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More effective rhizobial inoculants improve the persistence of lucerne (medicago sativa) in western Australia

P.M. Evans and J.G. Howieson

Western Australian Department of Agriculture, Clive Street, Katanning WA 6000
Western Australian Department of Agriculture, South Perth WA 6000

In the medium rainfall areas of Western Australia, provided certain soil and management conditions are met, lucerne has the potential to help reduce salinity problems by using out of season rainfall and give a more even feed distribution than annual pastures. However, densities in sandplain soils can dramatically decline from season to season (1). As rhizobial strain specificity toward soil type and cultivars exists (2), a trial was conducted to test lucerne persistence and production in these soils using a range of rhizobial strains. If a successful symbiosis was achieved, then one of the major limitations to the expansion of lucerne in WA would be removed.


Rhizobium strains and cultivars used are shown in Table 1. The trial was sown on 21 August 1989 near Esperance, at a rate of 10 kg/ha, on a sandy soil which receives an annual rainfall of 400 mm. Plots were 4x3 m wide, arranged in a randomised block design and replicated four times. In early January 1991, plant density was determined by counting eight 0.25 m2 quadrats per replicate. Dry matter (DM) was obtained by oven drying material from four 0.25 m2 quadrats per replicate.

Results and discussion

Plant survival with WSM 922 was approximately double that of the next best treatment and no significant differences existed between cultivars in either density of DM. In the CC169 treatment differences in DM existed between cultivars, suggesting a better performance across cultivars by strain WSM 922. Although densities were similar, strain WSM 540 appeared less productive than CC169. No differences existed between strain WSM 837 and the uninoculated control (Table 1). The main effect of rhizobial strain in this experiment was to improve plant survival and persistence. Further rhizobial strain evaluation is in progress.

Table 1. Density (plants/m2) and DM production (kg/ha) of three lucerne cultivars in response to five inoculum treatments.


Holland, M., and Grimm, M. 1986. J. Aust. Inst. Agric. Sci. 52, 95-98.

Thompson, J.A. Curnow, B.C., Brockwell, J. and Chatel, D.L. 1979. 6th Aust. N. Fix. Conf. Perth, pp. 15-17.

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