The significant increase in nitrogen fertilizers over the last century has played a pivotal role in boosting agricultural output and enhancing food security for a growing global population. However, the misuse of nitrogen can lead to severe consequences, including the degradation of air, water, and soil quality, loss of biodiversity, and intensified climate change.
A recent report from the Food and Agriculture Organization of the United Nations (FAO), presented at its headquarters in Rome, outlines the complexities surrounding nitrogen use and the challenges it poses to agrifood systems. The report underscores the necessity for sustainable nitrogen practices and offers actionable recommendations.
Nitrogen is a vital element in food composition, particularly in amino acids and proteins essential for the growth of plants, animals, and humans. The development of the Haber–Bosch process in the early 20th century enabled the conversion of inert atmospheric nitrogen into ammonia, a key ingredient in fertilizers.
Currently, humans contribute around 150 teragrams (Tg) of reactive nitrogen to the Earth’s land surface annually through agricultural and industrial activities, a figure that has more than doubled since pre-industrial times. Projections indicate that climate change could elevate this number to approximately 150 teragrams (Tg) of reactive nitrogen to the Earth’s land surface each year through agriculture and industry. This amount is more than double the pre-industrial rate. Some experts suggest that climate change could contribute to this rate rising to about 600 Tg per year by 2100, which could increase the levels of nitrogen loss into the environment.
Livestock are the main contributors to nitrogen emissions and are responsible for about one-third of the total nitrogen emissions produced by human activity. Synthetic fertilizers, land-use change, and manure emissions are the main causes of nitrogen pollution in this area.
Nitrogen pollution is most severe in North America, Western Europe and certain Asian countries, where fertilizers have been extensively used and misused for decades.
In some low- and middle-income countries restricted access to fertilizers leads to the depletion of nitrogen, which reduces soil nutrients and leads to soil degradation.
A judicious use of nitrogen in agriculture, therefore, helps prevent soil degradation and nutrient depletion while increasing crop yields. In contrast, excessive use exacerbates global warming, degrades air and water quality, and depletes stratospheric ozone. Nitrogen pollution poses risks to human health by increasing the incidence of respiratory and heart diseases.
Therefore, sustainable nitrogen management that focuses on minimizing external inputs and losses and maximizing recycling is more urgent than ever.
“Nitrogen Use Efficiency (NUE) has seen improvements in recent years, which is encouraging. However, significant work remains to be done. This report provides a detailed set of recommendations to further enhance NUE, helping to reduce pollution while promoting environmental and human health,” stated Thanawat Tiensin, Assistant Director-General and Director of the Animal Production and Health Division at FAO.
Key Actions And Policy Proposals
The report presents several case studies illustrating ongoing efforts to improve NUE around the world and offers a series of recommendations.
According to the FAO, the fertilizer industry should take urgent action to reduce greenhouse gas emissions during the production of mineral nitrogen fertilizer and encourage the minimization of wasteful losses during storage, transport, and land application.
It also calls for the governments to encourage the widespread use of biological nitrogen fixation; a process in which nitrogen gas from the atmosphere is symbiotically fixed into the tissues of certain plants in locally appropriate crop rotations using leguminous crops, such as soybean or alfalfa.
The FAO also advised the creation of guidelines to assist livestock farmers in adopting the best manure management practices, concentrating on minimizing wasteful nitrogen losses to the environment and enhancing its effective use in productive agriculture.
Besides, agrifood system policies should encourage the use of organic nitrogen fertilizers to enhance sustainability. They should also promote spatial planning by redistributing livestock, reducing the number of livestock in areas with high geographical concentration, and promoting circular bioeconomy approaches, the Food and Agriculture Organization further stated in its report.
The FAO also recommended that national governments should pay attention to the Paris Agreement goal of 1.5 °C by promoting the integration of sustainable nitrogen management in nationally appropriate mitigation actions and nationally determined contributions, including targets to reduce nitrous oxide from agrifood systems to keep them in sight.
It is also important for governments to set national commitments to reduce nitrogen pollution, including ammonia and nitrates to meet global biodiversity goals.
Countries need to also intensify efforts to reduce food waste and loss at all stages of the agrifood system and promote the recycling and treatment of food unsuitable for human consumption as livestock feed.
It further called on governments, the private sector, international financial institutions, and local agricultural banks to integrate sustainable nitrogen management into development projects and programs in agrifood systems. They should also promote investment in high-efficiency, low-emission mineral fertilizers and the recycling of organic residues to improve system efficiency, minimize resource waste, and reduce environmental pollution.
“Sustainable nitrogen management is crucial for achieving the Sustainable Development Goals by 2030, particularly those related to hunger, health, clean water, sustainable production and consumption, climate action, and preserving life on land and underwater,” the report’s authors say. “Improving nitrogen use efficiency across the agri-food chain and reducing nitrogen loss can help increase food production in low- and middle-income countries by allowing more nitrogen resources to achieve their intended purpose, improve health by reducing harmful emissions, and protect water bodies from pollution.”
Reporting by Stephen Freeman
