Effect of urea and nitrapyrine on quantitative and qualitative characteristics of barley cultivars (Hordeum vulgare L.) under different tillage conditions

Tillage methods are among the most successful factors in agriculture that have a significant impact on the quality and quantity of agronomic plants. To evaluate different tillage methods and urea fertilizer with nitrapyrin on total chlorophyll content, grain protein, yield, and yield components of two barley (Hordeum vulgare L.) cultivars, an experiment was conducted as split factorial in the randomized complete blocks with three replications in the Research farm Nuclear Science and Technology in 2017-2018. Experimental treatments included conventional and minimum tillage, fertilizer treatments at three levels of 0, 150 kg urea ha-1 and 150 kg urea ha-1 + nitrapyrin nitrification inhibitor and wheat cultivars (Valfajr and Roddasht). The highest biological yield (14334 kg ha-1) and leached nitrate were obtained in minimum and conventional tillage. The highest plant height, leaf dry weight as well as nitrogen harvest index were observed in conventional tillage and Valfajr cultivar (90.7 cm), minimum tillage and 150 kg urea ha-1 + nitropyrin (287.07 g m-2) and conventional tillage and 150 kg urea ha-1 + nitropyrin (41.63 kg kg-1), respectively. The highest leaf area index (3.79) and leaf dry weight (309.4) were observed in Ruddashr cultivar and 150 kg urea ha-1 + nitropyrin. The highest grain protein (13.4%) and nitrogen harvest index (41.55 kg kg-1) were observed in Ruddasht cultivar and 150 kg urea ha-1 + nitropyrin. The interaction effect of tillage system, fertilizer and cultivar showed that the highest total chlorophyll content was obtained in the minimum tillage, treatment of 150 kg urea ha-1+ nitropyrin and Ruddasht cultivar. Minimum tillage, 150 kg urea ha-1 + nitropyrin and Ruddasht cultivar obtained the highest grain yield (6563 kg ha-1) and harvest index (41.9%). According to the results obtained from grain yield, grain protein, and biological yield, in minimal tillage, Ruddasht cultivar and simultaneous application of urea + nitropyrin are recommended.