July 23, 2018
By Larry Stalcup, Contributor for The Progressive Farmer
Ohio growers protect watershed and yields by adopting nutrient management plan.
Farming near Toledo, Ohio, and Lake Erie, David and his father, Lowell Myerholtz, work hard to limit their corn and soybean farm’s impact on the watershed. Father and son manage varying clay soils near Gibsonburg.
Wanting to respond to the water-quality issues reported in the Toledo media, the Myerholtzes wrote a nutrient management plan detailing how the farm manages its phosphorus, nitrogen and other nutrient applications. Based on the farm’s soil fertility levels, they set out to reduce their fertilizer usage by 20%—a goal they have since met. “We’re able to assure our landlords the changes we continue to make in fertilizer applications reduce their liability as land owners to the environment.”
Their plan wasn’t an overnight response to public pressure. The farm has practiced conservation tillage for more than 30 years.
David credits strip tillage, made possible by GPS technology, with improving their conservation-tillage practices. Strip tillage has enabled them to take advantage of crop residue. It encourages warmer soil temperatures and improves root zone tilth. “It has become our best nutrient management plan, especially since we can use this system to variable-rate multiple products and be in compliance with Ohio fertilizer application guidelines,” David explains. “It also leverages our investment in RTK [Real-Time Kinematic] autosteer and geographic information [GIS] recording data management.”
David contends that strip-till combined with variable-rate deep placement of nutrients at 5 to 8 inches proactively addresses public concern for water quality. “We can control and document the amount, time and placement of the banded fertilizer application, plus it is placed below surface [controlling] runoff,” he says.
Variable-Rate Application (VRA)
The Myerholtz family has used variable-rate technologies for 10 years. “With the heightened concern with runoff, tracking and fertilizer recommendations from The Ohio State University and pure economics, [variable rate] has become a necessity,” David says.
Data collection and prescription management was made with the Veris soil-mapping system. The Myerholtzes teamed with The Andersons Grain Group crop consultant John Fritz, and with consulting firm Widmer and Associates to measure soil nutrients. The Veris system measures the electroconductivity of the soil. “The higher the electroconductivity number, the heavier the soil.
The smaller the number, the lighter the soil,” Fritz says. Information from the Veris system is combined with GPS-specific soil samples and yield history to map management zones and make site-specific nutrient applications.
“With the increased amount of data available, management zones are no larger than 12 acres in size to be more precise and efficient in nutrient applications,” David says. “We can determine more efficient nutrient placement without hurting yield.”
Better Placement, Better Return
Cost of production is the driver of most agronomic decisions. Good stewardship is a bonus. “We’ve been forced to cut our nutrient costs due to narrow margins,” David says. “With strip tillage, I’m confident we’re using 25% less fertility than we did with conventional tillage and fixed-rate broadcast nutrient applications.”
In the farm’s corn program, there are no fall nitrogen applications but multiple treatments during the growing season. “First, we band on a 28% subsurface application as a starter with the planter, then apply another 28% with a [urea] inhibitor in a tank mix with herbicides,” David says. “We then go with a 28% sidedress injection after the crop emerges. Some N may be applied late season if deficiencies are noted.”
With soil data, variable-rate machinery enables the Myerholtzes to treat soil with exact amounts of lime, phosphorus and potassium on the subfield management zones. “Placement of all phosphorus is below the soil surface,” David says. “I’m getting more ears per foot of row.” Corn yields range from 162 to 190 bushels. “VR fertilizer applications combined with strip tillage are providing more consistent yield across varying soil types.”
The Myerholtzes’ soil and nutrient management programs earned their farm recognition from The Fertilizer Institute, which named them a 4R Advocate for 2016. The 4Rs represent applying the right nutrient source at the right rate, at the right time and at the right place. “A 4R protocol and statement helps show that what we’re doing makes good environmental sense,” David says.
Fritz commends the Myerholtz family on its dedication to conservation tillage. “They have been very active in conservation practices and learning how they can improve management of their soils,” he says. “Because of their use of strip-tilling, their work with the NRCS [Natural Resources Conservation Service] to develop a cover-crops program and other conservation practices, we at The Andersons nominated them for the 4Rs program. Anything farmers can do to prevent phosphorous from getting into ditches and eventually Lake Erie is an asset to our region.”
David says a more precise placement of nutrients and a 25% reduction of fertilizer applications benefit his bottom line.
“This whole concept with placement of fertilizer and VRA is all a cost-control incentive,” he concludes. “It might be prioritized more than environment impact due to how margins have come down more than 30%. As a bonus, we’re learning that new varieties and hybrids are being more nutrient-use efficient. We would have a difficult time convincing ourselves to change production method.”