Growth and Yield Responses of Cocoyam (Colocasia esculenta (L.) Schott) to Organic Wastes in the Humid Agro-Ecological Zone of South-Eastern Nigeria

Aim: To evaluate the growth and yield responses of cocoyam to different rates of application of cow dung and rice husk.

Study Design: 2 x 4 factorial arrangement in a randomized complete block design replicated three times.

Place and Duration of Study: The experiment was conducted in National Horticultural Research Institute (NIHORT), Mbato sub Station, Okigwe, Imo State, Nigeria in 2012 and 2013 cropping seasons.

Methodology: The treatments comprised of two manure sources (cow dung and rice husk) at four levels (0, 10, 20 and 30 t/ha) each. The treatments were assigned randomly to the plots and incorporated into the soil two weeks before planting. Data were collected on plant height, number of leaves, leaf area, leaf area index, number of suckers, number of corms, corm weight and corm yield. The data collected were subjected to ANOVA at 5% probability level.

Results: Cocoyam growth and yield increased significantly (P = 0.05) with increased application of cow dung up to 20 t/ha when the soil had 0.03% N and 0.65% OM in 2012, but not beyond the rate of 10 t/ha in 2013 when the soil had 0.06% N and 1.22% OM. Average of the two years of cropping gave optimum yield of 18.0 t/ha at 20 t/ha cow dung rate. This rate increased yield by 58% over the control. Rice husk applied at 30 t/ha significantly (P = 0.05) increased cocoyam growth compared to the other rates while cocoyam yield was not significantly increased above the rate of 20 t/ha rice husk in 2013. 20 t/ha rice husk recorded yield of 17 t/ha, which was higher than the control by 19%, on the average.

Conclusion: Results of this investigation showed that cow dung and rice husk are potential organic soil amendments for increasing cocoyam production. It is therefore reasonable to recommend the use of 10-20 t/ha cow dung and 20 t/ha rice husk in the cultivation of cocoyam in humid agro-ecological zone of South-eastern Nigeria.