Abstract:
The ability of three strains of Rhizobium trifolii used in legume inoculants to form nodules on inoculated Trifolium subterraneum L. was examined in field experiments on a soil containing a large natural population of clover rhizobia. The identity of cultures isolated from nodules on young seedlings was established by a gel immune diffusion technique. When a mixture of broth and peat inocula was applied to seed, a large proportion of nodules was attributable to peat-borne rhizobia. In competition with the natural population in the production of nodules on the roots of the host legume, strain WA67 = TA1 > UNZ29. In competition with each other as well as with the naturally occurring rhizobia, WA67 > TAI > UNZ29. The significance of the findings in relation to the persistence in soil of Rhizobium strains applied as inoculant to clover seed is discussed.