Farm Progress

Switch from cotton to corn brings some new management guidelines

Roy Roberson 2

April 18, 2007

6 Min Read

There is little question that eastern North Carolina will see a big drop in cotton acreage and a big increase in corn acreage in 2007, but how these changes in cropping systems will affect long-term agricultural production may not have been adequately calculated according to leading crop consultants in the area.

Stan Winslow, a consultant in northeast North Carolina and southern Virginia says the extra corn acres will help growers do a better job or rotating herbicides and to reduce the chance of herbicide resistance, if cotton comes back to the acreage now being planted to corn.

Winslow adds that growers hoping to reduce nematode numbers by planting corn may find root-knot nematodes to be a bigger problem, while other nematodes that damage cotton may be reduced.

Billy McLawhorn, who is a consultant in Cove City, N.C., says advances in soybean varieties may help more with root-knot nematode problems and may influence some growers to back off corn acreage and plant more soybeans.

“In our area there have been some last minute shifts to soybeans from corn, probably because it's easy to make that shift late. However, several growers who planned to grow soybeans back in the winter have shifted to corn, primarily because of the lower soybean prices,” McLawhorn says.

Winslow says he has seen a number of growers shift from corn to soybeans because of higher nitrogen requirements for corn and increasing nitrogen prices.

“In our area, in the past, growers have felt compelled to get their cotton crop in at all costs — they won't feel that way this year. If they haven't planted cotton by May 20 or so, they will quit planting cotton and go to soybeans,” Winslow says.

Bill Peele, a consultant in Washington, N.C., says initially the shift to soybeans in his area was driven by high prices. Once soybean prices went down, growers went back to planning for corn. In the long run, Peele contends corn and soybean acreage will be directly related to weather at planting time.

Peele adds that some growers who were planning on shifting from cotton to corn may end up planting cotton because of high fertilizer costs. Growers who don't have a good pre-plant fertilizer program for corn, and who didn't buy fertilizer early — before prices went up, are the most likely to shift back to cotton.

“In our area, I wouldn't be surprised to see that happen on a fairly large scale,” Peele notes.

“In our area, it looks like cotton acreage will be down by better than 50 percent,” Winslow says. That's all because of the high price of corn and low price for cotton, plus the relative cost of production for the two crops,” the North Carolina crop consultant says.

“We haven't had real good years on cotton for the past two years, and in some cases bankers are deciding that growers need to plant more corn, or at least switch from such heavy dependence on cotton,” Peele adds.

“Among the growers we work with, we are seeing a better than 50 percent reduction in cotton acreage,” McLawhorn says.

“Back in January, I thought we would see maybe a 25 percent drop in cotton acreage. Surprisingly a lot of the drop in cotton acreage comes from farmers who are heavily invested in cotton gins, which is something few people thought would happen,” he says.

For those growers making a big switch from cotton to corn, all three consultants agree a big change will be in nematode control. While Temik or Thimet at planting, followed by foliar application of a systemic insecticide has provided excellent nematode and seedling insect control, those are not options for corn.

“I think we will see a dramatic increase in the use of Counter insecticide in fields formerly planted to cotton,” Peele says. “Some growers may try planting seed treated with an insecticide, but that may be risky in some areas prone to heavy insect populations,” he adds.

“In our area we see a lot of stubby root nematode. When growers shifted to using nematicide seed treatments only, we began seeing a lot of fields with broken rows early in the field, and when they dug the plants they found a lot of damage from stubby root nematodes, and we had never noticed it before because it had Counter under it,” McLawhorn notes.

“We pulled nematode samples for all growers this year, and we were surprised at the number of fields that came back high in stubby root nematodes.

“Next most common are lesion, followed by root-knot. Cyst nematodes are not a problem, and it was a huge problem prior to the big increase in cotton acreage in our area,” says Peele.

A big factor cotton growers turned corn growers need to understand is plant populations. Though most of the corn has been planted in North Carolina, McLawhorn says he met regularly with his growers encouraging them to be sure vacuum is set right and disk is matched up to seed size.

If they have been growing cotton and soybeans, they don't have to plant so precise. With corn, plant spacing is critical, he adds.

“For growers who haven't grown corn in the past 12-15 years, they will find that what used to be maximum plant populations — 22,000-24,000 seed per acre are now low.”

On some soils, Peele points out seed populations of 32,000 to 33,000 may be needed to maximize production and take advantage of the high prices being offered for corn.

The increase in acreage planted to Bt cotton has increased the risk of damage from stinkbugs. It is likely, the consultants agree, that on land previously planted to cotton, brown and green stinkbugs will be a problem on corn. Growers who haven't grown corn in 12-15 years are going to find a whole different set of pest problems, the consultants agree.

“In the past the programs that most consultants ran with corn growers ended at layby. Now, with corn nearly twice as valuable as it was a year ago, we are extending those programs to consider such things as stinkbugs and the use of fungicides.”

Growers who haven't grown corn in 12-15 years will find there are many things that are different now,” McLawhorn points out.

“Many of the same unknowns are true for wheat, which showed a dramatic increase in acreage across the Southeast in the fall of 2006. That probably means more double-crop beans,” says Weldon.

“In our area we have growers who have contracted wheat for July 2009 and some of these are farmers who didn't plant wheat last year,” he adds.

For farmers who have increased acreage to take advantage of low production costs in the past for cotton, and who now find a better economic situation with corn, soybeans and wheat, switching from a fiber crop to a food crop will include far more than buying and planting seed.

Making a profitable switch from large cotton acreage to large grain acreage will require new information and timely application of modern grain production techniques.

Growers, especially those making large acreage switches from cotton to grain crops, need to be aware of the changes in cost associated with growing high value grain crops, rather than growing low value rotation or cover crops.

In many cases, knowing what to switch to may not be as critical as knowing how to grow it, harvest it and store it.

The infrastructure for such dramatic increases for corn is simply not in place in most areas of the Southeast. Now that most corn is planted, the next critical issue may be getting it harvested, dried, stored and or sold.

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