Monday through Friday, Howard W. (Bud) Kerr roars around the Agriculture Department peddling ideas and trying to shatter what he sees as intellectual ennui. When he thinks he's right, which is often, he'll push until he gets his way. He jangles nerves and stirs bureaucratic jealousy.

On summer Sunday mornings, Kerr can be found cajoling and bantering with the customers who crowd around his truck at a Baltimore farmers' market to buy the juicy peaches and blackberries that he grows on a small farm west of the city.

There's no great dichotomy. What we have here is one of the rarer Washington species: the hands-on bureaucrat who practices what he preaches. Rides a tractor. Gets his hands dirty. Figures out better ways to market his fruit. I-d-e-n-t-i-f-i-e-s.

Kerr, 54, is USDA's one-man braintrust on small-scale farming. That only one person is working full time to deal with the needs of more than a million small farmers and would-be farmers speaks volumes about priorities at USDA, where "bigger is better" long has been the abracadabra phrase.

Kerr's role, in a job that did not exist until early 1984, is to make the department pay more attention to the problems faced by farmers who try to squeeze some income out of 50 acres or less.

Their need could be equipment for small-scale production of crops and fruits. It could be better ideas for marketing, forming cooperatives, dealing with pests. It could be cheaper, more imaginative ways to handle livestock. Or it could be no more than governmental recognition that small farmers play an important role in the country's ability to feed itself.

"In the early 1970s, we saw the beginning of this type of small farm," Kerr said recently. "They have no ambition to become big farmers and they don't ask for anything except the loyalty of the consumer. It's really time that the government recognized this development -- and I think there are some positive signs that we are."

Unlike their larger counterparts, these farms are burgeoning. The number of farms with 50 acres or less has increased about 17 percent since 1978 and most experts see the trend continuing. Many of them, of course, are subsidized by off-farm income and are not much more than country residences that qualify for census purposes as farms.

But many others -- some subsidized by off-farm income, some not -- are serious and quite profitable operations devoted to producing specialty foods and nursery or floral crops for special markets. Their operators are as much entrepreneurs as farmers, scouting for ways to break into new markets and give buyers more freshness and variety for their money.

The 17-acre peach and berry farm that Kerr set up in 1970 is prototypical. Its owner holds a fulltime job in town, and spends only weekends pruning, harvesting and marketing. Profit is not the all-consuming force.

"The small farmer has land for consumption -- for pleasure, for profit, not always to pass on to the next generation, like the traditional family farmer. I knew from my own success with the farm that there was something in this," Kerr said. "These people still buy tractors, seeds, equipment and they put money into the economy. This is important to rural communities."

"We have to accept the reality that the trend in this country is to part-time agriculture. Young people today just can't go out and get land. If you don't have a father's land to fall into, you have to do it another way -- and that is why we are seeing so many people who have established themselves in some other line now going out and trying their hand at some form of farming."

Kerr's job is a liaison between the Agricultural Research Service (ARS) and the Cooperative Extension Service, which means he is supposed to make the two agencies talk to and help each other more and, in turn, give small farmers new information on their problems.

"Bud Kerr was uniquely qualified for this job," said Dr. Orville G. Bentley, the assistant secretary for science and education who appointed him. "He has been very successful as a resource person, conveying what's going on in research and at the federal and state level to benefit the small farmer."

However, the institutional mindset at USDA is still fixed on big-scale farming and its problems. So to make his liaison work, Kerr has to make noise and occasionally bruise bureaucratic egos. The legend on a farm cap hanging in Kerr's office says it tersely: "Think Small."

The results speak for themselves.

While some superiors were criticizing his aggressive promotion of ideas, Kerr was being praised by then-secretary John R. Block for "outstanding" contributions. Kerr's efforts have helped redeem USDA's name among many small farmers who despaired of ever being heard in what some derisively call the Department of Agribusiness. Kerr is increasingly mentioned in farm publications, asked to speak on small farm issues, recognized as an in-house champion of the little guys.

Kerr, an agricultural economist, went to work for USDA in 1960 after earning a master's degree at the University of Maryland. Life began afresh in 1978 when the ARS chose him to help oversee a new research program ordered by Congress to improve small-farm operating skills.

Kerr's Northeast region quickly became a standard-setter. Several of its projects produced groundbreaking innovations to help farmers extend growing seasons and improve fresh-market sales potential.

In 1981 Kerr staged a small-farm technical symposium that attracted 650 participants and worldwide acclaim. It caught the eye of higher-ups at USDA, who suddenly worried that the department was missing the small-farm boat.

"That really was a turning point, for we got people in the department to realize that small farming was very much a viable thing with tremendous interest and potential for growth," Kerr said recently.

All this made Kerr a natural to be moved from his Beltsville office to USDA's downtown headquarters when Bentley, Block and others decided it was time to give small farm activities a little more time of day in the department.

"The interest is here, no question about it. The trend to smallness and part-time farming is going to continue and we had better be ready to deal with it. We have to start looking at what's needed ahead, in terms of people who can make a cash register ring, make a school bell and a church bell ring. That's the important thing," Kerr said. "I like to talk about the future, because that's where I plan to live."