Case Studies of Chitosan Applications in Agriculture

Against the backdrop of modern agriculture’s continuous development towards green, efficient, and sustainable practices, the application of natural biomaterials is receiving increasing attention. Chitosan, as a widely available natural polymer material with unique properties, is gradually demonstrating its unique value in the agricultural field.

This article will systematically review practical application cases of chitosan and its derivatives in agriculture, providing practical ideas for agricultural production.

Introduction to Chitosan and its Derivatives

Chitosan: The product obtained after deacetylation of chitin, which has a certain water solubility, and its solubility depends on the degree of deacetylation.

Chitosan Oligosaccharides (low molecular weight chitosan): Obtained by degrading chitosan using bioenzyme technology, with a degree of polymerization of 2–20 and a molecular weight ≤3000 Da. It has good water solubility, high biological activity, and is easily absorbed, and its functional effects can be several times that of ordinary chitosan.

The Core Role of Chitosan in Agriculture

• Regulating plant growth, improving germination rate, plant height, root development, and crop yield

• Improving crop quality, increasing protein content, vitamin C content, and soluble sugar content

• Inhibiting the growth of pathogenic bacteria and enhancing crop resistance to pests and diseases

• Natural, environmentally friendly, and biodegradable, suitable for organic agriculture and green planting systems

Case Studies of Chitosan Application in Agriculture

1. Seed Soaking Application

• Corn Seed Soaking Case: Use a 0.1% chitosan solution, diluted 1:1 to obtain a 0.05% solution. 2000 ml of the solution can soak approximately 1.67 kg of corn seeds. After soaking for 16 hours, dry the seeds and sow them. This can effectively improve the germination rate and seedling growth.

• Cucumber Seed Soaking Case: Dilute a 1% chitosan solution 1:5.7 to 0.15%. 670 ml of the solution can treat 0.6 kg of cucumber seeds. After soaking for 24 hours, sow the seeds. This helps to ensure uniform seedling emergence.

2. Seed Coating Application

• Soybeans: Spray coating with a 1% chitosan solution. 100 ml of the solution can treat 1 kg of seeds, promoting root development and protein synthesis.

• Cabbage: Use a 1% chitosan solution. 100 ml can treat 1.67 kg of seeds.

• Potatoes and other root and tuber crops: 100 ml of a 1% solution can treat approximately 1.25 kg of seeds.

3. Foliar Spraying to Promote Growth

• Cabbage: 40 ppm concentration, starting when the cotyledons are fully expanded, spray every 4 days for a total of 5 times.

• Potatoes and other root and tuber crops: 20 ppm concentration, promoting the growth of underground roots and tubers.

• Cucumber: 100 ppm concentration, starting at the three-leaf stage, spray every 7 days for a total of 4 times.

4. Antibacterial and Disease Prevention Foliar Spray

1% chitosan solution can be directly applied as a foliar spray; for preventative purposes, it can be diluted to 0.2%, exhibiting significant inhibitory effects on various pathogenic bacteria.

5. Soil Improvement Application

Diluting a 0.1% chitosan solution to 250 ppm and mixing it with zeolite powder, diatomaceous earth, or fertilizer before applying it to the soil can effectively inhibit soilborne pathogens and improve the soil microecological environment, especially suitable for protected cultivation and continuous cropping soil remediation.

6. Fruit and Vegetable Preservation Application

Spraying a 0.5%–1% chitosan solution onto the surface of fruits and vegetables forms a natural protective film. Studies show that a 1% solution can inhibit the growth of approximately 90% of pathogenic bacteria, significantly extending the shelf life of fruits and vegetables.

7. Soil Heavy Metal Immobilization and Remediation

Utilizing chitosan’s strong adsorption capacity for metal ions, soil heavy metal immobilizing agents can be prepared through modification and cross-linking processes, enabling the stabilization of heavy metals in contaminated soil and reducing their bioavailability.