If you are on the fence about whether to upgrade your navigation system to RTK, the question is whether you want greater accuracy or faster payback.

 “It depends on how much accuracy you want,” says Matt Darr, a precision agriculture specialist at Iowa State University. “Are you willing to accept 3 ft. of overlap, or do you want less than that? You can’t turn that into a number. It’s a personal preference.”

Darr says the trend toward higher-accuracy navigation systems continues to grow rapidly. But since many cropping operations can be run by either WAAS-level systems or higher-accuracy subscription-based or RTK systems, comparative payback calculations are imprecise. Paybacks tend to favor the less-expensive system, unless you plan to adopt practices that won’t work with less precision.

“RTK can unlock a lot of new potential, but if you can do the same applications with WAAS, the payback for RTK will be slower than with a WAAS system,” Darr says.

As you consider your need for a higher-accuracy navigation system, here are five areas to consider:

1. Controlled-traffic farming
In strip tillage and other controlled-traffic cropping systems, an RTK-level navigation system is a must. Precision fertilizer placement, which typically is separated from the strip-till planting operation, is hard to accomplish without sub-inch accuracy.

2. Drainage system design and installation
With an RTK navigation system, improving your operation’s drainage can be a do-it-yourself project. A WAAS system just won’t cut it.

3. Higher-resolution application system shutoffs
“Clutches in general have eliminated 90% of the overlap, even with WAAS,” Darr says. “Single rows, with two-row sections at end, can work with WAAS by setting the headland overlap at 2 ft. You would like to have an overlap more than a skip. But if you get rained out, you could have a 3-ft. drift if you come back and plant the next day. That would be eliminated with RTK.”

4. Slower follow-on field applications, such as sidedressing
Fast-moving over-the-top broadcast spraying typically works well with a WAAS-level system, Darr says. But if you plant with an RTK system, RTK guidance for sidedressing would make sense. Row-crop harvest systems often rely on feelers on the header for guidance, so RTK is less helpful for row-crop harvest than might otherwise be the case. 

5. Improved flexibility
If you farm large fields, WAAS drift may be a greater annoyance than if your fields are smaller. RTK also reduces drift hassles from field operation delays.

“Accuracy is addictive,” Darr says. “Calculating a strict payback can be difficult. But higher-accuracy systems really do add value back to the farm.”