The effects of iron and zinc foliar application on nutrients absorption improvement, seed yield and water use efficiency of sunflower under drought stress conditions

This experiment was conducted to investigate the effects of drought stress and foliar application of Fe and Zn on agronomical characteristics of sunflower

a farm experiment was carried out in the Fars agricultural research center in the split plots form base on a randomized complete block design with three replications during 2014. Irrigation at three levels (irrigation after 60, 120, and 180 mm of evaporation from A class evaporation pan) as the main plots and foliar application at four levels (water, iron sulfate, zinc sulfate, and iron sulfate+ zinc sulfate) were used as sub-plots.

The results showed that the delay in irrigation from 60 to 180 mm of evaporation caused a decrease in the number of seeds per head, grain yield and biological yield by 24.8%, 37.5% and 30%, respectively. The foliar application of iron sulfate + zinc sulfate compared to the control treatment increased the number of seeds per head, 1000-seed weight and grain yield by 24.1%, 16.6 percent and 14.3 percent, respectively. The delay in irrigation, increased the water use efficiency by 50.9%. The interaction between irrigation and foliar application had a significant effect on leaf and grain iron concentration and leaf zinc concentration, so that with delay in irrigation, absorption of nutrients decreased, but foliar application under drought stress conditions increased iron and zinc absorption in sunflower

According to these results, it can be stated that with micronutrient foliar spraying, the severe drop in sunflower yield can be prevented under drought stress conditions