Agro-Morphological Traits And Root Yield Of An Improved Cassava (Manihot Esculenta Crantz) Variety Under Nutrient-Applied Conditions In Offinso Municipality Of Ghana

Field studies were undertaken at Offinso in the Ashanti Region of Ghana during the 2015/2016 growing season to evaluate growth, root and dry matter yields of an improved cassava variety (Bankyehemaa) treated with poultry manure (PM), NPK 15-15-15 and NPK 23-10-10 fertilizers. The treatment structure was a 3 x 4 factorial, laid out in a Randomized Complete Block Design with three replications. Three levels of fertilizer (600 kg/ha NPK 15-15-15, 600 kg/ha NPK 23-10-10 and 2 t/ha PM) were applied at 6, 8, 10 and 12 weeks after planting. The parameters measured included plant height, fresh and dry shoot weights, number of stems per plant, stem girth, fresh and dry root yields and total dry matter yield. The data collected were subjected to analysis of variance using the Genstat Statistical package. Main effects of fertilizer type and time of fertilizer application on most of the parameters measured were not significant. However, the interaction effects of the two factors were significant in all the parameters measured. Vegetative growth of Bankyehemaa increased when mineral fertilizers were applied earlier than 12 weeks after planting. The highest fresh and dry shoot weights and the biggest stems were produced when NPK 15-15-15 fertilizer was applied at 6 weeks after planting. Plants treated with NPK 15-15-15 fertilizer at 10 weeks after planting were the tallest, while those treated with NPK 23-10-10 fertilizer at 8 weeks after planting produced the highest number of stems per plant. Application of poultry manure at 6 weeks after planting produced the highest fresh cassava root yield of 28.10 t/ha. The highest dry matter yield of 19.80 t/ha was obtained when poultry manure was applied at 12 weeks after planting.