Effects of five leve)s of nitrogen (n0=0, n1=40, n2=80, n3=120 and n4=160 kg/ha) and two levels of rhizobium (r0= without and r1= with rhizobia) were studied on three varieties of soybean (Clark 3= v1, Lindarin=v2 and Williams= v3). A split-plot design with three replications in which varieties were as main plots, rhizobia as sup-plots and nitrogen as sub-sub—plots was used. Each experimental unit had four 5—m long rows. One of the replications was discarded from the experiment due to poor germination.
Traits studied were nodule count, flowering time (days), plant height (cm), number of pods per plant, number of seeds per pod, yield (g), seed weight (g), oil percentage and amount of oil per plot (g). The data were analyzed statistically and means were compared by LSD test.
Results of the experiment showed that: (1) rhizobium increased oil percentage (2) nitrogen increased number of pods per plant and decreased number of seeds per pod, (3) an interaction effect of nitrogen variety was observed for oil percentage, and (4) a three factor interaction was found for number of seeds per pod, oil percentage and amount of oil per plot.
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