Agronomic performance and profitability of maize and cowpea intercropping as affected by increased rows of cowpea in Ethiopia

This study assessed the effects of row arrangement and cropping systems on maize (Zea mays L.) agronomy and profitability in a maize–cowpea (Vigna unguiculata L.) intercropping system under field conditions in Ethiopia. A factorial combination of two cowpea varieties, TVU and White Wonder Trailing (WWT), a three-row arrangement (1 maize [M]: 1 cowpea [C], 1 M: 2C, and 1 M: 3C), and three cropping systems (sole maize, maize+WWT, and maize+TVU) were evaluated using a randomized complete block design with three replications. The results revealed that row arrangement significantly (p < 0.05) affected seeds cob⁻¹ and harvest index, with the TVU variety yielding the highest values. The 1 M: 2C arrangement with the TVU variety produced the highest harvest index value, grain, and biological yields. Overall, the traits assessed were more evident in solo cropping than in intercropping. The land equivalent ratio (LER) and area time equivalent ratio (ATER) for intercropping surpassed critical thresholds in all cases. The TVU variety achieved the highest LER and ATER in the 1 M: 2C arrangement. Additionally, the 1 M: 2C+TVU combination yielded a monetary advantage index score of $2017.35 ha⁻¹, a net benefit of $3614.22 ha⁻¹, and an acceptable marginal rate of return. Therefore, it is recommended that the TVU variety be grown in a 1 M: 2C arrangement for the study areas and similar agroecological conditions.