This study was conducted at the plantation of Solid Disposal Facility, and Compost Production, "N9", Alexandria, Egypt, to pinpoint the effect of treated sludge on the growth, yield of Acacia saligna, Casuarina glauca and Eucalyptus camaldulensis trees aged 10 years and on the dynamic of activity and population of vescicular- arbuscular mycorrhizal fungi. The study aimed also to investigate the bioextractional – remediation role (if any) of trees against sludge pollutants.
Data obtained indicated that, except for height of A. saligna, all growth and yield parameters of sludge amended trees (tree height at diameter outside bark at breast height (dodh), commercial volume of wood per tree, yield per feddan, av. of annual yield per feddan and basal area) were significantly higher than those of the control, since the solid dry timber was accounted for 3.76 and 4.76 ton/ feddan in unamended and amended A. Saligna with sewage sludge, respectively. At the same order, the yield was 124.81 and 135.47 ton/ feddan in C. glauca and 60.6 and 117 ton/ feddan in E. camaldulensis. Concentrations of macro-elements, N, P, K and Na and heavy metals (Cd, Zn and Pb) in soil, shoots and woods from bark to pith of sludge- amended and unameneded trees and rhizosphere were increased concentration of macro elements and heavy metals in foliage and wood of trees applied with sewage sludge. However, trunk analysis revealed that the bark displayed the higher concentration of heavy metals followed by heartwood. Specific gravity, either of sapwood or heartwood was significantly higher in unamended trees compared with amended ones due to its increased growth rate.
The data also revealed the presence of clamydospores of AM fungi, namely, Glomus aggregatum, G. fasciculatum and G. mossae.
Infection level (%) of feeder roots and population (number of spores per 10 g of dry rhizosphere soil) of clamydospores of AM fungi were affected negatively by sludge amended. It can be concluded that the growth and yield of tree stand studied can best be managed by amendment with sludge to achieve better results. Also, E. camaldulensis and C. glauca trees displayed potential phytoextraction remediation towards heavy metal pollultants concomitant with positive yield. It is recommended, however, to capitalize on sludge for establishment several tree species and others in afforestation programs in low fertile soils in arid zones which being inadvisable to edible crops and manage native tolerant AM fungi under pollution situations as well.