SUMMARYSoya bean, Bengal gram and lentil plants were grown under field conditions and sprayed with suspensions of different strains ofRhizobium. Irrespective of crossinoculation groups beneficial effects were similar to those observed in nitrogen-free sand culture with respect to dry weight, chlorophyll and N contents. The beneficial effects of sprayingRhizobiumstrains compared favourably with seed treatment by appropriateRhizobiumstrains and application of urea. Both an ineffective strain and a mutant strain ofR. japonicumshowed similar beneficial effects. Acetylene reduction by theRhizobium-leafassociation ranged from 497 to 890 nmol/g leaf/h. The ectosymbiotic association ofRhizobiumwith foliage of legumes, thus, may meet to a large extent the nitrogen requirement of such plants.