Boron Fertilization Effects on Nutritive Parameters of Alfalfa

With early pre-plant incorporation of limestone to raise soil pH to 6.8 to 7.0, alfalfa (Medicago sativa L.) may be grown successfully on acid, Coastal Plain, sandy loam soils. Fertility and forage quality for hay and/or grazing require alternative management of alfalfa on these Coastal Plain soils. A two-year experiment evaluated alfalfa fertilized with three rates of boron to quantify effects on nutritive entities, especially fiber components. On a whole-plant basis in year 1, only crude protein was increased (P \u3c .05) at one of six harvest dates. In year 2, chemical analyses of leaf-stem components indicated consistent increases in crude protein of leaf fractions at each harvest (P \u3c .05), reduction in neutral detergent fiber at three harvest dates (P \u3c .06), and reduced lignin (P \u3c .07) at the final harvest. Stem sections were affected by rate of boron at only the June harvest with an increase in crude protein (P \u3c .05). Rate of boron fertilization had indirect effects on nutritive value (crude protein) by either delaying physiological maturity or enhancing nitrogen fixation in leaves, and had a direct negative effect on certain fiber components