Municipal sewage sludge contains considerable amounts of macro and microelements essential for plant nutrition. With decreasing use of natural and organic fertilizers, there is a need to search for alternative sources of organic matter (which is a substrate for humus reproduction). In a field experiment carried out on heavy soil with neutral reaction, the effect of single application of municipal sewage sludge in a dose of 5.34 Mg·ha−1 DM was compared to an equivalent dose of mineral fertilizers. The test plant was spring barley. After application of municipal sewage sludge, slight positive changes in the chemical properties of the soil were observed. The sewage sludge increased the yield of spring barley grain and straw by, respectively, 14 and 13% in relation to treatment with mineral fertilization. Spring barley fertilized with sewage sludge contained more elements than barley grown only on mineral fertilizers. It was shown that application of municipal sewage sludge to the soil had a significant effect on increase in nutrient uptake by spring barley. Fe was taken up in the highest amount, followed by Al and Mn, and Co was taken up in the smallest amounts. Utilization of Fe, Mn, Co and Al from sewage sludge by spring barley was at 6.0, 4.7, 0.7 and 0.7%, respectively of the amount applied to the soil with this waste. The mass ratios (Fe:Mn, Fe:Al, Mn:Co) analyzed in spring barley biomass were much wider in straw than in grain. In terms of grain feed value, Fe:Mn ratio in grain and straw was greater than optimum.
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.
Municipal sewage sludge from rural sewage treatment plants is characterized by a substantial content of organic matter and macronutrients, which can be used in cultivation of cereals. In a farm located in the commune of Iwanowice in the south of Poland (Malopolska province), municipal sewage sludge was applied under spring wheat cultivation. The experiment was set up on heavy soil with slightly acid reaction and medium content of available forms of P, K, Mg. Application of sewage sludge in a dose of 23 Mg fresh matter per hectare (4.21 Mg d.m.) led to no significant changes in chemical properties of the soil. Application of sewage sludge significantly increased yield of spring wheat. That increase led to a significant decrease in the content of N, P, K, Na, Mg and Ca in spring wheat. Utilization of N, Mg, K, P and Ca from sewage sludge by spring wheat was at a level of 82, 63, 44, 36, 9 %, respectively, of the amount introduced with the waste. Application of municipal sewage sludge significantly decreased the value of Ca : P ratio in spring wheat grain and straw. The sewage sludge did not cause a significant change in the values of Ca : Mg, K : Na, K : (Ca+Mg), K : Mg and K : Ca ratios in spring wheat grain and straw. Municipal sewage sludge can be used environmentally, including for fertilization of cereals, provided that environmental standards are kept.