A field experiment was carried out at the Agricultural Experimental Station in Lipnik near Stargard Szczeciñski in 2008-2009. It was set up on soil classified as soil quality class IVa and good rye complex (5). In the study, the GWDA compost produced at the Municipal Sewage Treatment Plant in Stargard Szczeciñski was used. This compost was characterised by neutral reaction (pHH2O 7.15). The total content of heavy metals, which limits its possible use as fertiliser, did not exceed the standards given in the Regulation of the Minister of Agriculture and Rural Development (Official Journal of Law No. 119, item 765 of 2008). Compost doses were determined based on the total nitrogen content. It was assumed that 100 kg N ha–1 was added to soil with the 1st dose, 200 kg N with the 2nd dose, and 300 kg N with the 3rd dose. The experiment was carried out in two series: with and without addition of the active substance PRP SOL. In autumn 2007, respective compost doses were introduced into soil on established plots according to the experimental design. The active substance PRP SOL was applied at a 150 kg ha–1 dose before sowing or seeding test plants. The whole experimental area was fertilised with multicomponent fertiliser Polifoska 6 in a 200 kg ha–1 dose in 2008 and 2009. Due to a small content of nitrogen in Polifoska 6 (6% N), top-dressing nitrogen fertilisation was applied in the form of urea (46% N) at a 100 kg N ha–1 dose. The test plants were winter wheat cultivar Korweta in 2008 and spring rape cultivar Bosman in 2009. The results indicate that the total average manganese, lead and nickel content in soil increased by 15.1%, 5.0% and 3.0%, respectively, under organic fertilisation with and without the active substance compared to the initial content. In the course of time, manganese, nickel and lead content decreased to a different extent. This resulted from these microelements being taken up by the cultivated crop or their leaching outside the rhizosphere. With respect to the soil abundance, it can be stated that it is characterised by medium abundance in manganese soluble forms.

17.3.2012