The effects of limestone, N, K and Mg fertilizers on Mg absorption by oats and barley

Abstract

Oats grown in a pot experiment on two sandy loams were sampled at four stages of growth. Neither KC1 nor MgSO4.7H2O had any effect on yield but % Mg and total Mg uptake were consistently decreased by applying K and increased by applying Mg.Ca(NO3)2 increased % Mg more than did (NH4)2SO4, but yield and total Mg uptake were higher where (NH4)2SO4 was applied. The effects of fertilizers were similar on both soils.The effects of applying (NH4)2SO4 and NaNO3 to the soil on % Mg in barley were compared in a field experiment on an acid loam to which several rates of limestone had been applied. Treatments had no effect on the % Mg in grain or straw at maturity. At four earlier stages of growth (NH4)2SO4 increased % Mg in the plants more than did NaNO3. Limestone slightly increased % Mg. Nitrification of NH4 in the soil was rapid.