Effects of the Zeolite, Plant Growth Promoting Rhizobactria (PGPR) and Humic Acid on early growth of Atriplex canescens L. seedlings in Arak

To investigate the effects of Zeolite, Plant Growth Promoting Rhizobactria (PGPR) and Humic Acid on growth of Atriplex canescens L. seedlings, an experiment was conducted in a factorial randomized complete block design with three replications under dryland conditions at Arak in autumn 2010.Treatments consisted of zeolite (0, 500 & 1000 g per plant), PGPR (0 & 25 ml per plant) and humic acid (0 & 10 ml per plant), were mixed with the soil in the hollows. Each replication consisted of five seedlings and in total, 180 seedlings were examined. In next fall, plant height, stem diameter, above ground biomass and underground biomass were measured. Results showed that with consuming of zeolite, plant height (10.49%), stem diameter (11.20%) and root biomass (67.99%) were significantly increased compared with control. Plant height (6.16%) and stem diameter (6.01%) showed a significant increase by using PGPR and also plant height (6.30%) and stem diameter (6.14%) showed a significant increase by using humic acid. Results showed that 500 g of zeolite, with the use of PGPR and humic acid had the greatest effects on early growth of seedlings and using of 500 g zeolite per plant, lead to 68% increase in root biomass. Since the lack of proper development of roots in first year is an important reason for the failure of seedling plantation projects, according to abundance and low price of zeolite, so this treatment is recommended to increase the success of Atriplex seedling plantation projects.