Journal of Environmental Biology

Evaluation of soil enzyme activities as soil quality indicators in sludge-amended soils

Efsun Dindar*, Fatma Olcay Topa? Şağban and H?seyin Savaş Başkaya

Department of Environmental Engineering, Faculty of Engineering and Architecture, Uludag University, 16059 G?r?kle, Bursa, Turkey

*Corresponding Author?s Email : efsun@uludag.edu.tr

Publication Data

Paper received:

05 October 2013

Revised received:

07 May 2014

Accepted:

28 November 2014

Abstract

Soil enzymatic activities are commonly used as biomarkers of soil quality. Several organic and inorganic compounds found in municipal wastewater sludges can possibly be used as fertilizers. Monitoring and evaluating the quality of sludge amended soils with enzyme activities accepted as a beneficial practice with respect to sustainable soil management. In the present study, variation of some enzyme activities (Alkaline phosphatase, dehydrogenase, urease and β-glucosidase activities) in soils amended with municipal wastewater sludge at different application rates (50, 100 and 200 t ha^-1 dry sludge) was evaluated. Air dried sludge samples were applied to soil pots and sludge-soil mixtures were incubated during a period of three months at 28?C. The results of the study showed that municipal wastewater sludge amendment apparently increased urease, dehydrogenase, alkaline phosphatase and β-glucosidase activities in soil by 48-70%, 14-47%, 33-66% and 9-14%, respectively. The maximum activity was generally observed in sludge amended soil with dose of 200 t ha^-1. Urease activity appeared to be a better indicator of soil enhancement with wastewater sludge, as its activity was more strongly increased by sludge amendment. Accordingly, urease activity is suggested to be soil quality indicator best suited for measuring existing conditions and potential changes in sludge-amended soil.     

 Key words

Enzyme activities, Incubation, Soil amendment, Wastewater sludge 

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