Sewage sludge is increasingly used as an organic amendment to soil, especially to soil
containing little organic matter. However, little is known about utility of this organic
amendment with N-enriched or adjusted C: N ratios in soil. We studied the effects of adding
of different doses (0, 100, 200 and 300tha− 1) and C: N ratios (3: 1, 6: 1 and 9: 1) of sewage
sludge on enzyme activities (β-glucosidase, alkaline phosphatase, arylsulphatase and
urease) in a clay loam soil at 25° C and 60% soil water holding capacity. Nitrogen was …