Changes in soil quality in response to short-term application of municipal sewage sludge in a typic haplustept under cowpea-wheat cropping system

AbstractRecycling of sewage sludge as an organic amendment and source of macro- and micro-nutrient in agricultural fields can be a potential option for proper disposal of organic wastes. A field experiment was conducted at the experimental farm of Indian Agricultural Research Institute, New Delhi, to examine the short-term effect of municipal sewage sludge application on soil physical, chemical and biological properties of a sandy loam soil (typic haplustept) under cowpea-wheat cropping system. Control and four treatments adopted in this study were, 100%NPK (nitrogen, phosphorus and potassium), and three sludge applications i.e. equivalent to 5, 10, 15tha−1. The results showed a positive effect of sewage sludge on different parameters. Bulk density was decreased by about 21% in surface layer, increased the mean weight diameter (MWD), porosity, dehydrogenase activity and microbial biomass carbon. A higher amount of aggregate associated organic carbon was associated with soil macro-aggregate (>0.25mm) in comparison to micro-aggregate (