Cover crops on 95% of land pay off

Dana Norby wants only clean water leaving his north-central Iowa farm and going into Rock Creek, a stream where he fished and swam as a kid.

Norby's goal is ambitious. And it needs to be.

He and other area farmers are working to significantly reduce the nutrients entering the Rock Creek watershed — cutting nitrogen by 41 percent and phosphorous by 29 percent.

It's a goal that will take two decades and $5 million in wetlands, buffers and other conservation infrastructure, along with $750,000 in annual spending, to accomplish.

The watershed's combined 45 percent reduction mirrors Iowa's goals to reduce the fertilizers leaving the state and entering the Gulf of Mexico. Nutrients from Iowa and 30 other states contribute to the Gulf's so-called dead zone, an area the size of Connecticut that's unable to support aquatic life each summer.

Farms contribute about 70 percent of the nutrients going to the Gulf, according to a U.S. Geological Survey report. Cities and businesses contribute 9 to 12 percent.

Norby is getting close to the target, said Adam Kiel, state water resources manager for the Iowa Soybean Association.

Here's how Norby's work tallies up: He uses cover crops such as winter rye on about 95 percent of his land, on both corn and soybean acres. That reduces nitrogen, and potentially phosphorous, losses by about 30 percent, Kiel said.

And Norby gets 6 to 7 percent closer by applying fertilizer in the spring, when the plant is up and can use it. And he uses less nitrogen than what's recommended.

Kiel believes the nutrients trapped in Norby's cover crops over the winter help feed the plants until nitrogen is applied in the spring — and reduce the amount needed.

Additionally, Norby strip-tills his corn acres — using a small 8-inch strip in each row that creates a bed for the seed. Otherwise, he no-tills — a practice that leaves corn stalks, husks and other residue that soybeans are planted into. The corn stover adds nutrients to the soil as it decays.

No-till practices that reduce soil erosion can slash phosphorous losses by 90 percent, according to the Iowa Nutrient Reduction Strategy. He's also invested in improving existing terraces, an effort that also reduces phosphorous and nitrogen loss.

But here's the challenge: Iowa needs broad adoption of the farming practices to meet the state nutrient reduction goal. Iowa has nearly 90,000 farmers, according to the U.S. Agriculture Census.

"You can't have some farmers doing 41 percent of the practices and the rest doing 10 percent," Kiel said. "The math doesn't add up. It's a scale issue."

And even with all the work Norby has done, he may still consider an "edge of field" practice like a bioreactor — essentially a trench with a carbon source like wood chips that help break down nitrates.

Norby said he and two brothers, who have separate operations but share equipment and labor, started picking up conservation practices more than two decades ago.

"We started farming some farms that are not a Class A farm, if you will," he said. "They were some farms that need some TLC. They're farms that some people would pass on, but we're able to raise respectable crops on them by using the farming methods we're using."

Not every practice they've adopted has gone smoothly, he said. For example, the first year the brothers strip-tilled all their corn acres, they were unable to have nitrogen sidedressed, or incorporated into the soil.

"Instead it was broadcast," he said. "If it would have rained, it would have been wonderful. But it was dry for a couple of weeks ... and it hurt our yields."

The brothers also initially struggled with cover crops, getting the right variety that would begin growing in the fall.

"It's called paying tuition," he said. "I've paid a lot of tuition. I just don't want to pay for the same lesson twice."

Norby believes in the work's broader environmental benefits, but he sees it helps his farm operation's profitability. "Not only do I not want to pollute the water, but I don't want dollars leaving my farm," not in nutrients nor fuel needed for tillage, he said.

"I cannot control grain prices. I cannot control yield, which is dependent on the weather," he said. "The thing I can control is lowering my costs."

And even though practices like cover crops cost money each year, Norby said the long-term benefit of healthier soil has improved profitability. An analysis showed his productivity and profitability was consistent over the past three years, even though farmers struggled with crippling rains and drought.

"The system we've built makes it easier to deal with the extremes," he said.