Farmers finding benefits to cover crop adoption: Soil Health Partnership

Adoption of cover crops in rotation with cash crops is helping farmers manage soil to improve organic matter and achieve better rainfall infiltration, according to a recently published report from the Soil Health Partnership (SHP).

The 2019 Cover Crop Planting Report from SHP is a detailed survey on cover crops with more than 80 farmers across 11 states in the SHP network about cover crop usage on their trial sites in the fall of 2019. The SHP is a sustainability program of the National Corn Growers Association.

"We know farmers in our network are innovators, and that there is a huge range of cover crop management practices across our network depending on the farmer's management goals, where they are located, their soils, and cropping systems," says Maria Bowman, Lead Scientist for the Soil Health Partnership.

One key finding from the survey is that more than half of farmers planted their cover crops between the middle of September and the beginning of November. Nearly 40% planted before or after these dates. In addition, 25% of farmers responding to the survey interseeded or overseeded the cover crop into a standing cash crop.

"This means that farmers are using a wide range of strategies to get cover crops out on their fields, especially in higher latitudes where there are timing and labor constraints to getting a cover crop in after harvest," said Bowman.

Cereal rye is a staple

Almost half the farmers responding to the survey planted a single species cover crop, and of those, 80% planted cereal rye.

"Cereal rye is popular because it produces a large amount of biomass, which can keep soil in place, scavenge residual nitrogen, or provide weed-suppressing residue depending on the cover crop goals," says Jim Iserman, SHP Field Manager in Illinois and Wisconsin. "It also is winter hardy, allowing for a wide planting window, relatively easy to chemically terminate, and seed is rather cheap."

The average seeding rate is 48 pounds per acre, with seed costing $12.97 to purchase and another $14.13 to seed. More farmers drill cereal rye than any other application method.

Other findings

Most farmers surveyed planted a mix of at least two species, the survey shows. Forty-seven percent of the farmers used a single species cover crop. The most common species within mixes include cereal rye (50%), followed by rapeseed (45%) oats (42%), radish (37%) and clover (29%).

Farmers spent, on average, $14 per acre on seed for a single species cover crop $16.66 per acre for a two-way or three-way mix, and $22.50 per acre for three-species or more mixes. Seeding costs varied from $10 per acre for broadcast, to $13.88 per acre for aerial seeding, to $14.50 per acre for drilled seeding.

"Broadcast seeding is fairly quick and inexpensive. Yet drilling is one of the more consistent ways to get a stand. At the same time, it is slower and more labor intensive," Iserman says.

The survey is intended to provide farmers more context on cover crop usage, practices and cost. The dataset will help answer important questions about what type of management practices lead to successful outcomes. The most widely planted cover crop species was cereal rye. Of the farmers who planted a single species, 80% planted cereal rye, and it was also present in 50% of cover crop mixes.

Additional data are being collected this year to see how the cover crops developed and the impact on agronomic outcomes for the 2020 cash crop.