Page 26 - AWA Vol.41-No.2

SOIL NUTRITION

Nitrogen use efficiency must be improved

to reduce harm to human and environmental health

he rise in nitrogen fertilizers over the past century has signifi-
Tcantly contributed to enhancing agricultural production and
bolstering food security and nutrition for an expanding global
population. Nevertheless, improper use of nitrogen can severely
damage air, water, and soil quality, result in biodiversity loss, and
exacerbate climate change.
A new report from the Food and Agriculture Organization of the
United Nations (FAO), launched today at an event at its headquar-
ters in Rome, provides a comprehensive overview of nitrogen use
and the resulting challenges in agrifood systems. It emphasizes
the importance of ensuring sustainable use and offers recommen-
dations to achieve this goal.
Nitrogen is an essential component of food constituents, particu-
larly amino acids and proteins required for the growth of plants,
animals, and humans.
Thanks to the invention of the Haber–Bosch process in the early gen fertilizer and encourage the minimization of wasteful losses
20th century, humans have been able to convert unreactive nitro- during storage, transport, and land application.
gen, abundant in the atmosphere (the same nitrogen that makes • National governments should encourage the widespread use
the sky blue), into useful substances like ammonia, which is now of biological nitrogen fixation (a process in which nitrogen gas
commonly used as fertilizer. from the atmosphere is symbiotically fixed into the tissues of cer-
Humans currently add approximately 150 teragrams (Tg) of re- tain plants) in locally appropriate crop rotations using leguminous
active nitrogen to the Earth’s land surface each year through ag- crops, such as soybean or alfalfa.
riculture and industry. This amount is more than double the pre- • National governments should create guidelines to assist live-
industrial rate. Some experts suggest that climate change could stock farmers in adopting the best manure management prac-
contribute to this rate raising to about 600 Tg per year by 2100,
which could increase the levels of nitrogen loss into the environ- tices, concentrating on minimizing wasteful nitrogen losses to the
ment. environment and enhancing its effective use in productive agri-
culture.
Livestock are the main contributors to nitrogen emissions and
are responsible for about one-third of the total nitrogen emis- • Agrifood system policies should encourage the use of organic
sions produced by human activity. Synthetic fertilizers, land-use nitrogen fertilizers to enhance sustainability. They should also
change, and manure emissions are the main causes of nitrogen promote spatial planning by redistributing livestock, reducing the
pollution in this area. number of livestock in areas with high geographical concentra-
tion, and promoting circular bioeconomy approaches.
Nitrogen pollution is most severe in North America, Western Eu-
rope and certain Asian countries, where fertilizers have been ex- • National governments should promote the integration of sus-
tensively used and misused for decades. tainable nitrogen management in nationally appropriate mitiga-
In some low- and middle-income countries restricted access to tion actions and nationally determined contributions, including
targets to reduce nitrous oxide from agrifood systems to keep the
fertilizers leads to the depletion of nitrogen, which reduces soil Paris Agreement goal of 1.5 °C in sight.
nutrients and leads to soil degradation.
A judicious use of nitrogen in agriculture, therefore, helps pre- • National governments should set national commitments to re-
vent soil degradation and nutrient depletion while increasing duce nitrogen pollution, including ammonia and nitrates to meet
global biodiversity goals.
crop yields. In contrast, excessive use exacerbates global warm-
ing, degrades air and water quality, and depletes stratospheric • National governments should intensify efforts to reduce food
ozone. Nitrogen pollution poses risks to human health by increas- waste and loss at all stages of the agrifood system and promote
ing the incidence of respiratory and heart diseases. the recycling and treatment of food unsuitable for human con-
sumption as livestock feed.
Therefore, sustainable nitrogen management that focuses on
minimizing external inputs and losses and maximizing recycling • National governments, the private sector, international financial
is more urgent than ever. institutions, and local agricultural banks should integrate sustain-
"Nitrogen Use Efficiency (NUE) has seen improvements in recent able nitrogen management into development projects and pro-
years, which is encouraging. However, significant work remains to grams in agrifood systems. They should also promote investment
be done. This report provides a detailed set of recommendations in high-efficiency, low-emission mineral fertilizers and the recy-
to further enhance NUE, helping to reduce pollution while promot- cling of organic residues to improve system efficiency, minimize
ing environmental and human health," stated Thanawat Tiensin, resource waste, and reduce environmental pollution.
Assistant Director-General and Director of the Animal Production "Sustainable nitrogen management is crucial for achieving the
and Health Division at FAO. Sustainable Development Goals by 2030, particularly those relat-
Key actions and policy proposals ed to hunger, health, clean water, sustainable production and con-
sumption, climate action, and preserving life on land and under-
The report presents several case studies illustrating ongoing ef- water," the report's authors say. "Improving nitrogen use efficiency
forts to improve NUE around the world and offers a series of rec- across the agri-food chain and reducing nitrogen loss can help in-
ommendations.
crease food production in low- and middle-income countries by
These include: allowing more nitrogen resources to achieve their intended pur-
• The fertilizer industry should take urgent action to reduce pose, improve health by reducing harmful emissions, and protect
greenhouse gas emissions during the production of mineral nitro- water bodies from pollution." Circle 36 on enquiry card
24 Vol. 41 No. 2