A blue-ribbon committee of U.S. foreign-policy specialists yesterday proposed a new, long-term development strategy toward economically depressed black Africa. It calls for tripling U.S. aid to $3 billion annually and a new emphasis on African agriculture.

Led by former high-ranking State Department officials Lawrence S. Eagleburger and Donald F. McHenry, the panel issued a report proposing creation of a "Compact for African Development" involving a far larger U.S. aid commitment in return for a pledge from African governments to begin implementing long overdue economic reforms.

The report asserts that Africa is suffering from "an extraordinary crisis. Its proportions are mythic, its severity almost impossible for the rest of the world to imagine or comprehend."

Though the causes of the crisis are "many and varied," it said, "something more must be done urgently unless the cycle of catastrophe is to be repeated . . . with the bulk of African and outside energies spent on staving off disaster rather than building for the future."

A $300,000 joint project of the New York-based Council on Foreign Relations and the Overseas Development Council, the report lists 12 proposals for a U.S.-led strategy aimed at making sub-Saharan African states economically viable.

Eagleburger admitted that, given pressure to cut spending to reduce the federal budget deficit, it would take "a lot of hard work" to persuade the Reagan administration and Congress to triple aid to sub-Saharan Africa. "I'm not absolutely confident we'll get it," he said.

He and McHenry insisted that now is the time to boost aid, tied to reform, and cited increased willingness of African leaders to deal with economic problems and take unpopular steps that have long been advocated by aid donors.

In addition to tripling U.S. aid, one proposal calls for using U.S. food to pay for development projects. Another advocates that longer term food-aid programs be offered to African nations that have agreed to policy reforms and increased investment to boost agricultural production.

Others deal with the $100 billion sub-Saharan African debt burden and some governments' inability even to service their debt. The report seeks African reaffirmation of responsibility for that debt in return for a U.S. offer to extend the U.S. share of it over a longer period.

Another option would be for the U.S. government to accept repayment in local currencies that would be used to finance development projects, the report said.

The report notes that Africa's population could approach 1 billion by the year 2000 and that many African states regard population control as "a priority concern" in their need to feed themselves.

It asks the U.S. government to restore recent funding cuts to the International Planned Parenthood Federation and the U.N. Fund for Population Activities and to work with them to institute a major population program in every country where a bilateral U.S. aid program exists.