The environmental costs of corn: should the US change how it grows its dominant crop?Guardian Wed 3 Dec 2025 Ames Alexander ......article was produced in partnership with Floodlight  Amid concerns over greenhouse gas emissions, the Trump administration has abolished climate-friendly farming incentivesFor decades, corn has reigned over American agriculture. It sprawls across 90m acres – about the size of Montana – and goes into everything from livestock feed and processed foods to the ethanol blended into most of the nation’s gasoline. But a growing body of research reveals that the US’s obsession with corn has a steep price: the fertilizer used to grow it is warming the planet and contaminating water. Corn is essential to the rural economy and to the world’s food supply, and researchers say the problem isn’t the corn itself. It’s how we grow it. Corn farmers rely on heavy fertilizer use to sustain today’s high yields. And when the nitrogen in the fertilizer breaks down in the soil, it releases nitrous oxide, a greenhouse gas nearly 300 times more potent than carbon dioxide. Producing nitrogen fertilizer also emits large amounts of carbon dioxide, adding to its climate footprint.The corn and ethanol industries insist that rapid growth in ethanol – which now consumes 40% of the US corn crop – is a net environmental benefit, and they strongly dispute research suggesting otherwise.

Industry is also pushing for ethanol-based jet fuel and higher-ethanol gasoline blends as growth in electric vehicles threatens long-term gasoline sales. Agriculture accounts for more than 10% of US greenhouse gas emissions, and corn uses more than two-thirds of all nitrogen fertilizer nationwide – making it the leading driver of agricultural nitrous oxide emissions, studies show. Since 2000, US corn production has surged almost 50%, further adding to the crop’s climate impact. The environmental costs of corn rarely make headlines or factor into political debates. Much of the dynamic traces back to federal policy – and to the powerful corn and ethanol lobby that helped shape it. The Renewable Fuel Standard (RFS), passed in the mid-2000s, required that gasoline be blended with ethanol, a biofuel that in the United States comes almost entirely from corn. That mandate drove up demand and prices for corn, spurring farmers to plant more of it. Many plant corn year after year on the same land. The practice, called “continuous corn”, demands massive amounts of nitrogen fertilizer and drives especially high nitrous oxide emissions. At the same time, federal subsidies make it more lucrative to grow corn than to diversify. Taxpayers have covered more than $50bn in corn insurance premiums over the past 30 years, according to federal data compiled by the Environmental Working Group. Researchers say proven conservation steps – such as planting rows of trees, shrubs and grasses in cornfields – could sharply reduce these emissions. But the Trump administration has eliminated many of the incentives that helped farmers try such practices 

Experts say it all raises a larger question: if the US’s most widely planted crop is worsening climate change, shouldn’t we begin growing it in a different way?How corn took over the US.....In the late 1990s, the US’s corn farmers were in trouble. Prices had cratered amid a global grain glut and the Asian financial crisis. A 1999 report by the Federal Reserve Bank of Minneapolis said crop prices had hit “rock bottom”.Corn production really took off in the 2000s after federal mandates and incentives helped turn much of the US’s corn crop into ethanol......read on   https://www.theguardian.com/environment/2025/dec/03/environment-corn-farming-trump-administration