Abstract

The single application of either sewage sludge with high aluminium concentration, wheat straw or the mixture of both residues to soil did not increase the growth of Eucalyptus globulus Labill. However, inoculation with either the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis, the saprobe fungi Coriolopsis rigida (Berk. Et Mont.) Murrill and Phanerochaete chrysosporium Burds or the combination of each saprobe with the AM fungus increased both the P concentration and dry weight of E. globulus shoots. These effects were greater in the presence of wheat straw or sewage sludge, but were greatest in the presence of the mixed residue. Phanerochaete chrysosporium had the greatest effect on plant dry weight when co-inoculated with R. irregularis in the treatment with mixed residue. The co-inoculation of AM and saprobe fungi increased fluorescein diacetate and beta-glucosidase activities in the bulk soil of E. globulus grown in the treatment with mixed residue. However, only the AM fungus increased dehydrogenase activity, and phosphatase activity was similar in all treatments tested. Our results showed that sewage sludge with high aluminium concentration could be used as a soil amendment to improve the growth of E. globulus when mixed with wheat straw and co-inoculated with saprobe and arbuscular fungi.