Introduction
Agricultural biodegradable mulch films are essential materials in modern agriculture that promote crop growth and development through soil temperature control, weed management, moisture retention, and nutrient preservation. Conventionally, most of these films were made from non-biodegradable materials such as polyethylene, which have become a significant environmental issue due to their inability to decompose in the soil. To address this problem, researchers have developed compostable agricultural mulch films , which are biodegradable and enhance the sustainability of agricultural practices. The aim of this article is to provide an overview of compostable agricultural mulch films in terms of their production process, advantages, disadvantages, and applications.
Production Process
The production of compostable agricutural mulch film involves several steps, including the synthesis of biodegradable polymers, extrusion of film, and compounding with additives. Biodegradable polymers used in CAMFs manufacture include polylactic acid (PLA), starch, polyhydroxyalkanoates (PHA), and cellulose. PLA is derived from lactic acid, which is obtained from corn or sugar cane. Starch-based polymers are obtained by converting corn, wheat, or potato starch into thermoplastic materials. PHA is a naturally occurring polymer produced by bacteria, while cellulose is derived from plant-based materials like cotton or wood. The extruded film is then compounded with additives such as UV stabilizers, antioxidants, and plasticizers to improve its physical and chemical properties.
Pollution of soil by traditional mulch film
The mulch fims may seem like a thin layer, but it has a huge effect. It can not only increase ground temperature, conserve water, soil, and fertilizer to improve fertilizer efficiency, but also has many functions such as killing weeds, preventing pests and diseases, preventing drought and waterlogging, suppressing salt and protecting seedlings, improving light and heat conditions near the ground, and making the product hygienic and clean. For those newly emerged seedlings, it has the function of mulching and promoting growth. However, traditional plastic mulch films are not biodegradable and will pollute the soil and affect the next generation of farming. Mainly manifested in the following aspects
The accumulation of residual film in farmland increases, reducing soil water vapor passage efficiency
Block soil fertility from dispersing and reduce microbial activity
Affects the early emergence and later root development of crops and leads to yearly reductions in yields
Disintegrating mulch films are more difficult to recycle after they become fragments, making the pollution more serious.
It also poses a huge threat to the safety of livestock and other animals
Recycling of residual film requires a lot of manpower
Residual film on farmland can easily lead to drainage obstacles, and long-term water accumulation affects crop growth.
Characteristics of biodegradable mulch film
1. It is fully biodegradable and does not degrade normally. It can only be degraded by microorganisms after being in contact with the soil for a period of time;
2. Good mechanical properties, good longitudinal and transverse tearing, and can meet the requirements of mechanical laying;
3. The mulching film processing efficiency is high, which can meet high-strength shearing and good opening properties, and can produce mulch films of more than 8 microns on ordinary mulching equipment.
4. It has good heat preservation and moisture retention, and has a good balance between water retention and air permeability, which is beneficial to regulating temperature and the respiration needs of crops in the later growth period, and is of great benefit to the respiration of root crops;
5. Solve the problems of ordinary mulch film not degrading, starch-based film degrading too quickly, film laying reducing production and secondary pollution;
6. Resistance to hydrolysis and photoaging can be adjusted according to different regions and crops to meet planting requirements.
7. Greatly improve the utilization efficiency of chemical fertilizers in farmland and reduce fertilizer loss and secondary pollution.
Advantages and disadvantages of biodegradable mulch films
Advantages
One of the primary advantages of CAMFs compared to traditional non-biodegradable films is their positive impact on the environment. Since they are biodegradable, CAMFs decompose naturally in the soil, reducing soil pollution and decreasing the amount of film waste that ends up in landfill sites. Decomposition of the CAMFs also enhances soil fertility by increasing the organic matter content of the soil. CAMFs have also been reported to regulate the soil temperature better than traditional films by retaining heat during colder periods and balancing the temperature during warmer periods. This temperature regulation promotes plant growth and yields. Additionally, CAMFs act as a natural mulch, promoting water retention in the soil, reducing weed growth and helping to control erosion. CAMFs also promote plant health by reducing the likelihood of pest infestations by removing hiding places for pests.
Disadvantages
Despite its numerous benefits, CAMFs have several drawbacks that still need to be addressed. The primary drawback is the high cost of production compared to the conventional films. CAMFs require more technology and specialized equipment, more expensive raw materials, and a longer production time compared to traditional films. The performance of CAMFs is also dependent on environmental conditions such as temperature, humidity, and soil type. This dependency means that the degradation of the films may take longer than expected in dry or low-temperature environments where microorganisms do not thrive.
Comparison between biodegradable mulch film and traditional plastic mulch film
Applications
Compostable agricultural mulch films have numerous applications in modern agriculture. They can be used in vegetable and fruit production, flower cultivation, and landscape maintenance. Compostable agricultural mulch films have also been found to be useful in improving soil fertility in organic farming practices. Additionally, the films can be used in greenhouse production systems to reduce weed growth and preserve moisture. In countries where the traditional non-biodegradable films are not allowed, CAMFs offer a sustainable substitute.
How to choose fully biodegradable mulch films scientifically?
1. Meet crop needs
Refer to the safety period of mulch films of key crops in major regions, and select suitable fully biodegradable mulch films to avoid premature degradation and rupture due to insufficient weather resistance of biodegradable mulch films, which cannot meet the functional needs of crops such as moisturizing and heat preservation.
2. Choose the right color
For the main purpose of weed control, black mulch film should be selected to inhibit weed germination and growth. For warming as the main purpose, white transparent mulch film should be selected.
3. Pay attention to the quality of the mulch films
Like traditional mulch films, when covering with fully biodegradable mulch films, it is necessary to press the edge film with soil to minimize damage to the mulch film, and press it tightly to prevent strong winds from blowing over the mulch film.
4. Optimize supporting measures
The temperature-increasing and moisture-retaining function of biodegradable mulch film is weaker than that of traditional mulch film. Therefore, crops with higher accumulated temperature requirements need to be supported by other agronomic measures, such as the application of water-retaining agents.
5. Pay attention to planting methods
There are great differences in the use of biodegradable mulch films in different planting methods. When crops are sown directly, the mulch covering time needs to be appropriately extended; in the transplanting planting mode, the supporting machinery and operating efficiency of large-scale operations need to be considered.
6. Validity period of mulch films
Leaving the fully biodegradable mulch film for too long may result in a decrease in product strength and functionality, which cannot meet the needs of crops for mulch covering functions. It is recommended to use biodegradable mulch films produced in the same year.
7. Suitable crop selection
Fully biodegradable mulching film is mainly suitable for short growth period crops and crops covered with soil, such as potatoes, rice, tobacco, vegetables, processed tomatoes, peanuts and fresh corn.
Summarize
The biodegradable mulch film has good stretchability, is not fragile when picked up, is resistant to aging, and is easy to recycle. It reduces the residual time of the mulch film in the soil, reduces the harm of soil residues, effectively controls soil pollution, ensures the crop emergence rate and the quality and safety of agricultural products, and is beneficial to agriculture. Sustainable use of land ensures both quality and efficiency of agricultural products.
Therefore, the promotion of biodegradable mulch films can greatly reduce the amount of waste mulch film residues, reduce mulch film pollution, and prevent and control the “white pollution” of farmland film residues, which is of great significance to promoting the green development of agriculture.
Conclusion
In conclusion, Compostable and biodegradable mulch films offer a sustainable alternative to the traditional non-biodegradable films used in agriculture. Their ability to decompose in the soil, retain moisture, and regulate soil temperature make them an indispensable part of modern agriculture. Although biodegradable agricultural mulch films have several drawbacks, their benefits far outweigh their disadvantages. With continued innovation and investment in compostable agricultural mulch films production technology, this sustainable agricultural practice is poised to revolutionize the industry and contribute to a sustainable and healthy planet.
