Reducing nitrogen use key to human and planetary health: study

Reducing nitrogen pollution from global croplands is a “grand challenge,” the group of international researchers said in a study in Nature outlining a dozen urgently-needed reforms. Today, more than half the nitrogen in fertilisers seeps into the air and water, leading to deadly pollution, soil acidification, climate change, ozone depletion and biodiversity loss.

The world is naturally awash in nitrogen, which is critical for the survival of all life on Earth, especially plants. Nearly 80 percent of Earth’s atmosphere is nitrogen, albeit in a gaseous form (N2) of little direct use to most organisms. It is made available to plants when microbes that live within plants or soils turn it into ammonia through biological nitrogen fixation. This process funnels some 200 million tonnes of nitrogen into the soil and oceans every year.

Researchers led by Gu analysed over 1,500 field observations from croplands around the world and identified 11 key measures to decrease nitrogen losses while still enhancing crop yields. One such method is crop rotation where a variety of crops are planted on the same plot of land, optimising the flow of nutrients in the soil.The benefits of slashing agricultural nitrogen pollution are some 25 times higher than the implementation costs of about $34 billion, they found. Nearly half-a-trillion dollars in avoided costs are spread across reduced premature deaths from air pollution, less damage to ecosystem services and increased crop yields.

Source: RFI