The use of digestate after biogas production as an organic fertilizer for field crops, monitoring its effect on the environment and environmentally acceptable involvement in nutrient cycling and energy is aim to the research project conducted by the Department of Crop Production since 2001, on the Slovak University of Agriculture in Nitra. It is readily digested source of nitrogen, which is physiologically more useful than from of mineral fertilizers. Digested has a pH of 7.63 to 8.5, non acidifies soil and results in better utilization of phosphorus. Digested on light soils reduces the density and improve the consistency, water storage capacity, and water stability of soil aggregates.