How to navigate zone management decisions to realize the benefits of variable-rate technology over time
Editor's Note: This article is part of the Farm Journal multimedia series, which is designed to help improve bottom lines by maximizing yields, minimizing inputs and improving stewardship. Use this as your business guide to understand and implement zone management and the tools that make it possible.
Every risk has its reward. With zone management, the reward is higher yields and profitability. Farmers who want to vary inputs such as seed and nitrogen have to first get a handle on managing the zones in their fields. Farm Journal Field Agronomists Ken Ferrie and Missy Bauer encourage farmers to be students of their soils to minimize the risks associated with implementing variable-rate technology (VRT).
"When farmers establish solid fundamentals, it eliminates the surprises," Bauer says. "Understanding soil characteristics will help farmers weigh the risk factors involved with changing inputs by zones."
Weston Wiler, who farms near Hillsdale, Mich., spent five to six years reviewing soil data and refining zones before moving forward with VRT population and nitrogen.
"Zone management gives you the confidence that you’re putting inputs where they’re needed in the soil, and you’re not spending money you don’t need to," Wiler says.
The decision to vary population and nitrogen should be grounded in the fundamentals, but the risk factors for the two practices are different.
"Population rates are based on water-holding capacity. Soils that have higher organic matter and cation exchange capacity (CEC) will support higher populations," Bauer explains.
Before adjusting populations based on the zone, Bauer stresses the importance of farmers knowing how effective they are at their current populations.
"Farmers must know their ear count. Increasing population without knowing that ear count also
increased will not accomplish the goal," she says. "Compare planted population to ear count ratios. The thresholds should be no more than a 2,000 difference in corn-on-corn or 1,200 in corn-after-soybeans."
Bauer also advises farmers to evaluate how ear tips fill and understand if the hybrid has a fixed or flex ear.
"When working with farmers on VRT populations, they get frustrated in making yield advances when they didn’t first understand ear count, uniform emergence and planter performance," Bauer says.
A struggle that Ferrie has encountered is farmer opposition to dialing back population rates.
- February 2014