Influence of fertiliser nitrogen on higher fatty acids and on Mg, Ca, K, and P in grazed grass-clover herbage

Abstract

Abstract Total and individual higher fatty acid contents, and Mg, Ca, K, and P contents were measured throughout a year in a grass-clover pasture fertilised with lime-ammonium nitrate at 0, 112, and 448 kg N/ha. Higher fatty acid content of the herbage was highest for all treatments during late winter-early spring. Total higher fatty acid was significantly correlated with herbage total N and “protein” N contents. The rate of fertiliser N application had no significant effect on levels of total or individual higher fatty acids. The proportions of individual higher fatty acids remained constant throughout the year, linolenic (c. 65%), palmitic (c. 14%), and linoleic (c. 10%) acids being the major components. Concentrations of Mg, Ca, K, and P in the herbage varied markedly throughout the year with Mg and Ca at a maximum during summer and early autumn. Nitrogen fertiliser application had no overall significant effect on the concentrations of these elements in the herbage; however, from May to January the tot...