How did Texas get its crop circles?

From above, the farmland surrounding Dalhart, Texas, looks like a board game for the gods. Credit that tessellated expanse of green in what was once the heart of the Dust Bowl to center-pivot irrigation, or CPI, a watering system of pipelines studded with spray nozzles, each typically a quarter mile long and swiveling around a fixed point on wheeled, motor-operated towers.

In the roughly 75 years since its invention by a Colorado farmer, CPI has turned agricultural landscapes around the world into vast mosaics of adjacent circles—more than 25 million acres of them in the United States alone—often coaxing huge yields from what had been marginal farmland. The method spreads water more uniformly and with less labor than the ones it replaced, which often involved flooding fields by diverting surface water. CPI, by contrast, relies on wells pumping groundwater, and in the U.S., it’s been a particular boon to the rather arid lands above the Ogallala Aquifer, an underground reservoir that stretches from South Dakota to Texas. Nearly a fifth of all American wheat, corn, and cotton is grown in the Ogallala region, supported by more than 100,000 pivot systems, rigs that University of Nebraska irrigation engineer Saleh Taghvaeian describes as “basically making rain.”

Today, Taghvaeian says, CPI is undergoing a spurt of intense innovation aimed at improving efficiencies. Above the Ogallala and elsewhere, producers are extracting water faster than it’s being replenished, so engineers have developed pivot-mounted infrared sensors to measure soil moisture and automatically adjust water usage. AI-integrated pivots can analyze crop conditions and deliver targeted amounts of fertilizer, minimizing groundwater pollution. And farmers are increasingly using extendable, GPS-guided arms at the ends of their pipelines to water the corners that traditional CPI doesn’t reach—boosting productivity by squaring those iconic circles.