Effect of Different NPK Doses for Growth Response of Cassava Varieties in Rivers State, Nigeria

The present study was designed to evaluate the effect of two NPK fertilizers on the growth response of three cassava varieties. The most of cassava varieties can tolerate marginal soils thereby playing a vital role in food security in Africa as a major staple food. Nigerian farmers in cassava-growing regions plant it as either a main or supplementary crop, and use bush fallowing and crop rotation to keep the soil healthy. Study on the growth response of three cassava varieties (TME 419, TMS 95/0289, TMS 96/0523) using two levels NPK fertilizers (NPK 20-10-10, NPK 15-15-15kg/ha) was carried out at the Rivers State University Teaching and Research Farm, Port Harcourt, Nigeria. The study was designed using Randomized Complete Block Design and replicated thrice. Parameters measured were number of stands, number of stems, stem weight, fresh leaves weight, dry leaves weight and stalk weight. Result showed that cassava variety TMS 96/0523 interacting with NPK fertilizer level 15-15- 15 kg/ha produced the highest number of stems while TME 419 interacting with NPK 20-10-10 produced the least number of stems at harvest. Cassava variety TMS 95/0289 interacting with NPK 15-15-15 produced the highest stem weight (57.3) and stalk weight (27.0) while TME 419 interacting with NPK 15-15-15 had the highest mean value in fresh/dry leaves weight respectively. The monocropping of cassava leads to rapid depletion of major plant nutrients especially N and K and will require fertilizer supplement to give economic yield. In varietal differences, TME 419 was higher (P<0.05) in number of stands and fresh/dry leaves weight, TMS 95/0289 produced the heaviest stalk weight and stem weight while TMS 96/0523 was higher in number of stems. NPK 15-15-15 was highest in number of stems, stem weight, number of stands, fresh/dry weight and NPK 20-10-10 was high in stalk weight. Thus, NPK 15-15-15 fertilizer is highly recommendable as it improved stem number, stem weight, fresh leaves weight and dry leaves weight of the studied varieties.