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Several months ago I wrote an article about curve compensation in planters and how these systems can help create more uniform stands and improved yield in fields with curves.


Another area where there is a lot of value with curve compensation is product application. Sprayers are getting larger, often coming equipped with 120- or 132-foot booms, which can cause drastic differences in application rates on the inside and outside edges of a curve. This can result in weed, disease, or nutrient problems as product is overapplied on the inside of the boom and underapplied on the outside.

There are several great systems that have been on the market for a few years with individual nozzle control, such as the CapstanAG system, Raven Hawkeye, and John Deere’s new ExactApply system. The ExactApply system not only features individual nozzle control which enables curve compensation, but also has technology that allows for pulse-width modulation at 30 hertz, a turret featuring six nozzles with automatic A/B nozzle switching, and improved monitoring of nozzles for issues such as flow rates and blockage. This monitoring system is visible on the in-cab display and through lights that are built into the ExactApply nozzle body.

I had the opportunity to work with the ExactApply technology this season and conduct a simple field trial illustrating the value of the new system. I worked with a team of Product Specialists at RDO Equipment Co. to conduct the field trial at a precision agriculture field day they held for customers. We made an oval track with a 180-degree turn on each end to put the curve compensation system to the test.

The field trial consisted of two treatments, curve compensation on and off, and evaluating the effect of a curve on spray coverage across the boom. We expected that, with curve compensation off, product would be overapplied on the inside of the curve and underapplied on the outside. With the system on, the application rate would then be consistent across the whole boom. To measure this, we put water-sensitive paper across the length of the spray pass and then calculated the percent spray coverage on each sheet.

The results showed that the new system works as advertised, and that with curve compensation off there was a statistically significant difference between the inside and outside edges of the boom. With the feature turned on, there was no statistical difference, meaning that the spray rate was maintained across the length of the boom in the curve.

Whether the system used is John Deere’s ExactApply, CapstanAg’s Pinpoint II, Raven Hawkeye, or another option on the market, there are several benefits for a customer. One of the biggest benefits is with the 4Rs of nutrient or product application: applying the right product in the right place, at the right time, and at the right rate. These systems ensure that product is delivered at the correct rate where it’s needed, enabling practices such as variable rate, and shutting off nozzles as you cross headlands and interior and exterior boundaries. This saves on product application costs and could help with issues such as weed, insect, or disease resistance.

To conclude the field trial, we put together a video for customers who could not attend the event. In today’s digital age it’s not only important to work with and show the value of the latest technology, but to use new ways to communicate this information to others.

Watch the field trial video below:

2 2 5 New Opportunities for Soil Moisture Monitoring