The Ecosystem Overviews provide a summary introduction to the main habitat types covered in APIS and the main air pollutant pressures on those habitats in the UK. In specific locations, e.g. close to a major source, other pollutants may be a concern for a habitat and the user should use the searches by location or by habitat/pollutant in these cases.
Introduction
Arable crops can be adversely impacted when exposed to high concentrations of various air pollutants. The impacts range from visible symptoms on the foliage, to reduced growth and yield, and to the premature death of the plant.
Arable Field Margins can be managed to provide valuable habitats for wild birds, invertebrates and mammals. Arable field margins are herbaceous strips or blocks around arable fields that are managed specifically to provide benefits for wildlife. They are usually sited on the outer 2-12m margin of the arable field. Margins can be managed in different ways including margins as buffer zones (not sprayed with insecticides or herbicides); margins sown to provide seed for wild birds; and margins sown with wild flowers providing food for important pollinators.
BAP Habitats: Arable field margins (priority); Arable and horticultural
Main Pollutant Impacts
Ozone
Exposure to ground level ozone can lead to yield losses for both arable crops and horticultural crops, with direct effects on leaf physiology and plant growth. In the US, annual losses of arable crop production, due to O3, were estimated at $2-4 billion during the 1980s, with an equivalent estimate for the EU of €6.7 billion in 2000 (Royal Society, 2008). Critical levels have been set based on AOT40 and stomatal flux to protect against yield reduction (UNECE, 2004).
Heavy metals
Heavy metals (e.g. lead, cadmium, copper and zinc) can, at high concentrations, have toxic effects on plants. Symptoms include reductions in growth, photosynthesis, mitosis and water adsorption, leaf-chlorosis. However large variations in inter-species sensitivity and bioavailability heavy metals must be taken into account when assessing possible effects. Non-atmospheric sources of heavy metals may be more significant that atmospheric inputs to arable habitats.
Other impacts of air pollution
There is evidence to show that there are increased levels of damage from insect herbivores in areas of high air pollution (Whittaker, 2001). In general, acidification and eutrophication are not problems associated with arable land. However, impacts may occur as a result of acute impacts. For example, reduced grass growth in a case study (Spears and Frost 1985) was attributed to soil acidification, due to NH3 deposition from a nearby poultry house. Arable crops are impacted by high concentrations of SO2 (e.g. Ayazloo and Bell 1981) and NOx. However, this is usually no longer an issue in the UK as typical rural background concentrations are below critical levels. An exception is NOx concentrations close to major point sources and roads.