Effects of dry sludge application on soil microarthropod communities in a reclaimed desert ecosystem

The ecological impact of dried sewage sludge addition to reclaimed soil was assessed by comparing soil microarthropod fauna (oribatid and collembolan populations) of sewage sludge treated plots with those of adjacent control plots. An Egyptian orchard of newly reclaimed soil cultivated with guava tr ees (sandy soil) at El Salheya region was selected for the present investig ation. Sludge application was performed at three doses i.e. 1.6 ton/ha, 3.3 ton/ha and 6.5 ton/ha. Four replicates were conducted for each dose applic ation through a one-year period (during the four seasons). Sludge applicati on had a marked influence on some soil microarthropods but no influence cou ld be detected on others. The intensity of the effect was strongly correlat ed to sludge doses. Also, a marked quantitative and qualitative influence c ould be observed on soil-bound mites. It was discovered that application of sludge up to 6.5 ton/ha over the period of a year to the reclaimed area pr oduced a marked significant effect on the oribatid community. Scheloribates laevigatus, Epilohmannia c. cylindrica and Isotomina thermophila may serve as bioindicators to evaluate the role of sewage sludge application on the soil habitat.