Impact of composts with the participation of municipal sewage sludge on the content of the total forms of copper, manganese and zinc in soil
Pot experiment was conducted in the hall of vegetation at University of Agriculture in Szczecin over the years 2001 - 2003 on the soil of IVa complex of agriculture usefulness (very good rye) numbered among loamy sand as regards to the granulometric composition. The composts used in the experiment were after 8 months of decomposition. There was more nitrogen and phosphorus in the composts in comparison with potassium. In the pattern of the research the doses of composts, corresponding with 100, 200 and 300 kg N·ha-1, i.e. 0.63; 0.99 and 0.126 g N pot were used. The experiment was conducted in four repetitions. In 2001 spring rape Licomos variety was the test plant, in 2002 it was the spring triticale Wanad variety and in 2003 oats Polar variety. In the second and third year of the research of the soil there was 0.475 g N, 0.137 g P and 0.315 g K applied into every pot. It corresponded with the doses of 150 kg N·ha-1, 43.6 P·ha-1 and 100 kg K·ha-1. Mineral fertilizers were used in the form of urea, double superphosphate, 60% potassium salt.
The obtained results of the research indicate that the content of the total forms of copper, manganese and zinc in the composts, with the participation of sewage sludge fulfilled the norms concerning the organic fertilizers.
Over the years, since the time of an application into the soil the composts with the participation of municipal sewage sludge, the content of the total forms of copper, manganese and zinc has decreased. It was caused by the uptake of these micronutrients by plants.