Cutting management of birdsfoot trefoil is different from that of alfalfa because energy reserves of trefoil remain relatively low during the growing season regardless of the number of harvests. Therefore, a cutting height of not less than 3 inches is recommended so that enough leaves remain on the plant to provide energy for regrowth.
Harvesting BFT During the Establishment Year
Birdsfoot trefoil seedling growth is slower than that of either alfalfa or red clover. In addition, trefoil is not competitive during stand establishment. Harvests in the first year should be delayed until the trefoil is in full bloom. For seedings made without a companion crop, one harvest can usually be made during the seeding year.
Harvesting Established BFT Stands
Since birdsfoot trefoil has relatively low energy reserves during the growing season, it is important not to harvest until trefoil has begun to bloom. The first cutting can be made at early bloom, and later cuttings should be delayed until at least mid-bloom (about six-week intervals). In the fall, four to five weeks of growth should be allowed before the first average killing frost date. To ensure a thick stand, trefoil can be allowed to reseed itself every two or three years by accumulating growth during the spring until seed set. The forage quality of trefoil at this stage of maturity is still adequate for classes of livestock that have moderate to low nutrient requirements.
Legume-Grass Mixture Harvest Management To optimize forage yield and quality, cutting management of a legume-grass mixture should be based on the harvest schedule of the legume. However, the planned legume cutting management influences what grass species should be grown with the legume. If the legume crop is under intense cutting (four or more cuttings per year), species such as orchardgrass, perennial ryegrass, and reed canarygrass are compatible because they are tolerant of frequent cutting. A less intensive system (three cuttings per year or fewer) is compatible with timothy or smooth bromegrass, which require longer intervals between cuttings and are generally do not tolerate early spring harvest.