Published online by Cambridge University Press: 27 March 2009
Nine experiments were carried out on three different soil types in the south-east of Ireland over three years (1989, 1992 and 1993) to test the effect of early, normal and late sowing at three rates of fertilizer nitrogen (100, 125, 150 kg/ha) on the yield and grain quality ex-farm of spring malting barley (cv. Blenheim). Early sowing (January or February) was not possible in 1990 and 1991 due to wet weather. Sowing date had a pronounced effect on grain yield and grain N content in all three years. In 1989 and 1992, the earliest-sown barley (January or February) gave significantly greater yields than latersown crops (March and April) in five of the six experiments. The earliest-sown barley gave the lowest grain N in all six experiments and there was a gradual and significant increase in grain N content as sowing date was delayed. In 1993 the earliest-sown barley (February) gave significantly lower yield and greater grain N than the March-sown crop in all three experiments. The lower yield of the February-sown barley in 1993 was due to the significantly reduced number of grains/ear. The Aprilsown barley gave significantly lower yield and greater grain N than the earlier-sown crops in eight out of the nine experiments. In 1989 and 1992 only one of the six experiments, Ferns 1992, gave a significant yield response to increased rate of N (125 kg/ha). But in 1993, 125 kg N/ha significantly increased grain yield in all three experiments and 150 kg N/ha gave a further significant increase in yield in two of the experiments. Increasing increments of fertilizer N significantly increased grain N in all nine experiments.