Test Plots: Push the Limit

February 11, 2014 08:07 PM
Test Plots: Push the Limit

Farm Journal Test Plots conclude high-yield three-year study

What does it take to push fields to the highest yield level? For the past three years, Farm Journal Asso­ciate Field Agronomist Missy Bauer set out to answer that with multi-site demonstrations in southern Michigan.

"To increase yields, farmers must identify the weakest link in their production practices," Bauer says. "The goal of the these plots was to push populations and push fertility to understand the lacking component in high-yielding environments—irrigated corn-on-corn fields."

The test plots were set up to compare the traditional fertility program (determined by soil tests) and the farmer’s standard nitrogen sidedress rate as a check to the higher fertility programs.

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A granular fertilizer was broadcast before planting at an above-average rate. In 2010, the MicroEssentials S10 (12-40-0-10S) product from Mosaic was applied at 250 lb. per acre.

"In the first year, early season tissue tests showed increased nitrogen, phosphorus and sulfur in the plants that received the MicroEssentials S10 product," Bauer says. "The average yield increase using MicroEssentials S10 in combination with extra nitrogen was 22 bu. per acre across management zones."

In the second and third years, Bauer wanted to isolate the fertilizer components. Zinc was added to the granular product, and the Micro­Essentials SZ (12-40-0-10S-1zn) fertilizer was applied at 200 lb. per acre. The MicroEssentials product is formulated so each fertilizer granule contains nitrogen, phosphorus, sulfur and zinc. Additional treatments included increasing the rate applied at sidedress with and without the MicroEssentials product applied. Each treatment was replicated at least three times in the field-sized plots.


Fertility treatments included a regular and increased rate at sidedress to isolate the potential response to more applied nitrogen.

"With each treatment, we are trying to isolate the component that increases yield—or what our limiting factor was," Bauer says.

In 2012, there was not a consistent yield increase to the higher fertility treatments, but early season plant weight and tissue tests reflected higher nutrient uptake.

"I think partly that is due to our warm spring and dry conditions; fertility was not the limiting factor in 2012," she explains. "Those fields averaged 239 bu. and 254 bu. per acre."

In 2013, the same protocol as 2012 was repeated at two locations, one planted in 30" rows and the second planted in twin rows. Fields were planted at two populations—36,000 and 40,000 plants per acre.

"We found as population increased we needed to follow with higher fertility to support a yield gain," Bauer says.

Additional results from 2013 are detailed in the charts below.

In the field planted in 30" rows, the hybrid responded to population and higher fertility treatments. The nitrogen program included dry broadcast; pre-plant weed and feed; starter; sidedress; and fertigation. The treatment with extra nitrogen had 40 lb. more applied at sidedress than the standard rate.

"Particularly in the lighter soils, those zones needed more fertility. When planted at the higher population with increased fertility, we saw yield increase," Bauer explains. "Plant uptake is critical for fertility to make an impact on yield."

At the V7 stage, the crew measured dry plant weight. The Micro­Essen­tials treatment had elevated nitrogen, zinc and phosphorus levels in the plant. Sulfur results were similar between the treatments. Tissue tests at silking showed higher levels of nitrogen in the plant in the treatments where the extra nitrogen was applied.

Thank You to Our Test Plot Partners

Our thanks go to: AGCOn Marx, Dave, Jaso Webster, Conor Bergin and Lindsey Pettyjohn; Williams Farm Machinery and Dave Gloor; Fast Distributing, Brian Johnson and Garrett Kelly; GeoVantage and Nate Taylor; Great Plains Manufacturing, Tom Evans, Doug Jennings and John Sites; Mosaic, Matt Wiebers and Jim Boswell; Crop Production Services, Morenci, Mich.; New Holland, Mark Hooper, Gary Wojcik and Paul Canavan; Burnips Equipment and Carl VanderKolk; Trimble and Brian Stark; OmniStar and John Pointon; Unverferth Manufacturing and Jerry Ecklund; Wells Equipment; Gary Cooper Trucking, Gary Cooper and Chad Roach; Jerry Reed; North Concord Farms and Dick Dobbins Jr.; and B&M Crop Consulting, Vicki Williams, Megan Tomlin and Amanda Anderson.

"In that tissue test, we saw 3.64% nitrogen; I’ve found there needs to be 3.5% in the ear leaf at silking to achieve high yields," Bauer says. "The check only had 3.43%"

At the location planted in twin rows, the hybrid did not consistently respond to the higher populations. However, the crew saw similar trends with the MicroEssentials product improving dry weight and phosphorus uptake. There was no significant difference in zinc or sulfur in the early season tissue.

At the R1 stage, where an extra 35 lb. of nitrogen was applied, the tissue test had 3.83% nitrogen and the check had 3.33% nitrogen.

"Both fields showed a consistent increase when the MicroEssentials product was paired with an extra nitrogen rate at sidedress," Bauer says. "The com­bina­tion of earlier phosphorus uptake enhancing root growth could have allowed the corn plants to take better advantage of the extra nitrogen.

Bauer reports that zinc was included in the starter blend, which could have adequately supplied zinc. Also in 2012 and 2013, both fields had 150 lb. of ammonium sulfate broadcast in the fall, which could have sufficiently supplied sulfur.

Bauer reminds farmers to double-check their planter setup and calibration when trying to achieve high yields.

"Overall, in high-yield irrigated corn-on-corn situations, there is a connection between high population with high-fertility including nitrogen, phosphorus, sulfur and zinc," she says. 

To see pictures of the plants and ears from these test plots, as well as results from previous years, visit www.FarmJournal.com/high_yield_study

You can e-mail Margy Eckelkamp at meckelkamp@farmjournal.com.

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