Looking for a legume to beef up forage quality on grass pasture? Birdsfoot trefoil, a non-bloating perennial, offers that opportunity.
What's more, birdsfoot trefoil holds its leaves at maturity, thus retaining its forage quality and offering a longer period of time to hay or graze it, says Colorado State University forage specialist Joe Brummer.
Suited for grazing or haying, interseeding birdsfoot trefoil into existing grass stands can improve crude protein content. Brummer says stands with birdsfoot trefoil average 10.5% crude protein content compared to 7.5% in pastures without trefoil.
In addition, because the protein in birdsfoot trefoil is less readily broken down by microbes in the rumen (a bypass protein), its protein is utilized more effectively by ruminants than is the protein in alfalfa or red clover.
Although not as productive as alfalfa, interseeding birdsfoot trefoil into grass stands can also boost yields. Brummer reports increasing total hay yield an average of 1,000 lbs./acre by adding trefoil to existing mountain meadow vegetation.
A benefit over alfalfa is that birdsfoot trefoil does well on lower fertility soils, especially those low in phosphorus. Trefoil also tolerates wetter sites compared to alfalfa and can even withstand short periods of flooding.
As a rule of thumb, Brummer says birdsfoot trefoil fits well between where alfalfa and clovers can grow. He says alfalfa likes drier sites, clovers can grow on wetter sites and trefoil fits sites in between.
Rhizomatous Variety A native of Europe and Asia, birdsfoot trefoil performs well in areas with sufficient precipitation and cool weather. This includes the eastern edges of the Dakotas, Minnesota, Iowa, Nebraska, Kansas, Missouri, Illinois, Kentucky, Indiana, Ohio and Virginia. Pockets of trefoil can also be found in the Nebraska Sandhills and mountain meadows of Colorado and Utah.
Birdsfoot trefoil, however, has only moderate drought and heat tolerance. "Above 40 degrees north latitude is better trefoil country," says USDA plant breeder Paul Beuselinck.
He says in areas south of 40 degrees north latitude the conditions are harsher (i.e., hotter, more humid, and have a shorter day length, but a longer growing season.)
"An extended growing season means more days of stress on the trefoil," says Beuselinck.
For example, while it's not as cold in the south, there also isn't snow cover to insulate plants, he explains. And since temperatures vary from cold to warm throughout the winter, plants want to break dormancy and start growing earlier, thus being susceptible to damage from freezing weather and early grazing.
Summers in the south are also hotter, which combined with moisture can provide conditions that favor diseases that can injure or kill trefoil.
Given those conditions, Beuselinck developed a rhizomatous variety of birdsfoot trefoil called Steadfast, which should be commercially available in 2000.
Beuselinck says the development of a birdsfoot trefoil cultivar with rhizomes should increase the persistence of trefoil stands in southern climates.
"A long fall, like southern areas receive, favors rhizome production and the growth of the plant can stay on track," says Beuselinck.
So what variety should you choose?
For producers in southern areas who have a hard time keeping trefoil stands, Beuselinck says, go for the rhizomatous variety.
In areas that can support seed production, Beuselinck suggests any good birdsfoot trefoil variety. One very good non-rhizomatous variety for the Midwest is Norcen, he says.
"Norcen should do a good job of reseeding from the Iowa border ( about 40 degrees north latitude) north," Beuselinck says.
On mountain meadows, Norcen has also found favor with Brummer, but he also recommends Leo, a Canadian variety, for high elevations. He adds, "If you don't use the right variety for your area, you're going to be disappointed."
And, no matter the variety, Beuselinck advises producers to always buy certified seed so there is no question of the purity.
Seeding Specifications Birdsfoot trefoil's downfall is its poor seedling vigor, which makes stand establishment difficult.
"It has a small seed and producers can have a hard time getting it established," says Beuselinck.
Brummer adds, "It is hard to establish, but once it's established, it competes well and is often longer lived than alfalfa."
Birdsfoot trefoil works well in grass mixes of bromegrass, fescue or orchardgrass, says Beuselinck. When establishing stands he makes the following recommendations:
--- Seeding birdsfoot trefoil into a new stand is usually not a problem, except for weeds, he says. "Competition on a new seedling can be detrimental. It doesn't like to be crowded," he says.
--- When interseeding into an existing stand like tall fescue, Beuselinck suggests grazing the grass hard into spring, and then broadcast seeding the trefoil before spring greenup.
--- If the stand is short, use a harrow to break up the sod and expose some soil before seeding.
--- Another option is a spring burn to eliminate grass residue. This provides a good environment to then broadcast or drill the seed into, Beuselinck says.
--- On mountain meadows, Brummer says birdsfoot trefoil establishes best in grass stands that are sparse. "It doesn't like a lot of competition," he says. He suggests using Roundup herbicide to burn down existing grasses and then interseeding birdsfoot trefoil in the spring.
--- Seeding rates for birdsfoot trefoil are typically 5-10 lbs./acre. The rhizomatous variety will be similar.
--- Another tip: use innoculated seed, says Brummer, to help offset some of trefoil's poor seedling vigor.
During the first year of establishment, Beuselinck warns that birdsfoot trefoil will have to compete with tall aggressive grasses. To hold the grasses back, he suggests not putting nitrogen on the stand that first year. "Producers need to understand they are seeding a legume that will put nitrogen into the soil for them," he says.
Once established, birdsfoot trefoil is ready for grazing in the Midwest in mid-to-late April through October, says Beuselinck. He suggests using it in a rotational grazing or intensive grazing system.
On mountain meadows, Brummer reports most producers hay birdsfoot stands mid-summer and fall-graze the regrowth. This haying/grazing rotation works well with the mountain meadows' short growing season, says Brummer.
Following establishment, birdsfoot trefoil must be managed for reseeding, says Beuselinck. "Emphasis should be placed on delaying grazing or stockpiling a paddock every few years to allow for some reseeding. It takes about 60 days for the seed crop to mature."
Peterson Seed of Savage, MN, will be offering the rhizomatous Steadfast variety in 2000. For more information contact them at 800/328-5898.