|NGUYEN, ANH - University Of Missouri|
|THOMPSON, ALLEN - University Of Missouri|
|Sudduth, Kenneth - Ken|
Submitted to: National Irrigation Symposium
Publication Type: Proceedings
Publication Acceptance Date: 6/29/2020
Publication Date: 12/6/2021
Citation: Nguyen, A., Thompson, A.L., Sudduth, K.A., Vories, E.D. 2021. MOPivot tool to define management zones for center pivot variable rate irrigation systems. In: Proceedings of the 6th Decennial National Irrigation Symposium, December 6-8, 2021, San Diego, California. Paper No. 20-072. https://doi.org/10.13031/irrig.2020-072.
Interpretive Summary: Better irrigation management is needed to conserve water and reduce environmental impacts due to off-field movement of fertilizers and chemicals. This paper describes and demonstrates the use of the MOPivot software, which was developed to improve management of variable-rate irrigation (VRI) center pivot irrigation systems. These VRI systems allow application of different amounts of water to different parts of a field, but determining how much water to apply where and when is a challenge. The MOPivot system considers the effects of variable soils, variations in plant growth, and historic crop yields in developing management zones to which different amounts of water can be applied. Examples of its use on fields in Missouri, Nebraska, and Washington are given. Irrigation decisions based on MOPivot can save water and improve environmental outcomes compared to traditional irrigation management.
Technical Abstract: Information from digital maps and remotely sensed imagery coupled with variable rate irrigation (VRI) technologies can provide more effective spatial management of crop production. Specifically, improved irrigation scheduling is possible by incorporating spatial variability of soil or remotely sensed vegetation index (VI) responses of crops to define unique management zones during the growing season. This paper presents practical examples using the MOPivot model to develop automated management zones for VRI controlled center pivots at several field sites. The model can accommodate individual sprinkler, zonal, and speed control systems, defining the smallest unique management area matched to field needs and pivot system characteristics. Examples include static prescriptions developed using soil SSURGO data and soil electrical conductivity. Dynamic management zones were developed using remotely sensed VI maps throughout the season to update unique management area based on crop status. Additionally, a yield map was used to modify soil-based management zones to improve future irrigation and/or chemigation prescriptions.