Valorization of Sewage Sludge in Tunisian Agriculture : Our Knowledge Publishing : 9786206644293 : 6206644294 : 26 Nov 2023 : Organic amendment is an important element in agricultural production, given its effects on soil fertility. In this study, a trial was carried out on a plot of barley cultivated with sludge from the Beja wastewater treatment plant. A comparative study was carried out between the physico-chemical parameters of the two plots, unamended and amended with residual sludge (nitrogen, carbon, potassium, phosphorus and trace element content, structural stability and water permeability). Pre-sowing and post-harvest samples were taken. The results obtained showed a more or less significant difference in the physico-chemical parameters of the soil in the study area. For other major and trace element parameters, the difference was small. A significant difference was also recorded for barley yields (Arkansas variety) in the two plots amended and not amended with residual sludg