Michigan forage producers would benefit from a perennial forage crop that maintained yield and forage quality later into the growing season than conventional alfalfa (Medicago sativa spp. sativa L.). Yellow-blossom alfalfa (M. sativa ssp. falcata Arcangeli.) is a perennial legume with indeterminate vegetative growth characteristics that has not been evaluated for forage dry matter yield (DMY) in Michigan. The objectives of this study were to: i) evaluate forage DMY, quality (crude protein [CP], acid detergent fiber [ADF] and neutral detergent fiber [NDF]), and stand persistence of cv. `SD201', falcata, under three, two, and one harvest per year compared to sativa (cv. WL346LH) and birdsfoot trefoil (Lotus corniculatus L.)(BFT)(cv. Norcen); ii) determine if differing levels of taproot starch, sugar, protein, and amino N reserves are the cause for slower post-harvest regrowth of falcata compared to sativa; and iii) evaluate forage DMY, quality, and pest resistance of falcata, sativa, varia cultivars and birdsfoot trefoil under a two-harvest per year schedule. The falcata cv. SD201 produced greater DMY in the seeding and first production year in two harvests per year than the sativa cv. WL346LH or the BFT cv. Norcen under three, two or one harvest per year. The CP concentration in forage biomass of falcata harvested twice per year was lower and ADF and NDF concentration was greater than WL346LH or BFT harvested three times per year. Crude protein, ADF and NDF of falcata were similar to WL346LH and lower than that of BFT within a harvest frequency. Crude protein and total digestible nutrient yield was greater for falcata harvested twice than sativa harvested three times. Harvest frequency had no effect on stand density, and falcata persisted at plant densities similar to that of sativa and greater than that of BFT.Taproot sugar concentration was similar between species but differed between years due to moisture availability. Greater taproot amino N, protein, and starch concentrations were found in WL346LH compared to falcata when defoliated in mid to late-June and for 30 days thereafter. Lower concentrations of all three components may explain the slow regrowth of falcata following defoliation. Forage DMY and pest interaction characteristics of SD201 are unique from currently marketed M. sativa, falcata, and varia cultivars. Greater DMY should be expected from SD201 than select M. sativa, falcata, and varia cultivars when one or two harvests are taken per year and the first harvest is after 600 growing degree days (GDD) base 5 °C in the first production year. Visual evidence of less alfalfa weevil [Hypera postica (Gyllenhal)] and potato leafhopper [Empoasca fabae (Harris)] damage of SD201 foliage than M. sativa and varia may suggest resistance or non-preference for falcata. M. sativa spp. falcata, like SD201, shows promise as a summer stockpiled forage crop which would allow greater harvest timing flexibility for forage producers who utilize fair to low quality hay. Additional benefits if falcata grown for forage may include: a reduction in insecticide requirements, prolonged cover for nesting birds, and reduced soil compaction from fewer passes across the field per year.
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