EFFECT OF PALM BUNCH, SORGHUM SPIKE AND MAIZE COB ASHES ON ROOT GROWTH AND POTASSIUM STATUS OF CASSAVA

The paper examines the effect of different sources of Organic manure as key nutrient (Potassium) on tuber yield of Cassava (Manihot esculenta Crantz). Ashes obtained from Empty Fresh Bunches (EFB) of oil palm, Maize Cobs (MC), and Sorghum Spikes (SS) were subjected to chemical analyses in the laboratory and discovered to contain high percentage of potassium nutrient. EFB Ash had the highest percentage of K, when compared with Ash of MC and SS. These organic K supplements were applied in different combinations using NPKF as control in an experiment conducted on a sandy loam soil in Ilorin to determine the best treatment that will supply high amount of potassium needed for cassava production. Results indicate that applying Ash of EFB two months after planting gave the highest root yield per plot, among the sole organic treatments applications. Also the treatment of EFB+MC+SS gave optimum yield of cassava root better than EFB treatment. However, the combination of EFB+MC+SS+NPKF was significantly different (5%) among all treatments, an indication that Potassium is highly responsible for root development. Laboratory analysis also showed that the ash of EFB was significantly different from all other ash sources in terms of K nutrient present. Thus, the EFB+MC+SS treatment was recommended as a soil amendment for organically cultivated cassava. A combination of at least two of the organic manure with NPKF was also suggested for optimum crop yield, soil pH control and improved soil fertility.