By Tom Block
Jeff Ellis has seen the difference that conservation measures like cover crops, no-till, terraces and buffers are making to improve water quality and soil health on his Lee County farm.
Ellis and his wife, Paula, began planting cover crops 15 years ago and have practiced conservation tillage for longer than that.
“We’ve used cover crops and no-till and used precision equipment to apply nutrients only when and where needed,” he said. “We’ve also reduced tillage and take soil samples to know what our crop’s needs are to apply more precisely.”
It’s safe to say they’re in it for the long haul.
“We originally started planting cover crops to control erosion on some of our hilly ground,” Ellis said. Since then, he’s noticed significant improvements in soil health, leading to better soil structure, improved water infiltration and higher yields.
“That’s one thing with cover crops is I don’t know if you see a return in one year or even three years, but after five years I think you start to see good things,” said Ellis.
“We could take a scoop of dirt out of one of our rye cover crop fields and you can just see the aggregation of the soil — it just kind of sticks together but still allows drainage. That’s one of the main signs of soil health.”
putting practices in place
A growing number of Iowa farmers like Ellis are planting cover crops to keep the soil covered between growing seasons to reduce erosion, absorb nutrients, suppress weeds and improve soil health. Iowa State University research shows cover crops can reduce soil nitrogen and phosphorus losses by 30% or more.
The number of cover crop acres in Iowa has increased dramatically over the past several years — from fewer than 10,000 acres in 2009 to more than 2.7 million acres for the 2021 crop year, according to a survey by the Iowa Nutrient Research and Education Council (INREC), which tracks data from Iowa ag retailers and co-ops. Cover crops are now grown on more than 12% of Iowa corn and soybean acres.
The INREC data also shows continued growth in other conservation practices, including conservation tillage, soil testing and variable rate nitrogen applications.
“Despite supply chain challenges, inflation and weather extremes, we continue to see record engagement in our state’s conservation activity,” said Iowa Agriculture Secretary Mike Naig. “The increased level of awareness and resources, coupled with an expanding list of partnerships, has led to the adoption of more conservation practices now than at any other time in our state’s history.”
Iowa farmers used no-till on nearly 42% of Iowa’s crop acres in 2021, a gain of more than 10% compared to 2017, the survey showed. No-till leaves crop residue on the ground, reducing soil erosion and filtering nutrients from runoff before it enters Iowa watersheds.
The number of farmers utilizing variable rate nitrogen application, which allows them to apply the right amount of nitrogen to their crops at the right time and in the right place, nearly doubled from 8.7% in 2019 to 16.1% in 2021.
The data also shows Iowa farmers are using soil tests at a high rate.
More than 80% of farmers are using soil tests to determine phosphorus levels, and 98% only apply phosphorus when tests show levels are at or below optimum levels.
“We’ve got a lot of farmers using soil tests and doing what those tests tell them to do,” said Shawn Richmond, an environmental scientist with the Iowa Farm Bureau.
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