Adoption of cover crops, no-till and other conservation practices have escalated in recent years, leading to soil health and water quality improvements.

A growing number of Iowa farmers are planting cover crops and implementing other conservation practices to improve soil health and water quality, according to the latest survey by the Iowa Nutrient Research and Education Council (INREC). 

The survey, now in its sixth year, uses sales data and field records from Iowa ag retailers and co-ops to track progress made by Iowa farmers in adopting in-field conservation practices such as cover crops, nutrient management and reduced tillage. 

The INREC survey found that cover crop adoption in Iowa in­­creased dramatically from 1.6 million acres in 2017 to 3.8 million acres in 2022. Cover crops are now grown on more than 16% of Iowa corn and soybean acres, according to the survey. Data from the U.S. Department of Agriculture (USDA) indicates fewer than 10,000 cover crop acres were planted in Iowa in 2009.

“Iowa cover crop planting has skyrocketed over the first decade of the Iowa Nutrient Reduction Strategy, and that clearly demonstrates that Iowa farmers and landowners are taking on the challenge of improving Iowa’s water quality by accelerating this important conservation work,” said Iowa Secretary of Agriculture Mike Naig. “With the help of ag retailers and other conservation professionals, as well as both public- and private-sector partners, programs and incentives, I know our farmers and landowners will continue to push these statewide cover crop numbers ever higher.”

Cereal rye is the dominant cover crop species, averaging 81.8% of cover crop acres in 2022. 

Cover crops offer multiple benefits by keeping 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 INREC survey also measures a variety of nutrient management practices, including timing, rate, source and placement. Timing of nitrogen applications are led by spring preplant with a six-year average of 45% of nitrogen applications. 

The data also shows Iowa farmers are using soil tests at a high rate. Approximately 80% of farmers use soil tests to determine phosphorus levels, and more than 92% only apply phosphorus when tests show levels are at or below optimum levels.

The 2022 INREC survey found that Iowa farmers use no-till or other conservation tillage on nearly 70% of corn and soybean acres. No-till leaves crop residue on the ground, reducing soil erosion and filtering nutrients from runoff be­fore it enters Iowa watersheds.

Iowa farmers also lead the nation in the construction of water quality wetlands, which are strategically positioned to capture water and filter nitrates from field runoff, according to USDA data. Studies show wetlands reduce nitrogen losses by 52% and provide wildlife habitat.

With dedicated funding for water quality infrastructure, the Iowa Department of Agriculture and Land Stewardship is partnering with farmers to ramp up the number of wetlands and other edge-of-field water quality practices through its innovative “batch-and-build” model. Batch-and-build modernizes conservation project management by installing batches of projects on multiple farms at the same time, allowing a faster acceleration of water quality progress.

“Iowa has set records for conservation adoption each of the last two years, and that takes individuals, partners, businesses, farmers and landowners working together to make that happen,” said Naig. “As we further accelerate our water quality and conservation progress in the years and decades ahead, it will take continued co­­operation by public and private partners in both urban and rural areas working together to make even more advancements toward our Nutrient Reduction Strategy goals.”