Rhizobium inoculation of lucerne ( Medicago sativa L.)

Abstract The Rhizobium content af cammercial inaculants has been increased since the time these preparatians were intraduced to replace the formerly used agar cultures. Regardless of the presence of ather arganisms, the powder inaculants now in use are effective in lucerne nodulation and nitrogen fixaJtion. No benefit was demonstrated in favour af disinfectian af lucerne seed priar to inoculatian, while in seed pelleted with lime there was a decline in the survival of rhizabia aver a 3‐months' periad. In a number of soils where lucerne establishment in the past has failed it has been shawn that indigenous lucerne rhizabia ( Rhizobium meliloti ) were absent ar ineffective, in sharp cantrast with the abundance and nodulation efficacy of Rhizobium trifolii an subterranean claver. In some of these soils lucerne was established by the inaculation of seed with effective rhizabia, aided by raising the sail pH with lime applicatians and the use af inaculated seed, pelle ted with lime or magnesium. Among seven varieties af lucerne different responses were obtained to inoculatian with single strains of R. meliloti , but the use af multistrain commercial cultures achieved satisfactary nodulatian and grawth of these varieties.