Application of refuse compost: Yield and metal uptake of three different food crops

The effect of refuse compost on the yield and metal uptake of three vegetable crops (Brassica chinensis, Daucus carota, Lycopersicon esculentum) was studied in a greenhouse experiment. Refuse compost was mixed with a loamy sand at the rates equivalent to 25, 50, 75, 100, 125 and 150 tonnes ha⁻¹ in plastic pots. A chemical fertiliser (NPK = 15-9-15) at the rate of 2 tonnes ha⁻¹ was also applied to the soil for comparison. 
The compost used was slightly alkaline (pH 8) and contained 28% organic carbon, 2.3% Ca and 0.8% Na. It had a C/N ratio of 17, and the amount of plant nutrients was lower than that of chemical fertilisers. The refuse compost also possessed high levels of heavy metals such as Cd, Cu, Mn, Pb and Zn. 
Results of the pot trial showed that, in general, crop productivity was in the ascending order of sandy soil alone < refuse compost < chemical fertiliser. As for the compost-treated soils, the highest yields were obtained in the treatment with 120 tonnes ha⁻¹ for Bchinensis and L. esculentum, and 50 tonnes ha⁻¹ for D. carota. Heavy metal concentrations were distributed differently in different species: in B. chinensis, the root had higher concentrations than the shoot; in D. carota, the aerial part contained higher concentrations than the edible roots; in L. esculentum, the fruit contained lower concentrations than any other part of the plant. When considering edible portions only, B. chinensis and D. carota were the greatest accumulators of heavy metal, whilst L. esculentum accumulated these metals to a lesser extent. Copyright © 1984 Published by Elsevier B.V.