Increase in growth and yield of cassava is attributable to release of nutrients such as N, P, K, Zn, Fe, Ca and Mg which are contained in poultry manure (Table 2). These nutrients were available for crop uptake. Tissue analyses confirm that the nutrients were released for crop uptake which led to significant increases in growth parameters such as number of branches and leaves/plant, leaf area index, and ultimately the tuber yield.