With two decades of data, the Farm Journal Test Plots in central Illinois, led by Field Agronomist Ken Ferrie, have shown starter fertilizer boosts yields, on average, 7 bu. to 10 bu.
In 2010, the plot program expanded on the lessons learned to find answers to year-to-year variability in response to starter. To diversify our test plot effort, Missy Bauer joined the team as Associate Field Agronomist, based in the Eastern Corn Belt.
Beyond using it for timing and placement of crop nutrients, there are numerous questions about starter.
"Mainly, farmers ask if it pays off for hauling the extra weight and handling another product at planting," Ferrie says. "Don’t think of starter as just starter. Think of applying starter as part of your Systems Approach."
In Bauer’s area, it’s common for farmers to apply starter because of cool soil conditions.
"I have seven years of starter studies, and the average response for us is 8 bu. to 10 bu. per acre," she says. In a year like 2009 that was really cool, we had some 20 bu. responses."
Starter can be applied at different rates, with a spectrum of attachments and formulations. These variations only complicate the uncertainty when determining what makes starter pay.
"One of the questions I get the most is about in-furrow starter fertilizer, which is the most common way we see starter applied," Ferrie says. "Farmers report that they see visual response early in the season but don’t always see the yield increase."
Ferrie says that one reason in-furrow application can start off strong is its placement. That placement in relation to the seed, though, restricts the rate at which it can be applied and still not damage the seed.
"Our previous plots have told us that pop-up can give the crop a good start but it doesn’t seem to yield as high when compared with the higher starter rates placed beside and below the seed. You’d kill corn with putting those high rates in furrow. With that in mind, we took a closer look at starter blends," Ferrie says.
In 2010, Ferrie oversaw starter plots that spanned three different fields, two corn on corn and one corn after soybeans. In the corn-on-corn plots, two different tillage practices were used: vertical tillage and no-till.
The same planter was used in all of these plots, providing commonality across the entire effort. Starter was applied with a Yetter 2959 face-mounted coulter that places the starter to the side and below the seed and a seed firmer to place in-furrow.
A tank was mounted on the tractor’s three-point hitch to apply the side-by-side while a tank on the planter was used for the pop-up. The rates applied with the Yetter 2959 were 10 gal. 7-22-5; 10 gal. 28%; 15 gal. 50/50 blend; and 15 gal. 60/40 blend (60% is 28%). A 3-gal. rate of 10-34-0 was applied in-furrow. All starter included chelated zinc.
Applying the various formulations and blends revealed which crop nutrients were the limiting factor in higher yields for these fields.
"Phosphorus makes corn taller; nitrogen makes it greener," Ferrie says. "Each nutrient has different roles in the plant, but if you do a better job absorbing phosphorus or nitrogen, you do a better job picking up the other nutrient as well."
Particularly with nitrogen management, starter fertilizer can help the corn plant get off to a good start.
"One of the ways to manage the carbon penalty, especially in a corn-on-corn field, is to put nitrogen on with the planter," Ferrie says. "With this plot, we wanted to take placement and timing and maximize those lessons."
Ferrie describes the carbon penalty as the amount of nitrogen needed during decomposition in the spring.
Each plot included replications of each treatment. The crop rotation and residue management along with the nitrogen management programs of the farmers highlighted why the yields responded as they did.
"In the corn-after-soybeans field, we had strong yields overall," Ferrie says. "We did get a response to more nitrogen in the starter.
"If nitrogen is the limiting factor in your fields, applying more nitrogen at planting will increase yields," he adds.
At sidedress, the cooperating farmer pulled nitrate samples, which showed the field was
nitrogen-deficient. In response, the sidedress rate was increased to compensate.
Compared with the corn-on-corn plots, this field had a lower rate of nitrogen applied up-front before planting. Then with the rains during the season, the applied nitrogen was lost through leaching, more in some soil types than others.
"At the end of the season, you could see which management zones lost more nitrogen and how important the nitrogen applied at planting came through for yield," Ferrie says.
Special challenge. In the corn-on-corn plots, Ferrie and the cooperating farmer knew that the 2009 harvest would create particular challenges for 2010. The late harvest and lack of decomposition in the fall upped the ante, increasing the carbon penalty that had to be paid in the spring.
"Knowing the amounts of residue that had to be processed in this field, the cooperating farmer increased his surface applied spring nitrogen rates and stayed with planned sidedress rates," Ferrie says.
Using nitrate tests at sidedressing time, the farmer could tell his up-front management had paid off. The nitrate samples indicated that they had achieved their goal of not allowing nitrogen to become a limiting factor.
In the vertical tillage corn-on-corn plot, the crop residue was incorporated into the soil.
"You would think nitrogen would be the most important in a corn-on-corn vertical tillage system," Ferrie says. "While the straight nitrogen did well, the straight starter blend outyielded it. This indicates that phosphorus, not nitrogen, was the weakest link."
In the no-till corn-on-corn plot, the results were similar to the starter blends. "With a combination of pop-up in the furrow and 28% on the side, we had a yield response similar to the straight starter rate," Ferrie says. "This tells us that both nitrogen and phosphorus were limiting factors."
Bauer reports that farmers in her area focus on running high nitrogen starters as part of their nitrogen program. But they also are concerned about phosphorus uptake.
"Our normal starter is a 50/50 blend of 28% and 10-34-0 applied below and to the side of the seed," Bauer says. "We run low salt starter as pop-up because of our sandy soils and the
potential to burn seed."
Bauer reports that early season phosphorus tests revealed nutrient uptake by the corn plant when starter is applied 2" below and beside the seed. The check had no starter but had 28% dribbled off to the side on the surface, resulting in 79 units of phosphorus. The starter treatment of 10 gal. of 28% was 81 units, and 15 gal. of 19-17-0 was 109 units.
Bauer says when pop-up was added to the application of 28%, the result jumped to 112 units, which was similar to the straight 19-17-0. "With 3 gal. of pop-up, we are getting phosphorus
in the plant as efficiently as straight starter in 2x2 placement. That’s how key the placement of phosphorus is."
Placement is more important for phosphorus because it is not mobile and needs to be strategically placed for uptake. Nitrogen is more mobile and can be banded behind the closing wheels or placed shallow because it will move down with moisture.
"If you are applying starter off to the side, you want to be at least at the seed depth or below to get within the roots’ proximity," Ferrie says.
To find the right approach to starter on your farm, conduct your own plots.
"When evaluating starter rates or mixes, I encourage farmers to test different rates in the field. Look first for a visual response, followed by a yield response. If adding nitrogen to starter gives you a big visual response, the corn plants are telling you there wasn’t sufficient nitrogen available to meet the needs. If there is no visual response, that is a good indicator that your nitrogen program is keeping corn satisfied."
Thank You to Our Test Plot Partners
Each Farm Journal Test Plot is a cooperative effort. Thanks go to: Yetter Manufacturing, Pat Whalen, Susan Wherley and Scott Kale; Great Plains Manufacturing, Tom Evans, Doug Jennings and John Sites; Kinze Manufacturing, Susanne Veatch, Laura Blomme and Mike Feldman; AGCO, Alexis Max and Reid Hamre; Farm Depot and Mark Laethem; Precision Planting and Gregg Sauder; Versatile and Adam Reid; McCormick USA, Doug Rehor and Kurt Schneick; Unverferth Manufacturing and Jerry Ecklund; Orthman Manufacturing, Adam Souder and John Bell; Dickey-john and Pat Fuchs; Jensen Electronics and Stephen Jensen; AutoFarm; Trimble and Sid Siefkin; OmniStar and John Pointon; The Andersons, Jan Finch and Jeff Balsley; Mike and Steve McLaughlin, Cole Dooley; Don Schlessinger; Bob and Mary Kochendorfer; Crop-Tech Consulting, Brad Beutke and Isaac Ferrie; B&M Crop Consulting, Vicki Williams and Gary Cooper.