Effect of long-term integration of sewage-sludge and fertilizers on wheat productivity, profitability and soil fertility

A field experiment was carried out to assess the effect of long-term combined application of sewage sludge (SS) and chemical fertilizers on yield, nutrient uptake, soil fertility status and economics of wheat (Triticum aestivum L.) grown in the experimental plot of ICAR-Indian Agricultural Research Institute (IARI), New Delhi, India. The experiment comprised of eight different treatment combinations including different levels of sludge and fertilizers. The sludge treatments were applied before sowing of kharif maize (Zea mays cv. PMH-1) in maize-wheat cropping system, while rabi wheat (Triticum aestivum cv. HD-3059) was grown with recommended dose of NPK. Results revealed that pH, electrical conductivity (EC) and available potassium (K) content in soil were not significantly affected by the application of sludge. However, soil organic carbon (SOC), cation exchange capacity (CEC), available nitrogen (N) and phosphorus (P) content in soil were significantly increased over control due to application of sewage-sludge. The combined application of sludge @ 2.5 t ha⁻¹ along with NPK showed the highest grain yield, agronomic efficiency and total N, P and K uptake by wheat crop. The maximum gross return, net return and B:C ratio were recorded under combined application of NPK and SS @ 2.5 t ha⁻¹. The present study showed that integrated use of 100% NPK along and SS @ 2.5 t ha⁻¹ could be an effective option for enhancing wheat yield, soil fertility status, and economic return.