Performance of grazed creeping-rooted lucernes on two soils in central Queensland

The creeping-rooted lucernes (Medicago falcata x M. sativa), cv. Walkabout and breeder's line ECRS 1, were compared with M. sativa cvv. Hunter River and Siro Peruvian for persistence and production under dryland conditions on alluvial and solonetz soils at Biloela and Theodore in central Queensland. The lucernes were sown with green panic (Panicum maximum var trichoglume cv. Petrie) and were grazed intermittently by cattle. Established lucerne populations were similar on each soil, but varied among lines in the range 25-55 plants/m2, with creeping-rooted lucernes having the lowest. Persistence on the two soils differed markedly; after two years, populations had decreased to between 7-22 plants/m2 on the alluvial whereas less than 3 plants/m2 remained on the solonetz. Survival of both creeping-rooted lines was inferior to that of Hunter River on both soils, but only significantly (P < 0.01) so on the alluvial soil. Dry matter yields from the creeping-rooted lines on the solonetz soil during the first year were similar and averaged 2.6 t/ha, compared with Hunter River, 3.4 t/ha, and Siro Peruvian, 6 t/ha.