EVALUATION OF THE EFFECTS OF LIMING, RHIZOBIUM INOCULATION AND PHOSPHORUS FERTILIZER ON GRAIN YIELD AND YIELD COMPONENTS OF SOYBEAN (Glycine max (L.)) MERRILL) IN THE GUINEA SAVANNAH ZONE OF GHANA

Abstract

An experiment was conducted to evaluate the combined effect of liming, inoculation and phosphorus fertilizer on growth, nodulation, nitrogen fixation, yield components and grain yield of soybean (Glycine max (L.) MERRILL) in the Guinea savannah of Ghana. The study was conducted between December 2015 and April 2016 in front of the greenhouse of the University for Development Studies at Nyankpala Campus. The experiment was laid out in a split-plot design with four replications. Liming (Organic, Inorganic and Control) was the main plot and soil amendment (Phosphorus, Inoculation, Phosphorus + Inoculation and Control), the subplots. The experimental soil had an initial pH of 4.5 and low cation exchange capacity (CEC) of 2.6 meq/100 g. CaCO3 treatments increased soil pH to 8.5 and CEC to 4.1 meq/100 g and leaf ash increased soil pH to 9.4. The study showed that, liming with CaCO3 at 18 g/10 kg of soil of pot increased plant height by about 58% over the other liming materials used. Inorganic lime (CaCO3) at a rate of 18g per pot performed higher in all parameters than oil palm leaf ash and control. Phosphorus at 148 kg per hectare TSP also recorded better results among the soil amendments in all parameters except number of nodules per plant and grain yield of the soybean. There was interaction between liming and soil amendment effects on days to fifty percent flowering, leaf area index, fresh shoot weight and grain yield. Inorganic lime (CaCO3) at 18 g / 10 kg pot of soil and phosphorus fertilizer at 148 kg/ha TSP gave soybean plants better chance to harness soil nutrients and had an influence on vegetative growth and eventually on grain yield by about 52% over the other combinations. It is therefore recommended that, liming and phosphorus fertilizer applications should be adopted by farmers growing soybean in northern Ghana.