Birdsfoot trefoil (Lotus corniculatus L.) is a perennial legume that produces high yields with high nutritive value forage. The plant is adapted to a wide range of environmental conditions and grows well in most parts of the United States.

This bulletin addresses some of the major factors that must be considered when establishing birdsfoot trefoil. Birdsfoot trefoil is adapted to conditions in Wyoming and performs well when grown either as a monocrop or in mixtures with compatible grasses and legumes. Although slow to establish, the plant produces high yields of high nutritive-value forage. Birdsfoot trefoil is a potential crop that can serve as an alternative to alfalfa, especially under poor acidic soil conditions and where a bloating-free forage legume is desired.

Birdsfoot trefoil contains special compounds (tannins) that make it non-bloating. Tannins also increase milk production in dairy cows fed birdsfoot trefoil. Additionally, the tannins increase protein utilization in livestock, reducing the amount of nitrogen (N) excreted by animals. This has huge environmental benefits. The plant also contains high concentrations of non-fibrous carbohydrates compared to alfalfa that is better for ruminant nutrition.

Birdsfoot trefoil can be grown in the same soils and climatic conditions required by alfalfa, nonetheless it is more tolerant to low fertility (for example, phosphorus), low pH, and poorly drained soils. It can be grown either as a monocrop or in mixtures with compatible grasses (such as meadow bromegrass) and legumes (alfalfa). Many factors should be considered

Birdsfoot Trefoil:
Establishment and Management
as Monocultures and
Mixtures in Wyoming

Albert Adjesiwor1 and Anowar Islam2

Department of Plant Sciences, University of Wyoming

1Graduate Assistant; 2Associate Professor and Forage Specialist

whether grown as a monocrop or in mixtures. For example, species selection affects yields and nutritive value as well as stand persistence and economic returns. Unlike other perennial legumes such as alfalfa and sainfoin, birdsfoot trefoil has poor seedling vigor mainly due to the smaller seed size. Special management is required at the seedling stage for successful establishment.

Site selection

Birdsfoot trefoil is adapted to a wide range of conditions and can grow on soils relatively poor and/or too acidic for alfalfa. However, productive soils must be selected where available because yields could be greatly improved under good soil conditions. The soil must be well-drained. Soils with pH between 6.0-6.5 are more suitable for good establishment. However, a wide range of pH (5.5-8.5) can also be tolerated.

Field preparation

Successful stand establishment requires a clean seedbed that is firm and well worked. Existing vegetation should be killed preferably using a burndown applica

tion of non-selective post emergence herbicide such as Roundup (glyphosate) that have little to no residual activity or planting restrictions. Soil must be settled and bigger soil clumps broken to produce a fine-tilled condition for good seed-soil contact. Tilling with a disk followed by tine cultivation or harrowing produces a good seedbed (Figure 1) for germination and emergence. Where soil moisture is not adequate, no-till drill can be helpful in conserving moisture as well as keeping weed pressure down.

Selection of varieties and compatible forage species

Birdsfoot trefoil varieties can be either prostrate, erect, or semi-erect (Table 1). Prostrate types are more suitable for grazing, and erect types are adapted to haying. Semi-erect types can be grazed or hayed; however, prostrate and erect types can be hayed or grazed depending on the goal and management. Moderate to high winter hardy varieties (Table 1) are suitable for Wyoming conditions.

Figure 2. Well-established birdsfoot trefoil (5 lbs per acre) and meadow bromegrass (10 lbs per acre) mixture at Sheridan Research and Extension Center in 2014.

Figure 3. Well-established birdsfoot trefoil (2.5 lbs per acre), alfalfa (5 lbs per acre), and meadow bromegrass (10 lbs per acre) mixture at Sheridan Research and Extension Center in 2014.

Birdsfoot trefoil can be grown in mixtures with compatible grasses such as meadow bromegrass and timothy. Fast growing grasses such as orchardgrass, smooth bromegrass, and tall fescue may also be suitable if the appropriate seeding ratio is used. Studies in Wyoming have shown a seeding rate of 10 lbs per acre is recommended for pure stands. In mixtures with less aggressive grasses such as meadow bromegrass, seeding rates of 5 lbs birdsfoot trefoil plus 10 lbs meadow bromegrass (Figure 2) or 3 lbs birdsfoot trefoil plus 14 lbs meadow bromegrass can be used. Three species mixtures of birdsfoot trefoil, alfalfa, and meadow bromegrass also performed well in Wyoming (Figure 3).

Seeding

Birdsfoot trefoil has small seeds. Seeding at a depth of 0.25 inches produces good stands and ensures faster establishment (Figure 4). August-September seeding gives seedlings a competitive advantage against weeds.

Fertilization

Birdsfoot trefoil nodulates and fixes nitrogen. Inoculating with appropriate bacteria (birdsfoot trefoil specific) is essential for nitrogen fixation if the land has not been previously planted with birdsfoot trefoil. Application of about 30 lbs nitrogen (N) per acre during establishment is beneficial in soils containing low N and less organic matter (<2 percent). Once well-established, N fertilizer application is not necessary. Moderate application of phosphorus and sulfur at planting would enhance establishment and growth. Residual soil

phosphorus and potassium of 30 and 180 lbs per acre, respectively, is adequate for average forage yields of 4,000 to 6,000 lbs per acre.

Weed management

Weed competition is one of the major problems with birdsfoot trefoil establishment. Seedlings are slow to establish and not as vigorous as alfalfa, partly due to smaller seed size. Planting a smother crop such as Siberian millet (Figure 5) or wheat during the spring of the seeding year and planting birdsfoot trefoil in the fall just after harvesting the smother crop helps reduce

Figure 4. Effects of seeding depth on emergence and yield of birdsfoot trefoil. (Source: Cornell University Agriculture Experiment Station).

weed pressure. Companion crops such as oats can be planted with birdsfoot trefoil to reduce weed pressure.

Pre-plant incorporation (2-3 inches depth) of Eptam (EPTC) or Balan (Benefin) is effective for controlling most annual grasses and broadleaf weeds. These herbicides should not be used if birdsfoot trefoil is planted in mixtures with grasses. Post emergence application of Butyrac (2,4-DB) is effective to control many annual broadleaf weeds. However, only small seedlings (3 inches tall) are controlled by this herbicide. In pure stands of birdsfoot trefoil, post emergence application of Poast Plus (Sethoxydim) is effective in controlling many annual grasses. Poast Plus can be used to kill companion crops such as oats and barley once birdsfoot trefoil is established. In both monocultures and mixtures, mowing is an effective measure in controlling annual weeds, especially when birdsfoot trefoil is small

or at seedling stage (Figures 6 and 7). In fall seeded (September) birdsfoot trefoil, mowing once in late spring (May) was effective at controlling weeds in Wyoming (Figure 7).

Irrigation

Birdsfoot trefoil does not require any special irrigation management. At the time of establishment, especially for the first two weeks after planting, light and periodic irrigation is necessary to keep the soil surface moist. This will help reduce soil crusting and improve emergence if the soils are heavier and clay textured. After establishment, any watering regime suitable for alfalfa should be sufficient for birdsfoot trefoil. However, observe plants for signs of moisture stress (wilting) and irrigate as necessary. In general, birdsfoot trefoil can grow well in areas receiving 20 inches or more of precipitation.

Figure 6. Birdsfoot trefoil monocrop (gold circle) dominated by weeds (red circle) at the initial stages of establishment at Sheridan Research and Extension Center.

Grazing and haying management

Birdsfoot trefoil regrows from buds in the leaf axils after haying or grazing. Cutting or grazing too close to the ground removes most of the buds and reduces stand life. Leaving at least a 4-inch stubble during cutting or grazing is recommended. Birdsfoot trefoil has slow spring growth, and grazing should commence when plants are at least 8 inches tall to ensure a prolonged stand life. Cutting birdsfoot trefoil twice in a year with the last cut in late August or early September is recommended. This allows enough frost-free growing days for accumulation of carbohydrates, which are essential for early spring growth and stand persistence. Birdsfoot trefoil has a large proportion of hard seeds, and stand persistence is greatly influenced by natural re-seeding. Allowing stands to grow to maturity and seed once in every three years enables reseeding and prolonged stand life.

Issued in furtherance of extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Glen Whipple, director, University of Wyoming Extension, University of Wyoming, Laramie, Wyoming 82071.

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Figure 7. Well-established birdsfoot trefoil after one-time mowing in late spring (May) to control weeds at Sheridan Research and Extension Center illustrating effectiveness of mowing to control weeds.

References

Bush, T. 2002. Plant fact sheet: Birdsfoot trefoil (Lotus corniculatus L.). USDA-NCRS Rose Lake Plant Materials Center, East Lansing, Michigan.

Hannaway, B.D., and W.S. McGuire. 1981. Growing birdsfoot trefoil for forage. Oregon State University Extension. FS 259. 2 p.

Hunt, S.R., J.W. MacAdam, and T.C. Griggs. 2016. Seeding rate, oat companion crop, and planting season effects on irrigated organic birdsfoot trefoil stands in the Mountain West United States. Crop Science. 56:463 - 473.

MacAdam, J.W., and T.C. Griggs,. 2013. Irrigated birdsfoot trefoil variety trial: Forage nutritive value. Utah State Univ. Ext. Fact Sheet AG/Forages/2013‐02pr, Logan, UT. Available online at: http://extension.usu.edu/files/ publications/publication/AG_Forages__2013-01pr.pdf.

MacAdam, J.W., J. Brummer, A. Islam, and G. Shewmaker. 2013. The benefits of tannin-containing forages. Utah State Univ. Ext. Fact Sheet AG/Forages/2013‐03pr, Logan, UT. Available online at:
http://extension.usu.edu/files/publications/publication/ AG_Forages_2013-03pr.pdf.

Schaller, F.W., W.F. Wedin, and I.T. Carlson. 1997. Birdsfoot trefoil for pasture. Iowa State University Extension. Pm-855. 4 p.

Undersander, D., L. Greub, R. Leep, P. Beuselink, J. Wedberg, D. Smith, K. Kelling, J. Doll, D. Cosgrove, C. Grau, S. Peterson, M. Wipfli, and J. English. 1993. Birdsfoot trefoil for grazing and harvested forage. North Central Extension Publication 474. 16 p.