Strip-till vs. planter attachments

Many corn growers question their tillage and planting systems from time to time. Bishop Mumford, Griffin, Indiana, is one such grower. Mumford has no-tilled most of his corn for the past 15 years. For several years, he used nothing but coulters and residue wheels. Now, however, he has several attachments on his planter.

"It didn't really come together for me until I added Case IH gauge wheel tires, Keeton seed firmers, spiked closing wheels, and chains," he says.

Although Mumford likes his current setup, he wonders if his soil would warm up and dry out more quickly with fall strip-till. That's why he posted the question at the top of the page in a talk group at Agriculture Online(tm), where it sparked a discussion among other growers. We've included some of their comments, along with comments from other growers, in this story comparing fall strip-till to using attachments on the planter to clear a strip in which to plant.

There are many approaches to strip-till. One of the most common involves using a smooth coulter, anhydrous ammonia shank with a mole knife, and oversize closing disks to place anhydrous ammonia and/or phosphate and potassium 6 to 8 inches deep. This setup builds a mound to plant into the following spring.

Likewise, there are a lot of different types of planter attachments to clear residue and lightly till a strip of soil to plant into. Residue wheels are almost standard equipment on many no-till planters. They're often run in combination with no-till coulters.

More recently, no-tillers who frequently plant into wet soil have added spiked closing wheels in an attempt to eliminate sidewall smearing in the furrow and compaction over the row.

A lot of strip-tillers are converts from pure no-till who had experienced poor stands in cold, wet springs. Others, like Darrell Dunahee, Melvin, Illinois, previously field-cultivated bean stubble ahead of planting corn.

"But I saw soil erosion where I ran the field cultivator," he says. "Ever since I was a little boy it's upset me to see soil washing away. I thought there had to be a better solution."

For Dunahee, the solution was fall strip-till, which he adopted nine years ago. "It's not without problems, but basically it works well," he says. "It looks like it is yielding right with conventional tillage. And the thing most people around here like is it plants nicely. The soil is loose and mellow. Generally, you donÕt end up with clods or smeary soil."

Two years ago, he bought the strip-till rig shown above and started doing custom work through the Melvin FS plant in addition to his own fields. According to plant manager Mike Moody, FS charges $7.50 for strip-tillage without fertilizer, $11 for strip-tillage with either dry fertilizer or anhydrous ammonia, $13 for strip-tillage with both forms of fertilizer.

Both strip-till machines and attachments on the planter will enable you to sidestep residue at planting. With strip-tillage, however, the soil is also warmer and drier at planting.

"The effect on soil temperature from strip-till is dramatic," says University of Illinois plant pathologist Wayne Pedersen. "We've created a planting zone that is 5° to 9° warmer than regular no-till, making it comparable to conventional mulch-till."

Moisture and temperature are interrelated. Jim Kinsella has worked with strip-till for 20 years on his Lexington, Illinois, farm. He says, "A lot of people think the residue is keeping the ground cold. But it is really the water that is keeping it cold. I don't care how much sun you've got, as long as the pores are full of water, the ground is not going to warm up."

Kinsella says mound height is the key to getting the strips dried out enough to plant. "I have seen level ground that has all the residue removed, but it stays wet because the water table is level there. If you can get a 3-inch mound, I don't care how much residue is on it, it is going to be drier than a flat area."

Many strip-tillers realize it's not going to pay every year. But they think the trip is worthwhile because in wet years it lets them start planting sooner the first time and after each rain.

Many corn growers question their tillage and planting systems from time to time. Bishop Mumford, Griffin, Indiana, is one such grower. Mumford has no-tilled most of his corn for the past 15 years. For several years, he used nothing but coulters and residue wheels. Now, however, he has several attachments on his planter.

One of the big drawbacks with strip-till is the power it requires. Just how much you need depends on your soil and your equipment. Obviously, it takes more horsepower if you are applying anhydrous ammonia and dry fertilizer in addition to strip-tilling. The rule of thumb is you need 15 to 20 horsepower per row. Dunahee uses a John Deere 9400 with 425 engine horsepower to pull his rig, which can be set for either 12 or 16 rows.

Jim Bassett is president of Dawn Equipment Company, which makes attachments for planters and strip-till rigs. "The thing no planter attachment can provide is time," he says. "The soil is not going to dry out or warm up in the seconds it takes to travel the 6 inches or 6 feet between the row cleaners, openers, and closing wheels.