Pearl Millet-Cowpea Forage Mixture Planting Arrangement Influences Mixture Yield and Nutritive Value in Semiarid Regions

Abstract

Pearl millet (Pennisetum glaucum (L.) R. Br.) and cowpea (Vigna unguiculata L. Walp.) are well-adapted to semiarid regions. A two-year study at New Mexico State University’s Rex E. Kirksey Agricultural Science Center at Tucumcari, NM, USA, compared monoculture pearl millet and cowpea with their mixtures in various row arrangements in four randomized complete blocks each year. Treatments included monoculture pearl millet (millet) and cowpea (cowpea), pearl millet and cowpea mixture planted in the same row (millet–cowpea), the species planted in alternate rows (millet–cowpea 1:1), the species planted in two adjacent rows alternating between species (millet–cowpea 2:2), and the species planted in four adjacent rows alternating between species (millet–cowpea 4:4), Mixture neutral detergent fiber (NDF) was reduced i millet–cowpea 1:1 and millet–cowpea 2:2 compared to millet (673, 662, 644, 646, and 666 g NDF kg−1 for millet, millet–cowpea, millet–cowpea 1:1, millet–cowpea 2:2, and millet–cowpea 4:4, respectively, LSD = 18, p ≤ 0.05). Crude protein tended to be increased in millet–cowpea 2:2. Based on these results two rows of cowpea alternated with two rows of pearl millet, all spaced at 15 cm and harvesting for hay at the pearl millet boot stage likely optimizes the compromise of DM yield and the nutritive value of the mixture.