to sustain their life so they can be productive for their intended purpose. Through the years and into today's literature there are many terms such as "artificial irrigation" and "supplemental irrigation." We know irrigation is real, not artificial! We know ALL irrigation supplements either precipitation (or just rainfall) resources, ground water uptake by crops, or existing soil water resources. Other terms such as "limited irrigation" and "deficit irrigation" emerged in the 1960s to 1970s, while more recently newer terms like "partial root zone drying (PRZD)" and "regulated deficit irrigation (RDI)" have emerged. We propose that "artificial" not be used to describe irrigation. We recommend that “deficit irrigation” should be the preferred term rather than "limited irrigation." We describe "regulated deficit irrigation" and illustrated clearly its difference from "deficit irrigation." We describe "partial root zone drying" as an irrigation management strategy, but we believe PRZD will be effective mainly in improving crop quality of tree or vine crops. It is important that irrigation literature utilize "correct" terminology to describe current technologies.