The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. III. Field inoculation trials.

Abstract

Field experience with crimson and subterranean clovers grown in the Lismore red soils has confirmed the importance of successful inoculation with an effective strain of a root-nodule bacterium. Strains of rhizobia, applied singly or in a mixture, differed markedly in their ability to form nodules in the red soils. A relatively heavy dose of inoculum (c. 10 times the usual) was desirable. Superphosphate and dolomite were favourable to nodulation but a trace element mixture that included copper sulphate at the rate of 10 lb per acre proved markedly toxic when put in the drill with inoculated seed. Yield was directly related to the proportion of plants effectively nodulated, whether the latter varied because of the nature of the inoculum or because of fertilizer treatment. Results of inoculation at other centres in the district were very satisfactory. Success has also been obtained with the inoculation of Medicago, pea, and vetch.