Evaluating Forage Sorghum-Cowpea and Pearl Millet-Cowpea Production and Quality in the Texas High Plains

Abstract

Despite declining water availability in the semi-arid southern High Plains, demand for high-quality forages by the livestock and dairy industries continues to grow. Alternative forage crops with high water use efficiencies should be explored to meet this demand. Grass-legume intercrops may improve the nutritive value of the forage product, but viable intercrops must maintain yield levels. The purpose of this study was to evaluate forage sorghum [Sorghum bicolor (L.) Moench]-cowpea [Vigna unguiculate (L.) Walp] and pearl millet [Pennisetum glaucum (L.) Leeke]-cowpea intercrops for forage production and quality. Four planting arrangements per grass species were included in the 2020 and 2021 growing seasons to evaluate forage production of sorghum-cowpea and pearl millet-cowpea intercrops under limited irrigation. Treatments were sole pearl millet, sole forage sorghum, sole cowpea, or mixtures of either pearl millet-cowpea or forage sorghum-cowpea planted in the same row, alternating rows (millet-cowpea 1:1 or sorghum-cowpea 1:1), or two rows alternating (millet-cowpea 2:2 or sorghum-cowpea 2:2). Intercrop biomass yields ranged from 11.6 to 16.2 Mg ha-1 in 2020 and from 7.2 to 12.4 Mg ha-1 in 2021. Results from both study years indicate that the studied intercrops are able to maintain yield, quality, and WUE levels similar to sole pearl millet and forage sorghum.