Cost-effective mitigation of nitrogen pollution from global croplands

Area of Science:

• Agricultural Science
• Environmental Science
• Agronomy

Background:

• Croplands are a primary source of global nitrogen pollution, posing significant environmental challenges.
• Mitigating this non-point-source pollution is complex due to farm-level constraints like financial resources and limited farmer knowledge.

Purpose of the Study:

• To identify and evaluate key measures for reducing nitrogen losses from croplands.
• To quantify the impact of these measures on nitrogen pollution, crop yield, and nitrogen use efficiency (NUE).

Main Methods:

• Synthesis of 1,521 field observations from global croplands.
• Identification of 11 key nitrogen-loss reduction measures.

Main Results:

• The 11 measures can reduce nitrogen losses by 30-70%, increase crop yield by 10-30%, and NUE by 10-80%.
• Global adoption could lead to 20% more crop nitrogen production with 21% less fertilizer and 32% less pollution.
• Societal benefits estimated at $476 billion USD, with net mitigation costs of $19 billion USD, partially offset by fertilizer savings.

Conclusions:

• A package of 11 measures offers a viable strategy to mitigate nitrogen pollution from croplands.
• Innovative policies, such as a nitrogen credit system (NCS), are proposed to incentivize the adoption of these beneficial measures.