The contribution of some tropical legumes to pasture yields of dry matter and nitrogen at Samford, South-eastern Queensland

Eleven legumes were grown individually with Paspalum plicatulum Michx. c.v. Hartley in grazed plots from 1959 to 1963. Yields of dry matter and nitrogen were recorded. Additional legumes and nitrogen fertilizer treatments replaced the non-persistent legume treatments from December 1960. Of the eleven legumes used initially, Phaseolus atropurpureus D.C., Phaseolus atropurpureus X (F3 seed from the cross C.P.I. 16877 x 16879), and Lotononis bainesii Bak. were the most productive and persistent. A diploid Indigofera spicata Forsk. sown in 1960 was less productive but appeared to be persistent. Vgna marina Merr., V. repens L., and two Desmodium sandwicense E.Mey. introductions persisted for two years. Five Glycine javanica L. introductions, Dolichos biflorus L., and Chamaecrista fasciculata Greene failed to persist for more than one year. The nitrogen yield of the best legume treatment (P. atropurpureus X) was equivalent to the nitrogen yield from grass fertilized with 170 lb of nitrogen an acre a year as urea, but the dry matter yields were only equivalent to those of grass fertilized with 90 lb nitrogen an acre a year. Yields of nitrogen and dry matter for the P. atropurpureus lines and L. bainesii were closely correlated with effective rainfall during the growing season over the four full years of the trial. Nitrogen transfer to the associate grass increased with time and was greater for the P. atropurpuretls lines than for L. bainesii.