Agricultural material headlines| as the largest amount of nitrogen-containing natural organic compounds on the planet in addition to proteins, the application of chitin and its derivatives is very important. At present, many companies have launched related products, although the effect is very good, but it has not yet attracted enough attention from the industry, and blindly chases the content of chitosaccharides.
Why is chitosan so unpopular?
Tracing back to the source, chitosan oligosaccharides and chitosan oligosaccharides come from the same substance. For the production enterprises of water-soluble products, because chitosan oligosaccharides are water-soluble and powerful, chitosan-oligosaccharides are favored by enterprises, and enterprises also tend to add such substances to products. In general, chitosan is insoluble in water, which limits its application in agriculture.
First of all, this is closely related to its molecular structure and water soluble properties (as shown in the following figure),
Chitin, chitosan oligosaccharide, chitosan comparison ↓
PreviousWe learned about the top ten applications of chitosan oligosaccharides in agriculture, today we focus on chitosan and its excellent functions in agriculture, such as positive performance in seed coating and soil improvement.
What is chitosan?
Derived from shrimp and crab shells and other substances, it becomes chitin after decalcification and deproteinization, and forms carboxymethyl chitosan after carboxylation reaction, which is a water-soluble chitosan derivative. Chitin, on the other hand, is deacetylized to form chitosan, which becomes chitosan oligosaccharide through further degradation.
Chitosan cannot be directly soluble in water, but can only be dissolved in some dilute inorganic or organic acids. For chitosan with higher deacetylated degree, when the deacetylatability is controlled at 50 to 60%, water-soluble chitosan can be obtained. In addition, chitosan salts are soluble in water.
Chitosan production process ↓
However, chitosan in the production process needs to be cleaned, dried and chemically treated many times, which will produce a certain amount of waste liquid, and the industry's call for clean production is high, if this problem can be solved, the application road in agriculture will be smoother.
As one of the important components of chitin products, chitosan has excellent film-forming properties and ..., and its excellent function in agriculture cannot be ignored.
Application of chitosan in agriculture
1. Seed coating
Because chitosan has good film-forming properties, it can be used as an ideal seed coating material to form a film around the seed, which can not only retain seed moisture, but also inhibit the invasion of pathogenic bacteria. In addition, after seed germination, some active substances can be slowly released to ensure the normal growth of seedlings, so that they will not cause drug damage or fertilizer damage due to the sudden accumulation of pesticides or nutrients. Studies have shown that chitosan is most commonly used in seed coating. Chitosan alone as a seed coating agent or compound with other types of seed coating agents can promote seed germination, improve seed germination rate and vitality, promote seedling growth, and achieve yield increase.
It can be used for wheat seed mixing, which can promote tillering, increase the effective number of panicles, and increase the yield by 10.9% to 22.5% compared with the control group, which significantly improves the quality of wheat. If used in combination with other fungicides, the occurrence of blight can be inhibited, and its incidence is reduced by 30% to 50% compared with the control group. When rice and corn are treated, the germination rate and yield have increased significantly.
After soybean seeds are coated with chitosan, their germination rate and germination potential are improved. After seed sowing, it can promote the growth of seedling roots, nodules and underground parts, promote the protein synthesis of seedling leaves, and improve the photosynthetic rate.
The use of hydroxymethyl chitosan (ncmc) aqueous solution to treat corn seeds, can promote seed germination, improve germination rate, germination potential, with ncmc aqueous solution treatment of corn fruit ears, can improve the soluble protein of maize immature grains, can improve the content of storage protein of mature seeds.
In addition, the physiological and biochemical indicators of the seedling stage and the resistance of crop stress can also be improved during the growth process of seedlings.
2. Soil improvement
If chitosan oligosaccharides are better combined with water-soluble fertilizers, then chitosan will perform better in the soil.
Chitosan can not only improve the physical and chemical properties of the soil, activate the soil nutrients, but also change the microbial flora after being decomposed by microorganisms, adjust the types and quantities of microorganisms present in the soil and the intensity of metabolic activities involved in the material cycle, promote the beneficial activities of soil microorganisms and control their harmful effects.
(1) Increase soil aggregate structure
Chitosan can synthesize soil and soluble proteins (such as collagen) into liquid soil conditioners, which have a certain degree of degradability and stability, and can degrade and dissolve high-quality organic fertilizers. At the same time, it can also improve the adglomerate structure of the soil.
(2) Increase microbial activity
Because of its degradability, it can be decomposed by microorganisms in the soil, providing more nutrients for plants, promoting the proliferation of beneficial bacteria such as self-nitrogen-fixing bacteria, fiber decomposition bacteria, lactic acid bacteria, actinomycetes, and inhibiting the growth and reproduction of pathogenic bacteria such as mold and filamentous bacteria, which can significantly reduce the disease caused by plant pathogens, and also increase the number of bacteria that decompose chitin and chitosan in the soil by 3 to 5 times, and the chitinase produced by these bacteria can inhibit the growth of some fungi or kill the eggs of nematodes.
According to the ultra-microstructure studies and fluorescence microscopy observation results, chitosan works by adsorption on the surface of bacteria, which can inhibit the growth of a variety of bacteria, and the minimum inhibitory concentration of different bacteria is 10~1000ppm, chitosan (molecular weight is 1130kda, deacetylatability >85%; molecular weight is 607kda, deacetylated >75%) shows strong antibacterial activity for bacterial white leaf blight and bacterial stripe spot disease.
For viruses, chitosan can not directly inactivate the virus, by inhibiting the spread of inter-plant viruses and viruses, improve the allergic reaction of crops to infection, inhibit local wound necrosis of crops, so as to achieve the effect of controlling plant viral diseases, molecular weight and deacety different chitosan inhibition rate of virus in 50% to 90%.
(3) Purify the soil
With the current development of industry, agriculture and metallurgy, more and more harmful metals enter the soil, not only polluting the soil, but also enriching crops and livestock and poultry, and eventually entering the human body, seriously affecting human health.
The application of chitosan products on this type of soil can use its excellent ion exchange, adsorption, chelating function to combine with metal ions, and its own structure has not changed, but the nature of the product has changed, and sulfate ions will promote its binding.
In addition, chitosan is crosslinked with glutaraldehyde, formaldehyde, epichlorohydrin, cyclothiochlorothane and glycol diglyceride ether, which can obtain a series of products that can make chitosan better applied. After treatment, it can increase its surface area and pore size, enhance its adsorption performance and stability, and can be well combined with ag+, pb2+ and cu2+ to purify heavy metals in the soil.
(4) Seal the soil
Spraying it on the surface of the soil can form a barrier film, which can prevent the invasion of soil pathogens and the exudation of root nutrients to a certain extent, reduce the activity of pathogenic bacteria, and prevent the release of fungal mycline in pathogens.
Unlike traditional chemical fumigation of soil, chitosan can significantly improve soil and reduce the incidence of soil-borne diseases.
Obviously, its poor water solubility limits some of its applications in agriculture. Of course, at present, there are also enterprises that produce water-soluble chitosan and chitosan substances, such as Jiangsu Aoxin, which broadens the application dimension of chitosan in agriculture.
Regarding more market applications of chitosan in agriculture, what are your opinions, welcome to leave a message to share ~
(Author: Li Xiaoping, the headline of agricultural materials, data from the Internet)