The Effect of Nitrogen Fertilizer Treatments on Yield Traits, Essence Percentage, and Shoot Nitrogen Content of ‎Cumin under Different Irrigation Regimes in the Southern Region of Tehran

In order to study the effect of nitrogen fertilizer treatments on yield traits, essence percentage, and the amount of nitrogen in cumin stem and leaves under different irrigation regimens, an experiment has been conducted as split plot based on randomized complete block design with three replications in the 2016-2017 crop season at the Research Field of Agriculture Faculty, Shahed University, Tehran, Iran. In this experiment, the main plot is consisted of different irrigation regimes at three levels (no stress, mild stress or irrigation based on draining 40% of available water, and severe stress or irrigation based on draining 80% of available water) and the subplot includes four levels of nitrogen fertilizer treatments (100% and 50% fertilizer recommendation of nitrogen (urea), seed stained biofertilizer application (Nitroxin), and combination treatment of biofertilizer and 50% fertilizer recommendation nitrogen). The results show that increasing deficit irrigation at a mild level and, above that, at a severe level, while increasing the percentage of essence, has had a significant negative effect on yield and yield components, total chlorophyll, shoot nitrogen concentration, and essence yield. Application of combination nitrogen fertilizer (urea + Nitroxin) while increasing the yield and yield components of Cumin, increase the percentage and yield of essence, and shoot nitrogen concentration, generally causing the most desirable quantitative and qualitative yield of Cumin.