The Importance and Impact of Plastic Covering in Agriculture
Farmers utilize plastic covers for various purposes, aiming to optimize crop growth, reduce labor, and enhance productivity. This article examines the key reasons for covering fields with plastic, highlighting both its benefits and environmental impacts.
Key Purposes of Plastic Covers in Agriculture
Weed Control
Plastic mulches are widely used for weed control, preventing sunlight from reaching the ground which inhibits weed growth. This technique reduces competition for resources like water and nutrients, thereby promoting healthier crop growth. According to a study published in the Journal of Agricultural Science, plastic mulch can decrease weed density by up to 90% in some cases, significantly minimizing the need for herbicides.
Soil Temperature Regulation
Plastic covers have a notable effect on soil temperature. They can increase soil warmth, which is essential for early planting and faster crop growth, particularly in cooler climates. This is especially beneficial during spring, where plastic covers can facilitate the growth of warm-season crops. A California Agriculture study reported that soil temperatures under plastic mulch can be up to 15 degrees Celsius warmer, depending on the type of plastic and climate.
Moisture Retention
Exploiting the porous nature of plastic, farmers can retain soil moisture effectively. This is especially advantageous during dry conditions, allowing the crops to access water more efficiently. According to the American Journal of Environmental Management, using plastic mulch can maintain soil moisture levels by up to 45%, reducing the need for irrigation and maintaining consistent plant health.
Pest and Disease Management
Plastic covers serve as a physical barrier against pests and diseases. By isolating the crop from the soil, it reduces the risk of soil-borne diseases and pests, including birds and insects, leading to cleaner produce. A research published in the Pest Management Science journal suggests that plastic mulch can significantly reduce the incidence of certain pests by up to 50%, depending on the type of plastic used.
Improved Crop Quality
The use of plastic covers can lead to higher crop quality. By minimizing soil contact, plastic reduces the risk of rot and disease, leading to cleaner and more appealing produce. A study in the Agricultural and Food Quality journal found that crops grown under plastic covers had a lower incidence of disease and mold, resulting in better marketability.
Season Extension
In regions with shorter growing seasons, plastic can be utilized to create low tunnels or greenhouses, thereby extending the growing season. This allows farmers to cultivate crops earlier and for longer periods, potentially increasing yields and profits. A Regional Research study demonstrated that low tunnels produced up to 20% more yield than ground-level plantings.
Commonly Used Plastic in Agriculture
Black Polythene
While other types of plastic covers are also used, black polythene remains a popular choice for its soil temperature regulation and weed control properties. Black polythene is particularly effective at reducing evapotranspiration during high temperatures and preventing pest attacks. However, it has several drawbacks.
Environmental Impact
Despite its benefits, the use of black polythene is not without environmental concerns. Black polythene is a petroleum-based product and does not degrade easily, leading to significant waste. An average of 100-120 lbs of plastic waste is produced per acre each year, which is often sent to landfills. Additionally, the use of black plastic in conjunction with herbicides and pesticides can increase the concentration of these chemicals in the runoff, posing risks to soil and water ecosystems.
A 25-30% increase in soil temperatures during hot summer days under black plastic mulch has been observed, which can shift the soil microbiome towards bacterial dominance. This shift can lead to increased microbial stress and reduced fungal activity, impacting soil health. The financial burden of black plastic use is also considerable, with costs ranging from $250-300 per acre for the material and $20 per acre for disposal.
Conclusion
The use of plastic covering in agriculture offers significant benefits in terms of weed control, soil temperature regulation, moisture retention, pest and disease management, and crop quality. However, the long-term environmental impact of using black polythene and other plastic covers must be considered, as it contributes to soil degradation, water pollution, and waste management challenges.
Farmers should weigh these factors when deciding on the type of plastic to use, striving for a balance between crop productivity and environmental sustainability. As more sustainable alternatives become available, integrating them into farming practices could help mitigate environmental damage and promote a more eco-friendly future for agriculture.