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4 drought issues lingering into 2013

You might like to delete the dry 2012 crop season from your database of farming knowledge as the worst year of your career.

Roger Elmore sees it differently. “It was a good year to learn some things that will be important to us down the road,” says the Iowa State University (ISU) Extension corn specialist.

With that in mind, here are four impacts from 2012 that may influence the way you farm in 2013 – drought or not.

1. Weather

Some weather experts believe 2011 and 2012 are the beginning of a dry decade, with periodic recurrences. Ryan Siefken, corn product manager for Hoegemeyer Hybrids, thinks that could push farmers toward earlier-maturing crops, especially corn.

He points to eastern Kansas, where farmers practice a program informally called early-corn early. The theory is to plant early-maturing hybrids as soon as you can get them in the ground. Farmers plant 92- to 106-day corn on lighter soils, hoping the corn makes it on moisture in the soil profile before mid-July's heat.

“You could apply that idea in the heart of the Corn Belt,” says Siefken. Of course, he reminds, you never do all of anything. “The principle still holds to plant half your corn to your target maturity, 25% earlier, and 25% later,” he says.

Sheila Hebenstreit, an agronomist for West Central Co-op in Jefferson, Iowa, makes a good case for diversifying maturities. In her area in 2012, early-planted corn and late-planted corn did relatively better than corn planted on April 23-25. Normally, those would be ideal corn-planting days. But just by accident of catching the worst hot winds of the whole hot summer, corn planted on those dates cooked. The lesson is to diversify maturities and spread out planting dates.

Hoegemeyer had introductory quantities of its drought-tolerant corn (DuPont Pioneer technology) out in fields in 2012, and early reports are encouraging.

“To date, our Aquamax products have outyielded the plot averages by 10.5%,” Siefken says. “There will be quite a bit more of it available for 2013.”

Aquamax hybrids use native traits to deter drought. DuPont Pioneer sold 25 of these hybrids with a relative maturity range ranging from 96 to 116 days, with more planned for 2013. DuPont Pioneer is targeting water-limited environments for Aquamax hybrids.

“In most years, a hybrid will hit water-limited periods over part of the growing season,” says Josh St. Peters, corn marketing manager – North America for DuPont Pioneer.

A corn plant is not a cactus. If drought is too severe, eventually all hybrids surrender. The Aquamax hybrids, however, endured drought better than conventional hybrids in 2012, says St. Peters. Besides being visually greener, they shed more pollen during pollination, helping to ensure kernel fill. Root digs revealed healthy root masses, he adds.

2. Tillage

Your inclination after a drought may be to get out to your fields in order to open hard, dry soils to rain and snow.

Don't. It will be counterproductive, says Mahdi Al-Kaisi, ISU Extension soil management specialist.

Tillage will lead to soil crusting after rainfall, probably leading to more runoff. To prove it, he says you should spade up some ground and pour a bucket of water on it. Go back in a couple of days and you'll see the crust sealed off to recharge the subsoil.

“If it's my field, no tillage,” Al-Kaisi says. “I leave the residue right where it is, reducing moisture evaporation and capturing even any minimum moisture that falls. Every pass of tillage means I lose a quarter inch of moisture, at least.”

3. Fertilizer

Crop fertilization is a balancing act of putting nutrients on, harvesting them, and replacing what you remove. If you harvest half a crop, half the nutrients should still be there for 2013. Phosphorus and potassium do tend to stay where they are placed, and some of those should still be there for next year.

Nitrogen (N), though, is a different story, says John Sawyer, ISU Extension fertility specialist. It leaches out of the soil profile, or denitrifies into the atmosphere.

In the limited rainfall environment of 2012, N probably didn't leach and is still available for 2013. You can soil-sample for it. If the field is rotated to soybeans, any leftover nitrate-N (the available kind) won't help or hurt them. In continuous corn, you may be able to take advantage of leftover nitrate-N, but it's not a given.

“The biggest issue is the weather,” says Sawyer. “What's it going to do between now and next spring? If we get back to excessive rainfall, some N will be gone.”

Sawyer says the best rule of thumb is to give your field credit for half of what you think is the carryover N.

For example, if the total N application for the 2012 crop was 190 pounds per acre and the corn yielded 50 bushels per acre, the unused N would be 190 - 50 = 140 pounds. The 140 pounds × 50% = 70 pounds of N per acre to subtract from the 2013 rate.

4. Weeds

Some herbicides require rain for activation. That's one reason Mike Owen, ISU Extension weed specialist, saw more weed escapes than normal. Some escapes were of weed plants that show resistance to herbicides, meaning the bank of resistant seeds grew.

“We really lost the battle on marestail this year,” says Bill Johnson, Purdue University Extension weed specialist. “We've had glyphosate-resistant marestail for a decade. But this year was a complete train wreck; we had both spring- and fall-emerging populations. Typically in the fall, 80% of marestail plants will die due to winterkill. Last winter, we didn't have any winterkill. Those plants made it through the winter and quickly grew too large for spring burndown applications to kill.”

Johnson says Indiana farmers may need to start thinking like farmers in Tennessee who have wrestled with massive flushes of glyphosate-resistant marestail.

“Some of those farmers put down two burndown treatments – one early in the spring and another at planting,” he says. “If not, they lose the battle with marestail.”

You'll have to deal with more weeds in 2013, “with more diligence to good weed-management techniques,” says Owen. That would include cultivation, preplant herbicides, or multiple modes of herbicide action.

There is potential for herbicide carry-over, says Owen. Whether it occurs hinges on next spring's weather.

“If you have some carryover, it will be more of an issue if the young crop is under other stress next year,” says Owen. “Or if you plant a rotational crop, such as alfalfa that is sensitive to the herbicide, then it could be an issue. If you're worried, read the herbicide label carefully.”

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