Combined and Sole Application of Compost and Npk Effect on Okra Yield, Soil and Nutrient Content

An on-farm experiment was conducted at Uyinmwendin, Edo State, Nigeria in 2009 and 2010 to study immediate and residual effect of compost alone or combined with NPK fertilizer (NPK) on okra (Abelmoschus esculentus) and nutrient availability. Five treatments applied to okra on ultisol of Benin formation were a control, compost (CM) at 20 and 40 t ha-1, NPK 200 kg ha-1, 20 t ha-1 CM + NPK 100 kg ha-1 (CM + NPK). The test soil was slightly acidic, low in organic carbon, nitrogen and calcium. The CM, NPK and CM + NPK (at half rates) increased soil N, P, K, Ca and Mg on immediate and residual basis. The CM, NPK and CM + NPK also increased N, P and K uptake significantly. The control and NPK respectively had least values. Relative to control, 20 t ha-1 CM, 40 t ha-1 CM, NPK, 20 t ha-1, CM + NPK 100 kg ha-1 increased pod count by 12, 41, 29 and 33 %. Yields given by 40 t ha-1CM and CM + NPK were similar. The treatment (CM + NPK) is recommended.