section_path: Environmental impact/Plastic pollution
section_name: Plastic pollution
paragraph_text: Plastic pollution
  
  Plastic products are used extensively in agriculture, including to increase crop yields and improve the efficiency of water and agrichemical use. "Agriplastic" products include films to cover greenhouses and tunnels, mulch to cover soil (e.g. to suppress weeds, conserve water, increase soil temperature and aid fertilizer application), shade cloth, pesticide containers, seedling trays, protective mesh and irrigation tubing. The polymers most commonly used in these products are low- density polyethylene (LPDE), linear low-density polyethylene (LLDPE), polypropylene (PP) and polyvinyl chloride (PVC).
  
  The total amount of plastics used in agriculture is difficult to quantify. A 2012 study reported that almost 6.5 million tonnes per year were consumed globally while a later study estimated that global demand in 2015 was between 7.3 million and 9 million tonnes. Widespread use of plastic mulch and lack of systematic collection and management have led to the generation of large amounts of mulch residue. Weathering and degradation eventually cause the mulch to fragment. These fragments and larger pieces of plastic accumulate in soil. Mulch residue has been measured at levels of 50 to 260 kg per hectare in topsoil in areas where mulch use dates back more than 10 years, which confirms that mulching is a major source of both microplastic and macroplastic soil contamination.
  
  Agricultural plastics, especially plastic films, are not easy to recycle because of high contamination levels (up to 40–50% by weight contamination by pesticides, fertilizers, soil and debris, moist vegetation, silage juice water, and UV stabilizers) and collection difficulties. Therefore, they are often buried or abandoned in fields and watercourses or burned. These disposal practices lead to soil degradation and can result in contamination of soils and leakage of microplastics into the marine environment as a result of precipitation run-off and tidal washing. In addition, additives in residual plastic film (such as UV and thermal stabilizers) may have deleterious effects on crop growth, soil structure, nutrient transport and salt levels. There is a risk that plastic mulch will deteriorate soil quality, deplete soil organic matter stocks, increase soil water repellence and emit greenhouse gases. Microplastics released through fragmentation of agricultural plastics can absorb and concentrate contaminants capable of being passed up the trophic chain.