The quality and quantity of forage oats sown at intervals during autumn: effects of nitrogen and supplementary irrigation

Abstract

The quality and production of forage oats (Avena sativa cv. Acacia) sown on five occasions between late summer and late autumn was measured in an experiment near Armidale, New South Wales. Additional treatments were nil vs. 71 kg ha-1 nitrogen (N) and non-irrigated vs. supplementary irrigation. Nitrogen fertilizer did not significantly affect plant establishment, or the dry matter or digestible organic matter production from any sowing. Plant establishment declined linearly in association with reductions in the mean ambient temperature during the ten days after sowing. Crops sown on February 25 and March 13 produced at least 35 per cent more forage (P < 0.05) with irrigation than dryland crops but with all later sowings the effect of irrigation was not significant. Early sown crops contained up to 36 per cent senescent leaf and 44 per cent dead leaf in August. Organic matter digestibility contents of green and senescent forage differed little and always exceeded 69 per cent, but that of the dead leaf was at times as low as 45 per cent. Equations are presented relating digestible organic matter available in irrigated and non-irrigated treatments to the length and mean temperature of the growth period.