For several years, farmers in southern Minnesota have been using high-clearance sprayers equipped with Trimble’s GreenSeeker sensors to apply supplemental N to corn up until tasselling, says Kevin Jeurissen, agronomist with Crystal Valley Coop, Lake Crystal, Minn.

“We’re not trying to apply all a field’s N with this equipment,” Jeurissen says. “Typically, we put a base amount of N down in the fall and spring and then come back with an in-season supplement, which varies between 2 and 15 gal. N/acre, according to what the GreenSeeker technology indicates is needed.”

Success with the technology over multiple years is generating more demand for the equipment, Jeurissen says. “We’re at the point where a certain percentage of our clientele will likely end up using these sprayers to apply in-season N on all their corn acres,” he says. “We’ve got eight high-clearance sprayers equipped with GreenSeeker sensor technology right now, and we may be getting a couple more before next season to keep up with customer demand.”

Wet springs have delayed fertilizer applications for many farmers in the area over the last three years, Jeurissen says. “However, the high-clearance sprayers have helped get the job done, and we’re seeing good results,” he says.

Early in 2011, N deficiencies were easily evident in many fields as wet weather prevailed. Despite disappointing late-summer rainfall, adding more N in-season “did have a yield advantage,” Jeurissen says.

Every year is different, but multiple, 20-acre field plots show that in-season applications consistently pay a yield dividend, he adds. “In high-management zones, we are doing repetitive block trials, with yield monitors and weigh wagons, to evaluate our practices,” he says. “We know this system works, because we’ve seen yield increases from using it over several years of varying weather climates.”