Now is the time to try Cover Crops

by Ben Smith, Territory Manager-HTS Ag

If I told you that you can improve soil health and microbial activity, reduce soil compaction, increase soil organic matter, reduce weed pressure, improve water infiltration and drainage, increase soil fertility, and reduce nutrients leaving your fields and ending up in the water supply, would you be interested? What if I also told you that there are government cost share dollars available that will pay 50-100% of the cost of trying this practice? All of this can be done by planting cover crops on your farm this fall.

Most farmers can remember the days of a more diverse farming system, one that included crop rotations containing a small grain or hay crop, and livestock production with most acres regularly receiving manure applications. Everyone can also remember the benefits that came from this holistic system, such as a lower dependence on commercial fertilizers and increased soil health, water infiltration, and increased organic matter. But this type of system is more difficult to implement and manage in today’s larger and more vertically integrated row crop farms. Now a majority of Midwest farmland is devoted to corn and soybeans, which are warm season annual crops that provide living roots in the soil only 5 months of the year. This leads to a majority of nutrient loss in fields occurring in the other 7 months of the year. Cover crops are a great middle of the road solution to this dilemma. They will provide a living root mass that will scavenge these nutrients during the colder months and make them available for crop use in future years as the cover crop breaks down. But they will not be harvested as a cash crop, and the corn/soybean rotation or continuous corn systems can still be grown every year.

A majority of the growers we talk to about trying cover crops all have the same objections and concerns. Some of the primary ones are, “How do we get cover crops seeded/established early enough this far north to still provide benefits?” And, “I’m concerned that terminating a perennial cover crop in the spring, such as cereal rye, will be detrimental to planting my corn crop.” We at HTS Ag had many of these same concerns so we have spent almost the last 2 years attending numerous field days, researching articles, and talking with local experts and farmers who have been successful with cover crops in Iowa. We have learned that there are many different ways to overcome these obstacles depending on your farming practices, available labor and machinery, and growing conditions/weather in your area.

Many growers have had success seeding their cover crops in late summer, when foliage on the corn and beans start to turn. This provides the maximum amount of growing season to get the cover crop established, especially if we have an early winter. They overseed the cover crops using a plane, or a high clearance applicator. This custom application also helps with the labor and machinery shortage that many operations experience when trying to seed cover crops right behind the combine. And most growers report that the green cover crop causes very few problems when harvesting the corn and soybeans. But a higher seeding rate and timely rainfall are required to get an adequate stand using the overseeding methods.

Many other growers are very successful establishing cover crops by drilling them right behind the combine after the fields are harvested. Using a no till drill, air seeder, or vertical tillage machine equipped with an air seeder are all ways to perform high speed and accurate seeding of cover crops. This approach will provide the best seed to soil contact and better emergence at a lower seeding rate. Many of these growers have pictures of the seeder and combine running in the same field just a few passes away from each other. This approach does require available machinery and labor, or an available custom operator. Growers have reported that this method still provides great benefits from the cover crops, even when seeded in early November at the end of corn harvest. Growers have reported the cereal rye may be less than 12” tall when they terminate it in the spring, but it still has an extensive root system underground that is scavenging nutrients and building soil structure. HTS Ag has been compiling a list of custom applicators around the state who are available to overseed or drill cover crops.

All of the growers and experts I have spoken with agree that taking a simple approach when trying cover crops minimizes the risk, cost, and management involved. Using cereal rye is one of the easiest and most cost effective ways to get started with cover crops. It emerges very well when overseeded into standing crops, or when drilled late after harvest. It will grow very well in our cool, early spring weather and will terminate easily when sprayed during appropriate weather conditions. For additional benefits a perennial brassica such as rapeseed can be added that will grow a taproot into the spring to break up compaction and scavenge additional nutrients deeper in the soil. Becks Hybrids offers a ‘Wintermix’ product that is 95% cereal rye and 5% rapeseed that is ideal for this situation. Most experts recommend not seeding radish as a cover crop in Iowa after mid-September because it will not grow enough to provide benefit before winterkilling, and it is one of the most expensive cover crop seeds. We have learned that it is critical to wait to plant corn for at least 10-14 days after terminating cereal rye to avoid the allelopathic chemicals that cereal rye can release into the soil. This does not seem to be as big of an issue with soybeans. It is best to no-till plant into the terminated rye stubble before it falls down and creates a residue mat that causes the soil to stay too wet.

If no-till planting is not an option for you, using oats or spring wheat as your cover crop will still provide some benefits. These work best when overseeded into standing crop, or immediately after soybean harvest. These crops will winterkill resulting in less residue to deal with before planting corn or soybeans. This stubble can easily be tilled in the spring using your normal tillage practices, whereas taller cereal rye can make a mess of residue piles and bunches when tilled with spring tillage equipment. Becks Hybrids, as well as other companies, offer a great supply of oats and spring wheat which are also low cost. As you get more experienced with cover crops you can add legumes such as red clover or peas that will produce added nitrogen for the following corn crop.

Cover crops have the potential to reduce the nutrients leaching from our fields and ending up in bodies of water, such as the Gulf of Mexico, by 25-50%. Because of this they are an integral part of Iowa’s voluntary Nutrient Reduction Program. Cost Share dollars are available now through the Clean Water Iowa Initiative. Growers can apply for $25/acre for first time cover crop use on a particular farm, or $15/acre for repeated cover crop use on a farm. This program is capped at 160 acres. There is also money available from many counties for cover crop cost share. The federal EQIP program may provide up to $40/acre for growers to implement cover crops, which would cover 100% of the cost of seeding and terminating most cover crops. Growers need to apply for EQIP as early as October for the following crop year. All of these programs can easily be applied for at your county NRCS office by providing some basic field location and history information.

Most experts agree that cover crops require a long term investment to maximize benefits. Some benefits such as reduced soil erosion are immediate. The average farm field in Iowa loses 5 tons of soil/acre/year. It can take up to 500 years for mother nature to create one inch of new topsoil, so the economic benefits of reducing this soil loss are huge. Benefits such as improved soil structure, increased soil microbial and earthworm populations, improved water infiltration, and nutrient cycling and release all take consecutive years of no-till and cover crop use to obtain. Some growers report yield increases after the first year of cover crop use, but many say that typically doesn’t occur until around year 3 or 4. For growers switching to a no-till system, using cover crops can allow them to realize soil benefits twice as fast as without using cover crops. Some growers have been able to reduce their commercial fertilizer use by 50% and have increased their soil organic matter by 0.25-0.50% per year.

HTS Ag is very excited about the potential economic benefits for our farms, and environmental benefits for our neighbors that cover crops offer. We will be trying several different cover crop mixes and seeding methods to learn more about how to successfully use cover crops in Iowa. There also many organizations and institutions with many years of cover crop research and field trials. Entities such as Practical Farmers of Iowa, Iowa State University Extension, Iowa Learning Farms, and the Iowa Soybean Association can offer multiple publications, field days, and grower references to learn more about cover crops. I encourage you to contact HTS Ag and/or one of these organizations to help you create a plan to implement cover crops on your farm. I am confident that like me, the more you learn about the potential benefits, the more excited you will be to give cover crops a try.

653 Oak Road
Harlan, IA 51537
1920 Philadelphia #105
Ames, IA 50010
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