Promise found in strip till

Strip-till plots had 8.6 percent more organic matter than zero-till plots

Strip-till has been called the fence-sitter’s favourite form of farming, perfectly suited for those who can’t decide between an all-out conventional black seed bed preparation and total zero-till trash cover.

It might be an accurate description.

In strip-till, the narrow alleys where seeds are planted are worked with radical tillage tools designed to create what farmers once called the “ideal, black, trash-free seed bed.” Residue is incorporated, weeds are decimated by tillage and soil warms quickly in the spring sunshine, prompting quick and uniform germination. These address the shortcomings of pure zero-till technology.

Strip-till leaves the strips between crop rows alone. Trash is left undisturbed to conserve moisture, suppress weeds and reduce erosion from wind and water. In a sense, strip-till is a hybrid cross between the two extremes.

As a compromise method of farming, how does strip-till compare to the more commonly used zero-till technology upon which it’s based?

That’s what University of Minnesota researcher Fabian Fernandez hoped to learn in 2007 when he embarked on a five-year study of strip-till versus no-till. The research was conducted on silty, clay loam soil and his findings are available in the recently published Agronomy Journal.

An average four percent reduction of bulk density was one of the significant changes in strip-till plots, resulting in decreased penetration resistance of 18 percent. In other words, a root requires 18 percent less effort to move through the looser soil.

“Bulk density is less in strip-till because of increased soil organic matter content of 8.6 percent compared to no-till farming,” said Fernandez.

“We have more soil organic matter because strip-till in these trials gave us more yield than conventional till or no-till. There’s more bio-mass being produced and more carbon input into the soil, which reduces overall bulk density.”

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A prairie farmer might wonder how yield and organic matter could possibly be higher in strip till than no-till, and Fernandez said time determines the answer.

“As you produce a slightly higher yield in strip-till, you begin gradually to produce more bio-mass, which is returned to the soil as organic matter,” he said.

“Organic matter helps boost yield. So the more organic matter you incorporate into the strips, the more your yield increases.”

The strip-till plots had a slight yield benefit in the early years, which, over time, snowballed into significant organic matter numbers.

Fernandez said strip-till works fine on relatively flat ground, but tilled strips can create significant erosion problems in hilly land, particularly when the strips have to run up and down the hills.

The University of Minnesota’s soil, water and climate department had previously observed a consistent benefit of strip-till over no-till.

In an earlier study, its researchers measured many crop parameters that indicated strip-till allowed crops to be more efficient in taking up nutrients and water, thus increasing yield. Fernández said the best place for strip-till is fields with a lot of residue, that are cool and wet in spring and where farmers prefer not to do conventional tillage. He said strip till, when practiced where it is appropriate, can be a powerful way to improve soil physical properties.

“These soil properties impact a plant’s ability to maximize its resources,” he said.

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“If you can get these soil properties to an optimal level, they allow the plant to grow with more ease, allowing it to focus its energy on yield.”

Fernandez said it’s interesting that for all the attention and fanfare strip-till received a few years ago, the technology is all but ignored today. There are obviously a lot of strip-till acres on the east side of the U.S. Midwest, but they attract little media coverage and few field demonstrations.

“Dealing with the strip-till is more cumbersome than no-till or conventional. Many farmers don’t have the time, even though there are proven benefits to strip-till. It’s easier just to go out with the chisel plow,” he said.

“The other part is equipment. It takes more specialized equipment and time to work with the equipment and maintain it.

“Tillage is a little like religion. You tend to stay with what you’ve grown up with.”

For more information, contact Fernandez at fabiangf@umn.edu.

ron.lyseng@producer.com

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