Effect of sewage sludge on soil physical properties in a Clayey Oxisol

Abstract

Studies on sewage sludge, a by-product generated in urban sewage treatment shows that the sludge contains several nutrients, is rich in organic matter, and acts as a soil conditioner, thus improving soil structure. The objective of this study was to assess the physical properties in a Clayey Oxisol (Eutrophic Red Latosol) that received 12t ha-1 (dry weight) of limewashed sewage sludge for two years. Resistance to soil penetration was determined by using the impact penetrometer Model IAA/Planalsucar - STOLF, from topsoil to 0.50 m depth. Non-deformed samples were collected for the physical analyses of soil density and porosity. Results showed that 12 t ha-1 yea -1 of limewashed sludge decreased soil resistance to penetration and soil density, thus increasing total soil porosity.