Biosolid and municipal solid waste effects on physical and chemical properties of a degraded soil

Anaerobically digested biosolid and the organic fraction from a municipal s olid waste were surface applied at 80 Mg ha(-1) to a degraded highly carbon ated soil (Rensic Leptosol) from the southeast of Madrid (Spain) to determi ne the effects of these organic wastes on soil physical and chemical proper ties. After one year of the waste application, soil samples at 0-15 cm and 15-30 cm depths were taken. The structure of the soil was slightly improved by a small decrease in particle and bulk densities, an increase in water r etention accompanied by an increase of organic matter, Waste application al so increased the amorphous iron oxide contents and the total heavy metals i n the soil in particular the Cu and Zn contents in the surface level. The s ignificative increase of Zn in the subsurface level suggests that the Zn mi grated in this soil profile, probably because of its affinity with organic matter soluble fractions.