Effect of Shade and Level of Fertiliser Application on Nutrient uptake and Dry Matter Partitioning in Cocoyam (Xanthosoma saggitifolium L.)

The effect of shade and fertilizer on nutrient uptake and dry matter partitioning in cocoyam were evaluated by growing the plant under different levels of shade and fertilizer application levels at Forest and Horticultural Crops Research Centre, Kade within a period of nine months. The shade levels used were 80%, 70%, 50% and full sunlight exposure. The fertilizer rates used were 112 kg/ha and 120 kg/ha nitrogen, phosphorus and potassium (NPK) (15-15-15) of mineral fertilizer, organic fertilizer at 112 kg/ha N, P and K and no fertilizer as control. The split-plot design was used with shade levels as the main plot factor and fertilizer levels as the sub plot factor. The interaction effect of shade and fertilizer had significant effect (p ≤ 0.05) on dry matter of cocoyam leaves, petioles, corm and cormels as well as nutrient accumulation in plant parts. Cocoyam leaves of plants grown under 50%–70% shade stored significantly higher (p ≤ 0.05) quantities of nutrients (1.51ppm of N, 6.61ppm of P and 53.10ppm of K); and accumulated more dry matter (71.30 g) than leaves of plants grown under full sunlight exposure which accumulated 1.37ppm of N, 4.31ppm of P and 26.06ppm of K and 30.7 g dry matter, at the two rates of the chemical fertilizer application. Under full sunlight exposure, significantly higher amounts of dry matter were accumulated in the corms and cormels at mineral fertilizer level of 112 Kg/ha. At mineral fertilizer rate of 120 Kg/ha, nutrients accumulation were significantly higher (p ≤ 0.05) in the corm and cormels (1.72ppm of N and 7.72ppm of P) of plants grown under full sunlight exposure than those grown under 70% shade level (0.6ppm of N and 2.94ppm of P). Nitrogen and Phosphorus accumulation were significant in the petioles of plants grown under the 70% shade at fertilizer rate of 120 Kg/ha. It is recommended that cocoyam should be grown under 50%–70% shade at fertilizer rate of 112–120 Kg/ha for leaf production and under full sunlight exposure at 112 Kg/ha (NPK) for cormel production.