In Otho, improving soil health
By LARRY KERSHNER
OTHO – Although Iowa does not have a deadline for reducing its nitrate and phosphate levels of surface water, researchers urged farmers Wednesday to do their parts sooner, rather than later.
An estimated 60 people attended an Iowa Learning Farms field day at the Smeltzer Iowa Learning Farm in Otho to see the effectiveness of how various reduced tillage practices, cover crops and bioreactors are holding soil in place and keeping nutrients from flowing downstream.
Jacqueline Comito, program director for Iowa State University’s Iowa Learning Farms, said she hoped attendees would seriously consider adopting these practices, if they weren’t already.
Farmers were transported to three stops on the tour of farming practices, including looking over the root structure and soil tilth under no-till, strip-till and traditional tillage system, and cover crops and the farm’s bioreactor.
John Lawrence, associate dean of ISU’s College of Ag and Life Sciences, said central Iowa is in Des Moines’ bull’s-eye when it comes to nutrients in the Des Moines, Raccoon and Boone rivers as they flow south.
This spring, with May rainfall exceeding an all-time one-month record, the three rivers were tested and found to have excessive levels of nitrates and phosphorus.
Des Moines, which draws a significant amount of its drinking water from the Des Moines River, had to draw from alternate sources because its water department could not afford to remove the nutrients.
Lawrence said farmers need to get be proactive in reducing nutrient loading in surface waters, or others downstream will begin to mandate measures.
The Iowa Nutrient Reduction Strategy, which was released in December 2012, requires Iowa to reduce its nitrate loads in the Upper Mississippi River Watershed by 45 percent and phosphorus by 29 percent.
“We have to think globally,” Lawrence said, “but act immediately.
“It will take us a long time, but we need to keep making progress, even though Mother Nature has a deck of cards full of jokers.”
Sam Adams, district conservationist for the Natural Resources and Conservation Service for Webster County, conducted a cover crops talk.
Cover crops, he said, “is a third crop you don’t harvest. Cover crops feed your soil.”
Showing remnants of cereal rye that was sown as a winter cover last fall, Adams said cover crops add vital organic matter to the soil.
“Soil quality is a measure for producing crops,” Adams said. “Soil health refers to the micro-organisms that are needed to be present to break down minerals and feed it.”
Adams said increasing organic matter will allow the soil to retain more water and hold nitrogen in place, until the cover is killed. Decomposition returns nitrogen to the soil for the next cash crop.
Cover crops are also credited with keeping soil in place and stopping surface erosion.
In the pits
Barry Kusel, a Manning-area farmer and cooperator with ILF, spoke to the tour while standing in the three test-plot trenches – no-till, strip-till and traditional tillage.
The water-holding capacity of the no-till was displayed, compared to the much drier soil profile in the traditional tillage trench.
Also, because of a more mellow soil tilth, the roots of corn plants, all planted on May 17, were much deeper in the no-till and strip-till trenches.
Gary Nelson, a Webster County strip-tiller, said reduced tillage was a hard sell for him.
But after switching to strip-till for several years, traditional tillage “seems to have been unnecessary all these years,” Nelson said.
Tony Seeman, of the Iowa Soybean Association, and Karen Hansen, Webster County conservationist, discussed the Smeltzer farm’s bioreactor.
This is an underground device that filters nitrates from tile lines before discharging into a small stream that meanders through the farm before it meets the Des Moines River.
Comito said the bioreactor was working well and hoped farmers would see the value of such a device for their fields.
Mike Richards, an instructor in agriculture and sustainable farming at Iowa central Community College in Fort Dodge, said the bioreactor got his attention most.
Richards said he has brought agronomy students to the farm several times to study the various practices.
“At first,” Richards said, “you have to tell them to keep an open mind, because most of them come from farms using traditional farming practices.”
Matt Helmers, an ISU agronomist, said none of the reduced tillage practices, cover crops or the bioreactors will help Iowa meet the nutrient reductions by themselves.
“Farmers will have to adopt several of the practices to meet the mandate,” he said.
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