Identifying Advantages and Disadvantages of Variable Rate Irrigation: An Updated Review

Abstract

Abstract. Variable rate irrigation (VRI) sprinklers on mechanical move irrigation systems (center pivot or lateral move) have been commercially available since 2004. Although the number of VRI, zone or individual sprinkler, systems adopted to date is lower than expected there is a continued interest to harness this technology, especially when climate variability, regulatory nutrient management, water conservation policies, and declining water for agriculture compound the challenges involved for irrigated crop production. This article reviews the potential advantages and potential disadvantages of VRI technology for moving sprinklers, provides updated examples on such aspects, suggests a protocol for designing and implementing VRI technology and reports on the recent advancements. The advantages of VRI technology are demonstrated in the areas of agronomic improvement, greater economic returns, environmental protection and risk management, while the main drawbacks to VRI technology include the complexity to successfully implement the technology and the lack of evidence that it assures better performance in net profit or water savings. Although advances have been made in VRI technologies, its penetration into the market will continue to depend on tangible and perceived benefits by producers. Keywords: Center pivots, Crop water use efficiency, Irrigation, Management zones, Moving sprinkler irrigation systems, Precision irrigation, Sensor based systems.

Mapping Management Zones Based on Soil Apparent Electrical Conductivity and Remote Sensing for Implementation of Variable Rate Irrigation—Case Study of Corn under a Center Pivot

“…It can even be said that it is not only the first, but also a fundamental step, since the quality of HMZ will influence the irrigation prescription maps. There are usually three paths used to survey variability and define HMZ [2,5]: (i) soil ECa measurements with proximal sensors (the starting point for variability), (ii) monitoring of vegetation indices based on satellite images, mainly NDVI (the dynamic crop evolution), and (iii) yield data (the final objective of the production…”

“…Changing the pivot travel speed enables the establishment and management of individual pie shape zones where faster pivot travel results in less irrigation and slower travel speed results in increased irrigation at the selected pies [13]. Nevertheless, dynamic prescription maps are necessary because soil water content varies not only temporally, but also spatially, even in leveled fields [2]. The objective of this case study was to evaluate tools for definition of dynamic HMZ (EC a obtained by proximal sensor and NDVI obtained by remote sensing) and dynamic VRI maps to automatic center pivot travel speed control in corn.…”

Site-specific irrigation management in a sub-humid climate using a spatial evapotranspiration model with satellite and airborne imagery

“…Such variability may exist in terms of soil types, topography, pest attacks, crop growth, and nutrient availability (O'Shaughnessy et al, 2016). To account for spatial variability in crop water needs, variable rate irrigation (VRI) can be implemented to manage irrigation with spatial control and precision (O'Shaughnessy et al, 2019). VRI systems can apply different amounts of irrigation to different parts of a field during a single irrigation prescription (Hedley and Yule, 2009;Evans et al, 2013;Stone and Sadler, 2016).…”

“…This ability could be used to match irrigation prescriptions with spatially varying crop water needs. Spatial management capabilities of VRI systems range from relatively simple speed control systems to more complex zone control VRI systems, which can control individual or banks of sprinklers along the pivot (Evans et al, 2013;O'Shaughnessy et al, 2019).…”

Improving Water Distribution Uniformity by Optimizing the Structural Size of the Drive Spoon Blades for a Vertical Impact Sprinkler

“…At present, the promotion of advanced water-saving irrigation technologies presented by sprinkling irrigation and micro-irrigation is an important measure for developing water-saving agriculture and improving water utilization [1][2][3]. As one of the efficient water-saving irrigation technologies, sprinkler irrigation has advantages such as water conservation, productivity increase, labor-saving, maintaining ecological balance and improving crop quality [4][5][6]. The sprinkler is the key piece of equipment for sprinkler irrigation, and the hydraulic and operating performance determines the quality of the irrigation system to a great extent [7,8].…”