How Precision Agriculture Is Changing Farming

From the road, crop fields look pretty low tech: just neat rows of plants climbing toward the sun. But the systems controlling these fields may be much more sophisticated than you’d expect, relying on satellites, sensors and other high-tech innovations (coming soon: drones) to guide everything from planting to harvest.
 
It’s called precision farming, or site-specific crop management. By enabling farmers to essentially micromanage their fields, precision farming’s promise is to grow food using fewer resources — or, down the line, to grow more food without consuming more resources.
 
At the most basic level, precision farming begins with tractors. By outfitting a tractor with something called GPS kinematic signals, farmers don’t even have to steer. Their tractors are automatically guided using global positioning systems to within an inch of where they need to be. Farmers can lay down a row of fertilizer and then return to plant seeds in the exact same line, resulting in less chance for waste.
 
Farmers also can use sensors to monitor conditions such as soil temperature and humidity, which help make more efficient use of water, and spray nozzles that can differentiate weeds from crops. Other sensors detect nitrogen deficiencies so farmers can add extra fertilizer only where needed. Another instrument used in precision agriculture helps map the level of salt in arid soils by measuring how much electricity the ground conducts.
 
Understanding how electrons move around might seem like a far cry from growing wheat or lettuce — but in fact it helps farmers determine how well the soil will hold water and whether a plant will develop roots. The measurements are used to generate conductivity maps, which in turn help farmers know where to spray fertilizer or other inputs.
 
Meanwhile, satellite data provide highly specific weather information that can help farmers schedule application of fertilizer or decide into which fields to send workers. Satellites can even monitor soil moisture so farmers know exactly when and how much to water their plants. As site-specific crop management is adapted in other countries, it could make a difference to food production for a rising world population. A joint USDA/NASA program, for instance, is bringing satellite-based crop forecasting to countries in Africa and elsewhere in the developing world.
 
The Global Agriculture Monitoring project relies on satellite-based remote sensing to track how wet the soil is, around the globe, every two days. The U.S. provides international farmers with soil moisture estimates, which enable them to improve their crop forecasts and make better, more informed decisions about what resources to add and when to harvest. A new satellite that will aid this effort is scheduled for launch in 2014.
 

Hillary Rosner
Hillary Rosner is a Colorado-based journalist. She writes about science and the environment for The New York Times, Wired, Scientific American, Discover and more.