In assessing the effect of three planting dates (October 01, mid-October, and November 01) and dual spraying of four levels of potassium sulfate (0, 1000, 2000, and 3000 mg L^-1) and proline acid (0, 50, 100, and 150 mg L^-1) on the faba bean (Vicia faba L.), an experiment commenced in the winter cropping season of 2022–2023 at the University of Basrah, Basrah, Iraq. The experiment, laid out in a randomized complete block design (RCBD), had a factorial arrangement, with two factors and three replications. Results showed mid-October planting is superior for most studied traits, recording the highest average number of accumulated heat units from planting to 50% flowering. Likewise, optimum averages occurred for physiological maturity, leaf area, chlorophyll content, seeds per pod, 100-seed weight, and total seed yield in faba beans. The findings also revealed the combination of potassium (3000 mg L^-1) and proline acid (150 mg L^-1) excelled for all the studied traits. The combined treatment provided maximum average values for the number of accumulated heat units from planting to 50% flowering and beginning of branches, leaf area, chlorophyll content, seeds per pod, 100-seed weight, and the total seed yield in faba beans.

Keywords: Faba bean (Vicia faba L.), planting dates, potassium sulfate, proline acid, physiological indicators, growth and yield traits

Key findings: In faba beans, the mid-October planting showed superiority in most studied traits. Foliar application of potassium and proline acid individually and in interaction revealed significant differences for physiological, growth, and yield-related traits.