Studies on seed pelleting as an aid to legume seed inoculation. 2. Survival of Rhizobium meliloti applied to medic seed sown into dry soil

Abstract

Seed of Medicago truncatula and Medicago littoralis, with and without lime pelleting and inoculation, was sown dry into medic-free, Rhizobim meliloti-free soils at 12 sites in the Western Division of New South Wales. At the different sites, periods between 1 and 88 days elapsed before germinating rain fell. Seedling nodulation was used as the index of inoculant survival. Nodulation was variable, but the variation was independent of the time between sowing and germination. Best nodulation occurred in treatments in which peat inoculant was incorporated within a lime pellet around the seed. These treatments were superior to others where broth inoculant was incorporated in the pellet or where peat inoculant was applied externally to pelleted or unpelleted seed. Nodulation was improved by incorporating an increased level of peat inoculant in the pellet. In storage, a very low survival rate was recorded in all treatments except those incorporating peat inoculant within the pellet. The results are discussed in relation to the practicalities of pre-inoculation techniques and of sowing inoculated medic seed into dry seed beds.