Nebraska and Landsat: How Satellites Help Manage Irrigation, Rangeland and Cities

To many Americans, Nebraska stands for the nation’s heartland — cropland from border to border, country churches and weathered barns along gravel roads. Its pioneer history and farm heritage fit that picture, but the 37th state is more varied than its image. Agriculture is still its top industry, yet manufacturing makes up 12% of its gross domestic product and finance and insurance 8%; it is home to Berkshire Hathaway and Mutual of Omaha, named for the largest city, which grew nearly 12% between 2010 and 2020. Besides its cropland, Nebraska has 8 state parks, 5 national parks, 2 national forests and 3 national grasslands, and the grass-covered dunes of the Sand Hills, across the north-central quarter of the state, are a National Natural Landmark.

Landsat satellite data help study and manage all of it — monitoring crops, guiding rangeland management, tracking damage from floods and droughts — and land cover maps built from the 50-year Landsat archive reveal urban growth and changing land use.

Mapping irrigation

Nebraska leads the nation in irrigated farmland, with more than 9.3 million acres in 2020. Most of the water comes from the Ogallala aquifer, a vast but shrinking reservoir under 174,000 square miles of the Great Plains from Texas to South Dakota, whose largest stores lie beneath Nebraska. The state’s Department of Natural Resources has used Landsat’s decades of repeat images to map irrigated acres and manage water, and the archive has shown how irrigated acreage shifts in wet and dry years.

Center-pivot irrigation in northeastern Nebraska, July 23, 2021. Lance Cheung, U.S. Department of Agriculture.

Tracking grassland and crops

Nebraska is a leading producer of corn and soybeans and one of the top five cattle states, and its $12.5 billion cattle industry depends on healthy rangeland. Researchers have used Landsat to map biomass productivity across the Greater Platte River Basins at 30-meter resolution — each pixel about a quarter-acre — for ecosystem assessments and rangeland decisions. Because Landsat sees beyond visible light into infrared and thermal bands, it is also a powerful tool for tracking crop health.

The Department of Agriculture’s Cropland Data Layer, built on Landsat data, maps crop types nationwide; Nebraska’s main crops are corn, soybeans, spring wheat and winter wheat. U.S. Department of Agriculture.

Urban growth

Greater Omaha still has fewer than a million people, but steady growth and suburban sprawl have added miles of impervious surfaces such as parking lots and roads. These affect drainage and runoff planning and trap heat, making the city warmer than the countryside. Landsat’s thermal instruments let researchers find urban heat island hot spots, and its repeat observations feed the National Land Cover Database, which classifies every 30-meter plot of the country and tracks impervious cover in developed areas.

Landsat and the nation

Through the USGS National Land Imaging Program and its Earth Resources Observation and Science (EROS) Center, Landsat data are available worldwide at no cost. Landsat is the most widely used land remote-sensing source among federal civilian agencies, and local, state, tribal and federal agencies use it daily to decide about land, water and resources. A 2017 USGS study put its annual economic benefit in the United States at $2.06 billion, far more than it costs to build and run.

Landsat 8 and 9 together cover Earth’s land every 8 days, and NASA and the USGS were planning a successor, Landsat Next, to extend what is already the world’s longest continuous record of Earth’s land surface.

Sources

Based on "Nebraska and Landsat," U.S. Geological Survey Fact Sheet 2022–3056; a work of the United States government in the public domain. The source gives the Ogallala aquifer’s extent as 174,000 miles; the figure is square miles.