October 27, 2003
Strip tillage lays groundwork for spring planting, specialist says
WEST LAFAYETTE, Ind. When it comes to preparing a field for planting, farmers usually fall into one of two camps: those who till it all, and those who leave it all untilled.
There is a middle ground, so to speak, between conventional tillage and no-till systems. Strip tillage is catching on across Indiana and other Corn Belt states, said Tony Vyn, Purdue University Cooperative Extension Service cropping systems specialist.
"In Indiana alone, we had at least 150,000 acres of strip-till corn grown in 2003," Vyn said. "My guess is that strip-till acres are growing at the rate of 25 percent per year."
Strip-till combines the soil drying and warming benefits of conventional tillage with the soil-protecting advantages of no-till, Vyn said. In addition, corn grown in a strip-till system consistently yields as well as corn grown in a conventional-till system and can yield better than no-till corn crops planted on the same date, he said.
Soybeans also can be grown in a strip-till system, although no-till remains the preferred planting method. More than 3 million acres of soybeans are grown no-till annually in Indiana.
Vyn and other Purdue researchers have examined strip-till for the past decade. They've concluded that strip-till provides a host of planting pluses.
"The key advantages of strip-till compared to no-till are that strip tillage enables the soil to warm up faster and dry out sooner in the intended row zone," Vyn said. "This means much more planting flexibility in the spring. A strip-till corn farmer will be able to plant their corn sooner in the spring, giving them the potential to complete planting before the yield loss associated with delayed planting starts to take effect.
"Strip tillage also has the big advantage of retaining residue cover. With strip tillage, we maintain two-thirds and sometimes three-quarters as much residue as we do with an undisturbed no-till soil. So from a conservation tillage point of view, strip tillage is almost as effective as a pure, undisturbed no-till."
Like its name implies, strip-till involves plowing raised, narrow strips from one end of a field to the other. The raised strips, or berms, should be 3-4 inches high and 10-12 inches wide. Strip-till is normally done for crops planted in 30-inch rows. The soil on either side of the berms remains untouched.
Farmers perform strip-till operations in the fall, following harvest. By the time spring rolls around the berms have settled to a height of about 1-2 inches. Seed is planted directly into the strip rows.
"The ideal timing for strip tillage depends somewhat on where the farm is located, in terms of northern Corn Belt or southern Corn Belt," Vyn said. "In our region of the central Corn Belt, it is generally recommended that we do not start strip tillage before about Oct. 10 or so, because starting too early means that the berms that we work so hard to achieve may subside too quickly because of high intensity rainfall in September."
Field conditions also dictate when strip-till operations begin, Vyn said.
"We also need to pay attention to soil moisture," he said. "Soils can be too wet for strip tillage even though they may still be suitable for a full-width tillage system, such as that based on moldboard plowing or chisel plowing, which are considered the conventional tillage alternatives."
Technology advances have made it easier for farmers to plant into strip-till rows, Vyn said. Automatic tractor steering controlled by Global Positioning System (GPS) units allow farmers to plant within 1 inch of the berm center, even at night, he said. GPS devices also make it possible for farmers to strip-till fields with tillage equipment that's only half the width of their row crop planters.
"Another key feature of strip tillage is that it allows for fertilizer placement in the strip zone," Vyn said. "Fertilizer efficiency in both corn and sometimes wide-row soybean crops may be improved by placement of fertilizer right into the rooting zone, where the crop is going to develop the following year. In some cases we've found that strip tillage is being done not for the straight physical effect but for fertilizer banding, particularly for some of the dry fertilizers like phosphorous and potassium. Applying that fertilizer concentration to the area where extensive roots develop the following year can result in yield advantages for strip tillage."
Regardless of whether a farmer favors conventional or no-till systems, they should be pleased with strip-till yields, Vyn said.
"Our experience over the last 10 years or so of doing strip tillage research in the fall has been that corn yields with strip tillage are similar to those with conventional tillage, when the experiments are done on reasonably level soils that are not subjected to extensive erosion losses," he said.
"The next question might be, 'Are strip tillage yields better than no-till?' The answer is yes, strip-till corn yields have tended to be better than those for no-till, when corn is planted into high-residue situations, such as corn after corn or corn after winter wheat. But following soybean stubble, the yield advantage with strip tillage compared to no-till is not a certainty, and may be most likely in wet spring situations when no-till corn planting is delayed well past the optimum date."
More information about strip-till is available in Vyn's article "Strip Tillage Gains Ground and Planting Flexibility for Corn Producers." The article appeared in the Oct. 17 issue of the Purdue Pest and Crop Newsletter.
Writer: Steve Leer, (765) 494-8415, firstname.lastname@example.org
Source: Tony Vyn, (765) 496-3757, email@example.com
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