Evaluation of organic and inorganic sources of nutrients in maize (Zea mays) and their residual effect on wheat (Triticum aestivum) under different fertility levels

Abstract

A field experiment was conducted during 2004–06 at New Delhi to evaluate the response of maize (Zea mays L.) – wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system to different nutrients management practices. Application of recommended dose of fertilizers (120 N+ 26 P + 32 K kg/ha) to maize resulted in maximum growth and yield of maize during both the years. During second year 60 kg N/ha (farmyard manure) + cowpea green manuring + Azotobacter treatment proved as effective as 120 N+ 26 P + 32 K kg/ha in terms of growth, yield attributes and yields of maize. However, wheat showed the highest response on residual fertility of 60 kg N/ha (farmyard manure) + cowpea green manuring + Azotobacter. Application of 120 N + 26 P + 50 K kg/ha showed the superiority over 60 N + 13P + 25 K in both maize and wheat. The uptake of N, P and K also exhibited similar trend to both direct and residual fertility to different nutrient management practices applied to either crop. The value of soil organic carbon increased from the initial status of 0.39% to the maximum status of 0.52% with the application of 60 kg N/ha (farmyard manure) +cowpea green manuring + Azotobacter. Similar trend was also found in respect of available soil N, P and K. The mean productivity (10.77 and 11.72 tonnes/ha maize equivalents), production efficiency (44.3 and 47.1 kg/ha/day), net returns (Rs 50 123 and Rs 55 655/ha) and net returns/rupee (Rs 1.97 and Rs 2.17) of maize–wheat cropping system were maximum with the application of 60 kg N/ha (farmyard manure) + cowpea + Azotobacter to maize. Interaction data on system productivity indicated the 50% saving of NPK in wheat by application of 60 kg N/ha (farmyard manure) + cowpea green manuring + Azotobacter in maize.