Evaluation of remobilization rate, grain yield and antioxidant content of maize in reaction to biochar and humic acid amounts under water deficiency stress

In order to investigate the effect of biochar and humic acid on the rate of remobilization, grain yield and antioxidant content of maize under water deficiency stress, an experiment was conducted as asplit-split plot in the form of a randomized complete blocks design with three replications in Ahvaz, southwest of Iran. The main plot involved water stress with three irrigation levels after depleting 30, 40 and 50% of field capacity, non-stress, moderate stress, and severe stress, respectively, asubplot withbiochar with 2 control levels (no use of biochar) and application of 4 tons in biochar hectares and another subplot having humic acid with 4 control levels (no use of humic acid) and application of 2, 4 and 6 liters per hectare of humic acid. The results showed that the effect of water deficit stress, biochar and humic acid on grain yield, remobilization rate, current photosynthesis, share of current photosynthesis, catalase and superoxide dismutase enzymes was significant at the level of 1% probability. The highest grain yield was related to irrigation treatment after depleting 40% of field capacity and application of 4 tons per hectare of biochar. In total, the use of 4 liters per hectare of humic acid in moderate moisture stress conditions due to its positive role on the growth and hence on the 42% increase in the yield, compared to severe stress treatment and no consumption of humic acid, can be recommended under arid and serai-arid conditions to save water consumption, and reduce the effects of water deficit stress.