effect of azolla compost and various biofertilizers on growth and quality of zinnia flower (zinnia elegans thumbelina)

Zinnia is an annual plant with the long flowering period from late spring to midautumn. it is a popular plant for landscape. in the present study, the effect of two types of growth promoting bacteria and azolla compost on some ornamental characteristics of zinnia were evaluated in pot cultivation and greenhouse conditions. the factorial experiment was conducted in three replications based on a completely randomized design with two factors, including azolla compost in 6 levels (0, 10, 20, 30, 40, 50 percent) and growth promoting bacteria in 3 levels (without bacteria, azospirillum and azotobacter bacteria). the results showed that growth promoting bacteria (azospirillum and azotobacter) and azolla compost had a significant effect on the investigated factors. treatment of 50% azolla compost and azospirillum compared to other treatments had higher leaf and root fresh weight, leaf nitrogen and plant height. moreover, 10% azolla compost and azospirillum was the best treatment in terms of leaf and root dry matter content. according to conducted evaluation, azospirillum with less percentage of compost had a significant effect on dry weight and azospirillum with a higher percentage of compost had a significant effect on fresh weight. besides, a higher percentage of compost in azospirillum in treatment azospirillum and 50% compost had a significant effect on leaf nitrogen and height of the stem.