effect of biological and chemical fertilizers on oil, seed yield and some agronomic traits of safflower under different irrigation regimes

introduction safflower) carthamus tinctorius l.) is a tolerant plant to water deficit due to long roots and capability for high water absorption from soil deeper parts. safflower can growth successfully in regions with low soil fertility and temperature. behdani and mosavifar (2011) reported that drought stress affect on yield by reducing yield components and agronomic traits. biofertilizer during a biological process chanced the nutrients from unusable to usable form for plants in soils (aseretal, 2008). mirzakhani et al. (2008) found that inoculation of seed with free-living bacterium azotobacter and a symbiotic fungus productive mycorrhiza addition to increasing oil and seed cause increasing resistance against two factors of unfavorable environmental and to improve quality of product. in order to study the effect of biological and chemical fertilizers on oil, seed yield and some of agronomic traits of safflower under irrigation of different regimes an experimental design was conducted. materials and methods in order to study the effect of biological and chemical fertilizers on oil, seed yield and some of agronomic traits of safflower under irrigation of different regimes an experiment was carried out split plot based on randomized complete block design (rcbd) with three replications in experimental farm of payame-noor university of zabol during 2012-2013 growing season. irrigation regime in three levels include: i1 (control) irrigation in all growth stages, i2 stop irrigation from sowing to flowering (irrigation in growth stages flowering, and seed filling), i3 irrigation in growth stages rosset, stem elongation, heading and stop irrigation in flowering, and seed filling were as main plots and fertilizer resources in five levels included: f1 non application chemical fertilizer (control), f2 pure application chemical fertilizer (npk) 99, 44 and 123 kg.ha-1 respectively, f3 nitroxin application (2 l.ha-1) f4 azotobacter application (2 l.ha-1) and f5 nitrokara application (100 g.ha-1) were sub plots. bio-fertilizers mixed with seeds before planting based on manufacturer's recommendations. fertilizers were applied at ratio of 123 kg.ha-1 potassium based on (k2o), of sulphatedipotash, 44 kg.ha-1 phosphor based on (p2o5) of super-phosphate triple respectively, (based on the results of above soil analysis) along with one-third of 99 kg.ha-1 pure n based on urea prior to sowing. other two-third of n was applied at the start stem and heading stages respectively. all other agricultural practices (weeds control and irrigation), were performed when they were required and as recommended for commercial safflower production. a random sample of five plants was selected from each plot in physiological ripening to estimate the different parameters. data were analyzed by using mstat-c statistical package (mstat-c, version 1.41, crop and sciences department, michigan state university, usa). duncan multiple range test was used to do mean comparisons. results and discussion analysis of variance showed that the effect of irrigation and fertilizer resources on yield, yield components, oil yield and rwc were significant. results showed that seed yield in treatment non stress with mean 1539 than stop irrigation in vegetative phase (rosset, stem elongation, heading), and stop irrigation in reproductive phase (flowering, and seed filling) had increased 45 and 27 percent, respectively. high yield by increasing yield components under water supply reported by behdani & mosavifar, (2011). however there was no significant difference from aspect seed yield between biological fertilizers, but nitrokara bio-fertilizer showed 19 percent increase than non-application - chemical fertilizer (control). biofertilizer able during a biological process, chanced the nutrients from unusable to usable form for plants in soils. by increasing stress severity, leaf relative water content (rwc) than (control) irrigation in all growth stages decreased, so lowest rwc obversed when irrigation was cut in vegetative phase (rosset, stem elongation, heading). increasing duration and intensity of stress had an impact on loweringrwc. reduction in the rwc under drought stress by behdani & mosavifar, (2011), has been reported in safflower but with, application bio-fertilizers chances in rwc were increasing. data analysis showed that interaction effect of bio-fertilizer treatment and drought stress on seed yield was significant. conclusion in general, results of the present study revealed that irrigation in all growth stages, especially in stages sensitive to drought (flowering, and seed filling) and application of biological fertilizers adapted such as: nitrokara and nitroxin had positive effects in improving quantitative and qualitative yield of safflower.