in the branch of agricultural chemical products, there is an old and new category - biological stimulant.
according to the source, it includes humic acid, amino acid, small molecular peptide, oligosaccharide, seaweed polysaccharide, chitosan, molasses fermentation products, soil beneficial microorganisms and their metabolites, alkaloids (betaine), etc.
here to focus on the introduction of amino acids, fulvic acid, humic acid role and difference.
amino acid is the general name of a class of organic compounds containing amino and carboxyl groups. the basic component unit of biological functional macromolecular protein is the basic material for animal and plant nutrition. it is an organic compound containing basic amino group and acid carboxyl group. the amino group attached to α - carbon is α - amino acid. the amino acids of protein are all α - amino acids. one of its functions in plants is to directly participate in various physiological activities of plants and the synthesis of endogenous hormones.
① acid hydrolysis
the production cost is low and the process is relatively simple. hydrochloric acid or sulfuric acid is used for hydrolysis treatment. characteristic:
the hydroxyl amino acids (serine and threonine) were partially decomposed during acidolysis.
during alkaline hydrolysis, arginine will be deamination loss, and these amino acids have specific growth regulation effect on plants.
tryptophan is completely destroyed by boiling acid. tryptophan is the precursor of auxin synthesis, and the loss will affect the content of auxin.
the nucleotide content was low and most of them were destroyed.
the content of chloride ion in the amino acids produced is high.
② fermentation method
it can be divided into direct fermentation method and adding precursor method.
strict requirements on fermentation strains.
the product concentration is low, the degree of hydrolysis is difficult to control, and the production cycle is long.
compared with acid hydrolysis, the cost is relatively high.
the content of oligopeptide was high.
there are few harmful substances, the beneficial ingredients are not easy to be destroyed, and the activity is high.
function of amino acid (fertilizer)
amino acid fertilizer is an organic and inorganic compound formed by chelation (complexation) with plant amino acid as matrix, utilizing its huge surface activity and adsorption and retention capacity. when used as fertilizer, it will add some trace elements (calcium, magnesium, iron, copper, manganese, zinc, boron, molybdenum, etc.) needed by plant growth and development, and form organic and inorganic complexes through chelation (complexation); it can not only maintain the slow release and full utilization of a large number of elements it can also ensure the stable effect and long-term effect of trace elements, enhance plant respiration, improve plant redox process, and promote plant metabolism. at the same time, it can promote photosynthesis and the formation of chlorophyll, promote and activate the activities of oxide active enzymes, seed germination, nutrient absorption, root growth and development and other physiological and biochemical processes. in particular, its affinity with plants is incomparable to any other substance.
on the whole, the functions of amino acids are as follows:
① it provides basic components for protein synthesis.
② provide high quality nitrogen, carbon and energy sources for plants.
③ provide nutrition for rhizosphere microorganism (saprophytic bacteria).
④ passivation of a variety of heavy metal elements, reduce its toxic and side effects, reduce fertilizer damage; also has a certain inhibitory effect on nitrate.
⑤ stress resistance: it can improve the tolerance of crops to drought, high temperature and salt stress, especially the ability of small molecular peptide (a small amount of amino acid polymer) to scavenge free radicals, antioxidation and heavy metal toxicity, and repair crop diseases.
⑥ complex (chelate) a variety of medium and trace elements, provide stable chelated (chelated) mineral elements (calcium, magnesium, zinc, copper, manganese, iron, etc.) for plants, which can be quickly absorbed and utilized by plants;
fulvic acid (fulvic acid) acid (fa) is the water-soluble part of humic acid with the smallest molecular weight and the highest content of active groups. the interaction of its functional groups reflects a variety of specific physical and chemical characteristics. after entering the plant body, it can play a variety of physiological functions. it acts on the metabolism of plant body by inhibiting or activating enzymes, reflecting the obvious stimulating effect hormone secretion, regulation and improve the body's immune function and play a therapeutic role.
fulvic acid has the general characteristics of humic acid, that is: first, its molecular weight is small and it is easy to be absorbed and used by organisms; second, it has more functional groups, which has greater physiological activity than general humic acid, and has stronger complexation ability to metal ions; third, it can be directly dissolved in water, and its aqueous solution becomes acidic.
fulvic acid is a kind of broad-spectrum plant growth regulator. it should be called biological stimulant in the most fashionable way at present. it can promote plant growth, especially can properly control the opening degree of stomata on the leaf surface of crops, reduce transpiration, and resist drought. it can improve the ability of resistance to stress, increase yield and improve quality.
the function of fulvic acid
① stimulating plant activity: unknown growth promoting factors with high bioactivity can enhance the activities of oxidase and other metabolic activities in plants. although fulvic acid does not contain hormone substances, it has the similar effect with the chemical synthesis of auxin, cytokinin, abscisic acid and other plant hormones, and plays a comprehensive regulatory role in plant growth and development.
② enhance crop resistance: fulvic acid has a significant function of cold resistance and drought resistance.
③ slow release fertilizer: improve the use of chemical fertilizer and pesticide, improve soil aggregate structure.
④ chelating micronutrient elements: strong complexation ability, improve the absorption and operation of plant trace elements, so that it can be better used by plants.
⑤ control plant diseases, enhance disease resistance: fulvic acid as a pesticide synergist to improve the control effect, but can not replace pesticides.
⑥ anti flocculation, buffer, good solubility and strong interaction with metal ions. it is soluble in any acid-base water with ph 1 ~ 14. it can flocculate and not precipitate in saturated salt water with high calcium and magnesium, and has good stability and electrolyte resistance.
humic acid (abbreviated as ha) is the remains of animals and plants, mainly plant remains, after the decomposition and transformation of microorganisms, as well as a series of complex geochemical reaction process and a kind of organic matter accumulated. it is a kind of macromolecular organic acid composed of aromatic group and its various functional groups. it has good physiological activity, absorption, complexation and exchange functions.
classification of humic acids
the main elements of humic acid are carbon, hydrogen, oxygen, nitrogen and sulfur. it is a kind of polycondensate of polyvalent phenolic aromatic compounds and nitrogen compounds. it is widely distributed in low-grade coal, soil, water sediment, animal manure, organic fertilizer, animal and plant residues.
according to the solubility and color classification in the solvent, it can be divided into three components: ① the part dissolved in acetone or ethanol is called brown fulvic acid; ② the part insoluble in acetone is called black fulvic acid; ③ the part dissolved in water or dilute acid 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 activities of catalase and polyphenol oxidase, stimulate physiological metabolism and promote growth and development. for example, humic acid can promote early germination of seeds, high seedling emergence rate, especially under low temperature; it can stimulate the division and growth of extreme meristem cells of root system, make the seedling grow roots quickly, have more roots, increase the root quantity, and lengthen the root system, so as to increase the ability of crops to absorb water and nutrients. therefore, sufficient nutrient supply, strong stems, luxuriant branches and leaves, enhanced photosynthesis, accelerated nutrient transfer to fruiting bodies, and promoted fruit coloring and ripening in advance.
② changing chemical fertilizer characteristics
humic acid contains carboxyl group, phenolic hydroxyl group and other functional groups. it has strong ion exchange and adsorption capacity. it can make ammonium bicarbonate reduce the loss of ammonium nitrogen and improve the utilization rate of nitrogen fertilizer. nitrohumic acid can inhibit the activity of urinary enzyme and reduce the volatilization of urea. the degradation of nitrohumic acid increased the movement distance of phosphorus in the soil, inhibited the fixation of water-soluble phosphorus in the soil, transformed the available phosphorus into delayed phosphorus, and promoted the absorption of phosphorus by roots. the chelating reaction between humic acid and insoluble trace elements can produce humic acid chelates with good solubility and can be absorbed by crops, which is conducive to the absorption of trace elements by roots and leaves.
③ improving soil structure
humic acid can promote the formation of soil aggregate structure, regulate soil ph value, regulate soil water, fertilizer, gas, heat and other conditions, improve soil exchange capacity, achieve acid-base balance, improve soil water and fertilizer conservation capacity, promote soil microbial activities, increase the number of aerobic bacteria, actinomycetes, cellulose decomposing bacteria, accelerate the decomposition and transformation of organic matter, and promote the transformation of organic matter nutrient elements are released to facilitate crops to absorb nutrients.
④ enhanced stress resistance
humic acid can reduce the stomatal opening strength of plant leaves, reduce leaf transpiration, thus reducing water consumption, improving the water status of 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 has inhibitory effect on fungi. it can enhance the cold resistance of crops, be easily absorbed by cell membrane, change the permeability of cell membrane, promote the absorption of inorganic nutrients, prevent rot and root rot, and reduce diseases and insect pests.
⑤ improve seed quality
humic acid can form complex or chelate with trace elements, increase the amount of trace elements transported from root to leaf or other parts, regulate the proportion and balance of major and trace elements, and strengthen the synthesis and operation of enzymes on sugar, starch, protein, fat and various vitamins. it can promote the activity of enzyme, transform polysaccharide into soluble monosaccharide, increase the synthesis and accumulation of starch, protein and fat, accelerate the transfer of primary metabolites from stems and leaves or roots to fruits and seeds, making the fruits plump and thick.