Aerial seed cover crops
Cover crops can help offset feed costs for cattle, hold precious nitrogen in place and add important organic matter to soils, increasing their ability to soak up water during heavy rains. The potential uses of cover crops are many, and new momentum for this practice has increased dramatically.
Some farmers using cover crops are looking to free up time during the busy fall by contracting with aerial applicators to seed the cover crop into standing corn or soybeans. This seeding method is called overseeding.
Overseeding methods include using high-clearance equipment like a “high-boy” or a detasseling machine, aerial seeding by hiring an airplane, or broadcasting the seed at last cultivation. If you don’t cultivate and don’t have access to a high-boy, a time-efficient and cost-effective method is aerial seeding.
• Seeding a small grain or legume mix as a cover crop has several advantages.
• Late August and into mid-September are good times to plant a cover crop.
• Hiring an airplane to aerial seed the cover into standing crops is an option.
Aerial seeding is done by an airplane or helicopter. Planes fly 10 to 50 feet above the field. An airplane used for spraying pesticides can be switched over to plant cover crops in about 45 minutes. Greg Todd from Todd’s Flying Service at Ankeny says, “I just take out the pump and booms and put on the spreader under the airplane.” The cover crop planting rate is adjusted by a gate on the spreader.
Lighter seed like lawn mixes are not as successfully planted using aerial seeding as heavier seeds like small grains (rye, wheat, triticale, barley) or legumes (clovers, vetches, alfalfa).
Here are some planting rate suggestions: small grain, 1.5 to 2 bushels per acre; vetch, 20 to 30 pounds per acre; white clover, 5 to 10 pounds per acre; red clover, 10 to 15 pounds per acre.
What about organic fields?
If you are a certified-organic grower and want to fly-on a cover crop, Ray Yokiel from Wells, Minn., has certified his plane. Yokiel has mostly been using his plane to frost-seed clover and alfalfa into pastures in the spring. About seven or eight years ago, he flew on his first fall cover crop of winter rye. Yokiel, an organic farmer himself, certified his plane so it could be available for his farming system and to contract with other farmers for pasture renovation and cover crop establishment.
“Organic regulations would allow a pesticide applicator to wash out their plane and then use it for organics, but the applicator would not be able to switch back and forth between spraying chemicals and planting cover crop seed,” says Yokiel.
The same challenges exist under the plane for both conventional and organic aerial seeding. Wind and weather conditions are the biggest challenge to aerial seeding cover crops. Transmission lines and local electricity distribution lines add a little more challenge to the task. In addition, because seeding cover crops in the fall is a small part of these applicators’ regular business, other contracts like controlling aphids on both organic and conventional farms can compete for air time.
The best time to plant
To be successful, several farmers and researchers have concluded that planting must coincide with moist conditions or rainfall. Agronomist Tom Kaspar at the USDA National Laboratory for Agriculture and the Environment at Ames suggests these fall planting dates for small grains: late August for aerial seeding into standing soybeans, and mid-to-late September for aerial seeding into standing corn.
“You should seed legumes a couple weeks earlier because they are small-seeded and need more time to establish before a hard freeze,” says Kaspar.
Depending on the size and type of seed being planted, planes can carry enough seed to plant 12 to 100 acres each trip. Helicopters carry smaller loads but can land and reload closer to the planting site. A nearby grassy summit can be used as opposed to flying back to a runway.
Each plane is different, but both Todd and Yokiel emphasize the importance of using a nearby runway. “If a runway is grass versus concrete or if it is ‘short,’ that will affect how much weight the plane can hold and ultimately how many trips to and from the field during planting the pilot needs to make,” says Yokiel.
“The trips to and from the runway and the turns across the field while planting all influence the price per acre; the plane needs about a half-mile to turn around,” explains Todd.
Aerial is cost-competitive
Both applicators suggest that planting mile-long strips across the field would be ideal and would help decrease the number of turns, and therefore decrease the cost per acre.
Cost of aerial seeding is competitive with the cost of drilling or broadcasting the seed on the ground. Both aerial applicators quoted a range of $8.50 to $12 per acre. They recommend using 50-pound seed bags for hand loading at the runway.
Final price is determined by the number of total acres being planted, location to a runway, runway size and type of seed being planted. Both Yokiel and Todd and many other applicators across the state are flexible and willing to work with farmers to help increase this practice of seeding and growing a continuous living cover on the ground.
Carlson is research and policy director for Practical Farmers of Iowa.
This article published in the August, 2010 edition of WALLACES FARMER.