Previous research had identified four serogroups of Rhizobium trifolii
indigenous to Abiqua soil (fine, mixed, mesic, Cumulic Ultic Haploxerolls).
Nodulation of subterranean clover (Trifolium, subterraneum L.) by two of the
serogroups, 6 and 36, was influenced by the application of CaC0₃ to the soil.
The studies described in this thesis...