Heavy metal accumulation in calcareous soil and sorghum plants after addition of sulphur-containing waste as a soil amendment in Turkey

The purpose of this work was to evaluate the effect of sulphur containing industrial waste with respect to heavy metals on calcareous clay soil and sorghum (Sorghum bicolor L.) plant, as soil amendment. Pot experiment was established with a rate of 0, 20, 40, 60 t ha−1 air dry waste and 0.5, 1.0, 1.5 t ha−1 elemental sulphur and 0.5 t ha−1 sulphur + 20 t ha−1 waste. The use of waste on the soil with high CaCO3 and clay content did not create heavy metal (Ni, Cr, Co and Cd) build-up or toxicity. Even after the application of the high level of waste, it could not be seen any important toxic element accumulation in sorghum plant. Although the sulphur-rich waste, approximately up to 1 million t in the vicinity of Keçiborlu Sulphur Factory Isparta/Turkey, can be considered as amendment product for reclamation of saline-sodic and calcareous soils common in Turkey and other countries, repeated waste applications would result in different heavy metal accumulation rates. Therefore, it is needed to be examined with long term field experiments and different crops.