By Julie Buntjer
Worthington Daily Globe
WORTHINGTON -- More and more farmers throughout the area are pulling an odd form of farm implement behind their tractors these days -- rollers.
Commonly used in northern Minnesota for many years, the rollers are catching on with crop producers in this region looking to break up corn root residue and ultimately create better conditions for combining come harvest.
Roger Doeden of rural Worthington bought a roller after learning about its advantages from neighbors who had practiced with it.
Last year was the first time he took the 42-foot-wide pass, 18,000-pound machine over his newly seeded soybean fields.
"We like it real well," said Doeden, who farms with his brother, Larry. "A smoother surface for combining is probably the biggest advantage."
Doeden said the rollers push smaller rocks into the soil and reduce costly repairs from rock damage to combine soybean heads.
"You don't have to watch as close when you're combining," said Doeden, adding that running rocks and corn root balls through the combine are less of a concern and thereby reduce operator fatigue.
"Even in wet conditions for combining, the head slides better along the ground," he added.
Jodi DeJong-Hughes, a University of Minnesota Extension educator in soils, is in the third year of a study on the use of rollers in soybean fields. The dozen test plots she monitors for the study are located in northwest and west central Minnesota.
"It developed more in northwest Minnesota where they have a pretty good rock problem and we don't have as many kids to go pick rock anymore," she said. "It was a necessity to push down those rocks so they didn't go through the (combine) head. Just in the last few years it has spread like wildfire through western Minnesota."
Hughes said rollers were first used in alfalfa fields, but the advantage to using it on newly planted soybean fields is that the soybean head can operate lower to the ground, allowing for better collection of bean pods closer to the soil. Of the eight test plots she documented in 2009, only one noted an increased yield of approximately a bushel or 1.5 bushels per acre.
"In the research that we did, we looked at rolling before you planted, after you planted, when the bean started to emerge, when it had its first trifoliate and its third trifoliate out," Hughes explained. "We were trying to see how late you could roll without really damaging the plant."
Studies revealed there was no real difference in yield based on timing. However, there was some damage to the plants when rolling after they had already emerged.
"We still recommend pre-plant or post-plant," Hughes said, adding that rolling seems to improve soybean emergence.
Waiting to use the roller until after the plants have poked through the soil is not recommended.
"If you damage the stem, you can set it up for more disease issues," she said. "We saw some lodging ... and we saw a lot of crooking of the stem, and all those could be problems."
Statistics show approximately 75 percent of farmers rolling their soybean fields do so after planting and before emergence, Hughes said.
As for the Doedens, they've finished rolling their soybean fields and are now letting other farmers in the neighborhood use their roller. Roger said he likes the machine because it helps to break up the bigger, denser corn root balls, which are associated with Bt and corn rootworm-resistant varieties.
"I think they sure got popular this year," said Doeden of the roller.
Worthington Power and Equipment salesman Chad Wiener said his business has been renting out two rollers, and sales have been "pretty good."
"They've been limited by availability," said Wiener. "I think all farm equipment has been that way the last couple of years -- demand has exceeded supply."
With more farmers opting to use rollers on their soybean fields, Hughes will continue to monitor the practice and study potential drawbacks.
"My concern now is that everything is rolled," said Hughes. "Wind erosion and water erosion is something that we're going to need to get a better handle on."