The United Nations Food and Agriculture Organization today received pledges of food and financial aid from the United States and eight other countries after making an urgent appeal for emergency help for 26 African nations facing abnormal food shortages.

FAO Director General Edouard Saouma had called what FAO officials termed an "unprecedented" meeting of donor countries and international organizations because of the critical food situation in many African countries.

Saouma told the representatives of 28 countries today that 2.4 million tons of grains are needed for rest of 1980 and 1981 if widespread famine in more than two dozen countries of sub-Saharan Africa is to be averted. The situation is "very bad, very dramatic" he said Tuesday.

His appeal brought concrete pledges of assistance from the United States and eight other countries. U.S. Agency for International Development Administrator Douglas Bennett, who headed the American delegation, announced that U.S. food aid to Africa would be increased to 1.34 million tons, worth $425 million for fiscal year 1980-81 from 830,000 tons allocated for the current fiscal year ending Sept. 30.

Eight other countries, including Denmark, Norway, the Netherlands, Australia, West Germany, Switzerland and France, also promised special contributions in cash or grain. Algeria pledged $300,000 for African relief and another $500,000 for the international emergency food reserve, it becomes the first member of the Organization of Petroleum Exporting Countries to participate in a multilateral food program.

The current food shortages in Africa, which Saouma said made the delivery of 550,000 tons of grain over the next three months essential, are partly the result of production shortfalls that followed the 1979 drought.These were compounded by new droughts in some areas this year.

In addition, fighting or social upheaval has generated a large influx of refugees in many of the affected countries that has strained domestic food supplies and disrupted normal farming activities and transport. At the same time, balance of payments difficulties in most African countries mean they are unable to increase commercial food imports.

Since 1979 food aid worth $200 million a year has been pouring into Cambodia, compared with the 150 million people of sub-Saharan Africa. At a meeting with reporters earlier this week Garson Vogel, head of the World Food Program, said that Vietnam's 350,000 boat people had received far more attention than the refugees in Africa, who now number 1 million in the Sudan alone.