Investigating the Effect of Different Tillage Methods and Nitrapyrin on Increasing Nitrogen Utilization Efficiency on Physiological and Biochemical Traits in Different Wheat Cultivars

In the present study, the effect of different tillage methods and urea fertilizer plus nitrapyrin on increasing nitrogen utilization efficiency on physiological and biochemical traits of wheat cultivars was examined. It was conducted as a factorial split randomized complete block design with three replications in two years (2016-2017) and (2017-2018) in the Research Field of Institute for Nuclear Science and Technology, Atomic Energy Organization of Iran (Zafaranye Farm in Karaj). Experimental treatments included tillage system at two levels of conventional tillage and minimum tillage (only disk), urea fertilizer at three levels, including control (no fertilizer application), urea fertilizer (150 kg/ha), urea fertilizer (150 kg/ha) plus nitrapyrin, wheat cultivar at two levels, including Arg cultivar and Omidbakhsh cultivar. Tillage factor in main plot and urea fertilizer factors and wheat cultivars were placed as factorial inside the sub-plot.  The results showed that the use of minimum tillage system had a significant effect on chlorophyll content, leaf area index, leaf dry weight, total dry weight, nitrate reductase enzyme, seed nitrogen, plant nitrogen, nitrogen harvest index, nitrogen utilization efficiency, glucose, fructose, sucrose, leaf iron, leaf phosphate, auxin hormone, and gibberellin hormone. Triple interaction of tillage, nitrogen fertilizer and cultivar also had a significant effect on leaf dry weight, total dry weight, seed nitrogen, nitrate reductase enzyme, nitrogen harvest, glucose, sucrose, leaf iron, leaf phosphate, and auxin hormone. When the minimum tillage was used, all of the plant traits were affected and increased compared to the conditions in which conventional tillage was used. When the urea fertilizer and nitrapyrin were used, physiological and biochemical traits of the plant increased. By improving the conditions for the activity of nitrapyrin in soil, all plant traits increased compared to control. Therefore, minimum tillage and urea fertilizer plus nitrapyrin can be used in conditions where less nitrogen is available to the plant.