Effect of Levels of Drought Tension and Concentrations of Potassium Humate on two Hybrids of Hybrid Corn 604 and 704

Deficit water is one of the most important factors of reducing crop growth and yield that due to reduction of water resources, the intensity of this phenomenon increases more and more. However, by adopting managements such as selecting the suitable treatment and applying the stimulating generator of tolerance to Deficit water in plants, the effect of Deficit water in plants can be reduced. This experiment was conducted in order to study the effect of different levels of irrigation(irrigation after 70, 130 and 180 mm evaporation from the evaporation pan) and applying potassium humate (control, 10 and 50 per one thousand potassium humate) on two hybrids 604 and 704 in three replications and as split plot. The results of the present study indicated that the reduction in irrigation water, reduced seed yield significantly. As irrigation levels after 130 and 180 mm evaporation from the evaporation pan reduced 23.6 and 49.6 percent of seed yield compared to the irrigation level after 70 mm evaporation from the evaporation pan. Irrigation levels caused a significant reduction in seed number in maize and one hundred-seed weight. Using potassium humate had no significant effect on seed yield, but treatment of 50 per thousand of potassium humate caused a significant increase in the leaf biomass and leaf area. It seems that in the studied hybrids, the reduction in the irrigation water reduces seed yield and the use of potassium humate had no effect on the economic performance of studied hybrids of corn.