ST. CHARLES, MINN. – A few weeks ago I wrote about the John Peterson family and their farm near North Branch. Corn and soybean producers, the Petersons farm 900 acres, and are concerned not only about profits but about sustainability of their soils, with a nod toward wildlife: Benefiting deer and birds, they maintain 38 acres of woods in the middle of their crop fields.
At the end of that column, I asked readers to suggest names of other farmers whose properties I could visit. My intent, primarily, is to highlight those who are conservation-minded, not only about fish and wildlife but about runoff from their lands, which in some instances can pollute streams, rivers and groundwater, while contributing to the “dead zone’’ in the Gulf of Mexico at the mouth of the Mississippi River.
I intend also, when fitting, to point out how farming can adversely affect water and land, and fish and wildlife, particularly as corn and soybean acres expand nearly exponentially across Minnesota.
In coming months, I’ll try to visit some of the many farms that were suggested to me.
Meanwhile, today I’m at the Jeff Broberg operation near St. Charles, in Winona County, in southeast Minnesota.
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Spreading a map across the hood of his aging Toyota pickup, Broberg concedes he’s not a typical farmer.
He and his wife, Erica, own 160 acres bordering the south end of Whitewater State Park, with corn and soybeans covering about two-thirds of those acres in a given year.
But Broberg — like many landowners across the state — doesn’t plant and harvest crops. Instead he rents some of his acres to a farmer who does, and sets aside the balance of his land for wildlife.
“That’s one problem affecting our water down here,’’ Broberg said. “A lot of people rent out their land and don’t keep track of what their farmers do to it, particularly how much fertilizer they apply to their crops and when.’’
A licensed geologist with an office in Rochester, Broberg is both fascinated with, and concerned about, the southeast’s unique soil and rock underpinnings.
Known as the “Driftless Area,’’ the region of southeast Minnesota roughly east of Hwy. 52 never was covered by glaciers. Consequently, its powdery soils lay over limestone bedrock that sits, in places, relatively near the surface. The limestone itself, meanwhile, is quite porous, and in many places is marked by fissures that allow the quick disposition of surface water into aquifers.
A couple hundred years ago, when perennial plants covered most of the southeast, including Winona County, that didn’t present a problem.
Today it does, because most of the region’s tillable land is covered in corn and soybeans, and nitrogen-laden fertilizer — sometimes lots of it — is required to grow these crops at yields that ensure profits.
If the plants utilized all of the fertilizer’s nitrogen, fewer drinking wells would be polluted in the southeast with nitrate, which forms when nitrogen and water combine and which can adversely affect pregnant women and their young children.
But soil fertility can vary widely even within individual crop fields, meaning that applied nitrogen might be utilized in its entirety in some areas, while in others, excess nitrogen will leech fairly quickly into the soil and underground waterways, poisoning wells.
“That’s what happened to my well,’’ Broberg said. “We’ve had to install a reverse osmosis system to make sure my wife and I aren’t drinking water laced with 20 parts per million of nitrates, twice the safe level.’’
Because corn and soybeans in recent years have fetched near-record prices, competition is keen statewide for farmland, including in the southeast. Some landowners have even auctioned their rentable lands to the highest bidders, fetching rates of nearly $425 an acre.
“I charge my renter less, $168 an acre,’’ Broberg said. “But I require a lot more from him than other renters do from their farmers. He mows my CRP [Conservation Reserve Program] acres, for instance, and I require him to minimize the chance of overapplying fertilizer by splitting his applications and accurately predicting the amount he needs to prevent applying too much.’’