According to Moran, the term "precision farming" refers to the use of an information and technology-based system for within-field management of crops. "It basically means adding the right amount of treatment at the right time and the right location within a field—that’s the precision part," Moran explains. "Farmers want to know the right amounts of water, chemicals, pesticides, and herbicides they should use as well as precisely where and when to apply them."

Critical to the success of precision farming is the sophisticated new equipment that is now commercially available. Called "variable rate technologies," there are devices that can be mounted on tractors and programmed to control the dispersion of water and chemicals based upon the information gained from the remote sensors.

Thanks to the marriage of remote sensing data with GIS and GPS software tools, and on-tractor variable rate technologies, farmers no longer must treat a field of crops as one homogeneous unit. Charles Walthall, also a research physical scientist at the U.S. Department of Agriculture in Beltsville, recalls that the old way of doing business was planting a crop and then applying fertilizer evenly across the whole field.

"But now we’re characterizing zones within the field so we can optimize what inputs are needed to go into that zone according to what they need to produce the crop," Walthall says. "But if you limit your inputs—such as fertilizers, seeds, water, pesticides, or herbicides—to precisely where and how much is needed, you are putting less on the landscape. So the cost is less and energy is saved, which means better profit."
 

Perhaps more significantly, it can mean there is much less chemical runoff from farms to negatively impact the environment. According to Walthall, state-sponsored agencies are passing laws limiting the types and amounts of chemicals that farmers can use. The State of Maryland, for instance, passed a law requiring farmers to have a documented "phosphorus management plan." (This law is particularly enforced in the Chesapeake Bay region where the runoff of phosphates into the bay can contribute to harmful algae blooms and other negative environmental impacts.) Other states are considering similar laws aimed at regulating the use of nitrogen. Too much nitrogen in the water supply is a health hazard to both humans and animals.

But by using the tools of precision farming, growers can specifically target areas of need within their fields and apply just the right amounts of chemicals where and when they are needed, saving both time and money and minimizing their impact on the environment.

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