Years ago, a farmer's most important tools included simple pitchforks and ox-drawn plows. But today, farmers rely on items like global positioning systems (GPS), high-tech remote-sensing instruments, and sophisticated software programs.

It's all part of precision agriculture, a series of methods that uses the latest technology to reduce environmental impact and improve yields. The practice has exploded in recent years because it enables farmers to make better use of their land—after all, farmers figured out a long time ago that since no one is going to be making more land anytime soon, they need to continually improve their methods to do more with what they have.

Precision agriculture is based on the concept of in-field variability, which posits that today's large farms contain significant variations in soil types, nutrient availability, moisture content, exposure to sunlight, and more, all of which impact crop yields.

"In the early days, when farmers had small fields, they knew from practical experience which sub-areas were wetter and more fertile," Craig Daughtry, a research physical scientist at the U.S. Department of Agriculture told NASA's Earth Observatory in 2001, back when precision farming was in its infancy. "But as farms have grown…farmers start to lose touch with their fields."

But according to Dr. Barbara Glenn, Vice President of Science and Regulatory Affairs of CropLife America—a U.S. trade association representing the major manufacturers, formulators, and distributors of crop protection and pest control products—"Farmers today know what is happening on each and every acre of their farm."

With precision agriculture, a farmer can access detailed data about his entire farm with the click of a mouse. Using satellite imagery, farmers survey their fields and use information management systems to monitor the soil characteristics that affect crop growth.

Having this wealth of valuable information at their fingertips opens up a whole new world for farmers to manage their environmental impact. "Agricultural technologies and advancements, such as crop protection products, are allowing farmers to do more with less," says Dr. Glenn. "Today's farmers become trained and certified in environmental practices, and using practices like no-till farming and integrated pest management, they leave land in better shape than when they started."

Here are just a few of the high-tech (and really cool) methods of which today's farmers are taking advantage:

Soil Sampling

By testing soil samples from plots throughout a field and applying that information to a computer program, a farmer can determine the variables within the field: soil fertility, pH levels, drainage, moisture levels, and other conditions that affect how a plot of land should be treated for maximum crop yield. Precision agriculture is also referred to as "site-specific management" because of small size of the plots that are measured.

Variable Rate Application

Using a technique known as variable rate chemical application, a farmer can control exactly how much of a certain chemical is applied to each part of a field and use the least amount necessary. Variable rate systems contain sensors that identify where a chemical is needed (for example, if a weed is growing) and sends a signal to the nozzle to activate the sprayer.

Dr. Glenn says that modern tools are so precise, farmers can control their inputs so that there is zero overlap or unnecessary use of inputs—a result that is environmentally friendly AND lowers farmers' costs.

Farmers can also save water by using remote sensors to measure how much a crop is actually using, rather than relying on guesswork. In 2007, the U.S. Department of Agriculture estimated by updating irrigation systems with precision technology, a commercial farmer with a 250-acre farm could save up to 5.7 million gallons of water each year.

Yield Monitoring

Yield monitoring is a cornerstone of precision agriculture because a farmer can use data about this year's yield to make crucial decisions for the upcoming year. Using a yield monitor and a GPS system, a farmer creates a yield map that shows the relationship between crop yield and field condition variables. It can help farmers decide what type of seeds to purchase, what to plant where, what type and how much of a certain chemical to apply, and other key determinations that will increase next year's yield.

But even though today's farmers may have more advanced tools than they did years ago, they still have one thing in common with farmers of the past: they are committed to protecting their land and the environment, and to constantly improving their methods to improve crop yields. And that's one thing that's not going to change.

To read our full interview with Dr. Glenn, please click here.