Drones are coming, perhaps sooner rather than later to Ventura County, and the first place you see them might be the above the region’s fields and orchards.

Congress has asked the Federal Aviation Administration to pick six testing sites around the country for the civilian use of drones, also known as unmanned aerial vehicles, and the Ventura County Board of Supervisors has submitted an application.

The use of such aircraft, military versions of which were used to deadly effect by the United States against suspected terrorists, has alarmed civil liberties groups. They worry about the invasion of privacy by commercial interests and the potential for abuse by law enforcement agencies.

But the drone industry itself expects the primary use of their technology to be much more benign. About 80 percent of sales are expected to come from the agricultural sectors, according to a recent economic impact analysis by the Association for Unmanned Vehicle Systems International. They cite the explosive growth of the use of drones for agricultural in Japan, where the first systems became available in the early 1990s.

“The concentration is on the agricultural side. We’ve already seen that spraying [pesticides] with unmanned systems is much more safe, much more effective and consistent,” said Michael Toscano, president and CEO of the industry group. “More of the spray ends up on the plants and less of it ends up on the ground,” which helps with runoff pollution, he said.

But the most valuable uses of drones — and perhaps the most likely to be put to use in Ventura County — have yet to be imagined. Drones can carry many different kinds of sensors, from high-resolution cameras to infrared sensors to chemical vapor sensors that can sniff air samples. Computers can analyze that data to give farmers all kinds of useful information, from whether a certain part of a field needs more water to whether fruit is ripe to monitoring heat and humidity conditions on different parts of hilly vineyard. The personal computer serves as an analogy.

Once the hardware became cheap and widely available, software firms sprung up to create all kinds of applications.

“The farmer knows how to farm better than anyone else,” Toscano said. “What he needs is good information to make better decisions, and if he has good information, the result is more yield and more profits.”

If those applications take off as expected, the economic impact could be $82.1 billion between 2015 and 2025 and the creation of 34,000 manufacturing jobs, according to the industry group’s estimates, which were culled from surveys of companies and experts that many times were also members. California is expected to get the nation’s largest slice of that growth, with an estimated $14.3 billion in economic impact and more than 18,000 overall jobs created.

The report assumes a “net zero” impact of what’s known in economics as creative destruction, or the jobs that are lost when one technology displaces another.  Chris Thornberg, an economic forecaster with Los Angeles-based Beacon Economics who reviewed the industry’s impact study at the Business Times’ request, said that drones will definitely have a positive economic impact, but he said it will likely be more difficult to measure than the industry’s report would suggest.

“Take the example of what it means for law enforcement,” Thornberg said. “Is [drone technology] going to create jobs in law enforcement? No, you’re going to lose jobs. You’re using drones and replacing this expansive helicopter fleet — instead of having six maintenance guys, three pilots and air traffic controllers, they’re gone. However, when you have a cheaper more efficient police service, you can now use that extra funding to hire more cops to make the streets safer, which reduces crime and has a positive economic impact.”

There’s also the question of whether U.S. farmers will adopt drone technology the way that Japanese farmers did. John Krist, CEO of the Ventura County Farm Bureau, said he hasn’t heard much talk yet among his members or from other farm bureau leaders about the potential use of drones. And agriculture in the U.S. is very different from Japan, he said.

“The cultural practices, the scale, the entire economic structure of the business — it’s hard to imagine there’s direct transferability,” he said. “I’d put a big asterisk next to that.”

Then there are the privacy and civil liberties concerns. Assemblyman Jeff Gorell, R-Camarillo, co-sponsored a bill that would govern the use of drones in California. The bill, AB 1327, comes as about 30 legislatures across the country are working to pass laws related to drone use.

The California bill would require law enforcement officials to obtain a warrant before using a drone, except in cases of an “imminent threat to persons or property,” in which case officials could fly a drone for up to two hours.

Agencies would also be required to destroy data, images and footage obtained by drone use within 10 days of gathering it unless it’s being retained as evidence of a crime. There would also be a $5,000 per day fine for monitoring people without their permission, no matter whether the drone user is public or commercial.

California’s law is not the strictest being proposed but neither is it the loosest, according to an analysis by the American Civil Liberties Union. Stricter states propose an explicit ban weaponization of drones and would permit their use only to investigate felonies. Looser states, like North Dakota, would allow incidentally gathered evidence ­— such as footage gathered during firefighting — to be introduced into a criminal case without a warrant.

But some aspects of the California bill satisfy the requests of privacy advocates. California would require public agencies to give public notice when they deploy drones. And it would require any police or fire force to gain approval from its governing city council or board of supervisors, and that legislative body would also need to come up with rules for use of the drones via its usual process.

That closely mirrors the thrust of a petition the Electronic Privacy Information Center is preparing to send to U.S. Customs and Border Patrol to suspend its drone program until it goes through a public rulemaking process to govern the program.

“When public entities seek to use drones, they really need to promulgate privacy rules for the use of those drones,” said Amie Stepanovich, director of the domestic surveillance project with the group.

It’s unclear when drones might come to Ventura County. Though the county, in coordination with other groups, has applied with the Federal Aviation Administration to become a test site, so has an airport district in the Mojave Desert.  As the Business Times went to press, the Ventura County Star reported that lawmakers in Sacramento were pressing Gov. Jerry Brown to break the dispute between the two applications so that California could mount a united effort against other states.

But drones will arrive at some point, and Krist, of the Farm Bureau, said that with Ventura County’s expensive land and water, farmers here are always on the lookout for efficiency gains. “The growers in Ventura County have a long history of being early adopters of improved agricultural technology,” he said. “If anybody is going to find a use for this early on, I would expect it to be the growers here.”

• [Full Disclosure: Business Times Editor Henry Dubroff serves on the board of directors of the Ventura County Economic Development Agency, one group that is advocating for Ventura County to become one of the first six FAA test sites for the civilian use of drones. He was not involved in the reporting, writing or editing of this story.]