Changes of Nitrogen Dynamics in a Soil Amended with an Anaerobic Digestion Effluent by Organic Material Application

Abstract

Since anaerobic digestion effluents (ADEs) contain abundant amounts of ammonium-nitrogen (NH₄-N), their agronomic benefits as a liquid fertilizer are expected. However, soil application of ADEs may cause leaching of nitrate-nitrogen (NO₃-N) to groundwater. Therefore, effects of mixing organic materials on N dynamics, particularly N leaching from a soil amended with an ADE were evaluated using columns in this study. The different amendments did not cause significant differences in the cumulative amounts of NH₄-N leached. The application of sawdust and pruned branch decreased 16% and 22%, respectively, of the cumulative amounts of NO₃-N leached compared with that from the soil amended with ADE. It appeared that the organic materials physically absorbed NO₃-N against leaching, and caused increased soil microbial biomass to enhance N immobilization to contribute to reduced NO₃-N leaching from soils amended with ADE and organic materials.