Just 3 years ago, many strip-tillers in the Corn Belt struggled to harvest crops in wet fields, which limited or even eliminated fall strip-tilling.
This fall, it’s fields with dry soils that may pose problems for strip-tillers. But following three strategies can help strip-tillers manage dry soils, says , says Jodi DeJong-Hughes, University of Minnesota Extension crops and tillage educator.
“Farmers who have been strip-tilling for 5 years or more will likely have fields that are more mellow and have better soil aggregation,” DeJong-Hughes says. “But those who have been strip-tilling less than 5 years are more likely to have fields with dense, compacted soils.
“Without additional weight and/or down pressure, some strip-till rigs with coulters might bounce along on the top of dry soil …”
“When strip-tilling, dry and compacted soil can break up into chunks, which can cause seedbed problems next spring ranging from uneven seed-depth placement to erratic emergence and stands.”
Using Vertical Tillage
First off, DeJong-Hughes says, a strip-till rig with shanks or moleknives will dig into dry soil, while some strip-till rigs with coulters may not be able to penetrate the hard soil. But shanks and moleknives can tend to bring up chunks of soil, too.
“Without additional weight and/or down pressure, some strip-till rigs with coulters might bounce along on the top of dry soil,” she says.
Secondly, more strip-tillers who grow corn-on-corn — which is become attractive with current corn prices — are using a vertical tillage tool after harvesting corn and before strip-tilling in the fall, DeJong-Hughes says.
"They’re sizing the corn stalks, which improves residue flow when they strip-till, and they’re incorporating the residue just a little — usually 1 inch deep,” she says. “Running a vertical-tillage tool an inch deep before strip-tilling can crack the soil and reduce problems with soil breaking up into chunks.”
It’s possible that freezing and thawing during the winter will break up chunks from fall strip-till, if the weather cooperates, De Jong-Hughes says. If another mild winter leaves chunks in fall strip-tilled fields next spring, strip-tillers can run vertical-tillage tools over that ground.
More and more strip-tillers are using vertical-tillage tools in this way, she says. That includes one strip-tiller she knows who’s growing continuous corn on 22-inch rows.
Strip-Till Performs Well In Parts Of Minnesota
Strip-tilled performed well in western Minnesota this year, DeJong-Hughes says, although she cautions that yields west of the Minnesota River suffered because of the drought.
“I know a strip-till near the east side of the Minnesota River who harvested 200 bushel-per-acre on irrigated ground and 55-60 bushel-per-acre strip-tilled soybeans.”
In 2012, there were fewer pest and disease problems than in previous years, DeJong-Hughes says.
“There wasn’t much corn rootworm pressure and fewer growers needed to spray for soybean aphids,” she says. “There was little to no Goss’ Wilt this year, while last year Goss’ Wilt was all over the place. And unlike 2010, when sudden death syndrome (SDS) was bad, we didn’t have much SDS in soybeans.”
But having less residue from lower-yielding corn and soybean plants in the drought-stricken areas could reduce the amount of moisture in the soil, DeJong-Hughes says. That’s because the residue reduces the amount of moisture lost from the soil.
While DeJong-Hughes believes that the use of strip-till has remained stable, she’s also heard from several manufacturers that interest in strip-till was up at recent tradeshows. She also connected some South Dakota farmers who are interested in strip-tilling continuous corn with a Minnesota strip-tiller who’s already doing this successfully.
“He wanted to know what strip-till rigs would work with 74% residue,” DeJong-Hughes says. “There aren’t many strip-till rigs set up for 22-inch spacing on the staggered rows needed for residue flow. By running a Salford RTS over the field before strip-tilling in the fall, this strip-tiller reduced the residue level to 54%.”
However, there may be a downside to vertical tillage, DeJong-Hughes says. Using a these implements over fields every year may reduce soil aggregation and water infiltration — even if the tool is run only 1 inch deep, she says.
As a precaution, strip-tillers may want to use vertical tillage only just in field areas where residue really builds up.
The third strategy for strip-tilling in dry soils involves banding anhydrous ammonia.
“Sealing and covering the soil when strip-tilling with anhydrous ammonia is extremely important,” DeJong-Hughes says. “There’s less volatilization in dry year if anhydrous is placed deep enough and the soil seals. One of the advantages of strip-tilling in a dry fall is that the residue protects soil moisture. And there’s not a lot of moisture out there right now.”
The depth of fertilizer placement in strip-till affected yields for at least one Minnesota strip-tiller DeJong-Hughes has worked with. The grower compared banding about 160 pounds of anhydrous ammonia at 5½ and 7½ inches when he strip-tilled in the fall of 2011.
Corn yields on ground with anhydrous banded at 7½ inches were better than the shallower-banded anhydrous, she says. The farmer also applied 5 to 6 gallons per acre of 10-34-0 as starter when planting corn last spring.
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