Efficient increase in the content of available forms of elements in soil depends not only on their total content introduced to soil material, but also on the technology of its application. Technology consists of techniques and date of application as well as agronomic practices aimed at maintaining proper conditions for element transformations. The method of application of waste elemental sulfur and ground phosphate rock was assessed. Doses of 20 and 40 mg S as well as 40 and 80 mg P·kg−1d.m. were added to medium soil; 30 and 60 mg S as well as 60 and 120 mg P·kg−1d.m. were added to heavy soil. The soil samples were collected on the day of application of materials and after 15, 30, 60 and 90 days. The soil pH value decreased during the incubation. An increase in available sulfur content was observed in both soils after elemental sulfur application; the sulfur content in the medium soil depended on the dose of waste. The soils with the addition of a double dose of ground phosphate rock had the highest content of available phosphorus.
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.