Effect of Humic Acid and Foliar Application of Potassium on Growth and Yield of Melon

The increased use of chemical fertilizers as a sole input for production of horticultural crops has destructed the soil architecture and suppressed product quality. Therefore, a field experiment was implemented in the vegetable research field of research center Duhok province / Iraq at the summer growing season of 2019 to inspect the impact of soil drenching of humic acid at four levels (0, 500, 1000, and 2000 mg l^-1) and foliar spraying of potassium at four levels (0, 0.3, 0.6, and 0.9 mg l^-1) and their interactions on the growth and yield of melon. Both humic acid and potassium fertilizer increased the phosphorus (P) content significantly compared to the control. The results obtained from hot climatic condition displayed also no significant amelioration in vegetative traits [canopy height, leaf area, chlorophyll content (SPAD), and stem diameter] and yield traits [number of fruits per plant and total yield ] with soil drench application of humic acid and foliar feeding of potassium fertilizer as compared to control.