Evaluating effects of drought stress and bio-fertilizer on quantitative and qualitative traits of valerian (valeriana officinalis l.)

This study was conducted to investigate the effects of bio-fertilizers and drought stress on valerian. A split plot experiment based on randomized complete block design with three replications was conducted. Drought stress at three levels: 60, 90, and 120 mm evaporation from pan class A were randomized to the main plots and subplots consisted bio-fertilizers at eight levels: control (non-inoculation), Mycorrhiza, Azotobacter, Azospirillum, combination of Azotobacter and Azospirilum, combination of Azotobacter and Mycorrhiza, combination of Azosperilum and Mycorrhiza, combination of Azotobacter, Mycorrhiza, Azospirilum. The results showed that interaction effect of both factors on root and shoot dry weight, content of proline, carotenoids, nitrogen and potassium, essential oil were significant. The main effects of factors on relative moisture content, chlorophyl a and b, phosphorus, soluble sugars and essential oil yield were significant. According to the results, it is recommended to replace chemical fertilizers with bio-fertilizers to achieve sustainable agricultural goals.