https://doi.org/10.37229/fsa.fjb.2026.03.07

The University of Mosul's Vegetable Field was the site of research for the 2024-2025 growing season to assess the impact of ascorbic acid and potassium humate foliar application on growth, yield and physiological characteristics of two cultivars of lettuce (Rama and Nader). The experiment was made up of three factors, namely, ascorbic acid which was applied at three concentrations (0, 100 and 150 mgL⁻¹), potassium humate applied at two concentrations (0 and 2 g L⁻¹) and two lettuce cultivars. The experiment was arranged in a randomized complete block design with three replications.  The vegetative growth parameters, yield components, chlorophyll content, dry matter, protein, total soluble solids (TSS) and weight loss was recorded before and after cold storage for 21 days. The findings of the study reveal that mulching with wheat straw at 4-ton ha-1 along with the application of Pseudomonas fluorescens at 15 kg ha-1 was effective in controlling the disease and produced economic returns from white rust affected mustard. According to the research, all treatments of phosphorus and potassium had an effective impact on the improvement of the quality of Rama better than Nader on the traits of TSS, nitrogen, protein, potassium contents, and dry matter.  The growth, yield and postharvest leaf quality were appreciably improved by the three-way interactions of ascorbic acid, potassium humate and cultivars. The use of ascorbic acid and potassium humate can act as an efficient and sustainable approach to enhancing physiological performance and the productivity and marketable quality of leafy vegetables. Moreover, it could boost nutrition and cut postharvest losses. Thus, it is a new practical strategy related to the use of biostimulants.