Goal: Increase water use efficiency, improve yields and maximize profitability throughout the entire field. The EM Maps provide the information required for the variable rate irrigation. If a sprinkler system is being used, individual nozzle control is required to target different irrigation depths to different soil managed areas. Individual nozzle control also allows water to be shut off for example when traveling across raceways and over saturated areas.
Once a sprinkler system is modified for variable rate application there are multiple benefits:
- Keep water off exclusion areas such as wet ponded areas
- Decrease leaching and run off of chemicals
- Precision chemigation and fertigation
- Improve application accuracy at either end of the pivot
- Maintaining optimum soil water levels for better plant growth
Precision Water Works, starts by deriving EM and Landscape Change layers to identify water holding capacity variability across the field. These “fixed” yield influencing data layers are professionally processed and then delivered through software in preparation for field variability calculations, prescription generation and analysis reports.
Adjustments of the irrigation application rates are simply based on averages. For example, if the average EM value within a given sector indicates a lighter soil with a lower water holding capacity, the base walk speed may be decreased to apply more water. Likewise, if the average EM value within a given sector indicates a heavier soil with a higher water holding capacity, the base walk speed may be increased to apply less water. Landscape change will identify where speeds can be increased through depressions and decreased over ridges. This level of irrigation application management is commonly referred to as VRI Speed Control. VRI Speed Control is the low-cost way to match irrigation application depth to soil type and can be easily applied to any center pivot equipped with position-based speed control.
To further enhance fields with very specific variability, another option is to use zone control with your irrigation plan. Depending on what irrigation brand you use, a system of zones can be created using a series of valves and nodes that communicate with the system to turn certain sprinklers on and off during different stretches of each rotation. During the evaluation step, we can investigate the data collected and see how much of a projected difference the zone control upgrade would create. We also work closely with the irrigation dealers during this process to find a specific plan for each field that will maximize your yield at as reasonable cost as possible. Below is an example of a comparison of a field with the different controls applied.