干旱区生态环境知识资源中心

Reclamation of saline sodic soils is a main problem at most of arid lands. Improving soil properties with waste materials has been investigated earlier but the effect of these materials on saline sodic soils is not fully known. A fly ash and sewage sludge mixture was applied to saline sodic soils with the intention of soil reclamation and eco-friendly waste recycling. Fly ash and sewage sludge mixtures were applied at a ratio of 1:1 to soils with three different levels of electrical conductivity (EC) and exchangeable sodium percentage (ESP) (soil I: 4.27dSm(-1), 6.09%; soil II: 73.20dSm(-1), 51.03%; soil III: 38.2dSm(-1), 86.2%) at 3 different doses, that is, 40, 80, and 120tha(-1). Saturated hydraulic conductivity and porosity generally increased in all the soils tested, whereas bulk density and pH decreased. ESP and EC values of the amended layers decreased considerably with the application of increasing doses of waste material. These results indicate that when properly applied, two industrial residues, sewage sludge and fly ash, that are associated with a negative environmental impact, can be recycled allowing for the cheap reclamation of barren saline sodic soil.