The environmental costs of corn: should the US change how it grows its dominant crop?

"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,"

"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,"

Corn occupies about 90 million acres and supplies livestock feed, processed foods, and ethanol blended into gasoline. Heavy nitrogen fertilizer use sustains high corn yields and releases nitrous oxide when it breaks down, a greenhouse gas nearly 300 times more potent than carbon dioxide. Production of nitrogen fertilizer emits large amounts of carbon dioxide, increasing the crop's climate footprint. Ethanol now consumes about 40% of the US corn crop and benefits from policy support requiring gasoline blending. Corn uses more than two-thirds of all nitrogen fertilizer nationwide, making it the leading driver of agricultural nitrous oxide emissions, and US corn production has risen almost 50% since 2000.

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