The study reported here was to determine the effect of an application of organic and mineral materials and their mixtures, combined with mineral fertiliser regime, on the content of selected macroelements in cocksfoot grass and maize. The trial was a completely randomised arrangement with three replicates. Two experimental factors were tested: factor A – fertilisation with organic and mineral materials ( sewage sludge fresh and composted, hard coal incineration ashes , calcium carbonate, mixture of this components) and factor B – mineral fertilisation. The observed effects are indicative of the legitimacy of applying sewage sludge and its mixture with hard coal ash to fertilise agricultural crops as this would reduce reliance on mineral fertiliser, which is very desirable in sustainable agriculture. Mineral fertilisation applied to both the test plants significantly reduced their contents of calcium and magnesium but it increased their content of potassium.