Effect of sod-seeding oats or barley, renovation, herbicide and broadcast nitrogen fertilizer on forage production of dryland lucerne

Abstract

In four experiments at Tamworth, New South Wales in 1973 and 1974, forage production from dryland lucerne pastures (Medicago sativa cv. Hunter River) was evaluated following sod-seeding with oats (Avena sativa cv. Cooba and Coolabah) or barley (Hordeum vulgare cv. Beecher) in autumn, treatment with diquat and topdressing with 50 or 100 kg nitrogen (N) ha-1. Comparisons were also made with production from lucerne alone and with crops of oats and barley sown on conventional seedbeds. Total forage production from lucerne was approximately doubled (P < 0.05) in winter by sod-seeding with oats or barley. Differences between the cereal species were small and both responded significantly to N fertilizer. Herbicide did not significantly affect forage production. The sod-sown cereal reduced (P < 0.05) lucerne growth in winter, but in early summer when cereal growth had ceased neither the growth of lucerne nor its basal area differed significantly from that of unseeded lucerne pastures. In most experiments renovation or broadcasting N fertilizer gave small, but significant increases in lucerne production. Forage yields from conventionally sown oats and barley were 2 to 3 times larger (P < 0.05) than the total production of sod-sown plots. Per cent N in sod-sown oats or barley was almost always less (P < 0.05) than in conventional sowings. Per cent N in both cereals declined significantly between winter and spring