【Objective】 This study aims to analyze the physicochemical properties of two natural humus-modified materials (M1 and M2) produced by different processing methods, compare the differences between the two materials, and investigate their effects at different concentrations on the growth of maize under drip irrigation conditions. The goal is to explore the most suitable application concentration and amount of humus under drip irrigation and provide new perspectives and practical bases for agricultural production. 【Method】 The content of humus and its components in M1 (natural humus sand grinding fluid) and M2 (fully water-soluble potassium nitrohumate) was determined and the physical and chemical properties of the materials were analyzed through elemental analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR). Then, field experiments were designed to evaluate the effects of applying different concentrations (0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0 g·L^–1) and amounts (650, 1 300, 1 950 L·hm^–2) of M1 and M2 on the height, biomass, and yield of maize. 【Result】 The results showed that: 1) There were significant differences in chemical composition between M1 and M2. M1 had a higher content of humus, larger molecular weight, more complex structure, and stronger stability in soil. On the other hand, M2 had a lower total content of humus, a high content of fulvic acid (FA), a smaller molecular weight, and a lower degree of humification. 2) The microstructure of M1 and M2 differed. M1 had a rough and complex particle surface with uneven particle size while M2 exhibited a smoother and looser sponge-like appearance with no chaotic structure on the particle surface. FTIR analysis showed that M1 may contain more aromatic structures or carboxylate salts and silicate impurities while M2 may contain more carboxyl groups. 3) Although the application of M1 and M2 had little effect on plant height, it significantly increased the biomass and yield of maize. Especially for M2, when its concentration was 1.0 g·L^–1 and the amount was 1 300 or 1 950 L·hm^–2, the biomass of maize plants increased significantly by 40.11% and 40.74% and the yield increased significantly by 25.75% and 27.45%, respectively. 【Conclusion】 The application of different concentrations and amounts of M1 and M2 effectively promoted the growth of maize, with M2 exhibiting greater growth potential under the same conditions. This may be attributed to the role of humus in improving soil structure, increasing and retaining soil moisture and nutrient content, activating specific biochemical pathways, and enhancing soil microbial activity, thereby improving the nutrient absorption efficiency and photosynthetic capacity of maize plants. Considering factors such as cost, it is recommended to apply M2 at a concentration of 1.0 g·L^–1 and an amount of 1 300 L·hm^–2 in the field to fully exploit its effects in promoting maize growth potential and increasing yield. This provides new perspectives and practical bases for the efficient utilization of humus in agriculture.