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Clean water, healthy soil

Carl Zimmerman in Earlville, Illinois, farms 1,600 acres of corn and soybeans on land that his father began farming in 1966.

Over time, the Zimmermans have increased their acres (his father started with 350), raised cattle and hogs, and built up the soil through cover crops and no-till management.

“What got us started with cover crops was growing sweet corn. Eight years ago, we decided to plant oats to help combat weed issues on about 120 to 160 of those acres,” Zimmerman explains. “Over the years, we gained more trust in cover crops and got by with less tillage.”

In 2015, the Zimmermans made a commitment with the Natural Resources Conservation Service’s Environmental Quality Incentives Program and Conservation Stewardship Program to adopt 100% no-till and cover crops on half of their acres.

Today, the farm has cover crops on all 1,600 acres.

Cover crops and no-till have resulted in financial savings, but Zimmerman is also focused on the future and proving those practices do more than reduce input costs.

“We’re located in the biggest watershed in the United States. It’s not a matter of if, it’s a matter of when we’re going to need to verify our practices due to legislation,” Zimmerman says. “We are starting to test for nitrates out of our tiles. We’re implementing solid practices, and trying to beat them to the punch.”

A farmer plants cover crops into standing crop
Photo credit: Megan Schilling

Crop Management Strategies

It hasn’t been an easy journey to scale up the soil health practices, but Zimmerman says the five-year contract and financial programs from the Natural Resources Conservation Services did what they were designed to do.

“We are now looking at different electives to see if something will fit the way we want to farm. If not, we’ll continue to do no-till and covers regardless,” he says.

Zimmerman says staying flexible by treating the failures as learning opportunities has been key. The changes he saw in the soil after about three years of cover crops and no-till turned into his aha moment.

“When we combined, we noticed improved soil structure. There were no depressions in the field from the combine when it was moist,” Zimmerman explains. “After six or seven years, we see fundamental change.”

He also has fewer issues with sudden death syndrome, has better weed control, and the soil has good tilth.

Erin Gundy, resource conservationist with the Champaign County Soil and Water Conservation District in Illinois, says setting water quality goals and measuring success depends upon the operation.

“An easy way to evaluate water quality is an estimation of the practices on the farm,” Gundy says. “Look at what the Illinois Nutrient Loss Reduction Strategy recommends for an average range of nutrient load reduction, factor in your practices, and then you get a rough idea based off of that research.”

For late adopters of conservation practices, she recommends first learning about nutrient use efficiencies and finding the maximum return to nitrogen (MRTN). MRTN calculators are available, factoring in current prices, to determine the economic return of nitrogen applications.

“Utilizing nitrogen applications in the correct way, including time, source, and place, is important. Overapplying leads to waste if it can’t be taken up by the crop. It also harms our environmental resources,” Gundy explains.

She also recommends limiting tillage passes, which saves fuel, labor costs, and time, and promotes healthy soil. Cover crops immediately reduce nutrient loss due to less erosion by having living roots in the soil year-round.

“A diverse crop rotation is another strategy that will impact water quality and weed management,” she says. “It’s a helpful tool if a farmer is nervous about going no-till because it can strategically manage weeds, especially when paired with cover crops.”

Nutrient Loss Reduction Programs

Many programs and resources are available by state in support of sustainable ag practices.

One of the newest in Illinois is the Saving Tomorrow’s Agriculture Resources (S.T.A.R.) initiative, a program that Gundy has been involved with. S.T.A.R. ranks fields on conservation management and is gaining in popularity.

“There is an old saying that Soil and Water Conservation Districts (SWCDs) are the state’s best kept secret,” says Grant Hammer, executive director of the Association of Illinois SWCD. “They’re integral to the conversation for the frontline delivery system for soil health and conservation, but are sometimes overlooked.”

AISWCD promotes the state’s Nutrient Loss Reduction Strategy, which contains a suite of management practices to improve water quality both in-state and downstream. 

Hammer’s team helps promote the Illinois Department of Agriculture’s Cover Crop Premium Discount Program, which is offered for acres of cover crops planted outside of state and federal incentive programs.

“The state rolled out its cover crop premium discount program in 2019. There were 50,000 acres available with a $5 discount per acre,” Hammer explains. “Those 50,000 acres went in a snap. That demonstrated to us that there is demand.”

Hammer says agriculture is now experiencing a transitional period of renewed interest in conservation. This is especially because people outside of the industry are becoming aware of how agriculture fits into the larger environmental picture. “They’re looking at agriculture with a new set of eyes. Farm operators realize this, want to be good stewards of the land, and always have been,” he explains.

Leading-Edge Conservation Technologies

In addition to in-field management, edge-of-field conservation technologies are effective and gaining traction.

One wood chip bioreactor can reduce nitrate levels by 15% to 60% on 30 to 80 acres of tile-drained fields.

A wood chip bioreactor on a farm
Photo credit: Megan Schilling

A bioreactor is a subsurface trench filled with a carbon source like wood chips that filters water from a field before it drains into nearby surface water.

A saturated buffer is another example. It intercepts tile drainage water before it enters a stream. The water, diverted by a control unit, moves through a perforated drainage pipe and into an existing filter strip of perennial plants. Instead of a wood chip trench, the water drains through the soil profile, where plants take up the excess nutrients.

A saturated buffer is installed on a Midwest farm
Photo credit: Megan Schilling

According to a Farm Services Agency and Agricultural Drainage Management Coalition study, about 9.5 million acres are potentially suitable for saturated buffers across the Midwest. That is about 22% of the tile-drained landscape.

In addition, the study found with this potential, 5% to 10% of the tile-contributed nitrate load could be removed.

It will take a suite of crop and conservation management strategies to reach water quality and soil health goals – from individual fields to states and beyond.

“An ounce of prevention is worth a pound of cure,” Zimmerman says in regard to the future of water quality management on the farm.

Living and farming in the Mississippi River watershed inspires Zimmerman to monitor nutrient management closely. So do the case studies in other areas of the country, like water quality in the Chesapeake Bay watershed.

“If we can get ahead and plan management practices on our own, maybe we won’t have to go through so much regulation,” Zimmerman says. “As farmers and stewards of the land, we need to be more proactive instead of reactive.”

Illinois Nutrient Loss Reduction Strategy

The Illinois NLRS was released in 2015 with interim goals to reduce nitrate-nitrogen runoff by 15% and phosphorus by 25% by the year 2025.

According to the 2019 biennial report, the estimated average annual nitrate-N load in Illinois rivers during 2013–2017 was about 7% greater than the 1980–1996 baseline. Estimated statewide average total phosphorous load during 2013–2017 increased by 26%.

Average water flow during this period was about 13% greater than the baseline, which likely led to the increase in nutrient loads. Additionally, 2012 was an extreme drought year that reduced corn yields, leaving greater unused nitrogen fertilizer in soils.

A wetland on a Midwestern farm
Photo credit: Megan Schilling

Illinois S.T.A.R.

In 2017, the Champaign County Soil and Water Conservation District developed the S.T.A.R. initiative. S.T.A.R. helps to educate and encourage farmers, ranchers, and landowners on conservation management.

Farmers complete a field form that includes practices in support of nutrient loss reduction. Fields are ranked on the five-S.T.A.R. scale and participants receive a sign for their fields to identify their ranking. Roughly 10% of fields undergo a verification process to validate field forms. The initiative has been adopted by Soil and Water Conservation Districts in Illinois, Indiana, Iowa, and Missouri.

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