The Food and Agriculture Organization of the United Nations (FAO) experts claim that the agricultural sector uses 12.5 million tons of plastic products each year. The vegetable, fruit, crop and livestock sectors are the largest users, followed by fisheries and aquaculture, then forestry.
Benefits of plastics in agriculture
The use of plastic products in agriculture has many advantages:
- Reduces weed growth, decreases water loss through evaporation and the need for pesticides, fertilizer and irrigation through the use of mulch films (plastic films used to cover the ground)
- Protects and improve plant growth by using polytunnel and nets
- Optimizes water use through tubes and driplines
- Controls the release of chemicals or improves germination by using coatings on fertilizers, pesticides and seeds
- Transporting seeds, liquid pesticides and fertilizers to fields using bags and bottles
- Protecting cultivations from extreme cold and sunlight through non-woven protective textiles
Plastic-related issues
However, plastic products create problems in the natural environment. Most of the products are single-use with a duration of less than one year. This factor will influence the ways in which they are managed at their end of life.
Plastics can contaminate the environment in different ways:
- The wind disperses films and flexible products in the air
- Heavy rainfall events disperse macroplastic fragments (plastics larger than 5 mm in size) in surface and ground waters
- Incorporation into the soil, then subsequent ingestion by soil invertebrates and vertebrates; both of which may in turn be consumed by animals living above ground
Damage caused by plastics
Plastics can persist in the environment for long periods of time and continue to cause adverse effects on both ecosystems and individuals long after they have reached the end of their useful lives.
Agricultural plastics can enter the environment through either being damaged, degraded, or discarded and cause several damages:
- Entrapment: plastic nets, bags, and cages trap animals in aquatic and terrestrial environments leading to their unintentional death
- Ingestion: animals ingest plastics either through grazing, or consuming contaminated animals; thus transferring ingested plastics up the food chain. Macroplastics accumulate in the animal’s gastrointestinal tract which can cause obstruction and perforation leading to starvation or death
- Uptake by plants and drinking water: microplastic particles (plastics less than 5 mm in size) are absorbed by terrestrial and aquatic animals as well plants and drinking water, thus entering the human food chain
- Biological impact: nanoplastics (fragmentation of microplastics) can cross cell membranes and compromise cellular physiology, evoking inflammatory responses (Landrigan et al., 2020)
- Productivity of soil: microplastics can affect the biochemical processes of microbes in soil, thus going to impact soil productivity
How to improve sustainability and reduce environmental impact of plastic products
Specific alternatives or interventions for improving each product’s sustainability will depend on the product, the type of agriculture and local laws which apply in that part of the world. It will involve a mix of technical solutions, legislation and behavioral change initiatives.
Possible solutions:
- Cover crops could be planted using them as mulch and avoiding the use of plastic. This would improve the soil and absorption of carbon
- Ban products that have a high risk of pollution
- Minimize the risk of products leaking into the environment and improve their recyclability
- Provide incentives for users to manage agricultural plastics sustainably (e.g. incentive schemes to encourage the return of used containers to distributors or manufacturers)
- Replace conventional non-biodegradable products with natural or fully biodegradable products. Biodegradable plastics are broken down by naturally occurring microorganisms – such as bacteria and fungi. The rate of biodegradation depends on environmental conditions such as temperature, humidity, the set of microorganisms present and the presence or absence of oxygen (Degli Innocenti and Breton, 2020)
- Introducing product labeling including expected effective working life
- Replacing short-term single-use products with reusable ones, such as stackable rigid harvesting crates instead of flexible bags
It is necessary to act as soon as possible to limit the problem of plastics in agriculture. There is an urgent need to adopt solutions based on the 6R model (refuse, redesign, reduce, reuse, recycle and restore) on which the possible interventions described above are based by encouraging and supporting farmers in adopting sustainable practices.
Source:
https://www.fao.org/3/cb7856en/cb7856en.pdf
Written by: Mariangela Difilippo