Performance of cowpea varieties under different phosphorus levels and spacing in Tanzania

The identification of cowpea varieties that can thrive in P-limited soils and optimal spacing has not yet been addressed in Tanzania. This study evaluated the recently released three cowpea varieties for growth parameters and high yield in different P levels and spacing. Field experiments were conducted over two consecutive rainy seasons, i.e. 2023 and 2024, to assess the effects of P, plant spacing, and variety on growth and yield performance. The experiment was laid out in triplicate under RCBD. The results revealed that P did not significantly affect growth parameters. However, the variety (Vuli-AR2) exhibited a considerable increase in growth and yield performance, even at low P levels, suggesting that its genetic potential traits contribute to higher P-use efficiency. The interaction [P40 kg/ha × (0.4 × 0.2 m) × Vuli-AR2] revealed a significant increase in yield per ha in the 2023 and 2024 seasons, with an average yield of 323.06 ± 12.30 and 376.04 ± 16.15 kg/ha, respectively. Moreover, the interaction [P40kg/ha × (0.4 × 0.2 m) × Vuli-AR2] revealed significantly (p = 0.001) high pod length and seeds per pod in both seasons. The variety Vuli-AR2 demonstrated high agronomic performance under low P levels. Upscaling Vuli-AR2 will maximize cowpea production even under marginal soils.