Congress may wrangle over how to cut the big federal money pie, but there are a few small, tasty slices on which there is little disagreement.

Mark O. Hatfield's mint beds, for one. Robert C. Byrd's fruit station, for another. Jamie L. Whitten's cotton program, to name a third.

Nor is there dispute over the greenhouses for Milton R. Young and Henry Bellmon. And there's no need to worry about Tip O'Neill's or Lloyd Bentsen's nutrition centers -- they'll be all right.

These and scores of other agriculture-related research activities, each with a congressional patron, will be in the fiscal 1980 appropriations bill that is nearing approval.

That really is not news; members of Congress, particularly those who sit on the key appropraitions panels, have for decades channeled federal agriculture research money into their home districts.

It is a side of the congressional spoils system often overshadowed by sexier bread-and-butter issues -- saving a military base from closing, landing a flood-control dam, finding a federal contract for a business at home.

And with appropriate irony it is one of the reasons House and Senate conferees are deadlocked over differing approaches to research spending in their respective farm appropriations bills.

In a way, it boils down to a test of wills between Rep.Whitten (D-Miss.), chairman of the House Appropriations Committee and Sen. Thomas F. Eagleton (D-Mo.), who heads the Senate Appropriations agriculture subcommittee.

Caught in the middle is the Carter administration, which began making waves in 1977 by proposing that a tiny part of the Department of Agriculture's $600 million-plus research budget to put out on competitive bid. a

The traditional research done by land-grant universities, funded by direct grants, would continue. But to inject new approaches and thinking, some of the work would be contracted to other institutions -- prestigious science centers not ordinarily known for agricultural work. A Harvard or a Yale, for example.

Whitten, a sort of congressional farm overlord by dint of his 25 years as agriculture subcommittee chairman, and others in Congress reacted skeptically.

They saw the new approach undercutting the century-old-land-grant program, complaining indirectly that it would mean less congressional control over the research dollar.

Whitten's subcommittee provided some funds for competitive research in 1977 but last year cut the funds off when the administration proposed trimming the land-grant money. The worst fear of the competitive-bid opponents -- that USDA was abandoning the old program -- seemed to be coming true.

But Eagleton's subcommittee, largely at his urging, agreed to fund the competitive program, and conferees compromised by providing less than the Senate wanted but more than the House wanted.

A similar dispute is going on now between House and Senate conferees. Figures produced by Eagleton suggest that the fears of the competitive-bid opponents were unfounded. In two years, about 70 percent of the $30 million in competitive money has gone to land-grant and public universities anyway.

An Congress has boosted spending on traditional noncompetitive research at the land-grant schools and at USDA extension centers on many campuses.

"I look upon the competitive grant program as an additional bonus for the land-grant schools," Eagleton said recently. "Some people think Harvard is kidnaping the nonland-grant competitive money, but it has not happened."

Harvard, as a symbol of the non-land-grant science center, in fiscal 1979 got only two competitive awards, totaling $275,000 out of USDA's $15 million kitty. The Massachusetts Institute of Technology, another symbol, got only two grants for $170,000.

In the eyes of many on Capitol Hill and in USDA, the real issue behind the research money squabble is power: how much Whitten and other influential legislators may control a secretary of agriculture and direct departmental activities.

Tempers have abated this year, but in 1978 the feeling ran so high that Secretary Bob Bergland was saying openly that Whitten, who knows USDA programs by heart, really wanted to run the department.

The flap and the larger debate over putting some research funds out on competitive contracts have tended to obscure another reality of the process. o

The time-honored procedure of using appropriations bills to channel federal goodies into home districts is alive and flourishing in the 1980 spending measures.

Eagleton's subcommittee this year heard from 60 senators who were interested in extra money for pet projects in their states. Whitten's subcommittee heard from close to 100 members with similar pleas.

The House and Senate panels accepted some, scaled down or rejected others. They overruled dozens of administration proposals to cut research spending and have given USDA specific instructions on how and where they want the money spent.

Much of the division of the spoils depends on membership on the appropriations panels.

It explains how Sen. Hatfield (R-Ore.), a ranking member, could persuade his colleagues to add $180,000 for research on mint at Oregon State University. He has been looking out for Oregon State's mint research program for several years, helping provide the federal impetus that someday may give us tastier juleps and jelly, tangier toothpaste and minitier gumdrops and chewing gum.

Why would the U.S. Congress take up its time on a matter of such seeming inconsequence as mint?

"Because," as one appropriations staff aide put it, "the senator from Oregon is interested in mint and some people in Oregon are interested. It is that simple."

The same reasoning explains how Majority Leader Byrd (D-W.Va.), also a member, could persuade the committee to approve $850,000 to hire staff for a new USDA fruit research station in the center of his state's apple and peach belt. The administration sought only $271,000 for the project.

It also explains how Whitten and others from cotton states could object to the administration plan to cut $869,000 from cotton research and put the money in other higher-priority crops. Although the Senate didn't like the change, it went along with restoration of the money rather tahn pick a fight with the cotton caucus.

In the same vein, Sens. Young (R-N.D.) and Bellmon (R-Okla.) offered powerful reasons for boosting the spending on USDA research facilities in their states. The committee went along with an extra $1.2 million for a greenhouse at North Dakota State University and $2.5 million for a plant-science laboratory at Oklahoma State University.

The senate, however, objected to the House increase of $2 million for nutrition research at Tufts University in Massachusetts, a program that ouse Speaker Thomas P. (Tip) O'Neal Jr. (D-Mass.) and former Sen. Edward Brooke (R-Mass.) helped land through USDA. The Senate cut it to $1 million, so a compromise is in order.

Similarly, the Senate objected to a House increase of $1 million for equipment at a Baylor University nutrition laboratory, a favorite of Sen. Bentsen (D-Tex.), which has received $1.5 million each of the past two years.

It is worth noting in passing that neither Texas nor Massachusetts is represented for the Senate Appropriations Committee.

Other examples abound in the House and Senate bills -- earmarking money for dozens of special research topics, ranging from whey and pickles to filberts and blueberries. Virtually every one has a congressional patron, who in turn has a farmer or a researcher or a packer or a university president pushing him at home to keep a project going or to start a new one.

"It's not as sinister as a lot of people like to think," said on staff aide.

"This is the way the system works. Once one of these programs get started, they may be very low priority, but a congressman's telephones ring off the hook when someone tries to cut them.

"These things happen around here for reason that are not entirely astounding."