COMPARATIVE EFFECT OF 6 CULTIVARS AT 4 RATES OF NITROGEN ON THE GRAIN-YIELD AND GRAIN QUALITY OF SPRING-SOWN MALTING BARLEY IN IRELAND

Nine experiments were conducted in the south-east of Ireland on three contrasting soils over a 3-year period (1988-90) to test the effect of six cultivars at four rates of nitrogen on the grain yield and quality (ex-farm) of spring-sown malting barley. Blenheim gave the greatest grain yield and lowest protein on average. Blenheim and Prisma had similar low protein values but Prisma gave significantly lower (P < 0.05) mean grain yields than Blenheim at all three sites. Corniche gave significantly lower (P < 0.05 to 0.01) grain yields than Blenheim in all nine experiments. Choice of cultivar had a considerable effect (< 16 %) on the yield and protein content of malting barley but season and soil type had a much larger effect (2-3 times greater). The application of increasing increments of fertilizer nitrogen generally increased grain protein and screenings significantly (P < 0-05 to 0.01) in all nine experiments but it did not always give increased grain yields. The levels at which nitrogen gave significant grain yield increases depended on season and soil type. Season and soil type had a much larger effect on grain yield and quality than nitrogen rate. It was not possible to relate grain yield to specific climatic factors except on the light textured soil in 1990 when severe moisture stress in the early part of the growing season reduced grain yield by 32.5 % compared with the previous 2-year average.