Effects of Potash Fertilizers on Sweet Potato in Sierra Leone

Abstract

SUMMARY The effects of frequency of potash fertilizer application and of different rates on sweet potato yields were studied in three different cropping systems on Njala upland soils. Fertilizers containing higher K rates (448 kg/ha sulphate of potash) and an N/K ratio of 3:4, gave maximum tuber and low vine yields with low vine/tuber ratios on intensively cropped areas, whereas fertilizers containing lower K rates (112 kg/ha sulphate of potash) and an N/K ratio of 3:1 gave maximum but relatively low tuber and relatively high vine yields, with relatively high vine/tuber ratios on newly cropped areas after seven years bush fallow. Two equal split applications of fertilizer is recommended under the weather conditions prevailing in this part of Sierra Leone.