The concentrations of available forms of trace elements in the soil are mostly determined by their total content and soil processes. Soil organic matter and pH are the key factors affecting the content and mobility of heavy metals in soil. According to many authors, the toxicity of heavy metals and their availability to plants increase due to soil acidification caused by sulfur deposition. The direct and residual effect of sulfur fertilization on changes in the heavy metal content of soil has to be taken into account in environmental analyses in agricultural areas, including environmental impact assessments and predictions. The objective of this study was to determine the effect of increasing doses of sulfate and elemental sulfur on changes in the concentrations of available zinc and copper in soil samples collected at a depth of 0-40 and 40-80 cm. A three-year field experiment was conducted on Dystric Cambisols (FAO), of the granulometric composition of heavy loamy sand. Soil samples were collected from each plot, prior to the establishment of the trials, after each harvest and before sowing the consecutive crop. The soil samples were used to determine the concentrations: Zn and Cu in soil (extractions with 1 mol HCl dm–3, the ratio between soil and extraction – 1:10) was determined by the AAS method using a Schimadzu AA apparatus. The results of the yields and chemical analysis of soil were processed statistically with the analysis of variance. The application of sulfate and elemental sulfur decreased the zinc content of 0-40 and 40-80 cm soil layers, as compared with soil sampled before the experiment. Sulfur fertilization had no effect on changes in copper concentrations in both soil horizons. The sulfur doses applied in the experiment did not affect the natural content of zinc and copper in the soil, and had no negative agricultural or environmental impacts.

17.3.2012