Influences of application of sewage sludge compost on N2O production in soils

Abstract

Laboratory incubation was conducted to determine the controlling factors affecting the production of N₂O in soil taken from short- and long-term experimental sites continuously amended with SS in three types of soil samples. Soil types and sludge application rates significantly affected the production of N₂O from soil amended with sludge compost. The yellow soil, with low organic matter content, resulted in higher production of N₂O with sewage sludge application probably due to ammonium oxidation in the soil. While andosol soil, with high organic matter content and heavy metal (Zn), resulted in lower N₂O production when amended with SS. Uncultivated brown forest soil amended with sewage sludge plus sawdust compost (SSS) at the rate of 20 ton ha⁻¹ showed a peak of N₂O production, while no N₂O was observed in the same soil at 10 ton ha⁻¹ application rate. These results help us to explain that N₂O production from soil amended with SS is greatly affected by soil types, types and application rate of the composts. It should be considered carefully to reduce N₂O emission from the recycling of nutrient between soil/agriculture and urban/water treatments in future.