Fall 2016

Fields of science

At the U of M, a focus on precision agriculture is changing the way we look at farming.

Professor David Mulla (front) uses a drone to gather aerial photographs and data with graduate students (left to right) Tyler Nigon, Aicam Laacouri, and Dimitris Zermas.
Photography by Mark Luinenburg

Centuries ago, it was common for farmers to tend small plots of land much like gardeners do, paying attention to the needs of individual plants and growing whatever did best in particular areas. But as farm operations grew larger and more complex, farmers began relying more on machines and standardized processes for tasks like soil preparation, watering, fertilizing, and pesticide application. 

While this approach has vastly boosted yields, it’s also become apparent that some sections produce higher yields than others because the one-size-fits all strategy doesn’t meet all plants’ needs. To remedy that, an increasing number of farmers and other agricultural producers are turning to precision agriculture. Perhaps more accurately named site-specific agriculture, precision agriculture is the strategy of using the right management practice in the right location at the right rate at the right time. 

“There are millions of plants in a field, and precision agriculture will ultimately give us the capacity to provide each plant with a customized application.”
David Mulla, Larson Endowed Chair in Soil and Water Resources

The University of Minnesota’s Precision Agriculture Center has long been a leader in precision agriculture research. Founded in 1995 by David Mulla, the University of Minnesota Larson Endowed Chair in Soil and Water Resources, and the late Pierre C. Robert, a professor in the Department of Soil, Water, and Climate, the Center was the first of its kind in the world. 

Researchers there conduct studies on farms across the nation and world, while also developing innovative techniques for precision crop monitoring and management. Robert was the Center’s director until his death in 2003, when Mulla took over. Mulla came to the U from Washington State University, where he’d been studying precision agriculture since 1984. 

“I’m one of the early pioneers of precision agriculture,” Mulla says, recalling how in the 1980s he began noticing a connection between variability across landscapes and crop yield. “I could see that crops didn’t perform as well in areas with light-colored soil, particularly on steep slopes, and I wondered why there was so much variability and how we could manage fields more effectively.” 

New approaches

Used properly, precision agriculture helps farmers get the most value and productivity from every acre of land. It also may decrease agriculture’s environmental impact by reducing waste, conserving water and energy, and reducing pesticide and herbicide runoff. Though the practice is used primarily for crops such as corn, sugar beets, potatoes, wheat, barley, oats, and soybeans, precision agriculture researchers are studying ways to use it for vineyards, orchards, livestock, and more.

Famers use advanced technologies—such as global positioning systems (GPS), geographical information systems (GIS), and remote sensing devices like satellites and aerial robots (also known as drones) —to precisely customize how they treat variable field conditions. 

For example, drones and ground robots can gather data to create detailed maps and diagnose pest problems and nutrient deficiencies. Tractors, combines, and harvesters use GPS to aid in planting in a straight line without overlap, applying fertilizers, and reducing fuel waste. And sensors can tell equipment when to spread manure, fertilize, and water at variable rates, depending on the data they gather.

Get a drone's-eye perspective of precision agriculture in this short video.

Though there are now several precision agriculture centers around the world, the University’s research team remains one of the most multi-disciplinary, crossing three colleges and numerous departments. Mulla’s research focuses on several areas, including groundwater and soil quality management, as well as the use of drones to estimate yields and detect plant diseases and nutrient deficiencies in farms and orchards.

Philanthropy helps pave the way, he says. “As the Larson Endowed Chair in Soil and Water Resources, part of my mission is to develop new approaches to protecting our soil and water. In addition to grants, the endowed chair makes this kind of research possible.” 

High-tech farming

Gary Wagner, an adjunct professor at the University of Minnesota Crookston (UMC), has been using precision agriculture concepts on his family farm not far from campus since 1993. A self-taught computer programmer, he developed a software program called Field History Manager that tracks factors like inventory, fertilizer applications, and tillage. And for more than two decades, he’s taught workshops and talked to U.S. and Canadian farmers about how his software, and other aspects of precision agriculture, can help them and the environment. 

At UMC, Wagner teaches a course on yield monitoring, showing students how farmers use data from sensors on combines to make accurate yield maps of their fields. “Now we can keep a database on the computer of information we collect in real time out in the field using sensors—even our phones,” he says. “It’s much easier and we’re able to make changes much faster.” 

Aerial view of corn, with nitrogen-deficient leaves indicated by yellow boxes
Photo courtesy of Dimitris Zerma

Wagner has found precision agriculture particularly useful for growing sugar beets because the color of the plants’ leafy tops indicates how much fertilizer to use—dark green equals more biomass, which means less fertilizer is needed. 

“Plants are more yellow when they’re under stress, and we can use satellite images to determine how we should vary nitrogen fertilizer across our fields based on what the leaves look like,” he says. Some stress is good because it prompts beets to store sugar, but too much can be problematic for the crop. 

Science and soil

While Wagner and other farmers use precision agriculture on their own, others opt to work with consulting firms like Farmers Edge. Based in Shakopee, Minnesota, Farmers Edge offers customized services to farmers around the globe. 

Aerial robots (also called drones) collect data to help farmers analyze which parts of a field might need more attention.
Photography by Stacy Nordstrom

José Hernandez, ’07 Ph.D., a former student of Mulla’s, was hired there in 2015. In his position as a regional agronomist, he uses science he helped develop at the University to do research and product development for the company. He also works directly with clients. 

“Growing up in Costa Rica, I always loved working with numbers and statistics, and I started studying precision agriculture because I liked the quantitative approach to farming,” he says. “Farmers want to maximize yields, and the data we collect helps identify variability in the fields so we can obtain the highest yields and avoid over-application of inputs like fertilizer and water.” 

Hernandez likens the concept to sustainable agriculture, only with more data collection and number crunching. “We help farmers make better decisions throughout the year. For example, we can use weather stations, crop modeling, and tools to measure nitrogen in the soil to tell farmers that they should add nitrogen to a certain part of their corn field in the next 10 days.” 

Mulla believes that demand for precision agriculture is only going to grow, eventually allowing farmers to manage not only entire fields, but also individual plants. “There are millions of plants in a field, and precision agriculture will ultimately give us the capacity to provide each plant with a customized application,” he says. 

That’s already happening in some grape vineyards, but apple orchards in Minnesota may one day do this with individual trees.

“Drones and robots can't do everything, but we will be able to replace a lot of our big field equipment, which would help prevent compaction and protect our soil,” says Mulla. “It’s just a matter of time.” 

Meleah Maynard is a Minne­apolis-based freelance writer and editor.