Effects of sodium fertiliser on the distribution of trace elements, toxic metals and water-soluble carbohydrates in grass and clover fractions

The distribution of trace elements, toxic metals and water-soluble carbohyd rates was examined in the leaves, stems and inflorescences of perennial rye grass and white clover, with and without sodium fertiliser. Copper and mang anese were observed in both species to concentrate in the leaves and stems and iron and molybdenum in the leaves. In clover, nickel concentrated in th e inflorescence. Differences in mineral concentrations between fractions we re related to the mobility of the metal and its function in the plant. Sodi um fertiliser approximately doubled the cadmium content of the leaves, stem s and inflorescences of both species, reflecting cadmium mobilisation from the soil. The sodium fertiliser also reduced the zinc, copper, manganese an d iron contents of grass but not clover and increased the molybdenum conten t of clover but not grass. Water-soluble carbohydrates were increased by so dium in grass but decreased in clover. Differences between the two species appeared to relate to nitrogen fixation by clover but not grass. (C) 1999 S ociety of Chemical Industry.