Abstract

An experiment was carried out at the farm of Field Crops Department, Agriculture College, University of Basrah, Iraq during two winter seasons of 2016–17 and 2017–18 to study the effect of spraying humic acids (0, 3, 6 and 9 g/l) at two growth stages (Tillering and 50% flowering stage) on the fodder and grain yield of oat cv. Shaffaa. Split plot design arranged by RCBD was used with three replications, stage of spraying was placed in the main plots, while foliar humic acid concentrations in the sub-plots. The best concentration of humic acid was 6 g/l which achieved the highest green fodder yield (50.6 and 54.4 t/ha), dry fodder yield (16.9 and 18.6 t/ha) and grain yield (6.19 and 5.97 t/ha) for both the growing seasons. Spraying at tillering stage was more efficient for increasing fodder and grain yield as compared to spraying at 50% flowering stage. The interaction was significant, plants that sprayed at tillering stage with concentration of 6 g/l of the humic acid were more potential for most studied characteristics. Therefore, humic acid @ 6 g/l during tillering growth stage proved most suitable for obtaining optimum yield of oat.