An experiment to examine the use of sewage sludge as a fertiliser for pole-stage Corsican pine (Pinusnigra var. maritima (Ait.) Melville) is described. Dominant and codominant trees responded markedly to additions of sludge at rates of 200 and 400 m3•ha−1, increasing sawlog volume by over 50% in treated plots. Foliar analyses suggest that the trees have responded to phosphorus in the sludge. The greatest impact of sludge on the soil occurred in the litter layer; concentrations of nitrogen, phosphorus, calcium, zinc, copper, cadmium, and lead were all greater compared with concentrations of untreated controls. Nevertheless, at rates of sludge application appropriate to fertilising (200 m3•ha−1), additions of heavy metals are considered small and are unlikely to cause adverse environmental effects.
Environmental Effects Of Sewage Sludge Carbonization And Other Treatment Alternatives