ABSTRACT
To examine the effect of humic acid and nano-chelate iron on the absorption of some nutrients and oil content and essential oil of (Nigella sativa) under two-year experimental drought stress (2018-and 2019-) in Agricultural and Natural Resources Research Station of Eqlid city, an experiment was conducted as a split factorial design in the form of a randomized complete block design with three replications. The main plots included irrigation at three levels (50, 75, and 100% of available water), sub-factors including humic acid at three levels (0, 250, and 500 mg/l), and nano-chelate iron at three levels (0, 1, and 2 g/l). The results revealed that drought stress decreased nutrient absorption and the amount of essential oil and oil content. Applying humic acid and nano-chelate iron decreased the effects of stress so that the application of humic acid and nano-chelate iron increased the yield by 21 and 27% compared to the control treatment. Interaction of humic acid, nano-chelate iron showed that the highest grain yield (1036) kg/ha) was observed in 500 mg/l of humic acid and 2 g/l of nano-chelate iron with 75% of available water. In general, it can be concluded that the use of humic acid and nano-chelate iron in conditions of water scarcity caused more absorption of nutrients, increased grain yield, and moderated the effects of drought stress compared to the control.
Disclosure statement
No potential conflict of interest was reported by the author(s).