Legislatures will convene in 49 of the 50 states this year, and, as Wisconsin Gov. Anthony S. Earl (D) observed recently, "the component parts of the Union look a lot better than the Union does."

Fiscal matters are likely to dominate the sessions, and several states expect budget surpluses. This is largely the result of tax increases and spending cuts imposed a few years ago when the national economy plunged and the federal government began to reduce state and local aid. Tax cuts are imminent in several state capitals this year.

Regional fortunes have shifted.

Among states with surpluses are some in the Frost Belt that were pummeled by the recession and losing industrial ground, such as Pennsylvania, Ohio, Wisconsin and New York. A few proverbially poor southern states also are doing well, including Alabama.

Texas and some other energy-rich states whose economies boomed a few years ago have been robbed of anticipated revenues by a stagnant energy market. Iowa and Kansas are among the farm states that also are awaiting economic recovery.

Politically, Republicans start the year stronger in the state capitals, holding 320 more legislative seats than they did a year ago, according to the National Conference of State Legislatures (NCSL).

But Democrats retain a solid majority in state government -- 34 governorships, 4,318 legislative seats and control of 66 chambers, compared with 16 governorships, 3,038 seats and 31 chambers for the GOP.

Only Kentucky holds no legislative session this year, although the Kentucky Legislature did meet to organize. Most of the other state legislatures already are in session. A few do not convene until spring.

This year's state legislative agendas include such diverse issues as whether motorists should be penalized for not fastening seat belts, whether some convicted murderers should be imprisoned with no chance of parole, and how best to provide -- or reduce -- health care for the poor and near-poor in the face of shrinking federal reimbursements.

Education is also a major issue. If last year's trends continue, some states could set new guidelines for the number of hours children spend in school and the number of pupils in each classroom as well as deciding whether some teachers should receive merit pay.

The governor of Kansas is asking his legislature to permit sale of liquor by the drink. The governor of Pennsylvania wants his state government out of the liquor store business. In Iowa, there is talk of going into the lottery business.

Florida legislators may decide to impose an "impact fee" on new residents to help defray the cost of more sewer lines. Wisconsin lawmakers are being asked to approve $17 million in "comparable worth" payments to some female state employes. In Virginia, the top item is improving management of the prison system.

Yet from capital to capital, the overriding issue continues to be money, and the states, many of them forced by law to maintain balanced budgets, start in far better shape than the federal government.

"State governments have reduced their appetite," said Maryland Assembly Speaker Benjamin L. Cardin (D). "We've gotten our house in order. What worries us is that the federal deficit is out of control, and we're worried that state legislatures might be penalized by Congress for their prudence."

Wisconsin's Gov. Earl is sitting atop a surplus of $300 million -- nearly as large as the $350 million potential deficit he inherited three years ago. "We've done what the federal government has not had the backbone to do," he said.

Wisconsin is only one version of the rags-to-riches story.

In Pennsylvania, weakened by slumps in the coal and steel industries, more people now are working in research and high-tech jobs than in manufacturing. The state is anticipating a $188 million budget surplus and an almost certain tax cut. "The world looks pretty good from Harrisburg," said Senate president pro tem Robert C. Jubelirer.

Massachusetts, once hard hit by unemployment, saw the creation of 140,000 jobs last year, and its 4.8 percent unemployment rate was one of the lowest among major industrial states. "We have an incredible success story here," said John R. Sasso, chief of staff for Gov. Michael S. Dukakis (D). "We've gone from a basket case in 1975 to a market basket in 1984."

In Alabama, Gov. George C. Wallace (D) has called a special session of the legislature to decide how best to spend -- or more likely squirrel away -- $347 million in windfall revenues from oil and natural gas leases.

But in Texas, Gov. Mark White (D) has ordered curbs on state hiring and capital spending to help stave off a projected $1 billion budget shortfall due in part to stagnant oil and natural gas prices.

In Iowa, state legislators lament that more than 10,000 farmers may lose their land this year and many families are paying living expenses out of borrowed money. Washington's only response, they say, is to threaten further cutbacks in farm programs and state aid and take inadequate action to lower interest rates and reduce trade deficits.

"If they hold the thumb on us in agriculture . . . and then they pour more down on us, we don't have any way out," said Senate Minority Leader Calvin O. Hultman (R). "We're basically at the saturation point on taxes."

And half a continent away in Oregon, the state's fabled "good life" is imperiled by what legislators describe as property and state income taxes raised to the limits. Prospects are considered more likely than ever for approval this year of a long-dreaded sales tax, probably 5 percent.

Cash-strapped federal budgeters argue that state and local governments can bear a substantial share of the burden of reducing the deficit without undue hardship.

But state officials argue that their budget surpluses are misleading -- and in some instances politically dangerous. Their $5.8 billion collective surplus is equal to 3.5 percent of the money the states spent last year and is nearly three times as large as the proportion on hand in 1983.

But it is less than the 4.5 percent surplus of 1981, just as the recession and President Reagan's first term were beginning, and far short of the 9.4 percent and 11.2 percent figures of 1980 and 1979, according to the National Association of State Budget Officers.

Anticipating more economic hard times and additional service burdens from further federal retrenchment, many states plan to establish "rainy day funds" with some or all of their surplus money.

California is anticipating a $1.1 billion surplus, and Gov. George Deukmejian (R) says he would like to put all of it in a municipal cookie jar. But Assembly Speaker Willie Brown (D) says the major issue before the legislature this year will be "how you give back the surplus." Brown would like to see some tax relief.

Governors and legislators in New York, Pennsylvania and Ohio are battling over how deeply to cut taxes now that surpluses are available. In Wisconsin, Earl plans to use part of his surplus to cut taxes at the same time he pursues a controversial tax simplification plan that could eliminate deductions for charitable contributions and home mortgage interest. Other states also are considering tax revision.

Earl S. Mackey, executive director of the National Conference of State Legislatures, said many state officials fear that unusually large surpluses can spark give-it-back rebellions among heavily taxed voters. Tax cuts and limited rainy day funds are two ways to head off such revolts.

In other instances, extra money is being earmarked for new or continuing programs.

Arkansas was one of five states to approve major education initiatives last year. This year, Gov. Bill Clinton (D) is asking the legislature to use some of the excess revenues from a 1-cent sales tax increase, enacted to bolster the education package, to attract new businesses -- a popular 1985 project among legislatures.

But Arkansas Republicans complain that the educational changes made last year are forcing some local school districts to seek property tax increases as high as 50 mills ($50 per $1,000 of assessed value). House Minority Leader Carolyn Pollan argued that the $80 million increase was advertised as support for education and should be used as such.

According to William T. Pound of the legislators' conference, an average 35 percent of all funds now go to education, and in some states the proportion is as high as 70 percent. Ohio Gov. Richard F. Celeste (D) is asking legislators to consider increases in teacher salaries, caps on undergraduate tuition at state schools, and "forgivable loans" for students who pursue selected fields.

Wisconsin hopes to close the gap between university teacher salaries and the national average. But it first may have to solve what House Speaker Tom Loftus called a "Balkan" feud between faculty members at the flagship Madison campus of the University of Wisconsin and their lesser-paid counterparts on other campuses. The educators disagree over whose salary increases should be the largest.

Massachusetts will ponder better standards to measure student progress, higher salaries for teachers, and mandatory computer literacy. Merit pay will be on the agenda in Iowa, where education appropriations consume 60 percent of the budget.

Concern about improving education extends beyond the three R's to economic development. From Nevada to New England, state officials have discovered the link between improving education and luring high-tech industries.

"If you look at the high-tech centers as they exist today, without an exception they tend to be near a strong university system," Pound said.

Pennsylvania Gov. Richard L. Thornburgh (R) proposed major education changes last year and said he will seek more this year. "The heart of the governor's economic development program," said press secretary David Runkel, "is a realization that we can no longer rely on those smokestack industries and we need to educate and train people for jobs in today's economy."