Impact of Sewage Sludge on Water Movement in Calcareous Sandy Soils

Abstract

The present study was undertaken to investigate the changes in soil physical properties and their effect on water movement under ponded irrigation. Sewage sludge was applied to 10 cm soil depth at rates of 0.25. 75  and 100 Mg-ha-1 to two disturbed soils differing in CaCO3 content. The results showed that cumulative infiltration (1) decreased with an increase in sewage sludge rates. Basic infiltration for slightly calcareous sandy soil was higher than that of moderately calcareous sandy soil, laboratory measurements showed an exponential decrease in saturated hydraulic conductivity and an increase in available water capacity with an increase in sewage sludge rates. For both soils, water diffusivity (D(Q)) decreased with an increase in sewage sludge rates. The (oral) values of slightly calcareous sandy soils were higher than those of moderately calcareous sandy soils.