Complementary Effects of Rice husk and Nitrogen Fertilizer on the Growth, Yield and Nutrient Uptake of Cocoyam (Colocasia esculenta (L.) Schott)

Cocoyam is one of the staples in the South east and South south zone of Nigeria. There is decline in cocoyam production in these areas because of inherent low fertility level of the soil occasioned by intensive agriculture with little or no fertilizer input. This work investigated the complementary effects of rice husk and nitrogen (N) fertilizer on the growth, yield and nutrient uptake (nitrogen, phosphorus, potassium) of cocoyam (Colocasia esculenta (L.) Schott) var. cocoindia. The treatments comprised two levels of application of rice husk (0 and 15 t/ha) and three levels of nitrogen (0, 50 and 100 KgN/ha) which were factored and fitted into a randomized complete block design replicated thrice. Analysis of variance (ANOVA) was employed in data analyses and LSD was used to partition significant means at P0.05. Rice husk application increased significantly growth, yield and P and K uptakes of cocoyam compared to the control. Nitrogen fertilization had no significant effect on cocoyam yield. However, 100 kgN/ha significantly increased leaf area index, number of suckers and nitrogen uptake over the control. Increasing nitrogen fertilizer above 50 kgN/ha decreased significantly P and K uptakes. Significantly higher yield (13.11 t/ha) was obtained with combined application of 15 t/ha rice husk plus 100 kgN/ha compared to when either rice husk (10.53 t/ha) or nitrogen fertilizer (8.82 t/ha) was applied alone or the control (6.57 t/ha). This rate, 15 t/ha rice husk + 100 kgN/ha, is therefore recommended for improved cocoyam production to enhance food security in Nigeria