the effects of trichoderma fungi symbiosis and nitrogen on essential oil and leaf pigments in green cumin (cuminum cyminum l.) under weed competition

Green cumin is one of the most widely utilized medicinal plants both in iran and globally, which is mainly exploited for the purpose of using its essential oil. it seems necessary to conduct an experiment in this direction to pay attention to sustainable agriculture, which can be achieved by using biofertilizers along with chemical inputs such as nitrogen. this research was carried out in maraveh-tappeh county and in two distinct regions (qarah-dam and shalami) during the 2023 crop year, as a split factorial experiment based on randomized complete block design with three replications. the experimental treatments were nitrogen fertilizer levels (control, 50 and 100 % recommended nitrogen from urea) as the main plot, biofertilizer treatments (control, seed inoculation with trichoderma longibrachiatum, trichoderma atroviride, and co-inoculation (trichoderma longibrachiatum and trichoderma atroviride) and weeding management (no weeding and weeding) as sub-plots. the results showed that the highest essential oil content and yield in both regions were achieved under the no weeding condition with 100 % recommended nitrogen and co-inoculation treatments. also, the use of trichoderma fungi and nitrogen had a positive effect on the content of chlorophyll a, chlorophyll b and total chlorophyll.