Effect of Soil Application of Humic Acid and Fluvic Acid on Agronomic traits of Barley

One of the most important issues affecting environmental health and sustainable food production is application of organic fertilizers instead of chemical fertilizers. This study set out to investigate the effect of application of soil humic acid and fulvic acid on barley plant. To this end a factorial experiment was carried out on the basis of randomized complete block design with four replications in the research greenhouse of Roudehen in 2012. The first factor included four levels of humic acid concentration (0, 0.5, 1, and 2 g per kg soil) and the second factor included 4 levels of humic acid concentration (0, 0.5, 1, and 2 g per kg pot soil). The results showed that humic acid and fulvic acid had a significant effect on dry weight of stem, leaf, and spike. Moreover, humic acid and fulvic acid had a significant effect on grain yield (at 1% level), biological weight (at 1% level), and 1000-grain weight (at 5% level), but their effect on harvest index was not significant. The highest rate of biological weight was obtained when 1 g humic acid per kg soil and 1 g fulvic acid per kg soil were applied. In general, the results of the research indicated that application of humic acid and fulvic acid had a positive effect on improvement of growth and yield of barley plant.