EFFECT OF NICKEL CONTAMINATION ON SOIL ENZYMATIC ACTIVITY

摘要

The aim of this study was to determine the effect of soil contamination with nickel, taking into consideration various rates of liming and organic fertilization, on the activity of selected soil enzymes - urease, acid phospha-tase, alkaline phosphatase and carbon content in organic compounds, total nitrogen and pH of the soil collected after cultivation of cock's-foot which was conducted in the facilities of the Siedlce University of Natural Science and Humanities, in a completely random design, in three replications. The experiment involved the following factors: I - liming (without liming and liming according to 1 Hh of soil in the form of CaCO_3); II - organic fertilization (without organic fertilization and sludge from the sewage treatment plant in Siedlce, in a dose which introduced to the soil 2 g C · kg~(-1) of soil); III - varied rates of soil contamination with nickel (without nickel, 50 and 100 mg Ni kg~(-1) of soil, by application of NiCl_2. 6 H_2O). Soil formation used in the experiment was collected from the arable layer of 0 - 20 cm of podzolic soil, of granulometric composition of heavy loamy sand. A test plant was cock's-foot (Daktylis glomerata L.), which was harvested in each vegetation season in four cuts. The soil was examined after each cut of the test plant. All factors examined in the experiment significantly diversified the features under analysis, but their effect was not always explicit and depended both on the feature and the time of collecting samples for analysis. The applied liming resulted in reduction of the activity of acid phosphatase, organic carbon content and total nitrogen in the soil under examination, and caused an increase in the activity of alkaline phosphatase and pH. A higher content of carbon and nitrogen, and a higher activity of all enzymes were found in the objects where sludge was applied, as compared to the objects where organic fertilization was not used. Growing amounts of nickel in the soil did not significantly diversify the features under analysis. The rate of nickel introduced to soil in this experiment did not result in any significant changes in the activity of the enzymes under examination, which can be explained by its small doses.