INFLUENCE OF SOIL ORGANIC AMELIORANTS ON DISSOLVED ORGANIC CARBON AND ANIONIC SOIL SOLUTION COMPOSITION

The influence of several types of organic waste materials, i.e. biochar, compost, manure of cow and sheep, and sewage sludge, composted on two types of soils with contrasting characteristics (Fluvisol and Vertisol) on the anionic composition of soil solution and dissolved organic carbon (DOC) was studied. An increase in pH values after amelioration in both soils was found, which is more expressed on the Fluvisol. The nitrate content was found to be the lowest in biochar ameliorated soils. It was observed that after amendment of both soils with sewage sludge, the nitrogen content in the solution increased significantly. The addition of manure, compost and biochar did not cause an increase in nitrates, and values were below or at the limit of maximum permissible concentrations. Lower contents of sulphates and phosphates were also reported after soil amendment with all the ameliorants used. Significant correlations between physicochemical characteristics of the amended soils and the composition of the soil solutions were found.