A modified strip-till rig and no-till planter enable Rhodes to place nitrogen, phosphorus and potassium in three different plant root zones – eliminating runoff and volatilization. Nitrogen is further protected with a stabilizer to prevent loss to groundwater. "I want the right nutrients available in the right place at the right time – the four 'R's," says Rhodes. "We know it produces higher yields with less crop nutrients.
"The question for us was: Can we use the same amount of fertilizer in a smarter way and grow a better crop? We've proven that we can," he adds. "The biggest yield bump we've seen comes from putting the right fertilizer in the right place — right in the strip, right below the seed."
Rhodes measured an 18.6-bushel per acre advantage to the system compared to standard no-till production. And it happened with substantially less N per bushel of yield.
Timing is also important. Using his strip-till rig, Rhodes split-applies fertilizer on his corn ground, placing part of the nutrients about four inches beneath surface just prior to when the crop approaches its peak nutrient demand. RTK accuracy makes that possible.
Tissue sampling during the growing season is used to assess plant nutrition status at each stage. That allows for further fine-tune fertilizer applications. Rhodes also plants forage oilseed radishes as a cover crop to retain N, P and K through winter and reduce spring soil compaction.
Learn more about the Fertilizer Institute's 4R nutrient stewardship initiatives at nutrientstewardship.org and on Twitter at @4rnutrients. Watch for more on Rhodes' crop management system in an upcoming issue of American Agriculturist.