Comparison of refuse compost and activated sludge for growing vegetables

Application of refuse compost and sewage sludge to soil for crop cultivation has become one of the feasible ways of disposal. However, trace element concentrations in these waters may pose a threat to soil productivity and edibility of crops produced. A greenhouse trial on two vegetable species, Brassica parachinensis and B. juncea, was conducted with refuse compost (5%, 15%, 75% and 100%v/v) and activated sludge (1%, 3% and 5%v/v) mixed with a sandy soil. Fertiliser (Nitrophoska Permanent) was also applied (0·2 kg m−2) to the sandy soil for comparison. The plants were harvested after 45 days. Dry weights and heavy metal contents (Zn, Pb, Cu and Mn) of plant tissues were determined. Higher productivity was found in the treatments with 3% and 5% activated sludge whereas lower productivity was obtained in the refuse compost treatments when compared with those with added fertiliser (p <0·05). The contents of Zn and Cu were highest in the root and shoot portions of activated sludge and compost-treated crops. The Zn content of the aerial parts was also generally higher than in the control. A higher amount of heavy metal was accumulated in the root portion than in the shoot portion of both species. Copyright © 1983 Published by Elsevier Ltd.