Complementary Use of NPK Fertilizer and Zinc on Growth and Yield of Cocoyam in an Ultisol of Southeastern Nigeria

Abstract

A study was carried out at the research farm, National Root Crops Research Institute, Sub-station Igbariam to determine the effect of NPK fertilizer and zinc on growth and yield of cocoyam. The study was a factorial type fitted into a randomized complete block design (RCBD) replicated three times. Five levels of NPK fertilizer (15:15:15) at 0, 150, 300, 450 and 600 kg ha^-1 in combination with zinc at five levels (0, 3, 6, 9 and 12 kg ha^-1) were applied as treatments. The test crop was cocoyam Colocasia variety (Ede ofe). Results showed that growth character such as plant height was influenced by the application of NPK fertilizer rate at 600 kg ha^-1. Application of NPK fertilizer at the rate of 450 to 600 kg ha^-1 appeared adequate for maximum tuber yield of cocoyam. Application at 600kg NPK ha^-1 and 6 kg Zn ha^-1 appeared adequate for maximum cocoyam production. However, application of NPK fertilizer rate should be based on soil test response. Integrated nutrient management strategy, using low input technology could raise the low nutrient status of the soil for sustainable cocoyam production. NPK fertilizer rate should be based on soil test response to alleviate the deleterious effect of chemical fertilizer arising from high fertilizer levels. With the application of NPK fertilizer balanced fertilizer with zinc should be adopted.