Mixed Municipal Solid Waste Compost as a Soil Amendment on Yield and Heavy Metal Accumulation in Okra and Watermelon

Application of compost in horticultural crops has the potential to provide many benefits and yet there are concerns regarding accumulation of heavy metals in the crop and on human health. Effects of amending soil with compost made from mixed municipal solid waste (MSW) on yield of okra (Abelmoschus esculentus L.) and watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] and on heavy metal concentrations (Cd, Cu, Cr, Ni, Pb, and Zn) in pods of okra and pulp and juice of watermelon were investigated. Four MSW compost rates were applied, 25, 50, 75, and 100 Mg·ha−1, and compared to a non-amended control with no compost application. Addition of MSWC increased yield of okra and weight of watermelons over the control. There were no differences among treatments in heavy metal concentrations in okra pods, watermelon pulp, or juice.