Changing Planet

Farmers manage crops from space

Satellite images of farms in northwest Minnesota show neat patches of different crops among recently harvested fields. It’s an enchanting view of nurtured farmland from hundreds of miles above the countryside.

But when looking at the same view through a different filter, the farmers of the land may see another story. Satellite images can help them spot infestation, over-watering, and pesticides encroaching on organic crops.


A growing group of Midwest farmers rely on satellite imagery from Landsat to maximize their harvest and minimize damage to their fields, accortding to NASA. “It’s become another crucial tool like their tractors and sprinklers.”

From space, Noreen Thomas’ farm in northwest Minnesota looks like a patchwork quilt, NASA said in a caption published with these images on its Earth Observatory Web site last week. “Fields change hue with the season and with the alternating plots of organic wheat, soybeans, corn, alfalfa, flax, or hay.”

The top true-color image, taken by the Landsat satellite on September 10, 2009, shows Thomas’s organic farm along the banks of the Buffalo River near the center of the image. “Lush green fields dominate the image, though some crops have already been harvested leaving squares of tan and brown,” NASA says.

The lower image shows the same scene in false color. Made with infrared light, the false-color image provides a wealth of information about crop conditions.

“To the untrained eye, the false-color images appear a hodge-podge of colors without any apparent purpose. But Thomas is now trained to see yellows where crops are infested, shades of red indicating crop health, black where flooding occurs, and brown where unwanted pesticides land on her chemical-free crops.”


The images help the Thomases root out problems caused by Canadian thistle and other weeds, NASA adds. “They help confirm that their crops are growing at least 10 feet from the borders of a neighboring farm–required to maintain organic certification. They can also spot the telltale signs of bottlenecking in the fields—where flooding is over-saturating crops–and monitor the impact of hail storms.”

Said Thomas, “We’d have to walk our entire 1,200 hundred-plus acres on a regular basis to see the same things we can see by just downloading satellite images.”

Thomas recently began providing her farm’s coordinates to her buyers in Japan. “There’s no more ideal way I know to show how healthy our crops are to someone thousands of miles away,” she said.

NASA images created by Jesse Allen, using Landsat data provided by the United States Geological Survey. Original NASA caption by Gretchen Cook-Anderson.

Related Links:

Landsat at NASA

Landsat at USGS

UMAC’s Agriculture Public Access Resource Center

More Earth from Space >>

Forty years in U.S., UK, and South African media gives David Braun global perspective and experience across multiple storytelling platforms. His coverage of science, nature, politics, and technology has been published/broadcast by the BBC, CNN, NPR, AP, UPI, National Geographic, TechWeb, De Telegraaf, Travel World, and Argus South African Newspapers. He has published two books and won several journalism awards. He has 120,000 followers on social media. David Braun edits the National Geographic Society blog, hosting a global discussion on issues resonating with the Society's mission and initiatives. He also directs the Society side of the Fulbright-National Geographic Digital Storytelling Fellowship, awarded to Americans seeking the opportunity to spend nine months abroad, engaging local communities and sharing stories from the field with a global audience. Follow David on Facebook  Twitter  LinkedIn

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media