Impact of integrated use of bio and mineral nitrogen fertilizers on productivity and profitability of wheat (Triticum aestivum L.) under upper Egypt conditions

Abstract The effect of integrated use of mineral N fertilizer and biofertilizer (Azotobacter and/or Azospirillum) on grain and straw yields, harvest index and net profit of wheat was assessed. A field experiment was carried out during two years on a sandy soil. The recommended N (230 kg N ha-1) and biofertilizer (Azotobacter and Azospirillum) were applied alone and in various combinations among them. A randomized complete block design, with three replications, was used in this study. Treatments significantly affected grain and straw yields, and harvest index. The highest values of such traits were obtained in treatment T11 (75% mineral N + biofertilizer with Azotobacter and Azospirillum). However, T12 (50% mineral N + biofertilizer with Azotobacter and Azospirillum) resulted also higher values for the above mentioned traits comparing with T1 (100% mineral nitrogen and uninoculated) but the differences among the two treatments almost did not attain the statistical differences. In addition, T11 and T12 gave the maximum return and net profit per ha. From this study, it can be concluded that the biofertilizers (double-inoculation of Azotobacter and Azospirillum) of efficient strains could save 25 or 50 % of the recommended dose of mineral N.