Growing corn and kura clover together can cut both nitrogen costs and soil erosion, says Ken Albrecht.
“Our preliminary research shows that we're significantly reducing the amount of soil and nutrient loss compared to conventional corn production,” says Albrecht, a University of Wisconsin agronomist.
At the heart of the system, which he and his students have been researching for eight years, are fields of kura clover that function as living mulch.
At several locations, Albrecht established stands of pure kura clover, a rhizomatous legume. He selected it for its longevity.
“Once established, kura clover doesn't need coddling and will likely become a permanent part of a pasture or field,” he says. “Plus, it tolerates low fertility, moderate soil acidity and wet soils.”
A few years after seeding, when the kura was well-established, he suppressed it with herbicides and planted corn for grain or silage. He planted the corn in 30" row spacings with a no-till drill.
Because kura clover fixes nitrogen and some of it is available to the corn after suppression, he only applied 50 lbs/acre of commercial nitrogen.
“Kura replaces at least 100 lbs of nitrogen fertilizer per acre and possibly could replace all of the nitrogen required by a corn crop,” says Albrecht. “But some nitrogen in the starter fertilizer is probably a good investment.”
The kura clover suppressed weeds during the growing season, so no additional chemicals were applied. Corn grain yields ranged from 170 to 190 bu/acre and silage dry matter yields came in at 7.5-8.5 tons/acre.
“Those corn yields are comparable to yields achieved with a comparable no-till system. And the kura recovered completely by June the year after corn production.”
After the corn is harvested for grain, cattle could graze the stalks in late autumn, with the kura providing extra protein and allowing for better utilization of the low-quality stalks.
Another possibility: “After harvesting the corn for silage, you can plant winter wheat,” says Albrecht. “That, along with the kura, will give you early season grazing the following year or you can make high-quality silage out of it.
“After the winter wheat forage is harvested, you can go back in with a no-till drill and seed sorghum-sudangrass for silage or summer and fall grazing.”
Kura clover has a reputation for being difficult to establish and unproductive its first year.
“The same steps recommended for establishment of other forage legumes apply, but kura clover is less forgiving than other legumes if these steps are not carefully followed,” he cautions. “The key is to control competition from weeds or existing grasses in a pasture.”
He says kura's leafiness gives it excellent forage quality, with a low fiber content and up to 25% protein.
“Properly managed mixtures of kura clover and grasses can match alfalfa for nutritive value in dairy cow diets,” says Albrecht.
Like most legumes, kura can cause bloat, so it should be grown with grass if it will be grazed. Albrecht hasn't yet tried grass-kura mixtures as living mulches. That research is slated for the future.