Amino acids, fulvic acid, and humic acid: the role and difference of the three major biostimulants

In the branch of agrochemical products, there is an old and new category - biostimulants.

According to the definition of the European Biostimulant Industry Council (EBIC): Substances containing certain ingredients and/or microorganisms, when applied to crops or around their rhizosphere, can promote the natural physiological metabolism of crops and enhance the absorption of nutrients And utilization, improve abiotic stress resistance, improve quality and yield.

Divided by source: including humic acid, amino acid, small molecule peptide, oligopolysaccharide, seaweed polysaccharide, chitosan, molasses fermented product, soil beneficial microorganisms and their metabolites, alkaloid (betaine), etc.

Let's focus on the role and difference of amino acids, fulvic acid, and humic acid.

Amino Acid

Amino acid is a general term for a class of organic compounds containing amino and carboxyl groups. The basic unit of biological functional macromolecular protein is the basic substance that constitutes the protein required for animal and plant nutrition. It is an organic compound containing a basic amino group and an acidic carboxyl group. α-amino acids are those whose amino group is attached to the α-carbon. The amino acids that make up proteins are α-amino acids. One of the functions on plants is to directly participate in various physiological activities of plants and the synthesis of plant endogenous hormones.

Production method of amino acid

①Acid hydrolysis

The production cost is low, the process is relatively simple, and hydrolysis treatment is carried out with hydrochloric acid or sulfuric acid.

Features

● Hydroxyl amino acids (serine, threonine) are partially decomposed during acid hydrolysis.

● During alkaline hydrolysis, arginine will be deaminated and lost, and these amino acids have specific growth-regulating effects on plants.

● Tryptophan is completely destroyed by boiling acid. Tryptophan is the precursor of plant auxin synthesis, and the loss will affect the content of plant auxin.

● Nucleotide content is low, most of which are destroyed.

● The produced amino acid contains high chloride ion content

②Fermentation method

It can be divided into direct fermentation method and adding precursor method.

Features

● Strict requirements on fermentation strains.

● The product concentration is low, the degree of hydrolysis is difficult to control, and the production cycle is long.

③Enzymolysis method

Compared with the acid hydrolysis method, the cost is relatively high.

Features

● Amino acid types are relatively comprehensively preserved, and the content of oligopeptides is relatively high.

● Less harmful substances, beneficial ingredients are not easy to be destroyed, and have high activity.

The function of amino acid (fertilizer)

Amino acid fertilizer is based on plant amino acid as a substrate. Using its huge surface activity and adsorption and retention capacity, when used as a fertilizer, it will add some medium and trace elements (calcium, magnesium, iron, copper, manganese, zinc, Boron, molybdenum, etc.), organic and inorganic compounds formed by chelation (complexation); can not only maintain the slow release and full utilization of a large number of elements, but also ensure the stability and long-term effect of trace elements; can enhance plant respiration, Improve the redox process of plants and promote the good effect of plant metabolism. At the same time, it can also promote photosynthesis and the formation of chlorophyll, and can significantly promote and activate physiological and biochemical processes such as oxide activity, enzyme activity, seed germination, nutrient absorption, and root growth and development. Especially its affinity with plants is unmatched by any other substance.

Overall, amino acids work as follows:

①Provide basic components for protein synthesis.

② Provide high-quality nitrogen source, carbon source and energy for plants.

③Provide nutrients for rhizosphere microorganisms (saprophytic bacteria).

④Passivating various heavy metal elements, reducing their toxic and side effects, and reducing fertilizer damage; it also has a certain inhibitory effect on nitrate.

⑤ Stress resistance: Improve crop tolerance to drought, high temperature, salt stress, etc., especially small molecular peptides (a small amount of amino acid polymers) can scavenge free radicals, resist oxidation, and resist heavy metal poisoning, and have a strong effect on repairing crop diseases.

⑥ Complexation (chelation) of a variety of medium and trace elements, providing plants with stable chelation (complexation) mineral elements (calcium, magnesium, zinc, copper, manganese, etc.), which can be quickly absorbed and utilized by plants;

Fulvic acid

Mineral source fulvic acid (Fulvic Acid, referred to as FA) is a short carbon chain molecular structure substance extracted from natural humic acid. It is the water-soluble part with the smallest molecular weight and the highest active group content in humic acid. Interaction reflects a variety of specific physical and chemical characteristics. After entering the plant body, it can exert a variety of physiological functions. It acts on the metabolism of the plant body by inhibiting or activating enzymes, reflecting obvious stimulation. It plays a therapeutic role by secreting, regulating and improving the body's immune function.

Features

Fulvic acid has the general characteristics of humic acid, that is: first, its molecular weight is small and easy to be absorbed by organisms; second, it has more functional groups, which is more physiologically active than ordinary humic acid, and has a strong effect on the complex of metal ions Third, humic acid can be directly dissolved in water, and the aqueous solution of these salts becomes alkaline, while fulvic acid can be directly dissolved in water, and its aqueous solution becomes acidic.

Mineral source fulvic acid is a broad-spectrum plant growth regulator. In the most fashionable term at the moment, it should be called a biostimulant. It can promote plant growth, especially properly control the opening of crop leaf stomata, reduce transpiration, and fight drought. It plays an important role in improving stress resistance, increasing production and improving quality.

The function of mineral source fulvic acid

①Stimulate plant activity: An unknown growth-promoting factor with high biological activity can enhance the activity of oxidase and other metabolic activities in plants. Although fulvic acid does not contain hormones, it has a similar effect to chemically synthesized auxin, cytokinin, abscisic acid and other plant hormones during use, and has a comprehensive effect on plant growth and development. Regulatory effect.

②Enhance the stress resistance of crops: Mineral source fulvic acid has a significant function of cold and drought resistance.

③Slow-release fertilizer: improve the utilization of chemical fertilizers and pesticides, and improve the structure of soil aggregates.

④ Trace nutrients in chelation: strong complexation ability, improve the absorption and operation of plant trace elements, so that they can be better used by plants.

⑤ Prevention and control of plant diseases and enhancement of disease resistance: Mineral fulvic acid is used as a pesticide synergist to improve the control effect, but it cannot replace pesticides.

⑥ Anti-flocculation, buffer, good solubility: strong ability to interact with metal ions. Its anti-flocculation ability is significantly higher than that of humic acid and similar products. It is soluble in any acidic and alkaline water with a pH of 1~14. It does not flocculate and precipitate in saturated brine with high calcium and magnesium hard water. It has good stability and strong anti-electrolyte ability.

Humic Acid

Humic Acid (HA for short) is the remains of animals and plants, mainly the remains of plants, which have been decomposed and transformed by microorganisms, as well as a series of complex geochemical reaction processes and accumulated organic substances. It is a high-molecular organic acid composed of aromatics and various functional groups. It has good physiological activity and functions such as absorption, complexation, and exchange.

Classification of humic acid

The main elements of humic acid are carbon, hydrogen, oxygen, nitrogen, and sulfur. It is a condensation polymer of polyvalent phenolic aromatic compounds and nitrogen compounds. Widely distributed in low-level coal, soil, water sediments, animal manure, organic fertilizers, animal and plant residues, etc.

According to the solubility and color classification in the solvent, it can be divided into three components: ①The part soluble in acetone or ethanol is called brown humic acid; ②The part insoluble in acetone is called black humic acid; ③The part soluble in water or diluted The acid part is called fulvic acid.

The function of humic acid

① Stimulate physiological metabolism

Humic acid contains a variety of active functional genes, which can enhance the activity of catalase and polyphenol oxidase in crops, stimulate physiological metabolism, and promote growth and development. For example, humic acid can promote early germination of seeds, and the emergence rate is high, especially at low temperature; it can stimulate the division and growth of extreme meristematic cells in the root system, so that the seedlings can root quickly, and the roots are more, the root volume is increased, and the root system is elongated. Increase the ability of crops to absorb water and nutrients. Therefore, the nutrient supply is sufficient, the crop stems are fast and strong, the branches and leaves are luxuriant, the photosynthesis is enhanced, the transfer of nutrients to the fruiting bodies is accelerated, and the fruits are colored and matured in advance.

② Change the characteristics of fertilizers

Humic acid contains functional groups such as carboxyl groups and phenolic hydroxyl groups, and has strong ion exchange and adsorption capabilities, which can reduce the loss of ammonium nitrogen in ammonium bicarbonate and improve the utilization rate of nitrogen fertilizers. The oxidized and degraded nitrohumic acid can inhibit the activity of urease and reduce the volatilization of urea. The degraded nitrohumic acid increases the moving distance of phosphorus in the soil, inhibits the fixation of water-soluble phosphorus in the soil, converts available phosphorus into late-acting phosphorus, and promotes the absorption of phosphorus by roots. Humic acid and insoluble trace elements can undergo a chelation reaction to form humic acid trace element chelates with good solubility that can be absorbed by crops, which is beneficial to the absorption of trace elements by roots and leaves.

③ Improve soil structure

Humic acid can promote the formation of soil aggregate structure, adjust soil pH, adjust soil water, fertilizer, air, heat and other conditions, increase soil exchange capacity, achieve acid-base balance, improve soil water and fertilizer retention capacity, and promote soil microbial activities. Increase the number of aerobic bacteria, actinomycetes, and cellulolytic bacteria, accelerate the decomposition and transformation of organic matter, promote the release of nutrient elements, and facilitate the absorption of nutrients by crops.

④Enhance the anti-stress characteristics

Humic acid can reduce the stomatal opening strength of plant leaves, reduce leaf transpiration, thereby reducing water consumption, improving the water status in plants, ensuring the normal growth and development of crops under drought conditions, and enhancing drought resistance. Humic acid is mostly amphoteric colloid, with high surface activity, which can inhibit fungi, enhance the coldness of crops, be easily absorbed by cell membranes, change the permeability of cell membranes, promote the absorption of inorganic nutrients, prevent rot and root rot, and reduce pests and diseases .

⑤ Improve fruit quality

Humic acid can form complexes or chelates with trace elements, increase the amount of trace elements moving from roots to leaves or other parts, adjust the ratio and balance of macroelements and trace elements, and strengthen enzymes for sugar, starch, protein , the synthesis and operation of fat and various vitamins. It can promote the activity of enzymes, convert polysaccharides into soluble monosaccharides, increase the synthesis and accumulation of starch, protein, and fat substances, and accelerate the transfer of various metabolic primary products from stems, leaves or roots to fruits and seeds, making fruits plump and thick.