Just when the stereotype of a Reagan administration appointee seems set in concrete, along comes Peter C. Myers to blur the images thoroughly and send the simplists back to the drawing boards.

Here's why.

Myers, the president's new deputy secretary of agriculture, has just enough political naivete, just enough Missouri forthrightness and just enough sense of what is right and what is wrong to disarm potential critics on the outside and to win over doubters on the inside.

Other dimensions make him more complex, nigh on to impossible to label.

Once a major hog producer, Myers has cut back on his pork intake for health reasons. Although a champion of free enterprise, he prefers his homemade granola to store-bought. He worries about heavy doses of toxic chemicals that farmers pour onto the soil, often abetted by the Agriculture Department. A conservationist/farmer who hasn't used a plow in 20 years, he once mounted a quixotic effort to get the plow removed from the USDA's official logo.

And since he came to Washington in 1982 to head the Soil Conservation Service (SCS), Myers has gone home to Missouri each summer to work as a harvest hand on his son-in-law's farm. That is his way of "staying in touch." Rain kept him out of the wheat fields when he went home this month, so he repaired machinery instead.

One must return to 1982 to find the quintessential Myers. He came to town under fire, resented and on notice that he had a lot to prove. In a move that infuriated conservationists and legislators, then-secretary John R. Block made his friend Myers director of the SCS -- the first nonprofessional to run the agency.

But Myers quickly won over the critics. "The criticism didn't bother me personally because it was the concept, the selection of an outsider, that they objected to," he said. "I wasn't a technical expert in conservation, although I had worked with it all my life. I learned to listen to the professionals, and I think that was the reason we got along so well."

Not coincidentally, Norman A. Berg, the professional who was fired by Block to make room for Myers, is now one of his strongest supporters. Berg went on to become a consultant to the American Farmland Trust and an influential force during debate over conservation sections of last year's farm bill. He and Myers often had their heads together on strategy.

"We were very fortunate to have Myers come in as the first person from the outside in the history of SCS," Berg said. "He has a great deal of capability to look at all sides of an issue; he relied on good staff advice; he developed good rapport with his people in the field . . . . It was awkward for both of us, but it became easy to work with Peter on what I was doing from the outside."

Myers said he left Missouri expecting to be head of the SCS for either three or seven years, depending on Reagan's incumbency. But when the next logical political spot opened -- assistant secretary for natural resources and environment -- friends encouraged him to go for it.

He was quickly confirmed for the job last year. And then when the No. 2 slot came open this year, friends again pushed him. As counterpoint to the California agribusiness background of Secretary Richard E. Lyng, Myers' midwestern hands-on farming experience made him an easy choice for the deputy's job.

One of the sharpest critics of Reagan administration farm policies, Sen. John Melcher (D-Mont.), has nothing but good to say about Myers. "He's been one of the brightest appointments at USDA in the last five years. I thank John Block for bringing him in," Melcher said. "He is known to be a pretty thorough and conscientious administrator. He admits mistakes -- and that is necessary. He is quite refreshing."

Even the American Agriculture Movement, which breathes fire and fury when Reagan farm policies are brought up, has been won over. David Senter, national director of AAM, put it this way: "We don't agree with his policies at all. But we view Peter Myers as one of the few appointments at the top with roots back to the land. He is easily accessible; he is a solid addition over there."

Another measure of confidence comes from Lyng. With just a week on his new job, Myers was handed the additional task of being Lyng's eyes and ears on civil rights enforcement at USDA, where a wave of discrimination complaints has created turmoil.

Before he was given that extra duty, Myers told a story on himself that seemed to inadvertently say volumes. When he became head of SCS, he decided to eliminate the complex rules that were supposed to guide the agency in equal opportunity and civil rights enforcement. He didn't think they were needed.

"I felt I was not a prejudiced person. I saw all these rules, and I thought we were beyond that. I feel very strongly about treating people on the basis of how they perform their work. But when the word started coming in that I was prejudiced, I didn't want any part of it. It was my introduction to the real world. We put the rules back to where they were supposed to be," he said.

Myers, 55, grew up in Racine, Wis., and by the time he was 5 he knew he wanted to be a farmer. He worked summers on a grandfather's truck farm, studied agronomy and animal husbandry at the University of Wisconsin, and after two years in the Army, moved to Missouri in 1955 to begin farming on rented and inherited land.

He went on to become recognized as one of the most proficient farmers in his southeastern corner of the state, but it wasn't always easy.

"My first crop was in 1956, and it was a good one. I was enthused. Then we had 100 inches of rain in 1957, and I got a liberal education in the perils of agriculture," Myers said. "Ten years ago the Lord really humbled me. A hailstorm nearly wiped us out. I had no crop insurance, and I was almost bankrupt . . . . I have awakened in a cold sweat in the night with a crop just having been planted and four inches of rain coming down."

Along the way, Myers jumped through all the requisite hoops for becoming a local pillar. Church deacon, Sunday school superintendent. Little League and PTA, conservation leader and 4-H promoter. Farm Bureau executive. Rotarian. University of Missouri adviser. Official in state hog, corn, cotton and cattle producer groups.

Myers' selection in 1966 as a Jaycees national outstanding young farmer led to an acquaintance with Block, who had won similar honors in Illinois. "We'd really only met three times, but we knew our philosophies were the same," Myers said. "Jack worked on me pretty hard to come to Washington, but I turned him down. When he offered the SCS job, it was hard to say no any longer."

His philosophy, in brief, is "the less government the better." His reality, however, is that government farm programs are not only here to stay for awhile, they are necessary to take economic peaks and valleys out of the marketplace.

"Six or seven years ago, when times were better, we could have gotten rid of the programs and let supply and demand take over," Myers said. "But I believe the new farm program gives us the tools to get there, to get competitive again in world markets and to stop the expansion by our foreign competitors . . . . Dick Lyng and I think similarly -- we'd like to get government out of agriculture tomorrow morning. But it's not economically or politically feasible.

"If I violently disagree with the administration's policy," he continued, "I'll go back to Missouri and do something else. But the basic philosophy, I agree with 100 percent. I'm selfish. I want to see a good healthy agricultural economy."

But don't count on Myers quitting. The farm, in effect, isn't there anymore. When he became assistant secretary, he had to give up his farming interests to avoid conflicts. The land and machinery are rented to a daughter and son-in-law who don't need a partner.