Part 1, Section 8: Forages
Forages
Birdsfoot trefoil
Seeding year management
Fertilization
Birdsfoot trefoil has a wider soil adaptation than alfalfa with regard to drainage, acidity, and fertility. Nevertheless, it responds well to lime applications. Determine lime and fertilizer needs by soil testing. Maintain pH between 6.0 and 7.0 for best results. Establishment applications of fertilizer should be based on a soil test. In the absence of a soil test, and assuming a medium- fertility soil, plow down 0-45-135 per acre and apply 20-60-20 per acre in the row (band place if possible).
Seeding methods
Birdsfoot trefoil or trefoil-grass mixtures may be seeded using conventional seeding equipment such as a cultipacker seeder or grain drill on a firm, well-prepared seedbed; or they may be seeded directly into corn stalk or small grain stubble using a special no-till seeder. No-till establishment requires special attention to weed and insect control, but if properly done it results in excellent stands with little or no soil losses. For specific recommendations, see No-Till Forage Seeding, below.
Plant in April to late May. Midsummer seedings on a prepared seedbed are less reliable and therefore are not recommended.
Band seeding no deeper than .25 inch is an excellent method of seeding. When band seeding or when using the no-till seeder, you may reduce recommended trefoil seeding rates by one-third. Press wheels used in conjunction with conventional band seeding provide additional stand insurance. If the seedbed is dry and press wheels are not used, cultipack before and after seeding in the same direction as band seeding, to ensure a firm seedbed. If oats are used as a companion crop, seed oats at a rate of not more than 1.5 bushels per acre and remove at heading stage for silage, hay, or greenchop. Do not apply additional nitrogen for the oats.
Fluid seeding-distributing seed in a carrier of water or fertilizer solution-is a new technique generally limited to forage legumes. Because fluid seeding requires special equipment for good seed suspension and distribution, it is recommended for custom application. Fluid seeding is a broadcast method, so for best results prepare the seedbed as in conventional seeding and cultipack after seeding.
Seeding rates necessary for successful stands are related to the condition of the seedbed and method of seeding. For suggested seeding rates, see Table 1.8-5, Forage Selection and Seeding Rates, below.
Use preinoculant seed or inoculate seed with proper inoculant. If seed is preinoculated, look for the expiration date on the tag to see if reinoculation is necessary. This may occur if seed is not used soon after purchase. Proper inoculation techniques are described in Agronomy Facts 11: Inoculation of Forage and Grain Legumes.
Cutting management
The seedling growth rate of birdsfoot trefoil is slower than that of alfalfa or red clover. However, under favorable growing conditions for seedings made without a companion crop, one harvest in the year of seeding is possible. Any cuttings made during the year of establishment should be delayed until the birdsfoot trefoil is in bloom.