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ARLINGTON, Wis. - Warning: Your neighbors might think you're crazy if you try this. Plant corn one day, and the next day interseed alfalfa.
The idea might sound odd, but that's just what researchers from the University of Wisconsin-Madison and the USDA Forage Research Center have been doing. Mark Renz, a UW agronomist, talked about planting alfalfa into corn that's intended for silage at a recent agronomy/soils field day at the Arlington Agricultural Research Station, Arlington, Wis.
If there's a benefit to this interseeding, it's the head start alfalfa can get on its production the following year, Renz said. One big problem, though, is the competition between the corn and alfalfa for nutrients, sunlight and water. That competition often favors the corn, leaving the alfalfa stand to fail.
On the other hand, advancements in crop production technology have made this kind of interseeding more likely to succeed. Planting Roundup Ready corn and Roundup Ready alfalfa means weed control is simplified, Renz said. Clearfield corn and Pursuit is another combination being tried. And, the use of growth regulators can keep the corn in check so the alfalfa has a better chance of holding its own in the competition contest.
"Initial tests with growth regulators identified Apogee as a useful product for increasing alfalfa stand survival and subsequent yields," Renz said. "Current research is evaluating the effect of corn populations, alfalfa seeding rates, and various rates of single-versus-split Apogee applications on yields of corn silage and alfalfa following corn."
A trio of researchers is comparing corn populations of 25,000 and 35,000 plants per acre. Two alfalfa seeding rates are being examined - eight pounds and 16 pounds per acre.
As a control corn was planted alone for three years. The three-year, corn silage dry matter average at Prairie du Sac, Wis., home of the USDA Dairy Forage Research Center, was 11.1 tons per acre, with a range of 10.1 to 12.3 tons per acre.
Corn that had Apogee applied at 52 ounces per acre yielded 10.7 tons per acre. That was in 2011, the only year with data.
Corn with alfalfa interseeded generally yielded less than corn planted alone. The three-year average across 2009 to 2011 was 9.6 tons per acre, with a range of 8.5 to 10.7 tons.
Meanwhile, corn interseeded with alfalfa and Apogee applied averaged 9.8 tons of dry matter per acre. The range was 8.3 to 11.4 tons per acre.
Renz explained that the corn was planted in early May, with the alfalfa planted the next day. Researchers used a no-till drill and plugged the holes that corresponded to where the corn had been planted.
How did the alfalfa do? During the establishment year - without interseeding - it averaged 1.2 tons per acre, from one cutting. Actual yields were 2.6 tons and one ton. Data for 2011 was not supplied.
During the second year, alfalfa interseeded with corn averaged 2.7 tons per acre. In 2010, the yield was five tons, and 3.3 tons in 2012. But in 2011, the stand died.
Renz also offered numbers on one-year-old alfalfa interseeded with corn and the corn sprayed with Apogee, the growth regulator. Here, the three-year alfalfa yield average came in at 3.1 tons per acre. The high yields was 5.5 tons, with a low of 3.9 tons. Again, the alfalfa stand was dead in 2011.
The agronomist offered these initial conclusions from the research. Renz said, "Alfalfa can be established when it's interseeded with corn (for) silage. That was successful three out of four years. Apogee provided up to a 0.6-ton dry matter yield advantage."
Using the growth regulator on the corn also resulted in up to 10 more alfalfa plants per square foot.
"Many factors, control alfalfa establishment success. It appears to be related to the canopy closure of the corn," Renz said.
Planting density, weed populations and the weather are all contributing factors to the success or failure of interseeding alfalfa into corn, he added.
"While Apogee is not registered for use in corn," Renz said. "The results suggest that this product could be a viable option to improve the establishment of alfalfa."
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