Spring planting is a totally new ball game this year

Ten percent loss does not mean as much with corn at $4, but it is something to factor in," Wiebold said.

By Doug Rich

The 2007 corn crop could be the largest ever. Estimates of planted acreage range 85.6 million acres to 90.76 million acres. The market is demanding more corn and producers are responding.

To grow that much corn producers have made the decision to take acres away from other crops and to plant corn a second year on certain acres.

"Some producers will make no change from their 50-50 corn soybean rotation, some will plant a little extra corn, and some will go pretty heavy into corn," Bill Wiebold, University of Missouri Extension agronomist, said.

It will be a learning process for producers who have used a corn-soybean-corn rotation for several years. corn on corn production presents several challenges for producers.

"The biggest issue is something we don't really understand," Wiebold said. "That is rotation effect or lack of one with corn on corn."

Wiebold said research studies show a 9 to 10 percent yield loss in corn following corn compared to corn following soybeans. This yield drag cannot be overcome with more nitrogen, it is something about the second year of a crop. It would be the same with soybean following soybean.

"Ten percent loss does not mean as much with corn at $4, but it is something to factor in," Wiebold said.

Rural legend

There is a rural legend that corn yields will rebound in subsequent years if a producer decides to plant continuous corn on a field.

"Farmers may have their own experiences, but no research shows that it comes back," Wiebold said. "It does not continue to decrease. The third, fourth and fifth years could equal the second year."Even through extra nitrogen fertilizer will not make up for this yield drag, more nitrogen will be needed to make up for what is normally provided by the soybean crop. The extra nitrogen needed can range from 40 pounds to 70 pounds per acre.

"Corn on corn is going to require at least another 50 pounds of nitrogen," Steve Butzen, agronomy information manger with Pioneer, said. "If they are used to planting on soybean ground and now they are going back on corn it will be 50 pounds above what they normally use. This is simply because the corn residue it tying up the nitrogen more than soybean residue does."

Field selection can play an important role in success with corn on corn production. Particularly if they have poorly drained soils that stay cooler and wetter. Those fields would not be good candidates for corn on corn production just in terms of getting a stand established.

More residue means cooler wetter soils. Producers may have to adjust their planting dates if they are accustomed to planting at a specific soil temperature.

"If people are no-tilling corn afterSoybeansthat is a real nice situation," Butzen said. "It is not that hard to no-till into soybean ground. The issue is corn on corn is a totally different game."Butzen said with corn on corn or continuous corn production there is crop residue hanging around year after year which creates a better environment for certain disease and insects in corn. All of that crop residue is a good source for corn pathogens such as seedling blight, stalk rots, and leaf diseases. Gray leaf spot is an organism that builds up in residue over time.

"Corn rootworm is right at the top of my list and the biggest blip on the radar screen for corn after corn," Butzen said. "If a producer has been in a rotation and successful at rootworm control now he really has to worry about it."

"Effective control measures are critical for this pest, as corn rootworm pressure tends to be highest in the second and third years of continuous corn," Butzen said. "On the majority of corn after corn acres, corn rootworm management will be necessary. For control, choose a hybrid with a transgenic trait or an insecticide seed treatment or apply a granular soil insecticide."

The risk from disease that depends on spores blowing in from Texas will not change much with corn on corn but the risk from other diseases that depend on a local innoculum will increase.

Disease problems

"One of the things we talk about in disease control is a good rotation," Wiebold said. "Come out of that with the same crop in the same field and you need to be aware of disease problems. Just the fact that there is more corn in the neighborhood could create some problems. There will be more of an opportunity for diseases to get started."

The University of Missouri has started a field trial looking at no-till continuous corn production and how to handle the extra crop residue.

"Producers can take some of the corn stalks away if they then practice no-tillage," Wiebold said. "If they take a lot of residue away then have aggressive tillage that opens the soil up to erosion problems."Shredding corn stalks can speed up the breakdown process but is not the same as getting rid of it. Residue managers on planters can move residue off the row and get it out of the way so it is not in the furrow or on top of the furrow that will keep the soil cooler as the seed is germinating and trying to emerge.

More acres of corn means more bushels of corn to handle. Logistically producers need to consider more corn to dry, more corn to store, and a longer harvest season. In some areas it has been difficult to build extra grain storage because the crews that would normally do that work are busy building ethanol plants.

Stalk condition is a concern when the harvest season is extended. Butzen suggests making harvest decisions based on stalk condition as much as grain moisture content.

"Harvest weak stalk early even if it is wetter than other fields," Butzen said. "Set your harvest schedule based on crop conditions and not just on grain moisture content."

Many producers have already made up their minds about planting corn on corn for this season while others have purchased the usual amount of corn and soybean and will take back what they don't use after they make their planting decisions. Agriculture economists Matt Stockton and Roger Wilson at the University of Nebraska have developed a spread sheet to help farmers with their decision to grow continuous corn or keep a corn/soybean rotation.

Go to http://westcentral.unl.ed/agecon/ and plug in the yields, inputs costs, and prices that reflect conditions in your area. Stockton said it displays cost information from the 2006 University of Nebraska Crop Budgets and current harvest contract prices, but allows users to enter their own cost and price data.

"When yields of both corn andSoybeansdecrease by an equal percentage, the advantage of growingSoybeanscompared to corn increases," Stockton said. "When yields of both crops increase by the same percentage the advantage of growingSoybeansfirst decreases and eventually disappears. At a 10 percent increase in the yields of both crops, returns to corn are over $4 greater than for soybeans."Adjust the yields to reflect dryland production and the results are much the same as those found in the irrigated production case.

"If you think about it, the only increase in cost will be from extra tillage and extra nitrogen and perhaps fungicide," said Daniel Davidson, DTN agronomist. "And the promises of $700 per acre gross revenue for 200-bushel corn at $3.50 cash compared to $400 per acre for 55-bushelSoybeansat $7.50 cash is enough to convince almost any farmer continuous corn is worth the risk."

Doug Rich can be reached phone at 785-749-5304 or by e-mail at richhpj@aol.com.

Date: 4/12/07

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