Optimizing Groundnut (Arachis hypogaea L.) Growth and Yield in the Transitional Zone of Ghana: The Role of Planting Date and Plant Density

Abstract

Two field experiments were conducted at the multipurpose crop nursery field of the Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development, Mampong, Ashanti in 2022 and 2023 cropping seasons to evaluate the performance of groundnut under different planting dates and plant densities. The experiment was laid out in a split–split plot design with three replications, with variety as the main plot factor (Yenyawoso and Nkosour), sowing date as the sub-plot factor (mid-May, late May, and early June), and plant density as the sub-sub plot factor (low: 16 plants m-2 = 50 × 25 cm, medium: 20 plants m-2 = 50 × 20 cm, and high: 40 plants m-2 = 50 × 10 cm). The results showed that Yenyawoso produced taller plants (11-25 cm) with more branches (9-12), whereas Nkosour consistently achieved higher seed yield in both years with the highest yield (2800 kg/ha) in 2023. Yenyawoso produced significantly (P<0.05) higher haulm weight, pod yield, and shelling percentage than Nkosour in 2023. High plant density (50 x 10 cm) resulted in increased plant height and branching, and improved haulm weight, pod yield, and seed yield compared with low and medium densities in both years. Mid-May sowing enhanced pod number, pod yield, and seed yield relative to late May and early June in both years. Variety x planting date x plant density interactions significantly influenced seed yield in both years. The Nkosour × mid-May × high-density combination produced the highest yields of 2755.6 kg/ha in 2022 and 2800 kg/ha in 2023. The lowest yields in both years were observed when the varieties were planted in late May at low density, with Yenyawoso × late May × low density combinations producing the least yield. Farmers are encouraged to grow Yenyawoso and Nkosour groundnut varieties at higher densities (50 x 10 cm) in mid-May for effective vegetative growth and higher seed yield.