Contribution of Field Pea to Winter Forage Production and Nutritive Value in the South-Central United States

Field pea [Pisum sativum L. subsp. sativum var. arvense (L.) Poir] appears to hold promise as a cool-season legume option for the south-central United States. A 2-yr field study at two locations in Louisiana was conducted to evaluate forage dry matter (DM) production and nutritive value of an oat (Avena sativa L.)- field pea combination and an annual ryegrass (Lolium multiflorum L.)-field pea combination at different field pea seeding rates. Monocultures of the grasses at a range of N fertilizer rates were included for comparison. Increasing seeding rates of field pea increased forage DM production linearly (P < 0.05) and linearly (P < 0.01) increased crude protein from forage of interseeded plantings. Interseeding field pea did not improve in vitro true digestibility of oat-field pea or annual ryegrass-field pea forage at either harvest, even though the annual grasses maintained a similar high digestibility to field pea only at the first harvest. Nitrogen fertilizer, which produced a linear increase in forage production with increasing N rate, provides more flexibility and easier management than the use of legumes. Cost of N will determine when the use of legumes such as field pea is a preferred option. The improved forage nutritive value of interseeded field pea can be a meaningful benefit with specific classes of livestock and production goals.