Nitrification Potential of Soils under Pollution of a Fertilizer Plant

Abstract

Nitrogen compounds found in soil in the form of mineral and organic bonds are available to microbes and plants as NO ₃ ^- and NH ₄ ⁺, produced in consequence of ammonification, nitrification and N fixation. The laboratory experiment was conducted on samples of podzolic sandy soils. Soil samples were taken in the surroundings of a nitrogen fertilizer plant Achema, situated in the center of Lithuania. The objective of the study was to determine the effect of soil contamination on the nitrification process. Nitrification generally proceeded more rapidly in control soils than in soils under the Achema pollution. On the average, 0.004 mg NO ₂-N was nitrified per g N mineralized per hour in the plots under the influence of the nitrogen fertilizer producing plant pollution. In comparison with nitrified N in reference soils the values were significantly higher - 0.253 (p < 0.05). Soils from background ecosystems had, on the average, 63 times higher nitrification rate than in polluted soils. The eutrophication of pine sandy soils stimulated biological processes and that was likely related to higher soil pH and initial NH ₄ ⁺.