Effect of applications of sewage sludge on N, P, K, Ca, Mg and trace element contents of plant tissues.

A four-month study was conducted in a greenhouse with Larix laricina grown on sand and nursery soil. This culture was fertilized with anaerobically digested sludge at various rates and doses. No direct relationship could be established between the growth of seedlings and the quantities of sludge applied. Relationships were, however, established between the quantities of sludge applied and the elemental composition of the tissues. There was a significant, positive correlation between the growth of seedlings and the phosphorus and nitrogen content of their tissues. These elements originated from the wastewater sludge. Tissues had potassium deficiencies and an excess of calcium, magnesium and trace elements.