Afforestation may influence changes in tailing heaps in a long time

A soil and plant survey was carried out in a tailing heap afforested 30 years ago to gain information about the changes in the tailing and metal uptake by plants. A poor development of Technosol was found. It was observed accumulation of OMspatiotemporarily. Metal concentrations in the soil profile varied between plots. Extractable Pb concentrations ranged from 0.4 to 2.9%; extractable Cd varied 9.7-46% of the total concentration. PCA analysis shows DTPA-Zn and DTPA-Cu, Na, K, and OM have the widest concentrations range between soil layers.Casuarina equisetifoliaandPennisetum clandestinumformed a pristine uniform litter layer, whereasEucalyptus camaldulensisdid not form a litter layer.Casuarina equisetifoliahas a higher population density (756 p ha(-1)) compared toPopulus nigra(528 p ha(-1)) andE. camaldulensis(621 p ha(-1)).Pennisetum clandestinumgrew successfully and covered the tailing, but Cd and Pb concentrations were above the domestic animal toxicity limits, 0.5 and 10 mg kg(-1), respectively.Populus nigraabsorbed more Zn thanCasuarina equisetifoliaandEucalyptus camaldulensis. Trees species did not accumulate high foliar Cu and Zn concentrations, but Pb (47.7-124.3 mg kg(-1)) and Cd (5.7-26.8 mg kg(-1)) concentrations are over those reported for mature leaf tissues.

Automated summary

In a soil and plant survey of a tailing heap afforested 30 years ago, it was found that there was poor development of Technosol, accumulation of organic matter temporarily, variations in metal concentrations between plots, and higher Cd and Pb concentrations than domestic animal toxicity limits. Trees species did not accumulate high foliar Cu and Zn concentrations, but had higher Pb and Cd concentrations compared to mature leaf tissues.