Increase in price calls for increase in management. Don't skimp on yield goal.

Higher costs of production raise hard-to-answer questions by corn growers. Higher prices for fuel and fertilizer will drive up the cost of growing an acre of corn by $12 to $14, analysts predict.

Adding to the uncertainty is the real possibility that you may not be able to find all of the nitrogen you need when you need it—or not in the form you customarily apply. U.S. production of nitrogen fertilizer has been declining over the past decade and higher natural gas prices are limiting production still further. Higher prices here are pulling more nitrogen from foreign manufacturers, but most of those imported supplies must pass through Gulf of Mexico ports, which are still recovering from Hurricanes Katrina and Rita.

With the certainty of higher prices and the possibility of nitrogen shortages, some growers see staying in soybeans attractive compared to normal rotations to corn. The downside of beans after beans is that you lose more than 2 bushels in yield, compared with rotating soybeans with corn.

For some growers, grain sorghum may be an alternative crop to corn; milo generally requires less nitrogen. But milo doesn't compete with corn in the marketplace.

"Don't change good agronomic practices for the sake of fertilizer prices," said Paul Tracy, MFA staff agronomist. "If you use good management and follow soil testing recommendations, you can't Ôtweak' nitrogen fertilizer applications downward and produce optimum yields. If you reduce rates, you must simultaneously reduce nitrogen losses from your agricultural system or yield will suffer. By decreasing your nitrogen rate, you are greatly reducing potential yield goal in many cases."

"Most growers do a good job of nitrogen management," said Lyndon Brush, also an MFA staff agronomist. "For example, not many corn growers over-apply nitrogen and this is no time to waste any of it."

There are ways to get more bang from your nitrogen buck:

Don't apply too early

"We recommend a late-spring soil test and N application as late as possible, to avoid nitrogen losses from leaching," said Antonio Mallarino, Iowa State University agronomist, who admits that the ideal often must be compromised with what's doable in a busy spring season. "We're always gambling with nitrogen; we don't know ahead of time how much nitrogen the crop will need."

Protect your N

"You may want to use a nitrogen stabilizer like N-Serve to protect anhydrous ammonia, especially with early applications," Tracy added. "And consider a product like Agrotain if you're applying urea, to inhibit the loss through volatility." (See Paul Tracy's column on page 6)

Split applications

"Split applications, with a quarter to a third of the nitrogen applied pre-plant and a side-dress application when corn is 5 to 6 leaf stage, are actually more efficient and can increase yields, compared with applying all of the N at one time," said Tracy. "But not everyone is set up to side-dress, and another trip over the field will increase fuel costs."

"You might consider applying 80 to 100 pounds of nitrogen pre-plant, and then wait to see how the corn does," agreed Mallarino. "But timing is critical for side-dress applications."

Fertigate

"Growers with center-pivot irrigation rigs can spoon-feed 10 to 20 pounds of nitrogen solution through irrigation," said Brush. "Not everyone irrigates, but fertigation is an option for those who do."

Apply manure

"Manure can be a good source of nitrogen, phosphorus and potassium, if you're within hauling distance," said Tracy. "However, you'll need to incorporate manure to limit the loss of the ammonia form of nitrogen. You're limited on how far you can afford to transport manure, especially with higher fuel costs. Another problem: the nutrient content of manure varies from load to load." Tracy added that manure is best applied to meet soil phosphorous requirements. Nitrogen is not always released from manure at the right time for crop growth and utilization. "We typically recommend using phosphorous levels to gauge manure application and then supplement commercial nitrogen fertilizer to meet soil test and yield goal," he said.

Don't neglect P and K

"Don't neglect phosphorus and potassium, especially if you plant early," urged Lyndon Brush. "A good residual soil level of P and K lets plants get off to a faster, healthier start."

The curve is still valid

There is a well-defined response curve for corn yield and nitrogen levels. The curve is flatter for high-nitrogen supplying soils and steeper for low-nitrogen supplying soils. The first thing to remember is that as nitrogen inputs initially increase, yield response is dramatic. At optimum yield potential, the response per nitrogen unit decreases. The breaking point is where nitrogen decreases yield—but that occurs far above recommended rates. The chart below shows that even when fertilizer prices are high, nitrogen isn't an input you should reduce.

Credit from soil

You can also take credit for the previous crop and for organic matter in the soil. For corn following soybeans, you can cut nitrogen application rates by 20 to 40 pounds per acre. Also, each percentage of soil organic matter will release 20 to 30 pounds of nitrogen that is useable by the crop.

It's virtually certain that corn will cost more to grow in 2006. But corn can still be a profitable crop. And, if high prices bluff many producers out of raising corn, next fall's crop should find a better market.

"If you're already doing a good job of fertility management, don't cut nitrogen solely to try to save money," said Brush. "Nutrients shouldn't be the limiting factor."