Monocultures often rely on the application of nitrogen-based fertilisers to support the growth of a single crop.
When a single crop is grown continuously in the same area, it depletes the soil of nutrients, including nitrogen. To compensate for this nutrient depletion and ensure high crop yields, farmers apply synthetic fertilisers that contain nitrogen compounds. However, in monoculture systems, the crops cannot efficiently utilise all the nitrogen applied, leading to an excess amount of nitrogen in the soil.
The excess nitrogen can leach into water bodies or be carried away by rainfall, causing nitrogen pollution. This pollution, known as nitrogen runoff or nitrate leaching, can contaminate groundwater and surface water. When nitrogen-rich runoff reaches rivers, lakes, or coastal areas, it can lead to eutrophication, where excessive nitrogen promotes the growth of algae and other aquatic plants. This overgrowth disrupts aquatic ecosystems, depletes oxygen levels in the water, and harms fish and other organisms.
Moreover, nitrogen pollution contributes to air pollution when nitrogen-based fertilisers undergo volatilisation, releasing ammonia and nitrogen oxide gases into the atmosphere. These gases can contribute to the formation of smog and greenhouse gases, which have adverse effects on human health and the environment.
Reducing monoculture and adopting more sustainable farming practices, such as crop rotation, cover cropping, and organic farming, can help minimise nitrogen pollution. These practices promote healthier soil, improve nutrient cycling, reduce the need for synthetic fertilisers, and mitigate the negative impacts of excessive nitrogen use.