EFFICIENCY OF THE SMALL POND AS A BIOGEOCHEMICAL BARRIER TO DECREASE DIFFERENT KINDS OF NITROGEN IN THE AGRICULTURAL LANDSCAPE

摘要

The study included the measurement of the concentrations of N-NO_3~-, N-NH_4~+ and organic nitrogen in the ground water of cultivated fields, and in the water of the subdrain as well as in the water of a small pond. The investigation included different forms of nitrogen in the precipitation and the run-off water. The water of the subdrain was characterized by a relatively richness in nitrates. The highest concentrations of nitrates were measured in the water of the subdrain. However, N-NH_4~+ dominated in the precipitation water. Moreover, the contents of organic nitrogen were the highest in the water of the run-off. It was observed that 57% of the total amount of nitrogen supplies to the pond remained in a dissolved form. In general, the small pondshowed a high decrease in different forms of nitrogen and showed a high degree of biological transformation. Evidently, the small pond of the agricultural landscape functions as a very efficient biogeochemical barrier.