It used to be mostly the military that used small, unpiloted aircraft, called "drones." The little planes were very costly. But as they have dropped in price more people have begun to use them. Rescue workers and farmers are among the new users.

　　A company in France is using drones to help farmers examine their crops and limit the amount of fertilizer they use.

　　The fast rate of development of computer technology, image sensing devices, satellite navigation and smartphones has led to lower-priced drones. Researchers and developers have learned how to build smaller and less-costly drones sought by individuals, companies and governments.

　　Moviemakers are using drones to film from the sky. Historians use them when they explore ancient buildings. Rescue workers use them to look for people. And now farmers are using them to monitor their crops.

　　Romain Faroux is a French businessman who starts companies. His father was a farmer. He believed drones could help farmers. He helped create a company that developed a small drone that could be controlled by people on the ground. They called it "Agridrone." It uses a special "optical sensor" to examine crops.

　　He says the technology used is similar to that used by smartphones -- except it has wings. He says the industrialization of electronic parts for smartphones and tablets lets them get the technology -- including GPS -- at a very low price.

　　A computer program directs the drone to fly over the crops. The sensor on the drone records four different-colored "bands" of sunlight that are reflected off the crops.

　　Jean-Baptiste Bruggeman is a farmer. He says the drone flies over his crops at different times of the season. He says this provides a lot of information about his crops.

　　He says the drone pictures show him the exact amount of fertilizer the crops need. He says it also shows exactly where the fertilizer is needed. Some areas of a field may need more than others.

　　As a result, Mr. Bruggeman says there is reduced nitrogen from the fertilizer after the harvest. This helps nature.

　　Romain Faroux says farmers use information gathered by the Agridrone to place fertilizer only in areas where it was needed. This saves money and reduces pollution. Before they used the drones, farmers would put the same amount of fertilizer everywhere.

　　Drones also save time because farmers can examine up to three hectares in about a minute.

　　I'm Marsha James.

　　VOA Science and Technology Correspondent George Pubic reported this story from Washington. Christopher Cruise wrote it for VOA Learning English. Marsha James read and produced the program. Caty Weaver edited the story.