Effect of Humic Acid on some Agronomic Characters of some Varieties of Alfalfa (Medicago sativa L.)

To evaluate the effect of humic acid on some cultural characters of some alfalfa varieties, a field experiment was conducted as factorial split plot based on RCBD design with three replications in 2014. In this experiment, 5 varieties of alfalfa (Yazdi, Hamedani, Baghdadi, Bami and Ranger) and three levels of humic acid (5 and 10 lha-1 and without humic acid, as control) were considered as the first factor and harvest time was as the second factor. Result indicated that except plant height, other characteristics such as dry weight yield, dry weight per plant, root and shoot dry weight per plant, number of leaves and stem diameter were affected by triple interaction effect of harvest time×variety×humic acid. Plant height was affected by double interaction effect of variety×humic acid and also harvest time×variety. Yazdi and Bami had the highest and Ranger had the least values of traits under study in two cuttings, respectively. Also in the between of humic acid treatments, 10 lha-1 treatment produced highest traits measured as compared to control and 5 lha-1 treatment. Bami, Ranger and Yazdi varieties with 10 lha-1of humic acid in two cuttings produced the highest dry weight yield (3.64, 3.55 and 3.26 t.ha-1 respectively) in this experiment.