Do you, who sell Nongda fertilizer, really understand humic acid fertilizers?

　　At present, in China’s cultivated soils, about 30% are low‑yielding, characterized by low fertility, poor physicochemical properties, and modest crop yields. These soils can be summarized under the following key attributes: drought‑prone, waterlogged, saline, alkaline, acidic, compacted, and nutrient‑poor. Improving such low‑productivity soils is of great significance for achieving balanced yield increases and accelerating agricultural modernization.

　　Among the measures for improving low‑productivity soils, the extensive application of organic fertilizers to increase soil organic matter is one of the most important. Coal-derived humic acids share similar structures and properties with the humic acids found in soil organic matter; therefore, the widespread use of peat, lignite, weathered coal, and humic‑acid–based fertilizers derived from these sources has been shown in practice to yield significant soil‑improvement effects.

　　I. Amelioration of Saline–Alkaline Soils

　　The main hazards of saline–alkali soils are: excessively high soil salinity; elevated concentrations of harmful ions (such as Na⁺, Cl⁻, HCO₃⁻, CO₃²⁻, and Mg²⁺); excessive soil alkalinity; severe dispersion of soil particles, resulting in poor soil structure; and inhibition of crop growth and development.

　　Long-term, heavy application of humic substances can gradually alter the physicochemical properties of saline–alkali soils.

　　1. Promote the formation of soil aggregates

　　2. Reduce the salt content of the topsoil

　　3. Increase soil cation exchange capacity

　　4. Reduce the pH of saline-alkali soils

　　II. Improvement of White-Plastic Soil

　　White‑pulp soils are primarily distributed in Northeast China. In these soils, the lower part of the plow layer is underlain by an illuvial horizon approximately 5–10 cm thick. This horizon exhibits poor permeability, strong aggregation, high acidity, and a poorly developed soil structure, with weak biological activity; as a result, crop roots struggle to penetrate it—this is the principal reason for the low productivity of white‑pulp soils.

　　The application of peat has a significant impact on the increase in soil organic matter and on the composition of soil humic acids, primarily reflected in a marked rise in the absolute contents of humic acid and fulvic acid, with this effect being more pronounced in treatments receiving higher doses of peat. Peat amendment of white‑pulp soils improves their physical properties and nutrient status, elevates soil humus content, and enhances cation exchange capacity, thereby creating favorable conditions for crop growth. Following amendment, the levels of available nitrogen and phosphorus remain stable at 5–15 mg per 100 g of soil; soil water‑holding capacity is maintained between 40% and 50%; capillary porosity exceeds 50%; and bulk density hovers around 1.0 g/cm³—essentially meeting the physicochemical criteria typical of high‑yield, stable‑production soils. In these amended white‑pulp soils, yields of maize and soybeans are substantially higher than before treatment, resulting in markedly improved economic returns.

　　III. Improvement of Red Soils

　　The southern provinces of China, situated in tropical and subtropical regions, are characterized by extensive red soils. In these soils, high temperatures and abundant rainfall accelerate the decomposition of organic matter, leading to the leaching of nutrients with runoff and resulting in low levels of organic matter and essential plant nutrients. The frequent rainfall also causes the leaching of basic cations, while relatively immobile acidic elements such as iron and aluminum tend to accumulate; the increased concentration of aluminum, in particular, renders the red soils acidic or strongly acidic. Moreover, iron and aluminum readily fix phosphorus, reducing its availability to plants. Additionally, poor soil structure and excessive moisture cause soil particles to swell and disintegrate into a pasty consistency, whereas during droughts the soil hardens into compact, rigid clods. Thus, the defining characteristics of red soils can be summarized succinctly as “acidic, infertile, compacted, and dry.”

　　The application of humic substances primarily affects the chemical properties of red soils by increasing soil organic matter content, enhancing the availability of readily available nutrients, elevating base exchange capacity, and reducing soil acidity.

　　I. What exactly is humic acid?

　　Humic acid is a class of water-insoluble, high-molecular-weight organic acidic polymers whose main structural framework consists of aromatic nuclei and which contain various functional groups. It comprises humic acids—namely black humic acid and brown humic acid—and fulvic acid—yellow humic acid—and is widely distributed in nature, serving as an important constituent of soil organic matter. When combined with monovalent alkali metals such as ammonium, sodium, and potassium, it forms water-soluble humates.

　　Humic acid contains 52% carbon, 3%–4.5% hydrogen, 30%–39% oxygen, and 3.5%–5% nitrogen. It is generally believed to possess four aliphatic hydroxyl groups and three phenolic hydroxyl groups in its molecular structure, giving it a relatively high cation exchange capacity—typically 300–500 cmol/kg—and thus excellent nutrient‑retention properties. However, the complexes formed when humic acid binds with divalent cations are insoluble in water; consequently, humic acid is an indispensable component in the development of water‑stable aggregate structures.

　　Fulvic acid (humic acid) has a relatively low molecular weight, making it readily absorbed and utilized by living organisms. It contains a high proportion of functional groups, exhibits strong physiological activity, and is directly soluble in water. These characteristics account for its wide range of agricultural applications.

　　II. What is its primary function?

　　① It can reduce the aperture of plant stomata, thereby decreasing transpiration and helping plants and soil retain more moisture, making it an excellent drought‑resistant agent.

　　② It enhances the activity of multiple enzymes and chlorophyll content, boosts metabolism and photosynthesis, and increases sugar and dry matter accumulation, thereby improving crops’ stress tolerance—including frost resistance and disease resistance—raising yields, and enhancing crop quality. It is a novel plant growth regulator.

　　③ It forms pesticide–fulvic acid complexes through physicochemical interactions. These complexes not only reduce the toxicity of pesticides and minimize environmental pollution, but also enhance efficacy and allow for reduced application rates, making them an excellent pesticide slow-release adjuvant.

　　④ It can chelate trace elements, enhancing the crop’s ability to absorb them.

　　⑤ It can corrode minerals such as potassium feldspar, releasing various nutrients. However, the salts it forms with divalent cations are water-soluble, which is detrimental to the development of water-stable aggregate structures.

　　III. What exactly is humic acid organic fertilizer?

　　Fertilizers produced from raw materials such as lignite and oil shale, using various manufacturing processes to yield products rich in humic acids and containing oxygen, phosphorus, potassium, and certain secondary and micronutrients essential for crop growth and development, are known as humic acid organic fertilizers.

　　IV. How do humic acid organic fertilizers differ from farmyard manure?

　　Farmyard manure must be fully composted before it can be applied to the soil, and it requires a prolonged period of decomposition to ultimately transform into humic acids that crops can absorb. In contrast, humic‑acid‑based organic fertilizers directly supply crops with essential nutrients, making them easier for plants to uptake, more efficiently utilized, and delivering faster results.

　　Having discussed all this, I believe you now have a basic understanding of humic acid fertilizers. But does that mean any fertilizer containing humic acid is necessarily beneficial? Of course not. Humic acid fertilizers can only deliver their intended benefits after undergoing an activation process; unactivated products not only fail to provide the aforementioned advantages but may even compromise soil fertility. So, what exactly are the functions of activated humic acid?

　　V. What are the main functions of highly active humic acid?

　　Highly active humic acid is an organic combination of microorganisms and premium-quality humic acid, resulting in a product with high bioactivity and pronounced efficacy. Its primary 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. Enhance the fertilizer efficiency of chemical fertilizers: when humic acid is combined with nitrogen, the yield‑increasing effect of nitrogen fertilizers can be improved by approximately 10%, and the utilization rate of phosphorus can more than double.

　　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 root 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 enhance product quality.

　　VI. What is the difference between active humic acid and inactive humic acid?

　　1. Differences in appearance

　　After removing the active humic acid fertilizer from its packaging, gently rub it between your hands; your palms will feel slightly oily, and the fertilizer will take on a glossy sheen—its appearance markedly different from that of ordinary fertilizer. By contrast, other humic acid fertilizers, which have not been activated, show no change at all, no matter how much you rub them. This clearly demonstrates the superior activity of Nongda’s active humic acid fertilizer.

　　Nongda Active Humic Acid Fertilizer incorporates a measured amount of activated humic acid into compound fertilizer raw materials through a specialized process, where it forms complexes (chelates) with various ions in the fertilizer, resulting in a unified composite structure. The granules of Nongda Active Humic Acid Fertilizer exhibit uniform color throughout, whereas other humic‑acid fertilizers typically rely on a surface coating that can be easily stripped away, revealing the underlying material with a simple rub.

　　2. Internal Differences

　　So‑called activation of humic acid involves converting it from an insoluble form into a soluble one. Activated humic acid can generate soluble humate salts, hydrophilic complex ions, or hydrated metal chelate ions. When placed in pure water, activated humic acid dissolves rapidly, yielding a dark brown solution. In contrast, unactivated humic acid is insoluble in water; if similarly suspended in pure water, it lacks activity and quickly settles, forming a precipitate. Therefore, free humic acid is not the same as activated humic acid, and incorporating unactivated humic acid into fertilizers represents a significant waste of resources.

　　After activation, humic acid develops numerous functional groups. These groups act like human hands, capturing otherwise unavailable nutrients in the soil and activating them, converting them into forms that plants can readily absorb and utilize, thereby significantly enhancing nutrient-use efficiency. The more “hands” humic acid has, the greater its activity and the more pronounced its beneficial effects on crops. In contrast, other humic‑acid fertilizers lack this abundance of “hands,” resulting in lower activity, slower performance, and reduced efficiency.