اثر کاربرد کودهای زیستی نیتروکسین و بیوفسفات بر کارایی مصرف عناصر و شاخص برداشت گاوزبان (Borago officinalis L.) تحت تنش کم آبی

In order to study the effects of application of nitroxin and biophosphate on the nutrient use efficiency and harvest index of (borago officinalis l.) under water deficit stress, a split plot field experiment based on randomized complete block design with three replications was conducted in kermanshah, iran, in 2011. water deficit stress was the main factor with four levels, in vegetative stage, reproductive stage, vegetative + reproductive stages and without water deficit (control), which was applied by interrupting irrigation in the specific stages. fertilizers consisted of three levels, 100% chemical fertilizer, 50% of chemical fertilizer + biofertilizers (nitroxin and biophosphate), 25% chemical fertilizer + biofertilizers as sub factor. results indicated that treatments had significant effects on biological yield, economic yield, reproductive effort and use efficiency of nitrogen and phosphate. water deficit stress decreased the mentioned criteria. it reduced 45.1% harvest index of florescence in reproductive stage and 23.4% in vegetative stage. in the fertilizer treatments the highest amount of yield in difference levels of water deficit were achieved in 50% of chemical fertilizer + biofertilizers and the highest florescence yield (534.3 g/m2) and grain yield (19.9 g/m2) were obtained in mentioned treatment in non-stress situation. the 50% chemical fertilizer + biofertilizers treatment had higher use efficiency of nitrogen and phosphate in the water deficit stress and control in comparison with 100 % chemical fertilizers.