Due to the fact that soils in Poland are mostly light soils, there is a need to improve their physical, chemical and biological properties. In addition, as a result of the decrease in the number of farm animals, a decrease in production of natural fertilizers can be observed. Low production of natural fertilizers speaks in favor of agricultural use of municipal sewage sludge in Poland. Municipal sewage sludge is composed of large quantities of macronutrients necessary for plants. This waste also contains significant amounts of organic substance. Chemical properties, including a high content of nitrogen, phosphorus, and often calcium, speak in favor of environmental use of municipal sewage sludge. Increasing requirements with respect to environmental protection cause the necessity to assess the effects of using organic waste for fertilization. In a farm located in the commune of Iwanowice (Małopolska province), municipal sewage sludge was applied under spring barley cultivation. The soil on which municipal sewage sludge was applied was classified into the category of heavy soils with neutral reaction. When assessing the content of available nutrients (P, K, Mg) in the soil, their low content was determined. After application of municipal sewage sludge in a dose of 24 Mg fresh matter per hectare, which corresponded to 5.34 Mg DM·ha−1, under spring barley, beneficial changes in chemical properties of the soil were observed. An increase in soil abundance in organic carbon and total nitrogen was observed, as well as an increase in the content of available forms of phosphorus, potassium and magnesium. Based on the results of the conducted chemical analyses, it was established that biomass of spring barley fertilized with sewage sludge contained more macronutrients (N, P, K, Na, Ca and Mg), which improved its feed value. The field experiment showed that application of municipal sewage sludge increased uptake of macronutrients by spring barley.