THE EFFECT OF COMPOST AND SEWAGE SLUDGE ON SOIL BIOLOGIC ACTIVITIES IN SALT AFFECTED SOIL

Abstract

Saline soil was amended with 13.3 and 26.6 g kg -1 of Municipal Solid Waste (MSW) compost or sewage sludge, and arylsulphatase (ARY), phosphatase (PHO), dehydrogenase (DEH), β-glucosidase (β-GLU), urease (URE) and catalase (CAT) activities as well as physical-chemical properties were determined after 70 day of incubation under laboratory conditions. MSW compost and sewage sludge significantly improved soil physical-chemical properties, especially carbon and nitrogen contents. Accordingly, overall enzyme activities were substantially promoted in presence of both amendments and the higher increases were measured at 13.3 g kg -1 of MSW compost (increases by 107%, 43%, 20%, 11%, and 148% for, DEH, β-GLU, PHO, URE, and CAT, respectively). Lower beneficial effects occurred at 26.6 g kg -1 of sewage sludge possibly because of the increased salinity or the presence of trace elements by sewage sludge application. As a general response, MSW compost supplied at 13.3 g kg -1 seems