Effect of soil treatment with sewage and sludge on fungal populations

The effect of soil treatment with sewage and sludge at three doses (1%, 10% and 20% w/w) on its fungal population was studied in vitro. The treatment of soil with sewage significantly increased the count of total fungi after 1 week by the high dose, and after 12 weeks by each of the three doses. Fungi differed in their response to the different doses of sewage: some were promoted and others were inhibited. The count of total fungi was significantly raised by the low dose of sludge after 1 week of soil treatment, and by the medium and the high doses after 12 weeks. Counts of all fungi were significantly increased at certain treatments with sludge, except those of Aspergillus niger (at the high dose after 6 weeks), Fusarium (at each of the three doses after 3 weeks and at the high dose after 6 weeks) and Paecilomyces varioti (by the medium and the high doses after 1 week) whose counts were significantly lower than those in untreated soil.