Title: Soil microbial properties and functional diversity in response to sewage sludge amendments

Abstract

Soil organic matter has vital role in maintaining important soil functions. Consequently, using sewage sludge as soil organic amendment is considered one of the agricultural practices for improving soil fertility, which is also a safe approach for its disposal. The present research was carried out to analyze the different microbial activities and functional diversity of agricultural soil with regard to sewage sludge application. A laboratory experiment was set up by taking the agricultural soil from Haryana Agricultural University fields and amended with 5, 10, 20, 30 and 50 t ha−1 of sewage sludge. It was observed that soil microbial biomass increased upto 60% and potential activities of dehydrogenase, alkaline phosphatase and urease enzymes increased upto 50– 55% with increasing application rates of sewage sludge. In addition the community-level physiological profiling technique (CLPP) based on carbon source utilization was used to determine the microbial functional diversity of soil. The results indicated higher functional diversity of microbial population capable of exploiting different carbon substrates with sewage sludge application. These results are imperative for improving the approach of sewage sludge application to the agricultural soil in consideration of increasing soil fertility with reducing the use of chemical fertilizers.