Two biogas prodn. plant digestates and pellets of compost from the solid fraction of the digestates were added to soils used then for growing corn. The addn. of digestates resulted in a significant increase of silage maize yield. The soils were studied for pH and N, C, P, K, Mg, Zn, Cu and Mn contents. The single application of digestates and pellets had a negligible effect on assessed soil parameters.