Humic acid fertigation and Azotobacter priming improve the nutritional quality of wheat grain and flour

Abstract

The effect of humic acid (HA) on the nutritional value and quality of wheat grain and flour has rarely been studied. A field experiment to determine the effect of fertigation of HA and Azotobacter chroococcum UT1 (AZ) on nutrient elements (P, K, Zn, Fe, Mn and Cu), dry gluten, protein and essential amino acids of two wheat cultivars (Chamran and Kouhdasht), comparing four treatments (control, HA, AZ and HA × AZ) using randomized complete block design with four replicates was conducted at the research station of Chardavol in Iran. The 2 years data during 2019 and 2020 indicated that the fertigation of HA and its interaction with AZ (HA × AZ) improved the nutrient elements, dry gluten and protein concentration of wheat grain and flour in both wheat cultivars in comparison with the control treatment. Inoculation of AZ reduced dry gluten of flour in the Kouhdasht cultivar by 6.34%. The application of HA × AZ also significantly enhanced the concentration of essential amino acids of wheat grain and flour in both wheat cultivars by 7.24–11.6%. In similar treatments, the concentration of nutrient elements, dry gluten, protein and essential amino acids of the Chamran cultivar were higher than those in Kouhdasht cultivar. Therefore, it can be concluded that the combined application of HA and AZ can be a suitable recommendation for improving wheat quality.