NUTRIENT RELATIONS OF WINTER-WHEAT .1. ACCUMULATION AND DISTRIBUTION OF NA, K, CA, MG, P, S AND N

Maris Huntsman winter wheat was sown on 30 October 1974 and grown under typical farming conditions. Between sowing and harvest (5 August 1975), the crop was sampled on 23 occasions and dried samples of individual plant components were analysed for Na, K, Ca, Mg, P, S and N composition. The concentration of nutrients within the whole plant generally decreased throughout growth but different parts of the plant varied in their behaviour. Uptake of all nutrients ceased at, or shortly after, anthesis in mid-June while dry-matter accumulation continued slowly for a further 2-3 weeks and almost stopped 4 weeks before harvest. The major period of nutrient uptake occurred between mid-April and mid-June coincident with the period of rapid shoot growth. Large amounts of potassium and sulphur (almost 50 of the plant's anthesis content) and lesser amounts of calcium (15) were lost from the plant after anthesis and efflux from the roots into the soil appeared to be the most likely pathway of removal. Accumulation of nutrients in the ear occurred throughout grain-filling by translocation from other parts of the plant, particularly the leaves and stems: the effects of this redistribution on the production of dry matter after anthesis are discussed. © 1979, Cambridge University Press. All rights reserved.