Effect of Spacing on the Yield and Yield Attributing Parameters of Cowpea (Vigna unguiculata L. Walp)

Abstract

Introduction: Cowpea (Vigna unguiculata L.Walp) is a vital legume crop in semi-arid regions due to its adaptability to low soil fertility and limited water availability. Despite its considerable potential, cowpea yields in sub-Saharan Africa remain substantially low, which is partially attributed to the implementation of suboptimal agronomic practices. Aim: This study aimed to evaluate the effects of inter- and intra-row spacing regimes on the growth and yield of two cowpea varieties- Padi-tuya and Songotra- at the University for Development Studies, Nyankpala Campus.  Methodology: A factorial experiment was implemented utilising three distinct planting distances (60cm x 20cm, 75cm x 25cm and 90cm x 30cm) arranged in a randomised complete block design with three replications. Growth, phenological and yield parameters were measured and subjected to Analysis of Variance (ANOVA). Results and Discussion: The results indicated that the applied planting distance had no significant effects on the majority of the measured growth and yield parameters. However, variety was found to significantly influence critical traits including plant height, dry matter weight and number of pods per plant. Padi-tuya demonstrated superior plant height and greater dry matter accumulation, while Songotra produced a significantly higher number of pods per plant. Phenological traits such as days to 50% flowering and maturity were not significantly affected by either spacing or variety. Conclusion: The findings collectively suggest that while planting spacing may not critically impact cowpea performance, varietal selection is paramount for optimising growth and maximising overall yield potential. Further research is recommended by focusing on cowpea varieties with diverse growth habits to comprehensively validate these results across broader agricultural systems.