Wheat Yield as Influenced by Nitrogen Rates, Sources and Tillage Systems

Conservation tillage systems present a challenge for integrating an efficient fertilizer program in wheat (Triticum aestivum L.) production. A 2-year (2011–2013) field experiment was conducted to evaluate wheat response to three tillage systems (conventional, reduced and no tillage) and four nitrogen (N) [(0, 60, 120, 180 kg ha-1), and two nitroxin rates (0, 180 kg ha-1)] at School of Agriculture, Shiraz University, Shiraz, Iran. The experiment was conducted as a split plots arranged in randomized completely blocks design with three replications. Results showed that grain yield and most of the yield components were significantly influenced by tillage systems, N rates and sources. Nitroxin inoculation did not accomplish significant difference in grain yield, but it increased grain yield when it was applied with 180 kg urea ha-1 compared to no nitroxin treatment. The highest grain and biological yields were obtained when crop was sown under reduced tillage (RD) system combined with 180 kg ha-1 of nitroxin inoculation. Therefore, for sustained production of wheat in the region, integration of 180 kg ha-1 of nitroxin inoculation under RD system is recommended.