Off-season talks center on continuous corn

Off-season talks center on continuous corn

• Many discussions will take place this winter about the widespread yield problems with continuous corn in 2011. • With corn seed production hit hard in some areas, possible shortages of some hybrids have been reported.

For some Illinois farmers, 2011 has been a trying year.

With yields coming in less than many hoped and expected, Emerson Nafziger, University of Illinois Extension agronomist, offers some thoughts on the 2012 cropping season.

“The weather stress on the 2011 crop was severe, but we still got a crop,” Nafziger said. “Such weather 30 years ago would have done much more damage to yield than it did this year. “That’s because breeding works — it has given us crops that grow better and tolerate stress somewhat better than they did at one time.”

The U of I variety testing data can be viewed at This website shows results from a range of sites that represent both stress and good conditions.

Nafziger recommends looking for both high yields and consistency when buying seed, with the emphasis on consistency for the fields with average or below-average yield potential.

Rainfall from July through October across central Illinois totaled 6 to 10 inches, which is 4 to 10 inches below normal, leaving soils dried out over much of the region. At least half of this rainfall came after September 1, by which time the corn crop had more or less stopped taking up water, and use by the soybean crop was declining.

“When there’s no crop and temperatures turn cool, most of the precipitation we get stays in the soil,” he said. “If we get close to normal rain and snow over the next five months, the soils should be fully recharged as we come into the spring.

“Still, it could be late winter until we see tile lines running again in some areas, and a dry winter could leave some fields short by spring.”

Many discussions will take place this winter about the widespread yield problems with continuous corn in 2011. Nafziger said the one thing that is relevant now is whether or not part of this problem came from the large amount of fall tillage that took place in corn stalks last fall, the application of ammonia under dry soil conditions last fall, and then driving on these soils when they were still wet underneath to till and plant this past spring.

Not the only issue

“Soil management was certainly not the only issue, but we might at least keep in mind that breaking down soils with tillage almost to the point they’re ready to plant in the fall might not be that helpful come spring,” he said.

“It’s appropriate to till this fall to break up compaction again in many fields, but we should always ask ourselves if the second trip this fall is necessary.”

Dry conditions in the second half of the season usually result in less nitrogen uptake by the crop, and in accumulation of some nitrogen in the form of nitrate in the upper soil layers.

Normal precipitation between now and spring will allow much of this nitrate to move down, and some will exit through tile. But in fields where soils are dry now, where corn yields this year were lower than normal, and where we will follow corn this year with corn next year, he said growers might want to consider taking soil samples before applying nitrogen next spring.

With corn seed production hit hard in some areas, possible shortages of some hybrids have been reported. There are also reports that some winter production in South America was planted late, so seed could be late arriving next spring.

Soybean yields are not as high across Illinois as they were in 2010. The average yield is now projected at 46 bushels per acre, down from last year’s 51.5, which was an Illinois record. But yields are very high again in some areas, especially in northwestern Illinois, he said.

“We’ve heard of a few cases where the second year of low continuous corn yields has some people considering putting soybeans back into some fields in 2012, after a number of years in continuous corn,” Nafziger said.

“Having corn prices more than half the price of soybeans per bushel still favors corn at the moment, and it’s not unreasonable to hope for better corn following corn yields in 2012 than some of us had this year.”

Soybeans following five or more years of corn in a field typically yield somewhat better than soybeans in a corn-soybean rotation. He reminded growers to get soybean seed inoculated if corn has been in the field for five years or more.

Finally, a quick look at U of I data on corn plant populations reconfirms that stress conditions are not conducive to getting responses to population increases up to high levels. But high populations did not produce many of the disastrous yield losses like some saw last year.

“You might want to consider raising populations if they’re still not high enough, but don’t figure on increasing them much past the mid- to upper 30,000 range,” Nafziger said.

For more information, read The Bulletin online

TAGS: Management
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