Two field experiments were carried out during the winter seasons of 2017/2018 and 2018/2019 at a private farm (Tanboul El-Kobra), Al-Senbilawin, Dakahlia Governorate, Egypt. The present study was conducted to evaluate the influence of soil drench of tow organic polymers (Humic acids as K- humate (HAs) and Falvic acids as K-fulvate (VAs) alone or incorporated together under different rates of N, P and K fertilization on onion plants growth, yield, and its components and quality of bulbs (Allium cepa L.) cv. Giza Red. The treatments were arranged in a split-plot design with three replicates. Results indicated that 100% NPK treatment followed by 75% then 50% significantly increased all determined traits under the study contentions. Soil application of HAs and VAs was superior for on vegetative growth parameters, bulbs productivity, chemical constituents, and quality compared to the control (without applications). Under 75% NPK, in combination, the duel application of HAs and VAs showed a significant augmentation in all studied parameters compared to the control under 50, 75 .and 100% of the recommended mineral fertilization. Therefore, the application of HAs and VAs by soil drench in combination treatment with 75% NPK is important for improving plant quality and reducing environmental pollution due to partial replacement of mineral fertilizer with HAs and VAs.