Effects of Drought Stress and Humic Acid on Plant Growth, Yield Quality and Its Components of Quinoa (Chenopodium quinoa Willd)

BACKGROUND: Drought stress limits the growth and development of plants. The use of Humic acid (HA) is one of the topics commonly addressed by researchers to study the physiological efficiency and yield of crops under drought stress. OBJECTIVES: Based on this, a study was conducted to investigate drought stress and different levels of HA on the performance characteristics of quinoa. METHODS: Current research was conducted as a randomized complete block statistical design in the form of split plots with three replications. Treatments include main plots with three levels of drought stress including 60% evaporation from class A evaporation pan or non-application of drought stress, 90% evaporation from class A evaporation pan or medium stress and 120% evaporation from class A evaporation pan or severe stress and four levels of HA included non-consumption and doses of 50, 100, 150 mg.l-1 in the subplot. RESULT: The results showed that in the treatment without drought stress and consumption of 100 mg.l-1 HA, the highest biological yield of 6508 kg.ha-1 was obtained. The lowest rate was obtained in the treatment of severe drought stress and non-use of HA at the rate of 3068.6 kg.ha-1. Moreover, according to results, in the treatment without drought stress and consumption of 100 mg.l-1 HA, the highest grain yield was obtained at 2105.4 kg.ha-1 and the lowest obtained in the treatment of severe drought stress and no consumption of HA (999 kg.ha-1). Under drought stress, the application of HA fertilizer reduces the effect of drought stress on the growth processes of quinoa. In this study, it was found that the performance of quinoa at 100 mg.l-1 HA showed a better response than other levels of HA. Considering the improvement of quinoa yield components by optimally increasing HA and obtaining more grain yield, the results indicate the appropriate response of quinoa to HA. CONCLUSION: In general, the results show that drought stress had a significant effect on growth characteristics, quinoa yield. Considering the improvement of quinoa yield components by optimally increasing HA and obtaining more grain yield, the results indicate the appropriate response of quinoa to HA.