Field testing of a variable rate sprinkler and control system for site-specific water and nutrient application

• Published in: Applied engineering in agriculture Vol. 21; no. 5; pp. 847 - 853
• Main Authors: King, B.A, Wall, R.W, Kincaid, D.C, Westermann, D.T
• Format: Journal Article
• Language: English
• Published: 01.09.2005
• Subjects: algorithms; center pivot irrigation; fertigation; fertilizer application; fertilizer rates; field experimentation; irrigation water; nitrogen fertilizers; precision agriculture; site-specific irrigation; sprinkler irrigation; sprinklers; variable rate application; variable rate sprinklers; water distribution
• ISSN: 0883-8542; 1943-7838
• DOI: 10.13031/2013.19712

Development and implementation of site-specific sprinkler irrigation management has been limited due to the lack of variable rate sprinklers. Thirty-two prototype variable rate sprinklers were constructed and field tested on a three-span linear-move irrigation system. An algorithm was developed for a distributed control network to allow each sprinkler to be individually controlled in groups of six or seven along the linear-move lateral. Water application uniformity was monitored over a 36% to 100% range in application rate. Measured application uniformity equaled or exceeded 90%. Variable rate nitrogen application was monitored over a 1.1-ha area. Measured nitrogen application rate was within 4% of the target application rate. Results indicate that the prototype variable rate sprinkler and control system allows water and chemical application to vary over a 36% to 100% range in application rate with minimal effect on water application uniformity.