A geospatial variable rate irrigation control scenario evaluation methodology based on mining root zone available water capacity

Abstract

Increasing concern for sustainable water use has the agriculture industry working toward higher efficiency in use of irrigation water. Recent advancements have improved the capabilities of center pivot irrigation systems to vary water application depths across the field, a technology known as variable rate irrigation (VRI). The goal of this study was to provide a geospatial method for potential VRI technology adopters to evaluate control scenarios and potential water savings using freely available datasets. Root zone available water capacity (R) was estimated spatially across two case study fields using the Natural Resources Conservation Service Gridded Soil Survey Geographic Database. The difference in application depth between conventional irrigation (CI) and both sector and zone control VRI was then estimated based on R. Prescription maps were developed to mine undepleted soil water from each irrigation management zone based on a soil water balance approach with a management-allowed depletion of 50%. For CI management, the areal 10th percentile (PCTL) of R for the field was used, while for VRI the 10th PCTL of R for each management zone was used. The highest reduction in irrigation depth was 18 mm where higher digitalcommons.unl.eduM i l l e r e t a l . i n P r e c i s i o n A g r i c u l t u r e , 2 0 1 7 2values of R were estimated; however, field average reductions ranged from 0 to 12 mm. The greatest improvements in pumpage reduction resulted from converting from sector control to zone control, while increasing the angular resolution only had a minor impact. Energy savings generally increased with higher VRI control resolution. Conclusions support previous notions that VRI may result in small pumping water reductions for some fields; however, improved water distribution may be achieved throughout the field.

Agronomic Basis and Strategies for Precision Water Management: A Review

“…Some companies provide the ability to control zones of sprinklers, while others can control each sprinkler independently [46]. Currently, it is possible to achieve sector control with very small resolution, and zone control can add irrigation zones further to the sector at the small scales of lateral spans ( Figure 1) [48]. A study conducted in Canada to evaluate the performance of VRI found that the accuracy of water application was up to 90% in the center pivot system [49].…”

“…At a large scale, water pumpage and use can be reduced by adopting VRI. A geospatial method has been provided for potential VRI technology adopters to achieve potential water savings in the field using freely available datasets such as soil survey data from the Natural Resources Conservation Service (NRCS) [48]. In this study, the difference in application depth between conventional irrigation and VRI was estimated based on root zone available water capacity.…”

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

“…The field size was nearly 53 ha. Further details about the field can be found in Miller et al (2017) and Barker et al (2018b).…”

“…Spatial patterns in AWC can be characterized with electrical conductivity (Hedley and Yule, 2009;Evans et al, 2013;Vanella et al, 2019) or other hydrogeophysical datasets (Finkenbiner et al, 2018). Differences in AWC of a field could be used to compute VRI prescriptions, which may result in reductions in energy usage and water withdrawals (Miller et al, 2017).…”

Development of sprinkler with adjustable orifice using iris-type mechanism for variable rate irrigation

“…Research has justified the use of precision irrigation through modelling to establish scheduling of irrigation by management zones (Haghverdi et al, 2015;Ceresoli et al, 2016;Miller et al, 2018 . For anhydrous ammonia application, Bora et al (2005) On the development of zone control technologies, and proposed prototypes of sprinklers for centre pivots or linear-move systems.…”