Investigation of the Effect of Potassium Sulfate and Ascorbic Acid on Quinoa (Chenopodium quinoa) in a Saline Soil

In order to evaluate the effect of potassium sulfate fertilizer and ascorbic acid application on yield and yield components and growth of quinoa (Chenopodium quinoa Willd.), a field experiment was carried out at 2018-2019 at Isfahan, central Iran. A factorial experiment based on a randomized complete block design with three replications was used. Experimental treatments were potassium sulfate in four levels including: no fertilizers application (control), 50%, 100%, and 150% (1.5 times) of the recommended amount. Foliar application of ascorbic acid also was used in three levels including: control (spraying with distilled water), 100, and 200 mg L-1 ascorbic acid. Plant height, leaf relative water content (RWC), yield and yield components of Quinoa were measured. Analysis of variance showed that potassium sulfate fertilizer and foliar application of ascorbic acid had significant effects on measured traits. The results showed that leaf area index (LAI) and dry matter accumulation (DM) were affected by both potassium sulfate fertilizer and ascorbic acid, and these treatments increased these traits. Increasing rates of ascorbic acid and potassium sulfate increased the relative water content of leaves, plant height, and spikes/m2, seeds/spike, and 1000-seed weight. Grain yield and harvest index increased due to application of ascorbic acid (200 mg L-1) and potassium sulfate (150% (1.5 times) the recommended amount) by 79% and 2.6 times, respectively, compared to the control treatment. Therefore, these treatments were considered as a suitable combination to improve yield in the quinoa plant.