Throughout the years, precision agriculture has facilitated improvements to farming equipment, from auto-steer on combines to variable rate seeding on planters. These changes enhance functionality and allow growers to farm smarter and more efficiently.
Sprayer technology has remained relatively unchanged for the last several years, leaving room for improvement. Recently, however, there have been several advancements in the area of precision technology on sprayers, looking to change the way that products are applied.
Top manufacturers recognized the challenges of traditional application and have begun introducing solutions, such as independent section control to auto-nozzle switching based on speed. John Deere, for example, released its new ExactApply nozzle control system to give growers more control over everything from droplet size to pressure, and adapt to varying speeds, curves, and sensitive areas such as waterways.
The different brands of sprayers function in different ways, but regardless of which sprayer a grower chooses to operate, precision application equipment addresses the same challenges across all platforms.
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How It Works
In the case of John Deere’s ExactApply system, many features from traditional systems, such as section control and variable rate application, are maintained but have been further enhanced. For example, on traditional sprayers there were three sections, one for the center and one on each of the booms. With the new ExactApply system, growers have individual nozzle control and can have as many sections as there are nozzles. This increases accuracy and better controls input costs.
The systems also offers A/B nozzle switching, which allows for manual or automatic switching between nozzles to better adapt to field conditions, speed, and application rates. For example, a low-drift nozzle may be used on the field edges and headlands, and then the operator could choose to use a different nozzle for spraying the interior of the field.
While different products offer different features and degree of control for growers, they’re all based on one common principle: more control equals better spraying, which results in less product wasted, and therefore, greater savings. The value of precision application comes from five major capabilities.
1. Application Consistency at Every Speed
In order to be its most effective, spray application rate must be consistent. One of the biggest challenges to maintaining this consistency comes when changing ground speed. Traditionally, sprayers adapt to changing ground speed by modifying spray pressure, however this can result in poor crop coverage. With precision application products, growers can set sprayer nozzles to auto-adjust based on the sprayer’s current speed, which allows them to maintain a steady application rate.
For example, a sprayer’s auto-adjustment can be set so that nozzle X applies at speeds up to 5 mph. When the sprayer goes above 5 mph, nozzle X will shut off and nozzle Y will activate. When the sprayer reaches the highest speed, for example, 12 mph, both nozzles X and Y would activate, working together to maintain the target application rate, ensuring consistency in coverage.
2. Pressure and Droplet Size
As with application rate, droplet size must also remain consistent for best results. Some auto-adjust systems that don’t offer individual nozzle control can still adjust to the sprayer’s speed, but with a change in pressure instead. At lower speeds, the system lowers the pressure, applying less product. This is only somewhat more efficient, as it also results in a change in droplet size, which then leads to inadequate coverage.
Thanks to pulse-width modulation on newer systems, desired pressure remains the same in the boom. The system instead changes the frequency and duty cycle of pulsing to adjust the rate, resulting in consistent droplet size and therefore improved coverage.
3. Curve Compensation Coverage
Precision application systems are also designed to maintain specific coverage throughout a field, even when operating along curves. This concept of “curve compensation” (discussed in detail in this article) utilizes individual nozzle pulsing and the system’s auto-adjust capabilities. When the sprayer turns, the system adjusts, automatically applying less product to the inside rows and more to the outside rows. This ensures that inside rows won’t suffer from over-application and outside rows will still receive the prescribed rate. Coverage is ideal across the entire length of the boom.
4. Skip and Overlap Reduction
Individual section control is especially important when dealing with unique field characteristics such as border areas, waterways, or sensitive crops. Precision application systems provide this control by allowing individual sprayer sections to be shut off, which reduces skips and overlaps. For example, as a sprayer approaches a waterway, individual sections can be turned off, preventing product from being applied over the water. The sections then reactivate once the boom has reached an area to be sprayed, immediately pick up coverage again.
5. Drift Management
Some crops require much finer application, or smaller droplet size; however, it can result in chemical drift to adjacent fields or crops not intended to be sprayed. This problem can be reduced with A/B nozzle switching, mentioned earlier.
When outlining a field, a grower can switch to a lower-drift nozzle, reducing the amount of material that drifts, and preventing potentially harmful effects to surrounding vegetation. When working towards the interior of the field, the grower can then switch back to a more conventional nozzle.
While precision application equipment is designed to put more control in the hands of growers, it is still recommended that growers maintain a close partnership with trusted advisors, such as agronomists or dealership personnel.
Agronomists, for example, can provide information about the many products available, as well as educate growers on the various regulations that govern use, such as maximum application rate and nozzle specification. An agronomist or other knowledgeable precision product specialist can help growers follow guidelines and apply the right product at the right time.
Another good resource for growers is John Deere’s GoSpray app. This app provides instructions for proper equipment setup and maintenance, giving equipment operators and technicians the opportunity to best optimize their machines. Key personnel at most dealerships are familiar with these apps and can assist growers in putting them into practice on the farm.
By offering growers greater control over product application, new precision technologies make the process more accurate, effective, and economical.
Nate Dorsey is an Agronomist for RDO Equipment Co. based in Moorhead, MN. Connect with him on Twitter @RDONateDorsey. To learn more about precision application and John Deere’s Exact Apply nozzle control system, contact your local RDO Equipment Co. store.