Why can humic acid repair the soil? How to repair the soil? Application in fertilizer?
Why can humic acid repair the soil
Soil remediation refers to the use of physical, chemical and biological methods to transfer, absorb, degrade and transform pollutants in the soil to reduce their concentration to an acceptable level, or to convert toxic and harmful pollutants into harmless substances.
In the soil remediation industry, there are more than one hundred kinds of soil remediation technologies, and there are also more than ten commonly used technologies, which can be roughly divided into three methods: physical, chemical and biological.
Fundamentally, the technical principles of contaminated soil remediation can include:
(1) Change the existing form of pollutants in the soil or the way of combining with the soil to reduce their mobility and bioavailability in the environment;
(2) Reduce the concentration of harmful substances in the soil. In the process of agricultural soil pollution control and soil improvement, humic acid has shown better and better results.
Why is humic acid
Humic acid is a macromolecular organic substance that exists widely in nature.
Humic acid is the remains of animals and plants, mainly the remains of plants, a type of organic matter created and accumulated through a series of processes of microbial decomposition and transformation, and geochemistry. Some fermentation processes in modern industry can also produce humic acid.
The raw material sources of humic acid can be divided into two categories: coal-based materials and non-coal-based materials.
The former mainly includes peat, lignite and weathered coal; among them, the content of humic acid reaches 10-80%. my country's coal reserves are very rich. According to data, there are 5 billion tons of peat and 126.5 billion tons of lignite. There are no statistics on weathered coal.
The latter includes soil, water, fungi, and other non-coal substances, such as phenols, quinones, sugars and other substances, which can produce humic acid substances through biological fermentation, oxidation or synthesis. Humic acid produced.
Humic acid is the main component of humus. It has a complex chemical structure. It is a mixture of multiple active functional groups such as carboxyl, phenolic, ketone, and phenolic hydroxyl groups. The special structure and physical and chemical properties of humic acid determine its ecological restoration. Important role.
How humic acid repairs the soil
The remediation effects of humic acid on soil contaminated by "heavy metals and toxic organic pollutants" mainly include: the adsorption and precipitation of heavy metals and organic matter by humic acid; redox effect; and humic acid can promote the degradation of organic pollutants by soil microorganisms.
Practice has proved that the effect of humic acid on soil restoration and improvement is very obvious.
1. Humic acid changes the form of heavy metals in contaminated soil
The accumulation and enrichment of heavy metals bring great pressure to the soil. Most of the forms that exist in the soil are chelated or complexed. Humic acid is rich in a large number of ions, and it can replace chelating with its own ions. The heavy metal ions in the complex state and the complex state make it difficult for heavy metals to be absorbed by crops, and crops are not easily polluted by heavy metals.
Light humic acid (fulvic acid) has a low molecular weight, which is beneficial to the activation, compatibilization and desorption of heavy metals. For example, watering "super-accumulative plants" kidney fern (super-accumulative plants are plants that are tolerant to heavy metals or other pollutants) with a solution containing fulvic acid can significantly improve the absorption of various heavy metals.
Heavy humic acid (including palm humic acid and black humic acid) has a relatively large molecular weight and has the effect of reducing and adsorbing and fixing heavy metals, which can reduce the effectiveness of heavy metals, such as fixing cadmium, mercury, and lead.
2. Humic acid reduces the toxicity of organic matter in the contaminated soil
Another "destroyer" of the soil is organic pollutants, the sources are mainly petroleum and cracked products, pesticides, organic synthetic products (such as plastic mulch, etc.);
Humic acid can increase the adsorption and stability of organic matter, fix it in the soil, deactivate pollutants, or induce the photolysis and chemical degradation of active free radicals of organic matter, so as to achieve the effect of "" the soil.
The humic acid "degradable mulch" produced with heavy humic acid as the raw material can not only increase the temperature and protect the fertilizer, but also degrade into humic acid organic fertilizer after 2 to 3 months. The crops emerge naturally, saving labor and time, and avoid "White pollution" caused by plastic mulch.
3. Humic acid can be used for the treatment of saline-alkali land with a groundwater level below 1 meter
Humic acid can combine with the calcium and iron ions of other adjuvants to promote the formation of large-particle aggregates in the fine-grained soil of 20-30 cm on the surface, reduce the capillary phenomenon of the fine-grained soil, and greatly reduce the evaporation of water to carry salt to the surface and gradually The accumulation of salinization is an effective way to completely control saline-alkali land from the source.
Application of humic acid on fertilizer
Fertilizers are also one of the factors that bring heavy metals into the soil and cause soil pollution, such as low-content phosphate fertilizers, low-quality silicon-calcium soil conditioners, and low-quality organic fertilizers;
At present, humic acid is more and more widely used in the field of high-quality fertilizers, such as various humic acid-containing compound fertilizers, humic acid water-soluble fertilizers, humic acid-containing organic fertilizers, organic and inorganic fertilizers, etc., except for fertilizers In addition to the synergistic effect, it can also improve the soil aggregate structure and enhance the activity of beneficial microorganisms. It can also play a role in the gradual treatment of soil salinization, heavy metals, and organic pollution as described above.