An Evaluation of Barrel Medic (Medicago truncatula) as an Introduced Pasture Legume for Marginal Cropping Areas of Southeastern Australia

Abstract

The potential of barrel medic (Medicago truncatula) as a possible improved pasture legume for introduction to marginal cropping areas was examined with breeding Merino ewes at four stocking rates. Although the dry matter production was similar to that of natural pasture, the proportion of barrel medic, ranging from 5 to 30%, was higher than that of naturalized medics in adjacent natural pasture areas. However, although barrel medic persisted in the pasture under all stocking treatments, it was unable to compete with barley grass (Hordeum leporinum), which invaded the pasture soon after establishment. While the pasture could support 5 ewes per hectare under favourable seasonal conditions with only moderate supplementary feeding in winter, it could not adequately support any stocking rate under drought conditions without considerable supplementary feeding. Annual wool production per head declined significantly with increased stocking rate and adverse seasonal conditions. Stocking rate did not affect lamb growth rates, but drought caused a high lamb mortality rate. The usefulness of barrel medic at Trangie is questionable, since it did not significantly improve either carrying capacity or lamb growth rates above that of natural pasture. At the same time, lucerne pastures under rotational management were able to support higher stocking rates and improve lamb growth above those of either barrel medic or natural pasture.