It’s farm conservation at work
By LARRY KERSHNER
OTHO – Some of the Smeltzer Farm’s edge-of-field practices can be seen and some can’t, but according to a Sept. 2 field day near Otho, they are all at work to keep nutrients from reaching surface waters and soil in place.
Edge-of-field is a term for any practice designed to remove nitrate escaping fields via tile lines, and phosphorus from escaping through surface erosion, before the nutrients reach streams and rivers. The most common practices are bioreactors, wetlands and saturated buffers.
Iowa State University’s Iowa Leaning Farms has employed numerous conservation practices – strip-till, no-till, terraces, contour buffer strips, grassed waterways, cover crops, bioreactors, riparian stream bank support, oxbow restorations, no-till row cropping and prairie management – to demonstrate the number of practices that farmers can employ to work toward clean surface waters, while not sacrificing crop yield.
Mike Richards, who oversees ag curriculum at Iowa Central Community College, in Fort Dodge, said he uses the farm regularly as an outdoor classroom for ag students.
All farmers needed
Matt Helmers, an ISU Extension ag engineer, told those attending the Sept 2 event that cover crops alone cannot get Iowa to meet its nutrient reduction strategy goals.
He said once nitrates get into a tile line, much it can be diverted from reaching surface waters through edge-of-field practices.
“We need all farmers to using one or more practices,” Helmers said.
The Iowa Nutrient Reduction Strategy calls for reducing of nitrate, a threat to fresh water, and phosphorus, a threat to saltwater, by 45 percent before reaching the Mississippi and Missouri rivers, and eventually the Gulf of Mexico. The Hypoxia Task Force, formed within the Environmental Protection Agency, called for the reductions and Iowa developed its strategy and released it in 2013.
To reach the INRS goals Helmers said 60 percent – or about 12 million acres – of all Iowa’s crop land would need to be under cover crops; or 60 percent of all tiled fields should be channeled through a bioreactor or some type of wetland restoration, including saturated buffers.
He estimated that only about 300,000 Iowa row-crop acres will be under cover crops this winter, a long way from 12 million.
“The Hypoxia Task Force determined that to reduce the dead zone to 5,500 square miles,” Helmers said, “phosphorus must be reduced by 45 percent.”
He said the issue has always been one of land stewardship, but with the EPA’s involvement and with the lawsuit filed by the Des Moines Water Works against three north central Iowa counties earlier this year, regulatory and legal components to the issue were created.
“The INRS was approved in 2013 and the lawsuit was filed in 2015,” Helmers said, ‘So that shows that we’re already working on it.”
There is no deadline yet to meet the goal, he said, “but the EPA said it is watching ‘to see the needle going down.'”
In March 2013, Karl Brooks, former Region 7 director of the U.S. EPA, told reporters that he thought voluntary compliance would work, “because the EPA has identified farmers as the most flexible to changes, especially to safeguard the land’s heritage.”
But steady improvement has to be documented, Brooks indicated.
Falling short of do-it-or-else rhetoric, he said “using land for food is a public policy issue and it deserves the best thinking of the public and farmers.”
He said the issue is as much a political solution, as it is a scientific and land management issue.
“Get to work, it’s time to start.”
Farmers were reminded at the Smeltzer field day there are still cost-share funds for implementing conservation practices through the Iowa Department of Agriculture and Land Stewardship and the U.S. Natural Resources and Conservation Service, plus engineering and design expertise through other organizations including the the Iowa Soybean Association and the Agricultural Clean Water Alliance.
Keegan Kalt, an ISA watershed management specialist, explained how bioreactors are known to remove as much as 35 to 50 percent of nitrate from runoff before emptying into surface waters.
A bioreactor is an underground chamber, filled with woodchips. Tile lines empty runoff into the chamber where bacteria from the chips feed on the nitrate. the byproduct is nitrous gas, which rises through the soil and escapes harmlessly into the air. The water then exits the chamber and tiled into a near by stream.
At the Smeltzer Farm, an oxbow lake restoration also captures tile water, where wetland plants do the job of taking up nitrates before the water flow continues down the watershed.
According to 2010 water sampling, the farm’s west oxbow removed about 73 percent of the nitrate on May 10 and about 75 percent on May 18. Other samplings varied depending on the amount of rainfall runoff pushing the water into the watershed.
At the same time, the bioreactor removed 56.5 percent of nitrates on May 10 and 24.4 percent on May 18. However, when the water leaving the bioreactor was tiled into the farm’s east oxbow, that water came out with a total of 99.95 percent nitrate-free on May 10 and 99.8 percent nitrate reduced on May 18.
Kalt said there are now an estimated 60 bioreactors active throughout Iowa, with a total of 25 bioreactors and saturated buffer strips to be installed along Rock Creek in Mitchell County.
A saturated buffer strip is generally a grassed buffer zone near a stream. Tile water is directed laterally along the stream bank, saturating the buffer and allowing the plants to naturally remove nitrate and phosphorus, before it reaches the stream.
Kalt said ISA now recommends that if tile line is draining less than 30 acres of water, it should be channeled into a saturated buffer. Larger than 30 acres is recommended to be filtered through a bioreactor.
Farmers were introduced to two types of drones that can used to fly their fields to get real-time updates on the conditions of their crops.
The presentation included aerial photos, shot through an assortment of mediums to show a multitude of conditions, including various moisture, or nutrient stress, diseases and pests.
A quad-bladed drone, and a flying-wing drone were both demonstrated ending the field day.
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