Chitosan polymer is a linear polysaccharide composed of randomly distributed beta -(1→4)- linked D-glucosamine (deacetylated units) and n-acetyl-d-glucosamine (acetylated units). It is made by treating the chitin shells of shrimp and other crustaceans with an alkaline substance, such as sodium hydroxide.

Chitosan polymer has many commercial uses. It can be used in agriculture as a seed treatment and biocide to help plants fight fungal infections.

Properties of Agricultural Chitosan

1. Induce the plant's own defense response and produce broad-spectrum resistant substances

The biggest feature of chitosan is that it can induce crops to produce a large number of various resistant substances in a short period of time, greatly improving the crop's self-immunity. Once the pathogen invades, these resistant substances can be eliminated from multiple targets. The effect is long-lasting. It can induce the production of plant resistance protein; induce the production of lignin; change the phenolic metabolism of plants; induce plants to produce guaifen and strengthen plant cell walls.

2. Inhibit and kill plant pathogenic bacteria and pests, and have a certain repelling effect on nematodes, aphids and red spiders, etc.

Improve crop immunity and disease resistance, and make beneficial bacteria proliferate. It has obvious direct inhibitory and killing effects on viruses, fungi, bacteria and other pathogenic bacteria, especially on the prevention and treatment of viral diseases. The incidence of pests and diseases in crops where chitosan is frequently used is reduced.

Traditional plant protection techniques rely too much on chemical pesticides, and almost all pesticides follow the principle of direct killing. Under the leadership of this concept and technology, the resistance of pests and diseases is increasing, while the plant's own disease resistance and stress resistance mechanism is gradually weakened, passivated, dormant or even lost. This is the fundamental reason why pest control is becoming more and more difficult today. Practice has shown that the application of chitosan pesticides can prevent and directly control diseases such as anthrax, blight, virus, wilt, root rot and other diseases. When the plant encounters other diseases or the condition is serious, it can be compatible with external inhibitory pesticides (reduction), internal resistance and external inhibition, synergistic effect, and satisfactory results can be achieved in most cases. Chitosan induces crops to produce a variety of resistant substances, so it is effective in the prevention and control of viruses, fungi, and bacteria, showing characteristics similar to antibiotics. In particular, the prevention and treatment of viral diseases used to be a difficult problem for plant protection, but the control effect of chitosan products is very satisfactory, and these have been verified by practice.

The diseases that can be prevented and controlled are as follows: grape downy mildew, powdery mildew; apple powdery mildew, scab (scab); wheat powdery mildew; strawberry powdery mildew; melon blight; banana leaf spot; pepper anthracnose; tobacco Powdery mildew, anthracnose; tea tree anthracnose; mango anthracnose; solanaceous crop bacterial wilt; tomato wilt, etc.

3. Promote root growth, activate the rhizosphere state, shrink joints and make them thick

Roots are the foundation of plants, and the rhizosphere is well developed, which will enhance the ability of plants to absorb fertilizer and water, enhance drought resistance, lodging resistance, enhance immunity, and achieve the purpose of being strong and fruitful. Chitosan can promote plant seeds to germinate in advance, develop root system, greatly increase the number of root hairs, fibrous roots, and secondary roots, fully activate the rhizosphere state, dissolve nutrient molecules, and quickly form a soil solution, so that nutrients such as nitrogen, phosphorus, and potassium can be fully obtained by plants. effective absorption. In addition, chitosan has the function of regulating plant development. It can grow roots and promote stems, making the stems shorter, thicker and vigorous, which is conducive to the maximum supply of nutrients to the fruit. The trace elements are easily absorbed by the fruit under the chelation of chitosan. , thereby increasing the content of protein and amino acid, fundamentally improving the quality.

4. It has obvious fertilizer effect, strong plants, enhanced photosynthesis, and increased crop yield

Chitosan itself has a positive charge, can be closely combined with the plant surface (usually negatively charged), and has the characteristics of viscous solution, stretching effect, and easy film formation. Its extremely strong film-forming function can delay the release of fertilizer elements, reduce nutrient loss and greatly improve fertilizer efficiency. This can fundamentally solve the waste of fertilizers, save money, protect the environment, and benefit human health.

The effect of chitosan on crop production is very prominent, this is because chitosan can activate and enhance the physiological and biochemical mechanism of plants, promote the development of root system, thick stems and leaves, so that the ability of plants to absorb and utilize water and fertilizer and photosynthesis etc. be enhanced. Treating grain seeds with chitosan can increase the yield by 5%-15%; it can increase the yield by 20%-40% or more when used for fruit and vegetable sprinkler irrigation. It can improve crop quality, such as increasing grain protein and gluten content and sugar content in fruits and vegetables.

5. Improve the soil:

Biochemical polymer molecules promote soil aggregates, enhance soil activity and air permeability, have good effects on crop root growth and prevent continuous cropping obstacles (replanting), and prevent soil compaction caused by excessive use of chemical fertilizers. Studies have shown that chitosan can greatly promote the proliferation of beneficial bacteria such as nitrogen-fixing bacteria, cellulolytic bacteria, lactic acid bacteria, and actinomycetes after entering the soil, and inhibit the growth of harmful bacteria such as mold and filamentous bacteria. For example, the number of actinomycetes can be increased by nearly 30 times. Chitosan has broad-spectrum antibacterial properties, and has a good inhibitory effect on most genera of Gram-negative bacteria and Gram-positive bacteria. Chitosan fertilizer contains macroelements and microelements required for crop growth, and can regulate soil physical and chemical properties and microbial flora composition. Using chitosan as an additive can increase beneficial soil bacteria such as actinomycetes by 1000 times, significantly reduce harmful bacteria such as fusarium and nematodes, enhance soil fertilizer supply capacity, fundamentally improve soil, cure compaction, and improve soil organic matter content, easy for continuous cropping.