Response ofBradyrhizobium-Inoculated Soyabean and Lablab Bean to Inoculation With Vesicular-Arbuscular Mycorrhizae

SUMMARY Pot and field investigations were conducted to study the effects of vesicular-arbuscular mycorrhizal (VAM) inoculation and triple superphosphate fertilization on nodulation, dry matter yield and tissue nitrogen and phosphorus contents ofBradyrhizobium-inoculated soya-bean and lablab bean in the Sudan. Inoculation of both crops with the VAM fungusGlomus mosseaein clay and sandy soils in pots increased nodulation, dry matter yield and tissue nitrogen and phosphorus contents more than triple superphosphate fertilizer, but even greater responses were obtained fromG. mosseaecombined with fertilizer. Crop responses in the two soils were similar, despite the large differences in soil physico-chemical properties. In the field, inoculation of both crops with any of four VAM fungi enhanced nodulation, dry matter yield and plant nitrogen and phosphorus contents more than did triple superphosphate.Gigaspora margaritaandGlomus mosseaewere superior toGigaspora calosporaandAcaulosporaspecies and resulted in more extensive root infection, especially in soyabean.