EVALUATION OF PASTURE LEGUMES SOWN INTO A PREPARED SEEDBED AT TAMWORTH, NEW-SOUTH-WALES .1. DRY-MATTER YIELD

The potential dry matter production in autumn, winter, and spring of 1 5 annual and 7 perennial pasture legumes was assessed in un-razed plot s at Tamworth on the Northern Slopes of New South Wales. Seed was sown into a prepared seedbed, and dry matter yield was estimated on 24 occ asions from August 1983 to November 1987. The presence of green materi al at each sampling time, and the actual and total dry matters, were e xamined. Among the annual legumes, the highest proportion of plots pre senting dry matter at all sampling times, and the highest total yields , were found for Trifolium hirtum cv. Hykon (rose clover), T. subterra neum var. subterraneum cvv. Seaton Park and Woogenellup, T. subterrane um var. brachycalycinum cv. Clare (subterranean clovers), and Medicago aculeata (CPI No. 19416). The highest proportion of bare plots and th e lowest dry matter yields were found for local ecotypes of the natura lised legumes T. glomeratum, M. minima and M. polymorpha, Astragalus h amosus cv. Ioman (milk vetch), and T. subterraneum var. subterraneum c v. Nungarin. After October (day 300) in 1983-87 the proportions of plo ts with >10 kg/ha of dry matter present as green material were Clare 8 5%; Hykon 78%; Woogenellup 74%; M. aculeata, Seaton Park, and Vicia vi llosa var. dasycarpa cv. Namoi (woolly pod vetch) 67%; M. scutellata c v. Sava (snail medic) 56%; and M. truncatula cv. Sephi (barrel medic) 52%. Total annual yields of Nungarin were often lower than those of th e other subterranean clovers, with Clare having the highest yield in e ach year. Cumulative yields of Namoi declined markedly after 1985, whi le those of T. hirtum cv. Hykon increased. Little or no linear relatio nship was found between maturity grading and the relative yield of the annual legumes, although 4 of the 6 highest yielding legumes were lat e maturing. Among the perennials, yields of M. sativa cv. Pioneer 581 (lucerne) were above average in 1984-87. Lucerne cv. Pioneer 581 produ ced more dry matter over 5 years than Onobrychis viciifolia cv. Eski ( sainfoin), but about the same amount as O. viciifolia cvv. Othello and Remont. Sainfoin production was high in the first 2 years of the expe riment, but lower towards the end. The poor performance of T. repens c vv. Haifa and Huia (white clover) was attributed to high temperatures and low effective rainfall in summer. From these data, 5 annuals (Seat on Park, Woogenellup, Clare, Hykon, and M. aculeata) and lucerne show the most potential for sowing as ley pasture in the low elevation, sum mer rainfall environments of the Northern Slopes of New South Wales.