Effect of combining biological and chemical fertilizers on yield and quality of Black Cumin grain under different irrigation levels

Drought stress is one of the abiotic factors that reduces crop production. The use of biofertilizers can mitigate the negative effects of drought stress and reduce chemical inputs on agricultural systems. In order to investigate the effect of combined management of chemical and biological fertilizers on yield and quality-related traits of black cumin (Nigella sativa L.) under different irrigation levels, a split-plot experiment was conducted based on a randomized complete block design with four replications at a research farm University of Kurdistan during ۲۰۱۶ spring. Two irrigation levels (۱۰۰% and ۷۰% of plant water requirement) were randomized on the main plot. Five fertilizer levels (۱۰۰% chemical fertilizers, ۸۰% chemical fertilizers + biofertilizers, ۶۰% chemical fertilizers + biofertilizers, ۴۰% chemical fertilizers + biofertilizers, and non-fertilizer application) were randomized on a sub-plot. The results showed that irrigation by ۷۰% of the plant water requirement significantly ramped down plant height (۱۹%), number of capsules per plant (۱۲.۱%), number of seeds per capsule (۲۵.۱%), ۱۰۰۰-seed weight (۰.۵). ۷%), grain yield (۲۷%), biological yield (۲۱.۳%), harvest index (۲.۲%), phosphorus content (۹.۵%) and grain potassium (۱۲.۱%), essential oil ( ۱۲.۱%) as well as oil yield (۳۰.۲%). The combination of bio-chemical fertilizers had positive effects on the studied traits. Finally, the highest grain yield was obtained from the combined treatment of ۶۰% chemical fertilizers + bio-fertilizers (۷۹۸.۱۸ kg ha-۱). Due to the positive effects of combining bio-chemical fertilizers on the yield and quality of black cumin, it is recommended to replace the combination of bio-chemical fertilizers instead of using only chemical fertilizers.  

Keywords:

Azotobacter , Essential oil , Drought stress , Oil yield , Mineral elements , ازتوباکتر , اسانس , تنش خشکی , عملکرد روغن , عناصر معدنی