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Water Quality, Drop by Drop | Water-Quality Improvements Work Best From the Soil Up


Rick Juchems hopes that growers can be in the driver’s seat on water quality improvements rather than government. That’s not been the case during the six years he’s tracked the Chesapeake Bay’s nutrient-management problem. As past president of the Iowa Soil and Water Conservation district commissioners, he hears about it at national conservation meetings as evidence that “a lot that needs to be done.”

The Plainfield, IA, grower has seen successful grower-led efforts in northeast Iowa. For example, the grassroots style played out among 43 growers who voluntarily formed the Lower Coldwater Creek/Palmer watershed council. They tookthe initiative on rural water quality from the soil up. Using scientific measurement tools, watershed growers figured out what works best on their individual farms to reduce farm-nutrient losses.

For Juchems, that includes seeding arye/oats cover crop right after soybean harvest to anchor nitrates and sediment. “I hire it done so it’s not such a chore,” he says. Other conservation tools he uses to reduce nutrient loss are grass waterways, creek buffers, terraces, CSP windbreaks, no-till, conservation tillage and manure flow meters (to calibrate his hog manure application).

 “But each farm is different, and the grower is the best judge of what works there,” he says. Biofilters, for example, need to be site-specific based on available space and water flow. Similarly, cover-crop mixes are highly climate-specific.

The grower watershed group “took matters into our own hands before the government intervened to improve our streams’ nitrate levels,” says watershed group Chairman Scott Bruns, Allison, IA.

The group uses scientific tools (Iowa phosphorus index, the soil-conditioning index and the fall cornstalk nitrate test) to benchmark and reduce water-nitrate levels.

Of all the watershed’s growers, 70% took ownership of the problem by joining the group. “Having our streams on the EPA nitrate-impaired list got everyone’s attention,” Bruns says. For scientific support they relied on northeast Iowa Extension Watershed Specialists Chad Ingels and John Rodecap.

Anonymous environmental performance scores by field tell growers which agronomic practices work best to intercept phosphorus (P), sediment and nitrates before they reach streams and rivers.

The watershed average P index on 327 fields covering 14,861 acres is now 1.05 (low environmental risk). The soil-conditioning index is now 0.41 on a scale of -1 to 1.1. They reduced early season water-nitrate concentration by 30%.

Monetary incentives totaled approximately $325,000; $235,000 came from the Iowa Watershed Improvement Review Board (three years) and $90,000 from the Iowa Corn Growers Association. This included a $15,000 investment in a woodchip bioreactor at the Nashua, IA, Iowa State University (ISU) research farm.

These growers’ grassroots efforts are a contrast to federal and state mandates that seem sure to follow. The Mississippi River/Gulf of Mexico Watershed Nutrient Task Force ( has called for a 45% reduction in nitrate N and P load in the Mississippi River by 2013.

Iowa has announced a corresponding statewide nutrient-reduction initiative. “These are not easy targets,” says Iowa Secretary of Agriculture Bill Northey. “Because there are fewer of us (in agriculture), we’ll suffer if we don’t have a science-based program.”

ISU scientists estimated what needs to be done to meet at least a 35% reduction on northeast Iowa’s Cedar River watershed (lowering the river’s maximum nitrate level to 9.5 ppmfrom a total maximum daily load (TMDL) of 14.7 ppm). (See also

“Farmers want to preserve water quality; they just need the right information,” says Rodecap, the

former Extension water quality specialist. “The more feedback farmers got, the more keen they were to do it.”

This same grassroots approach to solving water-quality issues is used by NRCS in the Upper Mississippi River Basin Initiative, says Kurt Hoeft, a grower from Charles City, IA. He’s also the director of the eight-county Cedar Valley Resource, Conservation and Development, which ISU used to study recommendations for nitrate- and P-reduction measures. “It’s key that practices adopted by producers are economically sustainable for the farming operation after the project ends,” Hoeft says.


They Did it Their Way

Because these water-quality control measures ultimately play out on the farm, Corn & Soybean Digest asked growers from the Coldwater/Palmer Creek watershed group what’s worked for them to reduce farm-nutrient loss.

The most effective practice for Ted Pitzenberger to reduce nitrate loss was shifting fall N application timing to spring. The watershed group secretary abandoned fall N application 35 years ago, but still harvests 200-bu. corn yields.

“It’s a management issue,” says the Dougherty, IA, grower. “We buy liquid fertilizer in the fall, apply it in the spring, then sidedress through the growing season. On my continuous corn I use 135 lbs. of liquid N/acre preplant, then sidedress the heavier, more productive soils with 45 units. On the bean ground we use 135-145 units of total N, some of it sidedressed.

“Maybe it costs more, but we save 45 units/acre by waiting till spring, so that’s a financial cushion. And I save that extra trip across the field,” Dougherty says.

He and grower Dennis Cassmann each installed woodchip dentrification bioreactors to retain nitrates from tile-drainage flows.

Cassmann’s bioreactor reduced drainage water nitrates by 35% in one year, from 11 to 7.2 ppm.

The Bristow, IA, grower spreads his N applications through the growing season. “We see economic and environmental returns from splitting our applications,” he says. The first is anhydrous with a nitrification inhibitor injected deeply in the fall to place it below the roots, says the grower/cattleman/hog producer and treasurer of the watershed group. When he plants, he adds 32% N “over the row to nourish the microorganisms that decompose the crop residue.” And in June he sidedresses anhydrous “because it always gives me a yield boost.

“ISU research shows similar nitrate loss between spring and fall application when the fall application occurs at soil temperatures below 50° F,” Cassmann says.

Sidedressing is high on Jon Giselson’s list. The 20-year conservation-tillage veteran from Floyd, IA, says, “There isn’t a farmer in Iowa who would apply anhydrous ammonia in the fall if he was limited in the amount of total N he had. Fall application’s advantages are more logistical than agronomic.

“Getting it all done in the spring is not a problem. I cover 200 acres/day at 7 mph,” says the Iowa Learning Farm conservationist and chair of the Floyd County Soil and Water Conservation District.

Strip-tilling in the fall allows Giselson to place nutrients “where the plants use it.” In the spring, he sprays for weeds and sidedresses with 32% N solution after the corn’s up. “I save fuel, reduce my time in the field and save on input costs. I find my yields are the same, costs are less and profits higher than if I tilled the soil black,” he says.

 It’s all about risk, says grower and swine producer Dave Muth, Dougherty, IA. “We know what we should do, but we still have to profit.” As a member of the watershed group, his favorite tools were the cornstalk nitrate test (CNT), N stabilizers and phytase to reduce his hogs’ manure P content.

“The CNT gave us the scientific proof that we could trim our N rates and not affect yields,” he says. His initial CNT results dropped from over 3,000 ppm into the ideal 700-2,000-ppm range as he cut back on N rates and used N stabilizer.

Fear of yield hits from compaction prevents him from shifting his manure application to spring, so he uses N stabilizers.

“It’s interesting that focus has shifted back to water quality from carbon, which was the big focus last year,” says the Iowa Corn Growers environmental committee member.

“Spring N application is very viable but I think it will cost at least $10-15/acre more, between increased prices and labor,” says Scott Bruns, Allison, IA, grower and watershed project chair.

The bottom-up approach used producer experiences to make the most beneficial and profitable management changes, says watershed Bruns, grower-leader of the voluntary watershed group. “We worked harder to make the program work because it was our design.”


Scores Motivate Growers

The performance number “driving all of this good volunteer work,”is the NRCS soil-conditioning index, says John Rodecap, retired northeast Iowa Extension water quality specialist, who coordinated the efforts. A composite of soil loss, slope, rotation, tillage and other practices affecting N and P loss, “it was a tremendous yardstick for grower-volunteers. Once you let farmers know their performance numbers by field (anonymously), they worked hard to improve their scores.”

The fall cornstalk nutrient nitrate test (CNT) was also useful in measuring how much of a crop’s nitrates remained unused in the plant at the end of the growing season. Over four years, 43 Coldwater Creek growers reduced their CNT levels by 75%.

Growers set their own goals and adjusted incentives based on scientific guidance, results feedback and grower response. For example, watershed growers used annual performance reports to target grassed waterways, vegetative filters and tillage management; reducing annual sediment and P delivery by 1,294 tons and 1,681 lbs., respectively.

“This type of environmental-performance rewards have been cost-effective in reducing water quality problems in a changing agriculture with increasing land-rental arrangements by rewarding farm operators to do applied research cooperatively with their watershed neighbors,” Rodecap says. “The four northeast Iowa watersheds where they’ve been demonstrated include karst and prairie soils; also conventional and large livestock operations. This multi-year, multi-watershed demonstration is an alternative to direct payments in recent farm bills that are increasingly unpopular with taxpayers.”

Each grower figures out the best plan for his individual operation. Biofilters, for example, need to be site-specific based on available space and water flow. Similarly, cover-crop mixes are highly climate-specific. That might be the best argument of all for locally based nutrient-management efforts. 

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