Assessing the Effect of NPK Fertilizer on the Growth and Yield of Nsukka Landrace Okra (Abelmoschus esculentus (L.) Moench)

Abstract

Okra (Abelmoschus esculentus (L.) Moench) is an important fruit vegetable in tropical Africa, but its productivity may be constrained by inadequate soil fertility and inappropriate fertiliser rates. This study evaluated the effects of four NPK 15:15:15 rates on the growth and yield of the Nsukka landrace. A field experiment was conducted at the Teaching and Research Farm, Department of Crop Science, University of Nigeria, Nsukka, using a randomised complete block design with four replications. Treatments comprised 0, 150, 300, and 450 kg ha⁻¹ NPK 15:15:15. Data were collected at two-week intervals on plant height, number of leaves, stem girth, flowering, fruiting, fruit dimensions, number of fruits per plant, fruit weight per plant, and total fruit yield. The 450 kg ha⁻¹ rate produced the greatest plant height and stem girth at most assessment periods, whereas 300 kg ha⁻¹ produced the highest number of leaves at 6 weeks after planting. The 300 kg ha⁻¹ treatment also resulted in the shortest time to flowering and fruiting and produced the highest fruit length, number of fruits per plant, fruit weight per plant, and total fruit yield. Total yield reached 6.55 t ha⁻¹ at 300 kg ha⁻¹, compared with 5.29 t ha⁻¹ at 450 kg ha⁻¹ and 2.30 t ha⁻¹ in the control. Under the conditions of this study, 300 kg ha⁻¹ NPK 15:15:15 provided the most favourable overall yield response for Nsukka landrace okra.