Sustainable Nitrogen Management in Agrifood Systems report
Context:
Recently, the Food and Agriculture Organisation (FAO) released the Sustainable Nitrogen Management in Agrifood Systems report, which majorly talks about nitrogen pollution and its use and adverse affects on agriculture and the environment.
Relevance:
GS-03 (Conservation)
About Nitrogen Pollution and its Impact:
- Nitrogen pollution occurs when compounds like nitrogen oxides and nitrates accumulate in air, water, and soil.
- Key forms include:
- Air Pollution: Ammonia and nitrogen oxides worsen air quality.
- Greenhouse Gas Emissions: Nitrous oxide is a potent greenhouse gas, 300 times stronger than carbon dioxide.
- Water Pollution: Nitrate leaching leads to eutrophication and acidification of water bodies.
- Its adverse effects include global warming, soil acidification, and harmful algal blooms in oceans.
Key Highlights of the Report
Nitrogen Emissions
- Human activities introduce about 150 teragrams (Tg) of reactive nitrogen annually through agriculture and industry.
- Climate change could increase this figure to 600 Tg per year by 2100, more than doubling pre-industrial levels.
- These excessive emissions significantly contribute to environmental nitrogen pollution.
Primary Sources of Nitrogen Loss
- Livestock accounts for one-third of human-induced nitrogen emissions.
- Other major contributors include synthetic fertilisers, land-use changes, and manure mismanagement.
Exceeding Safe Nitrogen Limits
- Global nitrogen use has breached planetary boundaries, surpassing safe environmental thresholds.
- The intensity of nitrogen exceedance has sharply risen since 2015.
Global Crop Yields and Efficiency
- Crop yields increased from 19 kg of nitrogen per hectare in 1961 to 65 kg per hectare in 2022.
- Nitrogen Use Efficiency (NUE) fluctuated, dropping to 40% in the 1980s before recovering to 56% by 2022.
Regional Insights
- Asia: The Green Revolution boosted yields but caused severe nitrogen pollution due to fertiliser overuse.
- Africa struggles with low crop yields and nutrient depletion due to inadequate fertiliser access.
- Europe & North America: Improved NUE through better nutrient management practices.
- Latin America: Reliance on imported fertilisers and supply chain disruptions hinder nitrogen efficiency.
Efficiency Differences Across Crops
- Soybeans displayed high NUE (80% in 2010).
- Fruits and vegetables had significantly lower NUE (14% in 2010), reflecting substantial nitrogen losses.
Challenges in Developing Countries
- Limited fertiliser access and poor manure management degrade soil health and increase nitrogen emissions.
- These issues result in low agricultural productivity and heightened environmental impacts.
