The Ten Major Functions of Humic Acid: The Comprehensive Synergistic Effects of Its Diverse Properties

　　1. Humic acid is an organic colloidal substance with water‑absorbing and water‑retaining properties. It exhibits a high cation exchange capacity, strong adsorption‑buffering ability, and chelating power, thereby enhancing nutrient use efficiency in the soil and mitigating the adverse effects of acidity or alkalinity. As an organic macromolecular colloid, humic acid possesses exceptional water‑absorption and water‑retention capabilities; while clay particles typically absorb 50%–60% of their weight in water, humic substances can retain 500%–600%, making humic‑acid‑based fertilizers effective for improving soil moisture conditions.

　　2. Humic acid can improve soil structure.

　　Soil fertility is determined by the organic–inorganic complex. Inorganic mineral colloids typically account for more than 95% of the soil and exert a significant influence on its basic nutrient supply; moreover, their composition cannot be altered through artificial means. Organic colloids—namely humic substances—generally comprise only about 5% of the organic–inorganic complex, yet they play a role every bit as important as that of mineral colloids and can be regulated through deliberate management practices. Applying organic fertilizers, using humic‑acid‑based soil conditioners and soil‑improving fertilizers, and increasing the content of humic acids in the soil enable humic acids to act as binding agents, promoting the formation of soil aggregate structures, enhancing the degree of organic–inorganic association, and boosting the proportion of large‑diameter, water‑stable aggregates. As a result, soil structure is markedly improved. Consequently, the application of humic‑acid‑based fertilizers can effectively ameliorate the physical properties of various soils, which is why humic acid is widely regarded as a premium soil conditioner.

　　3. Foliar application of humic acid liquid fertilizer can reduce stomatal conductance, thereby decreasing water transpiration and losses. According to experimental results, spraying wheat with fulvic acid reduced leaf stomatal conductance by 33.7% compared with the control. Research conducted by the Academy of Agricultural Sciences shows that foliar application of fulvic acid not only lowers stomatal conductance but also narrows stomatal aperture and promotes stomatal closure, while simultaneously supplying essential nutrients to the crop.

　　4. Humic acid can stimulate root growth in crops and enhance their water‑absorbing capacity.

　　Humic acid contains a variety of chemically and biologically active functional groups, which stimulate crop growth and development by promoting earlier seed germination, emergence, flowering, and fruit set. It also increases root length, root biomass, and root vitality, thereby enhancing the roots’ capacity to absorb nutrients and water.

　　5. Humic acid can enhance plants’ intrinsic physiological regulatory functions and improve their cold tolerance.

　　Applying humic acid fertilizers can enhance enzyme activity in both the soil and plant tissues, regulate crop physiological and metabolic processes, and improve crops’ tolerance to adverse environmental conditions.

　　In summary, humic acid and humic‑acid‑based fertilizers can improve soil structure, enhance soil physicochemical properties, and increase the soil’s capacity to retain water and nutrients. They also stimulate root growth and development, boost water uptake, reduce leaf transpiration and water loss, strengthen crops’ resilience to adverse environmental conditions, and improve the efficiency of water and nutrient use.

　　What is humic acid organic fertilizer? It is a product derived from raw materials such as lignite and oil shale, produced through various manufacturing processes, and enriched with substantial amounts of humic acids as well as essential nutrients—such as nitrogen, phosphorus, potassium, and certain secondary and micronutrients—necessary for crop growth and development.

　　What is the difference between humic acid organic fertilizer and farmyard manure? Farmyard manure must undergo complete maturation before it can be applied to the soil, and it requires a lengthy period of transformation to ultimately convert into humic acids that crops can absorb. In contrast, humic acid organic fertilizer directly supplies crops with the essential nutrients they need, making it easier for plants to take up and utilize, with higher efficiency and faster results.

　　Functions of Highly Active Humic Acid: Highly active humic acid is an organic combination of microorganisms and high-quality humic acid, featuring high activity and pronounced efficacy. Its main functions are as follows:

　　1. Improves soil structure, promotes the formation of soil aggregates, and balances soil water, nutrient, air, and temperature conditions, ensuring both good aeration and effective water retention without compaction.

　　2. Enhance the soil’s capacity to retain and supply nutrients, maintain strong nutrient‑holding ability, reduce losses of available nutrients, and ensure a prolonged release of nutrients, thereby transforming the fertilizer efficacy of various quick‑acting fertilizers from “rapid, intense, and short‑lived” to “gradual, stable, and long‑lasting.”

　　3. Improve soil pH and mitigate the adverse effects of toxic factors.

　　4. It provides the nutrients required for microbial metabolic activities, promotes microbial proliferation and activity, and enhances microbial vitality.

　　5. Enhancing fertilizer efficiency: Humic acid binds with nitrogen, increasing the yield‑boosting effect of nitrogen fertilizers by approximately 10% and more than doubling the utilization rate of phosphorus.

　　6. It can promote earlier germination and increase both the seed germination rate and the emergence rate; soaking seeds in a solution of humic acid at an appropriate concentration can advance germination by 1–3 days and boost the emergence rate by 10%–25%.

　　7. Promotes root formation and enhances the root system’s water‑absorbing capacity. Soaking or dipping roots in humic acid accelerates root emergence, increases root number and biomass, and strengthens the roots’ ability to uptake nutrients.

　　8. It can promote the development of reproductive organs, advance flowering, increase pollination rates, and enhance grain and fruit weight.

　　9. Enhance crop stress tolerance: Crops treated with humic acid exhibit significantly improved resistance to cold, drought, and disease.

　　10. Stimulating crop growth and development: the application of humic acid can enhance the activity of various enzymes in crops, improve their ability to absorb water and nutrients, boost metabolic processes, accelerate growth and development, promote earlier maturity, and elevate product quality.