Is democracy really taking root in El Salvador?

President Reagan's confident assertion this week that there has been significant progress on human rights in El Salvador may have presented a rosier picture than is actually warranted.

But there is considerable evidence that the current Salvadorean government has, to some extent, cleaned up its act on the rights front.

That appears to be true in San Salvador, the capital, and in other metropolitan areas - in short, the cities. In the countryside, however, the record is less encouraging. There, the repression of innocent civilians continues without visible letup.

The Roman Catholic Church's office of legal oversight in San Salvador, which tallies ''murders of civilian noncombatants by security forces,'' says that 1, 296 Salvadorean civilians were killed in the first three months of 1983 - 430 in January, 537 in February, 329 in March.

Still, in the view of numerous observers, the government of provisional President Alvaro Alfredo Magana Borja has responded positively, albeit with limitations, to the entreaties of the Reagan administration on human-rights issues. This was one of the hopeful factors to which President Reagan alluded in his major policy address on Central America to a joint session of Congress Wednesday night.

Yet many careful observers of the Salvadorean scene make clear that the United States cannot be truly satisfied with the Salvadorean attitude and performance on human-rights issues - even given the limited improvement evident in recent months.

President Reagan, moreover, took a much more confident note on the whole Salvadorean situation than may be justified, say many specialists, including people within the administration. His assertion that ''democracy is beginning to take root in El Salvador'' is premature, they say.

On land reform, for example, the President indicated there has been considerable progress in reaching the goals of the program. In three years, he said, 20 percent of El Salvador's land has been redistributed to more that 450, 000 persons - 1 in 10 in the Salvadorean population.

But the land reform record may not be so good. Critics challenge the President on his figures. Exact numbers are hard to ascertain. It would appear, moreover, that land reform analysts in El Salvador's government are less optimistic than President Reagan on this front.

Actually, the whole agrarian reform program hangs somewhat in the balance. And for that matter, so does the viability of the current Salvadorean government.

President Magana has taken a middle-of-the-road position, carefully balancing military maneuvering, civilian politicking, and a badly shattered economy. He has done so with US help.

What the US is trying to do in El Salvador, in addition to keeping Mr. Magana in office until elections later this year and beefing up the fighting potential of the Salvadorean Army, is to breathe democracy into a nation and society that has known precious little democratic performance in its history.

This effort is essentially what the Carter administration also attempted. During the late 1970s, Washington pushed to create a democracy in El Salvador - to carve out a center, a moderate position that would respond to the legitimate aspirations of the Salvadorean people for change and reform, for improved living conditions, for free elections.

It is worth noting also that many of El Salvador's moderate leaders have been killed, others have left the country, and still others are unwilling to serve in any official capacity. President Magana is an exception, as is Jose Napoleon Duarte, the Christian Democratic leader who recently was named his party's presidential candidate for elections later this year.

There is no doubt that some progress on this score has been recorded in recent months.

But progress is slow, a suggestion that the US is involved in a long-term job in El Salvador. In fact, the US role there may be open-ended. It probably will go on for years. Some of the critics wonder whether the US has the stamina to continue over the long haul - or whether it will eventually yield as it did in Vietnam.

President Reagan, however, counters that US national security is at stake in Central America - and particularly in El Salvador. Moreover, unless the US makes a stand in countries close to its own border, how confident can the NATO nations and allies across other oceans feel about US defense treaties, some administration officials ask.

Many administration critics, however, question whether El Salvador, with its anarchic social structure and human-rights history, is the right place to make such a stand. The debate is joined. It will be with the American people for weeks and months.