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Better watersheds, better Iowa

By Staff | Mar 29, 2013

FARMERS AND OTHERS living in the Black Hawk Lake Watershed follow a presentation on March 22 in Breda, in Carroll County, in how conservation-minded farming can reduce sediment and nutrients getting in Carnarvon Creek, which is the main north-flowing tributary for Black Hawk Lake in Sac?County.



BREDA – Russ Schelle, who farms just north of Breda in Carroll County, is in his second year of using cover crops.

Roughly two miles north of Breda, along Granite Ave., one of Schelle’s 2012 soybean fields lies under a carpet of cereal rye. Schelle, who raises cattle, said he planted rye on some of his harvested acres last year in order to chop the grass for cattle feed.

Schelle was one of an estimated 80 people who attended a cover crops workshop on March 22 in Breda. He learned about the land management benefits of cover crops, reduced tillage methods and stream bank stabilization.

LINDA RITCHIE, who manages her family’s farm along Carnarvon Creek, near Breda, said she has worked out plans with the Black Hawk Watershed Project to do stream bank stabilization and establishing a small wetland on her farm that will filter nitrates from runoff water before it reaches the creek.

The meeting was sponsored by Iowa Learning Farms, Practical Farmers of Iowa, Iowa State University Extension and the Natural Resources and Conservation Service. The event was designed to encourage more area farmers to join the year-old effort to protecting the quality of surface water throughout the 13,156-acre Black Hawk Lake Watershed.

Besides gaining an extra feed source with cereal rye, Schelle said he’s also getting other benefits, such as the rye locking nitrogen in place and protecting soil from wind and water erosion, plus the extra root systems add to the field’s organic matter.

This he started before he knew there were cost-share funds to assist producers within the Black Hawk Lake Watershed Project to reduce the amount of field nutrients getting into nearby Carnarvon Creek, the primary tributary that flows north in the Black Hawk (Wall Lake Inlet) Watershed, which culminates in Sac County.

In fact, Carnarvon Creek’s official head waters begin in another of Schelle’s fields. He said he was approached by NRCS personnel to do stream bank stabilization along 855 feet of the creek, which was finished last fall.

Stabilization is designed to stem natural erosion, reducing sediments and soil nutrients from reaching Black Hawk Lake, which eventually flows into the North Raccoon River. T.J. Lynn, coordinator of the BHLWP, estmates that the armoring of the creek on Schelle’s land will prevent 34 tons of soil and 73 pounds of phosphorus from reaching Black Hawk Lake every year.

“If the soil isn’t moving, the phosphorus isn’t moving.” —Tim Smith Eagle Grove-area farmer

Linda Ritchie, who lives in Sac City, but manages 160 acres of her family’s farm near the community of Carnarvon, also situated along the creek, said she’s in the planning stages with NRCS to do a number of improvements.

In the 1990s, she said, her land had terraces built to correct and prevent water erosion.

“We didn’t know then that we were saving Black Hawk Lake,” she said. But she knows now and said she plans to establish a holding pond, or wetland, for filtering nitrates from runoff water, and do stream bank stabilization.

Lynn said that in the past year, a total of 2,435 feet of Carnarvon Creek’s banks have been stabilized, which is estimated to prevent 116 tons of sediment and 250 pounds of phosphorus from escaping downsrtream.

Lynn said the project is focusing early efforts at the top of the drainage pattern and working downstream.

As the farm’s manager, Ritchie said she’s concerned in “saving as much land as we can. It doesn’t have to go into the Mississippi and the Gulf.”

She said she has a concern that non-farming activists have an incorrect view of farmers.

“We’re trying our best to save the land,” she said.

Keep N, P in place

Tim Smith, an Eagle Grove farmer, said he’s in his last year of an NRCS cost-sharing program for cover crops, but said he’ll keep using cover crops when the program is finished.

His field management efforts, he said, keep the soil in place even in heavy rains. “If the soil isn’t moving, the phosphorus isn’t moving,” he said.

Smith farms 850 acres with rye over 300 of those acres. Located in a targeted area of the Mississippi River Basin initiative, Smith said he’s also installed a bioreactor, to filter nitrates from tile drainage, and has switched to strip-till to create as little disturbance in the field as possible.

He said he’s also adopted nutrient management practices to assure the right amount of nitrogen is being applied where needed and not over-applied in others. These include:

1. Delaying nitrogen application until spring, or side-dressing, to limit N leaching from fall rains.

2. Late-spring nitrate testing, for determining side-dress application.

3. Taking tissue samples of corn plants at V10 stage to determine nitrogen levels.

4. Late-summer nitrate stalk testing to determine if the plant had too much or too little nitrogen available.

“Cover crops enhance the residue left behind,” Smith said, “and the root bases feed the soil microbes.”

The extra water retention capabilities of his fields, he said, allowed him to harvest a 170-bushel per acre corn crop in a year that just 15 inches of moisture was received, when normally it required at least 21 inches.

When talking about reducing the amount of nutrients that get into surface waters through conservation practices, Smith said, “These projects are not only good for the watershed, but they’re just good for Iowa.”

And the faster farmers adapt to them, he added, the less likely the Environmental Protection Agency will be telling farmers how they have to farm.

He was referring to the Gulf Hypoxia Task Force’s report in 2012 that is requiring Iowa to reduce its nutrient pollution of the Upper Mississippi River Valley by 45 percent. The report said the vast majority of the pollution comes from farm fields.

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