A restored fen wetland in Ovando, Mont.
Wetlands and other restored natural areas, like this restored fen wetland in Ovando, Mont., can help mitigate nitrogen pollution by absorbing excess nutrients. Credit: U.S. Fish and Wildlife Service, CC BY 2.0
Source: Earth’s Future

Nitrogen, along with carbon, hydrogen, and oxygen, is one of the fundamental elements that make life on Earth possible. Nitrogen makes up nearly 80% of the air we breathe and is a key factor in food security, human and environmental health, climate change, and the economy. The problem with nitrogen today—at least with agricultural nitrogen in the form of fertilizers—is like many others: There is a geopolitical divide between haves and have-nots. And, according to the researchers behind a new study, large-scale efforts are needed to address the environmental, economic, and social problems that surround the use, and misuse, of nitrogen around the world.

Agricultural nitrogen that doesn’t enter crops contaminates the land, water, and air in many parts of the world, particularly in developed countries with ample access to fertilizers. Unused amounts represent wasted nutrients that do not contribute to farmers’ yields and contribute to numerous health problems, as well as to ozone depletion, climate change, aquatic dead zones, water pollution, and other environmental problems.

In developing economies, though, farmers don’t have enough nitrogen. Without fertilizer, exhausted soils cannot support the crops that local populations need, and food insecurity contributes to social unrest, economic stagnation, malnutrition, and famine.

In a new paper, Houlton et al. consider the problems of the global nitrogen imbalance as well as proposed solutions and present a five-pronged approach to maximize the positive effects of agricultural nitrogen on our planet.

First, we should build on the recent momentum of nitrogen efficiency gains in the United States, Europe, and China. With improved technology and farming practices, fertilizers can precisely meet the needs of growing plants. These efforts should extend to nitrogen in animal feed and waste as well. Incentive programs and more nitrogen-efficient crops can help farmers adopt better practices.

Second, nitrogen supplies should be distributed differently. Food-insecure areas, such as parts of sub-Saharan Africa and South America, would benefit from increased access to nitrogen fertilizers. These changes would require the cooperation of both national governments and private organizations and must account for farmers’ local needs and customs.

Third, nitrogen pollution should be removed from the environment by both reducing nitrogen pollution at its sources and restoring wetlands and floodplains. These restored ecosystems can sponge excess nitrogen out of water, and they provide habitat that may increase biodiversity. In addition, wetland soils can further mitigate climate change by storing carbon.

Fourth, we should waste less food. A quarter of all food produced is never consumed, so the fertilizer used to grow this food is wasted. Better on-farm storage facilities and public awareness both can help, as food waste occurs both on farms and at the consumer level.

Finally, we need a cultural shift to adopt diets with low nitrogen footprints. Farmers can breed and grow more nitrogen-efficient crop varieties, whereas consumers can opt to consume food with lower nitrogen footprints.

The researchers call on other scientists to model and explore the costs and benefits of these solutions. For example, quantitative modeling of how different practices might affect future climate change could spur governments to enact incentive programs. And research into which foods use nitrogen most efficiently would help consumers make more informed choices. (Earth’s Future, https://doi.org/10.1029/2019EF001222, 2019)

—Elizabeth Thompson, Freelance Writer


Thompson, E. (2019), Solving the global nitrogen imbalance, Eos, 100, https://doi.org/10.1029/2019EO132115. Published on 05 September 2019.

Text © 2019. The authors. CC BY-NC-ND 3.0
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