Changes in some chemical, rheological and structural properties of five important agricultural soils in north central Italy following amendments with either pig slurry (PS), aerobically digested sewage sludge (SS) or cattle slurry (CS) are reported in this study. On each soil these waste materials increased substantially the levels of exchangeable Ca, Mg, K and Na as well as the per cent base saturation. Improvements in cation exchange capacity (CEC) and pH levels following waste applications were generally less apparent. PS supplied mostly Mg and Ca, SS mostly Na and Ca, and CS mostly K and Ca. The magnitude of change in the rheological properties (liquid limit, plastic limit and plasticity index) was dependent on the soil and type and amount of the waste material used.On the more sandy soils waste application significantly increased aggregate stability to water at both the micro and macro levels but the magnitude of increase was soil-specific and also depended on the index of stability used. On the more clayey soil PS decreased the aggregate stability significantly, irrespective of the index used for evaluation. The least stable soil, a sandy loam Lamporecchio Entisol, benefited most from waste application whereas the most stable soil, a clay Modena Inceptisol, benefited least.
Bioresource Technology 01/1991; 37(1-37):71-78. DOI:10.1016/0960-8524(91)90113-X