EFFECT OF ORGANIC AND SYNTHETIC FERTILIZERS ON THE GROWTH OF COWPEA (VIGNA UNGUICULATA L.).

ABSTRACT The study investigated the effect of planting density on the growth and yield performance of cowpea (Vigna unguiculata) over an eight-week period. The experiment consisted of four treatments representing different seed densities, and data were collected on plant height, stem diameter, leaf area, dry biomass, and grain yield. A randomized experimental design was used, and all data were subjected to statistical analysis using Fisher’s LSD at p < 0.05 to determine treatment differences. The results showed that planting density had a significant influence on vegetative growth parameters. Higher densities, particularly T3 and T4, produced taller plants, larger leaf areas, and thicker stems at several growth stages due to increased competition for light, which stimulated vertical and canopy expansion. However, despite these improvements in vegetative traits, planting density did not significantly affect dry biomass or grain yield, indicating that enhanced vegetative growth did not translate into increased reproductive output. The findings suggest that excessively high densities may induce competition stress, limiting assimilate allocation to yield components. The study concludes that while higher planting densities improve vegetative development, they do not offer a yield advantage, and therefore, an optimum rather than maximal planting density is recommended for efficient cowpea production. Further research is suggested to explore density interactions with nutrient and water management for improved productivity.