Response of soybean (Glycine max (L.) Merr.) to inoculation and P-fertiliser application in the savanna zones of northern Nigeria



How to Cite

Response of soybean (Glycine max (L.) Merr.) to inoculation and P-fertiliser application in the savanna zones of northern Nigeria. (2022). Tropical Agriculture, 99(3), 244-260.


Soybean production in the savanna zones of Nigeria has continued to increase but yield in farmers’ fields has not been consistent due to ecological constraints, varying soil fertility, low adoption of inputs and low yielding crop varieties. In order to investigate these variations with a view to adopting strategies which would increase yield in smallholder farms, field trials were conducted in three agro-ecological zones of northern Nigeria during the 2012 and 2014 planting seasons to evaluate responses of soybean to P fertiliser application with or without inoculation with rhizobia inoculants and to evaluate the effect of soil fertility on the production of soybean in the northern Nigerian savannas. High yielding and medium maturing soybean varieties were planted in experimental plots consisting of a control plot where seeds were not inoculated and there was no fertiliser amendment, a plot where seeds were inoculated, a phosphorus (P) treated plot and a plot where seeds were inoculated and P was applied. The results showed significant responses to treatments, however, variations in yield were found due to differences in soil fertility across the savannas. Mean grain yield in the 2 years of study showed that inoculation and P increased grain yield by about 34% compared with the control, followed by P alone with a 27.5 % increase and inoculation alone resulted in a 22.5% increase. From the study, soybean production benefitted significantly from inoculation and phosphorus application in the savanna zones of Nigeria, however, locations where soil fertility was higher due to high content of P, organic carbon and soil clay had a comparative advantage. Therefore, locations with improved soil fertility conditions have better responses to input and greater potentials for sustainable soybean production.