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Covering Up

Saturday, January 1, 2022
filed under: Planting Systems

Editor’s Note: The following article is reprinted, with permission, from the 2021 annual edition of Succeed, a publication of Nuseed. A few minor edits have been made for consistency with The Sunflower’s editorial format and to update a couple article source observations from the initial publication.

black lentil in SF field — Black Lentil Interseeded into Sunflower (Photo credit: Hans Kandel)

        Agronomists and producers are becoming increasingly aware of the importance of protecting soil from wind and water erosion. Cover crops have become more important in farming systems and can boost soil fertility and reduce soil erosion.
        Emily Paul, sales and product development director at Pulse USA, has a broad background in the agriculture industry, including agronomy sales, crop consulting, production contracting and seed sales. She says planting a cover crop revolves around several factors and goal; and when it comes to using sunflower in a cover crop mixture, those reasons for incorporation are as unique as the next cover crop seed. However, the main benefit of using sunflower in cover crop mixes involves its roots. The deep root of sunflower is beneficial to sequester residual nitrogen.
        “Sunflower in cover crop mixtures is primarily used for soil health benefits such as cycling and scavenging nutrients, reducing soil erosion and alleviating soil compaction,” Paul explains. “Their deep taproot pulls nutrients and water up from soil layers that most other cover crop species cannot reach, adding diversity and synergy to a mixture.”
        Paul, who grew up on a family farm near Rugby, N.D., and dedicates her time to the pulse and cover crop industry, says sunflower as a cover crop benefits livestock and wildlife as well.
        “Sunflower is great to incorporate into mixes for livestock and wildlife, benefiting the land, the environment and the animal,” she says. The height of sunflower is attractive for food plot mixes to provide more shelter to deer, updated and other game birds. Their flowers are especially attractive for promoting sustainability in our ecosystem for bees, pollinators and other beneficial insects.”

Saving the Soil
        “Sunflower is a great crop for soil conservation, and much of that success can be attributed to its root structure and deep taproot,” says Paul. “The root structure holds soil together, alleviates soil compaction and biologically breaks through soil layers, reducing the need for conventional tillage practices.
        According to Paul, the sunflower taproot resembles an elevator bringing nutrients, microbes and water from deeper soil layers closer to the soil surface for subsequent crops to have better access to. “Sunflower improves overall field conditions, and farmers notice how well they can remedy their soils by softening and breaking the ground up for improved planting conditions,” Paul says.
        Wait, there’s more. Sunflower also has better salt tolerance relative to other crops like soybeans and dry beans.
“Fields with salinity issues that hinder crop production can [benefit] through the use of sunflower, allowing farmers to conserve the land they have to grow on,” Paul observes.
        Sunflower is a warm-season broadleaf, so Paul says it is best to use them in mixes planted once soil temperatures have reached 55-60°F.

Cover Crops into Sunflower
        To embrace sustainable farming practices and build soil health, farmers are now working on fitting cover crops into every phase of their rotation to achieve multiple goals. One practice that is currently gaining interest in the U.S. is seeding cover crops into sunflower.
        In this case, various mixes of cover crops could provide the following benefits:
        • Flowering throughout the growing season to attract beneficial insects and possibly reduce insecticide applications.
        • Competition with weeds in a crop where herbicide options are limited.
        • Diverse root structures to build soil health properties.

        The benefit to soil health and soil conservation is especially appealing.
        “Topsoil preservation and the maintenance or building of organic content in the soil are important management strate gies to increase soil health,” wrote Hans Kandel, extension agronomist-broadleaf crops at North Dakota State University, in an edition of the NDSU Crop and Pest Report that looked at the benefit of seeding a cover crop into sunflower.
        “Some potential benefits of interseeding a cover crop mixture, including a legume, in sunflower are: nitrogen fixation, soil erosion control, improved snow trapping, improvement of the soil structure and organic matter content, and fodder or green manure production the year after the legume establishment,” Kandel wrote.
        Timing is critical when it comes to interseeding a cover crop to ensure the sunflower crop still yields near its potential. According to Kandel, it is important to give the sunflower (the primary crop) a head start and plant the cover crop from the V4 to V8 growth stages. Planting too late in the season (from V8 to bloom) will not provide enough light for the cover crop establishment.

Cover Crop Experts
        Keith Berns and his brother Brian co-own Green Cover Seed and Providence Farms in Bladen, Neb., where their family has been farming for more than 100 years. They farm corn, soybeans, rye, triticale, peas, buckwheat and sunflower using continuous no-till and a variety of cover crop strategies to maximize the health of their soil.
        In 2007, the Berns brothers founded Green Cover Seed to fill the demand they saw for cover crop and forage seed mixes. Since then, their business has grown exponentially, becoming one of the major cover crop seed providers and educators in the United States.
        “Our goal when we farm is, we never want to see the soil unless we go looking for it,” Berns says in a video on the Green Cover Seed website. In the video, Berns shows off a cash crop of sunflower, along with a mix of cover crops he has planted into a field with a healthy thatch of triticale straw. Since the sunflower grows above the cover crops, he explains that he will be able to harvest those ’flower heads for their oil, leaving intact the cover below to protect the soil until the next round of planting.
        As noted earlier, sunflower is a great crop for soil conservation — a point with which Berns agrees. “A sunflower has a massive root system,” he says. “The roots are what’s really helping build our soil: [they’re] building soil structure, [they’re providing] an environment for all of the soil microorganisms to live. Earthworms love sunflower roots.”
        The Berns brothers have tried hundreds of crop cover mixes, and from that knowledge they developed an online tool to help farmers decide which blend of cover crop seeds is best suited for their purposes. Called the SmartMix Calculator, this online decision-making tool uses geographic and climatic data combined with user-provided planting dates and goals.
          To view informational videos and blog posts pertaining to the use of sunflower in cover crop mixtures, and to access the SmartMix Calculator, visit greencoverseed.com.