The Farm Journal Test Plots used a Great Plains Nutri-Pro toolbar to band nitrogen before planting. The design of the coulters places nitrogen 4" on both sides of the row. RTK was used for the nitrogen pass and planter pass for placement accuracy.
Nitrogen test plots confirm that timing matters
Ahigh percentage of the Farm Journal Test Plots revolve around one key nutrient—nitrogen.
"Time and time again, we see that nitrogen is king—it makes the biggest difference," explains Farm Journal Field Agronomist Ken Ferrie. "The nitrogen cycle is complex, but the first thing farmers must understand is that finding the right nitrogen timing, placement and rate requires more than using the simple equation of bushels per pound of nitrogen."
To shape their nitrogen management program, Ferrie encourages farmers to consider product in addition to timing, placement and rate. Comparing programs that use different sources of nitrogen at different times is like comparing apples to peaches.
The Farm Journal Test Plots have found no difference in yield when applying anhydrous ammonia or 28% when positioned the same way. (See "Bridge the Gap," Late Spring 2013.) Ferrie continues to learn more about how the variables in a nitrogen plan add up to yield success and how to fill in the weak spots of a nitrogen program.
"The goal is to find out how farmers can make their nitrogen dollar go as far as possible," Ferrie says. "In 2013, we saw 20 bu. to 60 bu. yield hits because we didn’t manage nitrogen effectively."
The right placement. This past year, Ferrie and his crew conducted two test plots focusing on nitrogen placement.
The first test plot, in its second year in 2013, is a season-long effort that compares four timings of nitrogen application: pre-emergence broadcast, preplant strip-till, nitrogen applied with the planter and sidedress nitrogen. The strip-till treatments were applied with a Great Plains Nutri-Pro toolbar with coulters 8" apart, placing the banded nitrogen 4" on both sides of each row and 3" from the surface. The nitrogen applied at planting included in-furrow starter fertilizer as well as 28% applied 2" to the side and 2" below the surface. The same total rate of nitrogen was applied overall but at different timing combinations.
In each field, the application and planter passes were made with RTK accuracy to ensure exact placement of nitrogen and seed.
The first year, 2012, included two corn-on-corn fields. "That was a tough year to start a plot because of the weather and environment, but we saw that the field was responding to the banded nitrogen. The more we banded, the stronger the response—with strip till, planter applied and sidedress banding being the strongest. On the flip side, the more we broadcasted, the more yield decreased," Ferrie explains.
As suspected, it quickly became clear that the environment matters. From central Illinois and north, Ferrie advocates for farmers to broadcast some nitrogen in heavy residue conditions to help decompose residue faster.
"In heavy residue fields, farmers must deal with the carbon penalty. Sometimes this can be done with broadcast, but when we combine broadcast with banded applications, we weatherproof a nitrogen program," Ferrie says. "Strip-till and nitrogen applied with the planter bypass the carbon penalty by keeping the plant happy while the microbes immobilize nitrogen to decompose the residue. Due to timing, those placements decompose less surface residue and are less susceptible to nutrient loss."
To verify results, all Farm Journal Test Plots are harvested with calibrated yield monitors, and each load is weighed with grain carts with scales.
Application timing depends on geography as well. Ferrie notes that Southern farmers who want to conserve residue should consider banded applications because they don’t speed up decomposition of surface residue.
When plants need it. After thinking about the planting environment, farmers should also consider the timing of their applications.
"When I talk about timing of nitrogen applications, I don’t necessarily mean when I apply but when does the plant need it," Ferrie says. "Farmers have to make sure the plant is happy from the beginning to the end and remember the environment sets the tone. For example, in corn on corn, front-end timing is key to manage the carbon penalty."
- March 2014