The effect of spraying humic acid on some morphological and physiological traits of bean (Vicia faba L.)

In order to evaluate the effect of spraying humic acid on some morphological and physiological traits of fava bean, a factorial experiment was conducted in a randomized complete block design with three replications in Chalous during 2014-16. The investigated factors included spraying time at three levels (before planting, mid-vegetative growth, and the beginning of reproductive growth) and the amount of humic acid spraying at four levels (0, 200, 300, and 400 mg/l/ha). The results of analysis of variance showed that the interaction of year × amount of humic acid on the most studied traits showed a significant difference at a probability level of 1%. Also, interaction of year × consumption time of humic acid had a positive and significant effect on dry weight of 100 seeds, grain yield, and nitrogen and potassium contents of seeds at p≤0.01. Triple interaction of year × amount × consumption time of humic acid on nitrogen, phosphorus, and potassium contents were significant at p≤0.05. Comparison of means showed that spraying humic acid at 200 mg /L/ha had a positive and significant effect on fresh weight of 100 seeds and grain yield. Also, spraying humic acid at 300 mg/L/ha at the second stage of vegetative growth in the second year was effective on the concentrations of potassium and phosphorus in seeds.