By Donnelle Eller, The Des Moines Register
Steve Berger pulls a bright yellow sponge and a small glass container filled with a silty soil from a box he carries to presentations.
The sponge represents what the 52-year-old says is happening in the soil on 2,200 acres he farms in southeast Iowa. The container shows dirt that's been beaten by rain, wind and machinery over several decades.
"We always want something covering the soil," said Berger, who with his late father, Dennis, worked decades building their farm's soil health so it would better hold water and nutrients.
The Des Moines Register reports that the men began no-till farming about 35 years ago, and 15 years ago started planting cover crops each fall — both part of the conservation practices the state is urging farmers to adopt to help improve Iowa's troubling water quality.
The state's Nutrient Reduction Strategy enlists aggressive conservation practices in its goals to cut nitrogen and phosphorus levels in Iowa's water by 45 percent. And although cover crops help get the state closer to that goal, only about 500,000 of Iowa's 23 million corn and soybean acres are planted to cover crops.
People like Berger are crucial to increasing the use of cover crops and other forms of conservation — because no one has more credibility to a farmer than another farmer, said Bill Northey, Iowa's agriculture secretary.
"Steve was using cover crops long before anyone had heard of it," said Bill Northey, Iowa's agriculture secretary.
"Farmers respect other farmers who have been out there and done it. Steve can talk about how it worked in wet years and dry years, how he's changed things, what he tried that didn't work."
The push for greater conservation has become more pivotal as farmers increasingly have been on the hot seat in the debate over agriculture's impact on water quality.
Further fueling the discussion is a Des Moines Water Works lawsuit filed nearly a year ago against drainage districts in three north Iowa counties.
The utility claims that underground tiles used to drain farmland are acting as conduits that dump high levels of nitrates into the Raccoon River, one of two sources of drinking water for 500,000 residents in the central Iowa metro area. The agency seeks federal oversight of drainage districts and ultimately farms.
Iowa politicians prefer a voluntary approach, enlisting the Nutrient Reduction Strategy, and farmers such as Berger are important to their recruitment efforts.
Sarah Carlson, the Midwest cover crops research coordinator at Practical Farmers of Iowa, said Berger is "generous with his information. He's a corn and soybean farmer who makes cover crops work in that system."
No sermons, she said. Berger just provides information — a lot of detailed data about rainfall amounts, yields and fertilizer applications.
And he gives examples — what his farm looks like after a 3-inch or 6-inch rain, where water has been slowed in deep cereal rye. Then he shows photos of that same rain digging deep gouges as it runs down bare, sharply rolling hills in southern Iowa.
Cover crops such as cereal rye, hairy vetch and winter triticale can cut nitrate loss about 30 percent in areas that rely on underground field tile, according to the state's Nutrient Reduction Strategy.
The plan is designed to cut nutrient losses that contribute to the dead zone in the Gulf Mexico, an area about the size of Connecticut and Rhode Island last summer that's unable to support marine life. Leaders believe the strategy will improve Iowa's waterway quality as well.
But the voluntary strategy has no set deadlines or measurement requirements and is frustrating Des Moines Water Works leaders and environmentalists.
In order to meet federal water quality standards, Water Works must run a nitrate removal equipment that costs about $1.5 million over two years because of the observed high nitrate levels.
And phosphorus contributes to cyanobacteria blooms, known as blue-green algae, that forced a record number of Iowa beaches to close last summer, and pushed Toledo, Ohio, to shut down its drinking water system for two days in 2014.
Northey said broad adoption of cover crops, no-till farming, terraces and other conservation practices in Washington County, where Berger and other early adopters live, shows how successfully nutrient-reduction practices can spread.
Berger and his father, a conservation champion who died in October, began questioning their farm's soil health in the 1970s.
Initially, "we really just wanted to stop erosion," said Berger, who worked for Gov. Terry Branstad's administration for two years on farm policy after graduating from Iowa State University with an agricultural business degree.
When Berger returned home to farm, he and his father noticed yields near fence rows that hadn't been tilled were higher than other places on the farm. And the organic matter, a key measurement of soil health, was higher, too.
They decided to stop tilling their land.
"Every time you run a tillage machine through the field, you lose organic matter," Berger said.
Then the Bergers started experimenting with cover crops — to help hold the soil in place over the winter and spring before corn and soybeans are planted. It also adds organic matter.
Berger and his father began to see soil improvements. Farms with cover crops seemed to absorb big rains better than some neighboring fields. And they performed better during droughts.
"Something begins to happen under your feet," said Berger, who has covered all his acres for the past eight years.
Transforming soil health takes time, Berger said. Nearly two decades of work has about doubled his farms' soil organic matter.
"It's not a light switch you flip," he said.
Northey said Berger has helped show farmers they can use cover crops without losing yield.
The Nutrient Reduction Strategy says farmers could lose up to 6 percent of their corn yield when using cover crops. The over-winter crops can compete with corn in the spring for nitrate. Soybeans show no yield loss, though, according to the strategy.
Berger believes no-till and cover crops have led to stronger yields, even in difficult growing years.
But, he said, farmers need to make adjustments to avoid yield losses. They need to modify planters to ensure seeds get a good start, providing small amounts of nitrogen earlier in the year, since nitrogen might still be tied up by the cover crops, and earlier insecticides to offset the pests that come with lively cover crops.
Berger is quick to say the answers he and his father have found may not necessarily suit every farm. Farmers in northern Iowa might find it more challenging to get cover crops established in the fall, for example, because of cooler temperatures.
And farmers may not feel they can park their tillage equipment, Berger said. He suggests those farmers make one less pass with their equipment.
Eventually, he believes, they'll begin to see benefits.
Even with cover crops across the entire state, Berger said it's not enough to meet the state nutrient reduction goals.
"It's not simple," he said, adding that information about his nutrient loss will tell him if he needs to add bioreactors, buffer strips or other conservation practices.
?"It's really going to take multiple practices," Berger said.