WELLMAN — Iowa’s tile-drained farms are notoriously “leaky systems,” by nature unable to contain all the nutrients both applied to them and inherent in their rich soil.
But Washington County farmer Steve Berger, through a sustained and disciplined regimen of no-till cultivation and cover crops, has plugged almost all the leaks.
“He’s got it down. He’s a superstar,” said Jody Bailey, coordinator of the English River Watershed Management Authority, of which Berger is a board member.
“He definitely sets a good example,” virtually eliminating erosion and substantially curtailing nutrients leaving his fields, said Adam Kiel, state water resources manager for the Iowa Soybean Association.
Nitrate concentrations last year in water leaving Berger’s tile lines were 31 percent lower than the average of all monitored in southern Iowa and 51 percent below the statewide average, Kiel said.
Berger’s impressive results have been accomplished not on a hobby farm or test plot but on a sprawling commercial enterprise encompassing 2,200 acres of corn and soybeans and 20,000 farrow-to-finish hogs each year.
Berger said his fields have not been tilled since the 1970s, when his dad, Dennis Berger, adopted no-till cultivation, and all of them have been blanketed with cereal rye cover crops from fall to spring since the 1990s.
“With no-till alone, we weren’t getting the job done,” Berger said.
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The slopes on Berger’s fields are interrupted by 14 miles of tile inlet terraces, which collect and drain excess water before it can roll destructively downhill.
Berger has taken many photos after heavy rains showing severe gully erosion on neighboring farms ending abruptly when the water enters his fields. The cover crops have enhanced the fertility of his soil, increasing his corn and soybean yields more than enough to cover the additional expense — from $25 to $30 per acre — of planting the cereal rye, Berger said.
His corn yield last year exceeded the 190-bushel Washington County average by 45 bushels per acre, he said.
“Conservation pays for itself, but it’s a longer term deal. It takes some patience,” he said.
Bailey said Berger’s financial success while integrating conservation practices has gotten people’s attention.
“The soil never lies. You improve your soil, and you will improve your crops,” said Berger, who recently received the top conservation honor bestowed by the American Soybean Association, its National Conservation Legacy Award.
Berger said the combination of no-till and cover crops has increased the organic matter in his soil by about 0.1 percent a year.
Regular soil probes on a 2.5-acre grid have documented the gains in organic matter, which now range from 3 to 4 percent in most portions of Berger’s fields.
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Along the fence rows, which have never been tilled, the concentration of organic matter jumps to 6.6 percent — almost double the concentration in the cultivated portions of the fields.
“That’s virgin soil. That’s never been touched. That’s what we are shooting for, but of course we can never bring it back to where it was,” Berger said.
Berger recently dug a 4-foot-deep trench in one of his fence rows to illustrate what virgin soil looks like.
From top to bottom it consists of black and crumbly soil clumps that Berger likens in consistency to cottage cheese. Air and water circulate freely in the spaces between the clumps, and the roots of the brome grass growing atop it penetrate to the depths of the hole.The no-till/cover crop combination has also changed the biology in the top foot of his soil. “It’s more conducive to the fungi, bacteria and other microorganisms” that help plants acquire nutrients and protect against pathogens, he said.
Manure from the 20,000 hogs Berger raises each year provides much of the nutrients for his corn and soybeans while also contributing to the annual gains in his soil’s organic matter content.
Berger said the elevated levels of organic matter and the increased pore space enable the soil to hold more water, which makes it more resilient both in times of drought and excessive rainfall.
The soil’s capacity to absorb water not only improves crop yields but also makes it less vulnerable to erosion, he said.
Berger, who’s in demand for workshops and seminars, also recently received the Spencer Award for Sustainable Agriculture from the Leopold Center for Sustainable Agriculture at Iowa State University.
“When he talks, people listen,” Bailey said.