Compost and Vermicompost as Soil Amendments to Immobilize Cu and Cd Under Wheat Growth Conditions

Field experiment was conducted during wheat cropping season on a calcareous soil to assess the efficacy of vermicompost and compost to immobilize copper (Cu) and cadmium (Cd) in soil. The soil amendments applied alone and in combinations with mineral fertilizers to compare their efficacy for metals immobilization. Both of amendments significantly reduced extractable Cu and Cd in soil at wheat harvest. Copper and cadmium fractionation showed significant decreases in the extractable fractions by the vermicompost 47.06% and 98.81% in untreated with heavy metals soil whereas 46.46% and 80.06% in treated soil with heavy metals respectively or compost 22.35% and 79.17% in untreated with heavy metals soil whereas 20.56% and 73.05% in treated soil with heavy metals respectively. Vermicompost and compost amendments enhanced metals immobilization which reduces their expected uptake by plant and subsequent accumulation in the grains of wheat, particularly with vermicompost. In conclusion, the results indicated that compost and vermicompost have great potential to remediate Cu and Cd contaminated soils.