Response of rainfed maize (Zea mays) to nitrogen management in mid hill acidic soils of Sikkim

Two field experiments were conducted during 2005 and 2006 at Tadong, Sikkim to study the effect of nitrogen scheduling and integrated nutrient management on yield, nutrient uptake and economics of rainfed maize (Zea mays L.) under nine schedules of nitrogen application and 11 combinations of urea, farmyard manure (FYM) and Azotobacter seed inoculation for integrated nutrient management. Amongst the various schedules of N application 1/3 N side-band placement (SBP) at sowing + 1/3 N SBP 25 days after sowing + 1/3 N SBP 50 days after sowing recorded the highest grain yield (6.24 and 6.46 t/ha), NPK uptake (161.2 kg N/ha, 50.3 kg P/ha and 150.1 kg K/ha) and return/rupee investment (1.97). The yield increase was more pronounced with enhancement in proportion of N supply through urea from 40 to 80 kg N/ha and decrease in the quantity of farmyard manure from 20 to 10 t/ha. Integration of Azotobacter seed treatment + 10t FYM/ha + 40 kg N/ha 25 days after sowing + 40 kg N/ha 50 days after sowing was the best treatment with the highest grain yield (6.77 and 6.93 t/ha), NPK uptake (168.4 kg N/ha, 49.0 kg P/ha and 154.7 kg K/ha) and return/rupee investment (1.99). Integrated nutrient management resulted in higher residual soil nutrients.