Leaf and stem properties of alfalfa entries

Alfalfa (Medicago sativa L.) has been considered as a biofuel feedstock. A system has been proposed to produce electricity from the stems and utilize the leaves as a livestock feed. We determined the effects of harvest regimes on yield and quality of leaf, stem, and total herbage of six alfalfa entries. We applied three harvest regimes involving three harvests per year at bud stage or early flower, or two harvests per year at late flower. An early flower harvest regime had the highest leaf yield (average of 5.6, 4.5, and 4.5 Mg ha^-1 for the early flower, late flower, and midbud regimes, respectively), and the late flower harvest regime had the highest stem yield (average of 5.8, 5.3, and 3.9 Mg ha^-1 for the late flower, early flower, and midbud regimes, respectively). Leaf concentration decreased with increased herbage maturity (average of 540, 517, and 458 g kg^-1 for the midbud, early flower, and late flower regimes, respectively) and was associated with total herbage crude protein (CP) (r = 0.65, P < 0.05) and acid-detergent fiber (ADF) and neutral-detergent fiber (NDF) (r = -0.76, P < 0.05). Harvest regime did not affect total seasonal herbage yield or stand persistence. Alfalfa entries differed in herbage quality, leaf concentration, and leaf yield, but did not consistently differ in total herbage or stem yield. Herbage yield and quality differences among entries were similar for all harvest regimes. Producers can affect stem and leaf yields by selection of harvest regime.