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

Abstract

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.

The Physiological Role of Abscisic Acid in Regulating Root System Architecture of Alfalfa in Its Adaptation to Water Deficit

“…However, local alfalfa varieties show decreased production owing to reduced growth and survival caused by environmental stress. The findings of this study showed that the growing point density and herbage accumulation of alfalfa generally declined under more severe water deficit, which is supported by the study of Gramshaw et al [43]. A soil water content of 60-65% of the water-holding capacity resulted in the highest alfalfa herbage production and residual shoot weight, and at this moisture level, AH and ZD had higher herbage accumulation and less root weight than GE in Experiment 1, which indicated that alfalfa can improve water-use efficiency by increasing herbage accumulation and reducing root weight under optimum soil water content.…”

Lucerne (Medicago sativa L.) Persistence Remains Unchanged under Variable Cutting Regimes

“…There is a decline in the density of a lucerne sward that occurs over time irrespective of the genotype, environment or management imposed [2]. Sudden and significant declines are often associated with waterlogged conditions [26] and this was observed at the Rutherglen site between June and December 2016 (Table 3). The density of lucerne crowns at the Burraja site at the highest density declined by about 38% over three years from an initial density of 36 crowns/m 2 to 22 crowns/m 2 (data not shown), which was consistent with patterns of decline reported in the literature [14,27].…”

Breeding lucerne for persistence

“…Breeding objectives to enhance stolon or rhizome production and reseeding ability are a good initial strategy to enhance persistence (Beuselinck et al 1994) and were the main reasons for the development of lucerne cultivars with the 'creepingrooted' trait (Heinrichs 1963). However, grazing trials with these cultivars showed poor results for increased grazing persistence (Leach 1978;Gramshaw et al 1982). The trait lacked expression in most environments and was also found to be associated with low herbage yield further reducing its use in breeding (Busbice and Hanson 1969).…”