Fighting plastic pollution in agriculture
The application of thin sheets of polyethylene film to farmland began in the 1950s when agronomists noticed that it could successfully moderate soil temperature, limit weed growth and prevent moisture loss. . All essential factors in agricultural production, this method has increased the yields of cotton, maize and wheat by an average of 30%. The promise of increased yields at relatively low cost has formed a multi-billion dollar industry for agricultural plastics. According to experts from the Food and Agriculture Organization of the United Nations, agricultural value chains use 12.5 million tonnes of plastic products each year. Crop production and livestock combined accounted for 10.2 million tonnes (Mt) per year of plastics, followed by fisheries and aquaculture with 2.1 million tonnes and forests with 0.2 million tonnes.
The dangerous toxins released from the polythene film can stay in the ground for centuries. Known as white pollution, polyethylene residues are increasingly prevalent in treated soils at levels of up to 300 kilograms (661 pounds) per hectare. Over time, this decreases soil porosity and air circulation, alters microbial communities, and compromises soil fertility. Polyethylene also releases carcinogenic phthalate acid esters into the soil which, along with other synthetic pesticides, can be readily taken up by crops. This is a significant risk to human health. Additionally, the polyethylene films used in the liners are low density by design, which makes the plastic extremely difficult to biodegrade. All the waste from this process is rarely accepted by recycling facilities and often ends up in landfills and the oceans, wreaking havoc on ecosystems around the world.
Plasticulture, i.e. the application of plastics in agricultural cultivation, is rapidly becoming the most sought-after technique for increasing agricultural yields and consequent farm income. In India, achieving the overall goal of doubling farm income can help.
A wide range of plastics are used in agriculture, including polyolefin, polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC) and, less commonly , polycarbonate (PC) and poly -methyl methacrylate (PMMA). These plastics are used in a wide range of applications, including:
Micro irrigation: This includes the use of drip irrigation and sprinklers on farms. With proactive measures taken by various state governments, such as requiring farmers growing sugarcane to switch to drip irrigation (Maharashtra) and continuing to streamline payment mechanisms subsidies, the domestic micro-irrigation industry is on a solid footing with solid prospects.
Artificial ponds: Creation of artificial plastic ponds to conserve water during the monsoons. Nationally, Rajasthan and Maharashtra are at the forefront of promoting pond liners and have strong growth prospects.
Greenhouses: A farming technique in which the crop is grown in a controlled environment and is covered by firm netting or plastic across a frame.
plastic mulch: An agricultural technique in which crops are grown through holes in a leaf, laid on the ground. It prevents soil contact with the atmosphere and therefore helps prevent moisture loss.
As with concerns about plastics in other sectors, their application in agriculture also poses challenges. Over time, film residue can reduce soil porosity and air circulation, alter microbial communities and potentially reduce the fertility of farmland, the scientists found. Cling film fragments have also been shown to release potentially carcinogenic phthalate acid esters into the soil, where they can be taken up by vegetables and pose a risk to human health when the food is eaten. Film fragments left in fields can also accumulate pesticides and other toxins applied to crops.
According to a study of a published report of data from the University of California and Santa Barbara, in 2015, approximately 6,300 Mt of plastic waste was generated worldwide, of which approximately 9% was recycled, 12% was incinerated and 79% accumulated in landfills or in the natural environment. If current trends in waste generation and management continue, approximately 12,000 Mt of plastic waste will be in landfills or in the natural environment by 2050.
The main benefits of plasticulture include:
Increased crop yields (more than 20%, water saving (~30-40%) and
Save in other agricultural inputs, viz. agrochemicals and fertilizers. Plasticiculture may well be absorbed as a central system within the framework of sustainable agricultural practices at the national level.
Its effective implementation should result in strong production of food grains and consequently an increase in agricultural GDP of more than 4%.
Plastic is undoubtedly a ubiquitous and “necessary” material for humanity. The country has taken a series of measures in recent months to ban the use of single-use plastics, mainly in the form of polythene bags and bottles. The use of plastics in agriculture could be the next big segment for plastic manufacturers to target, and it’s going to be disastrous given the effects on soil health, microbial communities, the potential release of carcinogenic compounds into the food chain and also the loss of commercial value. to crops such as cotton.
There are alternatives. A recent UN Environment report discusses the use of:
Alternative natural materials obtained from plants and animals
Next-generation biopolymers which are plastics made from biomass sources
The report highlights some relatively conventional alternatives to plastics – such as paper, cotton and wood – as well as less obvious solutions such as algae, fungi and pineapple leaves – among others.
With regard to agriculture in particular, some solutions may require a little more physical effort (use of organic mulch) or others at a slightly higher cost (biodegradable materials). Therefore, state and national policies must come to the rescue to encourage good and responsible behavior. Steps such as those taken by smart cities like Muzzaffapur and progressive states like Maharashtra to ban single-use plastics and enforce penalties for non-compliance will certainly help. But we must go beyond simply banning plastic bags and addressing their use in all sectors if we are to make a difference in the contamination of our soil, water, food and air.
And while research and development is helping to develop more alternatives as business options, the traditional resource management principles of reuse, reduce, recycle will continue to apply.
(The article was written by Arjuna Srinidhi, Associate Theme Leader, Ecosystem-Based Adaptation at the Watershed Organization Trust Center for Resilience Studies (W-CReS) and Divya Nazareth, Research Fellow, Climate Change Adaptation.)