Plastic Mulch in Agriculture: Boosting Yields, But at What Cost?

Introduction: Plastic mulch films (PMFs) have become an indispensable tool in modern agriculture, aiding in improving crop yields and quality. While their benefits are undeniable, the dark side of PMFs emerges when we consider their environmental repercussions. This blog delves into the significant role PMFs play in the generation of microplastics (MPs) and the adverse consequences for soil ecosystems, organisms, and even human health.

Why Use Plastic Mulch?

Plastic mulching is hailed for its ability to enhance water use efficiency, reducing losses due to transpiration and evaporation. This leads to more effective water utilization and better nutrient absorption by plants. However, the flip side of this practice is the non-biodegradable nature of the plastic films used for mulching. Over time, these films degrade into microplastics, which can be dispersed by wind or water, causing harm to the environment.

The Influence of MPs on Soil Ecosystems and Adverse Consequences

It's alarming to note that approximately 3.4% of global plastic production is used in agriculture. PMFs are a primary contributor to this plastic usage, with millions of tons consumed annually, especially in semi-arid and arid regions. These films, composed of various hard-to-biodegrade polymers, contribute to the growing issue of plastic pollution in agriculture.

As PMFs break down, they leave behind macro- and microscopic plastic residues, which persist in the soil for extended periods. This non-biodegradable residue can amount to 50-270 kg per hectare in densely covered areas, further exacerbating the problem.

Microplastics not only harm the environment but also affect the biophysical properties of the soil. They alter factors such as soil bulk density, water stability, structure, pH, respiration, and enzymatic activities. This deterioration leads to a decrease in soil fertility and nutrient content, making the soil less hospitable to organisms and potentially reducing crop yields.

Moreover, MPs can be absorbed by soil organisms, impacting their growth, development, and reproduction. This exposure can disrupt soil bacterial and fungal communities, impair the digestive system, gut microbial community, immune system, and reproduction of soil animals, and negatively affect crop growth.

Microplastics are not confined to the soil; they can be transported to the atmosphere, fluvial systems, and oceans. Wind-driven soil erosion can carry MPs into the air and surface water, contributing to their spread. Additionally, open burning of PMFs releases plastic debris into the atmosphere, which can then be deposited into the soil and surface water.

Conclusion:

The use of plastic mulch films in agriculture offers undeniable benefits in terms of water efficiency and crop quality. However, these advantages come at a significant environmental cost. The degradation of plastic mulch films into microplastics poses a threat to soil ecosystems, soil quality, and the well-being of soil organisms, potentially affecting crop yields and food chains. Moreover, the dispersion of microplastics into the atmosphere and water systems presents a wider environmental concern.

It is essential to consider the environmental impact of plastic mulch and explore more sustainable alternatives to mitigate the potential harm caused by microplastics in agriculture. Proper disposal and recycling of plastic mulch waste are crucial steps towards minimizing its adverse effects on the environment and human health.

Link to related article: https://doi.org/10.1016/j.ecoenv.2022.114030