Optimal nitrogen fertilizer consumption under sprinkler irrigation system in different seeding density and wheat cultivars in Karaj

The large area of wheat cultivation in Iran is located in arid and semi-arid regions and due to water shortage in end growing stage, there is competition between wheat and other crops for water allocation. In these conditions, using suitable seeding density and modern irrigation systems for yield increasing is important. Although Nitrogen is the most important element for quantity and quality of wheat, but over using of Nitrogen base fertilizers causes leaching, decreasing fertilizers use efficiency and groundwater contamination. This research was conducted during two years with Split Factorial Design experiment. The treatments of this experiment were: Three fertilizers application methods (conventional fertilizers application with full recommended amount, fertigation method with sprinkler irrigation and full recommended amount, and fertigation method with sprinkler irrigation and 70% nutrition recommended), three wheat variety (Pishtaz, Shiraz, and Bahar) and three plant density (300, 400, and 500 seed in each square meter). In this study the amount of water use, fertilizer requirement in case of fertigation, suitable density and variety of wheat under these conditions (sprinkler irrigation and fertigation) were determined and recommended for the region. Statictical test was used for identifying of data variation uniformity. Since the variation uniformity hypothises verified, the combine analysis of data was possible. Therefore, combine statistical analysis for two year were used. Maximum grin yield 6065, 5786 and 5943 kg/h were belonging to Pishtaz, fertigation method with sprinkler irrigation and full recommended amount and 400 seed density per square meter, respectively. Minimum grin yield 5517, 5708 and 5576 kg/h were belonging to Shiraz, fertigation method with sprinkler irrigation and 70% nutrition recommended fertigation and 500 seed density per square meter, respectively. Mean intraction effect comparison between fertigation methods, varieties and seed densities showed that maximum grin yield (6307 kg/h) was belonging to Pishtaz, fertigation method with sprinkler irrigation and full recommended amount fertigation and 400 seed density per square meter. However, minimum grin yield (5359 kg/h) was belonging to Shiraz, fertigation method with sprinkler irrigation and 70% nutrition recommended fertigation and 500 seed density per square meter. The most protein percentage were belonging to Shiraz variey, fertigation method with sprinkler irrigation and full recommended amount fertigation and 300 seed density per square meter. Also the leats protein percentage were belonging to Bahar variey, fertigation method with sprinkler irrigation and 70% nutrition recommended and 500 seed density per square meter. Maximum grin yield (5786 kg/h) and protein (20.8%) was belonging to fertigation method with sprinkler irrigation and full recommended amount, respectively. The amount of produced grin per appllied one kg Urea were 15.4, 15.5, and 22.8 kg in three fertilizer treatments, respectively. Therefore, the Nitrogen use efficiency in fertigation with 70% nutrition recommended (fertigation method with sprinkler irrigation and 70% nutrition recommended) was high. Results showed that the fertigation method with sprinkler irrigation and 70% nutrition recommended, Pishtaz variety and 400 seed density per square meter were suitable treatments in this experiment.