Effect Of Rhizobia Inoculation On Nodulation And Nitrogen Fixation Of Soybean Cultivars In Sudan Savanna Of Nigeria
A field experiment has been conducted to study the effect of rhizobia inoculation and nitrogen fixation of soybean cultivars. The experiment consisted of testing ten cultivars under bradyrhizobium inoculation and uninoculation conditions in a split plot design and replicated four times, with inoculation in the main plot and the varieties in the sub plot level. The parameters determined were initial physicochemical properties of the soil, number of nodules and nodule score, and biological nitrogen fixation. The result indicated that the soil was low in fertility with low organic matter, total N, available P and Sulphur. Nodule score and number of ineffective nodules were significantly affected as there were significant differences between the inoculated and uninoculated treatments. Similarly, varietal effect on number of effective and ineffective nodules and number of nodules were significant (P<0.05) but nodule score was not significantly affected. The highest number of effective nodules and number of nodules were observed in TGX 1945 and TGX 1935 3F, respectively, while the lowest was with SC SAGA. Highest N2 fixed (150 Kg N ha 1 equivalents to 63% was observed with TGX 1935 3F, while the lowest (100 Kg N ha 1 equivalent to 55% N was with SC SAGA. Generally, the proportion of plant N derived from atmosphere and the estimate of N fixed were not significantly (P>0.05) affected by inoculation and varieties. Keywords Inoculation, Nodulation, Nitrogen Fixation, Soybean, Kano, Nigeria