DISSOLVED ORGANIC CARBON CONCENTRATIONS IN DRAINAGE WATERS AND SOILS FROM AGRICULTURAL ECOSYSTEMS

The two-year field and laboratory experiments were carried out to investigate the influence of soil management, land use, climate conditions and soil properties on dissolved organic carbon (DOC) concentrations in drainage waters and soils. In the field experiment drainage waters were sampled from 12 drainage watersheds (in four research areas characterized by different soil properties each with three research sites - drainage watersheds were chosen each located in area differing in terms of land use and management practices). In the laboratory study pH values (3.5-7.5) typical for Polish soils were simulated in the soils sampled from the four research areas and DOC concentration was determined. It was found that DOC concentration may increase as the result of FYM an NPK fertilizer application, temperature rise and rainfall (during summer), as well as being depended on the soil properties (percentage of particles with a diameter below 0.02 mm, content of phosphorus and pH value). However the influence of individual factors on DOC concentration might be difficult to predict under field conditions due to their overlapping.