The 37-year-old Army veteran moved to this rich valley north of San Francisco a decade ago, took up agriculture, camouflaged his irrigation system, set up an emergency communications network and bought firearms.

He grows marijuana.

With his wife and their several children, he has joined a steadily enlarging band of agricultural entrepreneurs who drug officials estimate produce $1 billion in annual illegal produce in California alone, and who, if estimates of covert activities can be trusted, may be rivaling California's bigest cash crops, cotton and grapes.

The Drug Enforcement Administration has estimated that California provides 15 percent of all marijuana consumed in the United States. But growers in Oregon, Hawaii and Florida are trying to catch up, and the illegal cultivation, the agency says, goes on in virtually every state.

"Yeah, that's right, it is good for business," said Marc Nassar, 48, owner of the general store in Cazadero, a tiny resort town in the mountains north of here previously known only for sheepherding, fishing and a number of church and Boy scout camps.

Nassar was joking with some of his bearded, long-haired customers, many of whom spend money he knows is earned from the only crop that can yield high profits in steep, rock soil. "I'm just one of the old-fashioned people who feel what someone does on his own property is his own business."

"One of the things we would like people to know is how much hard work it is," said 37-year-old grower with several children, who agreed to be interviewed if his name were not used.

"You don't just go up and throw out the seeds and make $500,000. Everything has to be incredibly well hidden. I had to carry up 1,500 feet of irrigation pipe and bury it so that no one could find it. I estimate we carry up 100 pounds of fertilizer per plant, and several hundred feet of wire fencing to keep out deer and wild pigs."

The grower lives in a difficult-to-reach place on a mountain and plants his stalks near trees and rocks to frustrate detection from Cessna planes the county sheriff sometimes flies over the areas.

He does not have to grow many plants to make a living, however. The costs of importing marijuana from South America and new techniques of growing here have sent sky-high the price of California marijuana -- particularly the potent "sinsemilla" (seedless) variety. An average plant can yield a pound of marijuna, which brings $1,000 to $2,000 on the market.

Gina McGuiness of the California bureau of narcotics enforcement said authorities seized 156,784 marijuana plants in 1980. They could have been worth as much as $250 million.

Sheriff's officers here and in Los Angeles County say that they spend only a fraction of their time on marijuana plant seizures, and acknowledge the large majority of the crop is probably harvested and sold.

Ted Eriksen Jr., the agricultural commissioner for Mendocino County, estimated a $100 million marijuana crop for 1980 in his county alone. He said he derived the estimate from conversations with bankers and irrigation pipe and auto dealers. They derived their figures from cash transaction they had made over the last year.

"Some indicated that if it weren't for the marijuana crop and the business it produces, they would go from the profit side to the loss side," Eriksen said.

Politics and chemistry have fertilized the rapid growth of domestic marijuana. California and several other states have made possession of small amounts of the drug a minor offense, not much more bother than a traffic ticket, and although growing marijuana is still a felony here, most people assume they will get off easy in the changed political climate.

Also, American users like homegrown marijuana because they suspect that important plants have been contaminated by a defoliant, paraquant, which is still banned for use on marijuana in the United States.

The outgoing head of the DEA, Peter Bensinger, along with several state attorneys general have asked that this ban be lifted. Growers say this would force them to reach for their guns.

"Everybody I talked to says, up to now we've been peaceful hippies," said one grower, a 31-year-old carpenter who moved here from San Francisco several years ago. "But no one is going to let them spray poisons around."

Linell Broecker, a spokesman for the DEA in Washington, said a United Nations study showed no serious effects from ingesting plants that had been sprayed with paraquat.

Officials of pro-marijuana groups like the National Organization for the Reform of Marijuana Laws insist severe lung damage can result from using paraquat-treated plants. One grower in Los Angeles County was particularly enraged. He said his youngest child was born with a cleft palate, which he attributes to his pregnant wife's exposure to paraquat being sprayed on weeds in a Hawaiian park.

Some residents, particularly sheep ranchers and farmers who preceded the migration of urban youth to the county in the late 1960s and early 1970s, are just as outraged at the widespread marijuana growing.

They complain (as the marijuana growers do) of local delinquents who come into rural areas to steal marijuana but take anything they can find.

Sonoma County District, Attorney Gene L. Tunney, son of the famous boxer, said the marijuana growers "are not your average criminals" but I find that particularly offensive. They are educated, often people with extremely good backgrounds and good jobs, and they just made a conscious choice to change their life style. They decided to move to the beautiful county of Sonoma to grow marijuana. I find that particularly revolting."

The growers often describe their work in almost religious terms. They give pet names to some of their plants, which come in strikingly beautiful shades of green easy to detect from the air.

Mike, a 33-year-old grower in the San Gabriel Mountain of Los Angeles, spoke with a quavering voice about the little mud-walled greenhouse with a plastic roof he fashioned to grow several plants. When a sheriff's helicopter landed nearby, he was forced to rip them out and destroy them to avoid arrest.

"That was pretty traumatic," he said, sitting in his old house, his hair tied back in a ponytail. "You put a lot of love and devotion in to those plants. I was really upset."

Marijuana growing used to be centered in the remote, heavily forested northern counties of Humboldt and Mendocino. It has now spread here and to Los Angeles and other counties in the far south.

Sheriff's deputies here launched a big raid of the Cazadero area last September using a special weapons team and helicopter. During one raid of growers they arrested a member of the county grand jury.

Sgt. George Phillips, the bearded head of the Sonoma County sheriff's narcotics bureau, dressed in blue jeans and a baseball warmup jersey, said one sophisticated marijuana greenhouse discovered in the valley belonged to "a retired gentleman who seemed bored with retirement and wanted to supplement his retirement income. He decided to grow marijuana. It seemed like the reasonable thing to do."

The man and his wife pleaded guilty and were given probation. Many growers have no criminal records, and qualify in California for "diversion," a program that removes them from the criminal justice system to a series of rehabilitation classes.

Many of the growers say they like Phillips and other genial narcotics officers, such as Lt. Philip Groat and Det. Mark Ihde. Most growers say they will vote for the officers' boss, Sheriff Roger McDermott, next time. They were pleased when sheriff's deputies congratulated them for capturing two youths bent on theft, who fell victim to the Cazadero growers citizen-band network and quick call to arms. But they received bad publicity when some growers broke the nose of another young intruder.

Many of their neighbors still tip off the sheriff's office to marijuana locations. Groat and Phillips said they usually respond only to such complaints, and do not go out on "fishing expeditions."

Sgt. Eugene Rudolph, 49, has been a narcotics officer for the Los Angeles County sheriff's office for several years, and describes himself as "one of the most anti-marijuana officers on the force.

He says he is convinced that marijuana "has an effect on the brain," particularly on young people who begin using it in the 6th and 7th grades.

But times have changed, he said. Lessened penalties for possession of marijuana have made people so casual that one woman invited officers in to look at her plants, thinking they were legal.

The casual attitude extends to many of the younger officers, who say they put much higher priority on heroin, PCP, and other drugs that seem to lead to heavier crimes.

"When we find where a guy has been growing the stuff, and we pull out his plants, we often do leave behind one little plant," said one Sonoma County officer. "Because we figure when he gets back from court, he really is going to need a smoke."