With farmland recently selling for more than $21,000 an acre in Iowa, saving $5.93 an acre may seem like a drop in the bucket.

But paying attention to dollars and cents makes great sense to Cresco, Iowa strip-tiller Frank Moore, who’s been farming for more than 35 years.

Like an increasing number of strip-tillers, Moore splits his applications of nitrogen. In the fall, a custom applicator bands 15 pounds of nitrogen with DAP on soybean ground. After planting corn, Moore applies 30 pounds of nitrogen in the form of liquid 28%. The liquid nitrogen serves as a carrier for the herbicide and also helps as a burndown on small weeds, he says.

When the corn is 6 to 12 inches high, Moore relies on a system from Cornell University to make an economically sound decision on how much nitrogen to sidedress. Moore is a certified crop adviser and technical service provider in Iowa and Minnesota with the NRCS. He’s not only interested in how to apply the right rate of nitrogen for his corn, but also that of his clients.

Starting last year and again this year, Moore and four other independent crop consultants from Iowa evaluated Cornell University’s Adapt-N formula. By using daily weather information and factoring in soil-organic matter and soil types, Adapt-N enables farmers to determine how much nitrogen to sidedress and whether it’s profitable to do so.

Moore says Adapt-N helps farmers answer two major questions: First, how much of the nitrogen that you applied is still in the soil for the corn? Second, do you need to apply more nitrogen?

“Taking the real-time weather information, the formula gives you an answer that says, ‘As of today, with these conditions, we think you need more nitrogen, and here’s how much to sidedress,’’’ Moore explains.

“For sidedressing, my goal is to apply about 75 pounds,” he says. “After using a homemade sidedress rig, I bought a 16-row Fast sidedress rig, which I used last summer. It takes me about 5 days to sidedress about 950 acres of corn.”

Red-Flag Recommendation

As much as Moore relies on technology and loves to evaluate new practices that save and make money, he doesn’t blindly follow all of what the Adapt-N formula recommends.
Last summer, the formula called for zero additional nitrogen in one corn field, which raised red flags with Moore. So in that field he compared zero additional nitrogen vs. 45 pounds vs. 75 pounds sidedressed.

SAVING MONEY. This year, Iowa strip-tiller Frank Moore saved $5.93 per acre in a field where he sidedressed no nitrogen vs. a treatment with 75 pounds of nitrogen that yielded about 9.4 bushels more. This was the second consecutive year that Moore used Cornell University’s Adapt-N program, which calculates if previously applied nitrogen remains in the ground and how much more the corn may need.

(Photo courtesy of Frank Moore, Three Rivers Ag Consulting)

The results were 150.4 bushels where he applied zero nitrogen, 159 bushels for 45 pounds and almost 160 bushels for 75 pounds of nitrogen.

But Moore cautions that doesn’t mean his farm made more money. When he decided whether to sidedress nitrogen and how much to apply, corn for fall delivery was $5.75 a bushel.

“My maximum yield in the comparison came by sidedressing 75 pounds of nitrogen per acre,” Moore says. “On that treatment, the corn yielded 159.8 bushels per acre vs.150.4 bushels for 0 gallons of nitrogen sidedressed.”

Here’s how the economics worked out: On the lower yield, Moore didn’t harvest an additional 9.4 bushels of corn, which was worth $5.75 per bushel back in early June. That foregone income amounted to a loss of just over $54 per acre.

However, applying 25 gallons per acre (74.2 pounds) of 28% nitrogen, at $0.65 cents per pound, cost $48.23. So the fertilizer savings of $48.23 per acre and the application cost of $11.25 totals $59.98 per acre.

Subtract the foregone yield of 9.4 bushels per acre and the 150-bushel, zero-rate treatment saved Moore $5.93 per acre. (Moore used the Iowa State University Custom Rate Survey of $11.25 per acre for the cost of sidedressing.)

Soil Organic Matter

Moore says Adapt-N helps strip-tillers see how much sidedressed nitrogen the corn will take up.

CUSTOM STRIP-TILL. For the past 5 years, Iowa strip-tiller Frank Moore has had a custom applicator strip-till his soybean ground, banding potash and DAP. It typically takes about 5 days to strip-till 950 acres with the 16-row Blu-Jet with a dry fertilizer cart. The applicator uses RTK.

(Photo courtesy of Frank Moore, Three Rivers Ag Consulting)

“The corn is getting this nitrogen from the soil organic matter, which the nitrogen is feeding, in addition to the nitrogen fertilizer itself,” Moore says. “The soil is a complex biological system. Where fields have higher soil organic matter, you can, in many years, reduce the rate of nitrogen that you apply. But in cold, wet years, soil mineralization is inhibited and more fertilizer nitrogen tends to be needed. Leaching of applied nitrogen is also a factor in wet years.”

Adapt-N take these biological processes that are occurring and it sees if the soil is releasing or holding onto the nitrogen, Moore says.

“The Adapt-N program starts looking at the nitrogen in the soil in the fall of the previous growing season,” he says. “If you apply commercial nitrogen fertilizer or hog manure then, it takes that into account. For example, if the soil temperature is not cold enough, biological processes change the nitrogen into the nitrate form, which is highly susceptible to loss.”

Strictly from a standpoint of nitrogen leaching from fall application, spring application of hog manure may be preferred, Moore says.

“While spring application looks good on paper, there are several problems,” he says. “First, there can be incredible soil compaction, which will reduce yields. And second, many farms need to apply manure in the fall before the soil freezes up. Otherwise, the pits will fill up.”

Sample By Soil Type

Two key factors in determining how much nitrogen to apply with the Adapt-N formula are the soil organic matter and soil type, Moore says. By changing those two variables, nitrogen recommendations can change significantly.

“Because these are so important, I will change from grid soil sampling to sampling by soil type,” Moore says. “When soil sampling, many farmers only think about phosphorus and potassium, but there’s a huge difference where there’s 2% and 5% soil organic matter.”

“Where fields have higher soil organic matter, you can, in many years, reduce the rate of nitrogen that you apply. But in cold, wet years, soil mineralization is inhibited and more fertilizer nitrogen may be needed…”

— Frank Moore

Moore has been strip-tilling corn-on-soybean ground for about 5 years, having the strips custom built in the fall. This fall, the applicator used a 16-row Blu-Jet strip-till unit on 30-inch spacings, along with a dry fertilizer cart for potash and DAP. The applicator uses RTK and pulls the strip-till rig and fertilizer cart with a Deere 9900 tractor with four-wheel-drive.

“The strips look like those made by applying anhydrous,” Moore says. “The knives run 6 to 8 inches deep and the strips are about 10 inches wide. The berms have very little height.”

Moore says there haven’t been any problems with the berms inverting.

“But last year, my spring strips had a few erosion problems where they were up and down the hill,” he says. “The strip washed out, but we had some extremely hard rains.”

Moore says that Cornell constantly refines the Adapt-N program based on field results and recommendations from consultants like MGT, the three other Iowa interdependent crop consultants whom he works with.

“I had some long discussions this spring with them on the zero rate and they encouraged me to try zero nitrogen just to test the program,” Moore says. “We will evaluate my inputs into the Adapt-N program this winter to see what, if anything, needs to be changed or corrected based on the values I entered.”