Effects of humic acid and mycorrhiza on morphological characteristics and nutrients concentration of red bean (Vigna unguiculata L.)

In order to investigate the effect of interaction of mycorrhiza and humic acid on morphological characteristics, seed protein percentage, and nutrients concentration of red beans, an experiment was conducted as factorial randomized complete block design in three replications. Research factors included mycorrhiza at three levels of control, Glomus intraradice, Glomus mossea, and also foliar application of humic acid at three levels of control, 15, and 30 mg/l. The experiment was conducted as pot and under normal and uncontrolled conditions. Measured traits included plant height, root length, number of plant pods, number of seeds in each pod, 100 seeds weight, seed protein, and nitrogen and phosphorus concentration of leaves. Application of mycorrhiza and humic acid increased measured traits except for the number of seeds in each pod and 100 seeds weight. There was no significant difference between the two strains and also levels of 15 and 30 mg/l humic acid in the studied traits. Generally, foliar application of 15 mg/l humic acid in the presence of mycorrhiza was more effective than other treatments.