Fate of Composted and Non-composted Sewage Sludge in Sandy Soil in terms of Nitrogen Mineralization and Recovery of Organic Matter

An incubation study was conducted over a period of eight weeks under controlled conditions (30oC).‎ The study was conducted to assess the dynamics of N mineralization, organic matter decomposition, and pH change in a sandy soil amended with sewage sludge (SS), and co-composted sewage sludge-CSS (SS + green waste-GW).‎ The CSS and SS were obtained from Sharjah municipality and Dubai municipality respectively.‎ Sandy soil was amended with different quantities of CSS and SS (0, 5, 10, and 20 tons/ha).‎ Over the incubation period various observations were recorded to assess the accumulation of mineral N, change in soil organic matter content and pH.‎ At the completion of the study the recovery of organic matter was 56-74% in CSS and 64-72% in SS.‎ Gross nitrogen mineralization rate (N mass released expressed as a percentage of initially added N) ranges between 20-36% and 3-10% from SS and CSS respectively.‎ However, the change in the pH of CSS and SS amended soil as compared to control during incubation period was in significant.‎