S U M M A R YNine experiments were conducted in the south-east of Ireland on three contrasting soils over a 3-year period 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 < 005 to 001) 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 < 005 to 001) 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.

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.

Soils have been described in Ireland which meet the definition of thick manmade surface horizons conforming to Plaggen epipedons (Conry, 1969). Unlike the north-west European Plaggen soils these Irish Plaggen soils have not been formed by the prolonged addition of Plaggen material (heather sods, forest litter, or grass plaggen) and dung, but were formed by the addition of calcareous sea sand, applied either alone or mixed with stable dung. Although only small quantities of grass sods were used in the formation of the Irish Plaggen soils, they should not be separated genetically from the true Plaggen soils of NW. Europe. They occur in coastal areas, within one mile of the coast approximately, where sources of calcareous sand are readily available.These Plaggen soils generally have a loamy-coarse-sand to coarse-sandy-loam texture, a granular to single grain structure and loose to very friable consistence. Colour is directly related to the colour of the original soil. Depth varies from field to field and is related to population density.The Irish Plaggen soils are always base saturated. Phosphorus, potassium, magnesium, and sodium are very much higher than in the unsanded counterpart.Trace element deficiencies include boron, magnanese, and cobalt. Like the Plaggen soils of NW. Europe the Plaggen soils in Ireland are superior in productivity to their non-Plaggen counterparts ; not only has man's influence increased crop yield substantially, but the range of crops produced has also been enlarged. The Irish Plaggen soils show symptoms of a moisture deficit only in prolonged dry periods.

Beneath a layer of artificially deposited peat debris, an eluvial E horizon and thin iron pan (Bsm) has developed in the upper part of the Ap horizon of a brown podzolic soil (Haplorthod) near Castletownbere, Ireland. The thickness of the E horizon and the depth of the pan are directly related to the thickness of the layer of peat debris.The original soil (Haplorthod) was strongly podzolized with a significant accumulation of organic carbon, iron and aluminium in the spodic Bs. The iron pan of the upper sequum, on the other hand, is rich in iron. This iron pan seems to have developed as a result of reduction of iron in the E horizon, transport of divalent Fp2+ cations and precipitation in the Bsm as Fe2(0H)3, after the peat layer was deposited. We conclude that podzolization and iron pan development were fundamentally different processes.The study suggests a fundamental change in the iron pan-blanket peat development sequence previously postulated by palaeoenvironmentalists in Ireland.

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