Effects of post-planting applications of nitrogenous fertilizers on grain yield, grain protein content and mottling of wheat

Abstract

The effects of post-planting applications of nitrogenous fertilizers on grain yields, grain protein content and mottling of wheat (cv. Mendos) were studied at nitrogen-deficient sites on the Darling Downs in south-eastern Queensland in 1966-1968. The efficiency with which wheat plants could utilize nitrogen applied either as a spray or as a solid top-dressing appeared to be largely dependent upon subsequent rainfall. Urea sprays applied in dual applications at 4-5, 6-7 and 8-9 weeks after emergence in 1966 increased grain yield and protein content. These sprays (15, 30 and 45% urea applied at 112 litres/ha) also had a mixed effect on the degree of mottling, but had only a slight effect on reducing the total percentage. However, in the dry season of 1967, neither urea sprayed at the same rates at 4, 7 and 10 weeks after emergence or equivalent rates of solid urea applied at planting had any effect.