Moscow is buying corn again, New Delhi is a surprise buyer of wheat and promising new trade contacts have been made with Peking. Export sales of U.S. agricultural products this year are expected to run near $46 billion.

In farm country, on Capitol Hill and around the Reagan administration, that's good news.

But while the administration is promoting agricultural sales abroad, it is cutting back the long-standing Food for Peace program, which helps developing countries buy the same farm products through low-interest loans. And for millions of starving and malnourished people around the world, as well as their advocates in this country, that's bad news.

Meanwhile, there's another unsettling question in the minds of many food experts: is it wise for the United States to direct its farm policy toward expansion of markets when American land is already being worked at full capacity, demanding heavy use of energy and fertilizer?

In three days of House Agriculture Committee hearings late last month on global hunger and the effect of U.S. policy on the problem, some of the country's best-known food and feeding experts testified -- among them scientist Norman Borlaug, Tufts University president and nutritionist Jean Mayer, Lester Brown of Worldwatch Institute and writer Frances Moore Lappe. But few House members heard them. Most were attending budget reconciliation meetings, debating how deeply federal spending on farm programs should be slashed.

The irony did not escape Rep. Dan Glickman (D-Kan.). Apologizing to Mayer for the committee's distraction down the hall, he said: "We are deciding how much we are going to cut the agricultural support programs . . . but if U.S. farmers can't make it, the world is in terrible trouble."

In a way, it was as if the Congress and its witnesses were on different wavelengths. Throughout the hearings, the witnesses repeated a similar theme --that the administration's emphasis on expanded U.S. farm exports runs counter to a greater need for helping developing nations build their own agricultural bases.

Spokesmen for Save the Children Foundation, CARE, the Mennonite Central Committee and other private voluntary groups that assist with feeding programs around the world stressed that idea. "We feel the best contribution you can make is go into a community or village and teach people to grow their own food," said Ernest Grigg, executive vice president of Save the Children.

"People need to have access to land, credit, improved seed, fertilizers, insecticides, technical assistance, a reliable market and, most of all, assurances that they will reap a reasonable return for their effort," said Edgar Stoesz of the Mennonite committee.

For all its vaunted efficiency and abundance, many experts say, American agriculture is reaching the outer limits of its ability to produce and the era of major surpluses is over.

A common belief is that only the American farmer stands between massive starvation and a well-fed, more orderly world. There is some truth to that, but in fact most of the American farmer's production goes to countries that least need the help-- that is, to countries that can pay for their imports.

With hunger or malnutrition affecting an estimated fourth of the world's 4.5 billion people, and with global population expected to grow at least another 1 billion by the year 2000, it appears increasingly clear that U.S. farms will not be the salvation.

Through these sessions, that theme kept echoing. Variations of the theme included questions such as these:

Should U.S. soil, water and energy continue to be expended on growing of more farm commodities that sell at less than the cost of production?

Does the U.S. policy of promoting farm sales abroad actually discourage developing nations from building their own agricultural base?

Is it prudent for the United States, now sending 40 percent of its harvest abroad, to continue to supply the world with grain that is used in large part to produce meat rather than in direct human consumption?

Will intensified exports, relying on large-scale production techniques and high-cost machinery, drive more nails in the coffin of the diminishing American family farm?

The answers in large part will have to be provided by Congress, although the pending 1981 farm bills do not confront the questions. Paradoxically, perhaps, Agriculture Secretary John R. Block, a leading advocate of the administration's more-exports line, recognized in his testimony some of these questions, cautioning that food-poor nations must take more responsibility in developing their agricultural systems.

"The burden in the end lies with the governments of the food-deficit developing countries," Block said. "It is up to them to make the tough decisions necessary to meet the goal of greater food self-reliance -- to be able to grow or trade for the needs of their individual countries."

He told Rep. Frederick W. Richmond (D-N.Y.) that "the United States alone cannot begin to meet the world's demands for food; others will have to increase their production capacity . . . and we will have to see higher prices for our own commodities. When prices are higher, people figure out how to do it raise their own food ."

But Mayer, among others, complained that U.S. policy is not sufficiently directed toward stimulating low-income countries to build their own farm base. And, he and other witnesses added, it is time that Congress and the administration begin to pay more attention to the American farm base.

"This committee needs to make more of an effort to see that the public understands better how the 3 percent of our population on farms is living," Mayer said. "We are reaching a danger level in the number of people practicing our major industry. . . . The income of our farmers has to be sustained and we have to have more farmers than we need at the minimum. We have to give more glamour to agriculture because we are now bucking 2,000 years of depreciation of agriculture."

Mayer added, "This committee has a chance to play a unique role in developing a major component in foreign policy -- a new North-South policy for agriculture and food."

The message didn't get very far. As he spoke, the committee room was nearly empty.