Erosion and vegetation cover in road slopes hydroseeded with sewage sludge

► A study of roadside slopes in Arjona, Spain, was done comparing various methods of soil restoration during two vegetation cycles. ► Erosion on an untreated control plot was 3.5 times lower in the fill slopes compared to plots hydroseeded with sewage sludge. ► Erosion on an untreated control plot was 2.2 times lower in the cut slopes compared to plots hydroseeded with sewage sludge. ► The performance of the hydroseeded plots with sewage sludge was similar, with or without slurry mix.