Synthetic fertilizers are heating the planet. But there's an alternative.
The fertilizers are a major source of heat-trapping nitrous oxide emissions.
From raising livestock to growing vegetables, farmers help put food on our plates. But agriculture also creates emissions that warm the climate. And the most warming is caused by nitrous oxide, an especially potent global warming gas.
“The use of synthetic fertilizers is the biggest source of nitrous oxide emissions,” says Lauren Snyder, an education and research program manager with the Organic Farming Research Foundation.
“Fertilizers are basically providing a form of nitrogen to the plant,” she says. “And so when you add that to the soil, a lot of it is lost to the atmosphere as nitrous oxide.”
But she says that farmers can reduce those emissions by changing some of their practices.
For example, she recommends planting cover crops in the offseason instead of leaving fields bare. Some cover crops can reduce the need for fertilizer because they naturally fix nitrogen in the soil.
“Legume cover crops are excellent at taking atmospheric nitrogen and putting it in the soil in the form that plants can use. And so that’s another way that we can provide fertility to plants,” Synder says. “And it doesn’t result in the same kind of pulse of nitrous oxide into the atmosphere.”
So by enriching soil naturally, farmers can also help reduce global warming.