If we don’t watch out, agriculture could destroy our planet. Here’s how to grow all the food we need with fewer chemicals.

A century ago, when chemist Fritz Haber first learned how to capture nitrogen from the air, synthetic fertilizer seemed like an easy shortcut out of scarcity, delivering a limitless supply of agriculture’s most important nutrient. Yet new limits on nitrogen are appearing. This time the innovations that save us—and our planet—may not be invented in a chemistry laboratory. Instead they may come from farmers and fields in every corner of the world.