Response of Soybean (Glycine max (L.) Merr.) to Fertilizer and Rhizobium Inoculant in Northern Ghana.

Commercial inoculants provide effective rhizobium strains that stimulate N fixation, growth and yield in legumes. In Ghana, limited information exists on how commercial inoculant and different fertilizer sources affect the growth and yield of soybean. This study was conducted at CSIR-Savanna Agricultural Research Institute’s experimental field at Nyankapala, Ghana to evaluate the effects of different fertilizer combinations and rhizobium inoculant on the growth and yield responses of soybean. The treatments consisted of two levels of inoculation (with and without inoculation)  with a commercial inoculant, Legumefix comprise with Bradyrhizobium japonicum strain 532c (re-isolated from Brazil strain USDA 442 Wisconsin, USA) with (+Ino) and without (-Ino) and five fertilizer combinations consisting of mineral and organic fertilizers, namely None (no fertilizer), Single Super Phosphate {+SSP}, Triple Super Phosphate {+TSP}, Fertisoil+TSP and Fertisoil+ TSP+BoostXtra {Bo} laid out in a randomized complete block design (RCBD) in a split plot design. Statistical analyses were conducted on data on biomass and grain yield, stover dry weight, pod yield, pod load, nodule number and nodule dry weight in the 2011 and 2012 cropping seasons. Biomass yield was significantly affected by application with Fertisoil+TSP and Fertisoil+TSP+BoostXtra in both years. Similarly, Fertisoil+TSP and Fertisoil+TSP+BoostXtra produced the most significant grain yield and pod load in both years. In 2012, greater stover dry weight and 1000-seed weights were obtained due to the application of Fertisoil+TSP and Fertisoil+TSP+BoostXtra. Inoculation with Legumefix had a significant effect on nodulation (nodule number and nodule dry weight). However, nodulation did not affect yield and yield components. The integration of mineral (TSP) and organic (compost) fertilizers together with micronutrients enhanced soybean productivity in northern Ghana.