John Deere's high-tech, self-driving tractors (pictures)

John Deere is one machinery maker who has been building auto-steering technology into its tractors and combine harvesters since the 1990s.

The tractors use GPS to automatically steer through fields. Some planters have technology that automatically turns them off when they reach the edges.

Because the tractor steers itself, farmers can take their hands off the wheel in the field.

Machines like planters for seeds have gotten much bigger, making it harder for farmers to make sure they're not overlapping the same area.

Auto-steering technology makes the tractor much more accurate with staying in the rows than a farmer on his own. This sprayer has as width of 100 feet.

John Deere tractors have yellow globes, called StarFire receivers, that sit on the machine and work as their own GPS links, making mapping more accurate.

Tractors and combines come with monitors that can show the progress of planting or harvest in the field, or in this case, show that the autosteering technology is staying on track.

Farmers already get a lot of data from their tractors -- like yield, moisture levels and other factors. But many aren't really using the data to help them. Experts see data as the next big frontier to help agriculture.

Auto-steering technology and other features tend to come default in new tractors today.

Farms are getting bigger, but farmers don't always have more help to work the land. Technology like auto-steering makes them more efficient and lets them work longer hours.

John Deere runs a test farm in the suburbs of Iowa's capitol of Des Moines. It's here the company makes sure its apps and other technology work correctly in the machinery.