Africa's famine worsening despite aid. Coup leader in Mauritania faces war and drought

The sand-blown streets of Nouakchott, capital of the West African state of Mauritania, are reported calm after last Wednesday's military coup. But the conditions that made the nation ripe for a coup - dissension over the war in the neighboring Western Sahara, worsening economic difficulties, and devastating drought - are expected to remain troublesome. Government corruption, much of it over distribution of food aid, was also a factor leading to the military takeover.

The nation's new leader, Lt. Col. Maouya Ould Sidi Ahmed Taya, is widely perceived to be more moderate than the president he ousted, and he enjoys a rare reputation for honesty among Mauritanian leaders.

But it is difficult to gauge how much these traits will help his government come to grips with the drought that is devastating Mauritania's agriculture and threatening its livestock industry. The country - some 420,000 square miles in area with about 1.6 million inhabitants - is largely an empty desert. Its economic situation is so serious that some analysts have written off the country as neither ''savable nor solvable.''

International recession has depressed world demand for iron ore, which normally provides some 75 percent of the country's export earnings. Drought has forced thousands of nomads to seek refuge in towns. The population of Nouakchott has swollen to an estimated 50,000, twice the planned size.

Many analysts say Mauritania will need major support from Western aid donors and more political stability if its economy is to survive.

It is in the area of stability and moderation that Lieutenant Colonel Taya may make most headway, analysts say. The man he ousted - President Muhammad Khouna Ould Haidalla - was criticized by some Mauritanian military figures as too sympathetic toward the Polisario rebels who are fighting Morocco for control of the Western Sahara.

Taya is seen by observers as an advocate of a more balanced approach toward the conflict between Morocco and the Algeria-backed Polisario. Former President Haidalla, who was born in the Western Sahara, broke diplomatic relations with Morocco in 1981 after Morocco's alleged involvement in an abortive coup in which eight people were killed.

Then last February he decided to recognize the Polisario's shadow government over the Western Sahara, the Saharan Arab Democratic Republic (SADR). The move was highly controversial and caused a major reshuffle in the ruling Military Committee for National Salvation. Among those to go was Colonel Taya, who at the time was prime minister as well as Army chief. Taya was allowed to keep his Army position, mainly because he is popular with troops and other officers.

Taya, like Haidalla, is from northern Mauritania. But because Taya comes from a minority tribe, he is seen by many as better able to establish a tribal balance. He is also seen as one of the few northern Moorish leaders acceptable to the black African tribes in the south.

At the time he was ousted, Haidalla was in Burundi attending a Franco-African summit. Nouakchott radio later explained that the bloodless coup had been organized to prevent Haidalla from amassing too much personal power and in order to raise moral standards.

Many will be watching Taya to see if he is able to clean up corruption. Corruption in the mining and fishing industries and in the distribution of food aid has reached unprecedented levels, observers say.

Mauritania receives over 100,000 tons a year of food aid, and control over its distribution has become an important means of amassing wealth and political power.

Ousted President Haidalla, who had ruled the country for nearly five years, had survived three previous coup attempts. The country has experience growing political instability since the military deposed President Moktar Ould Daddah in 1978. Mr. Ould Daddah had ruled since independence from France in 1960.

The military said it intervened at that time to end the war in the Western Sahara and to try to resurrect the economy. It also promised to restore democracy as soon as possible.

The war has continued in the Western Sahara despite attempts to end it and this caused continued disruption of Mauritanian politics. This instability has delayed the country's return to civilian rule.

Prolonged drought has devastated agricultural production. Food output is expected to total only 15,000 tons in 1984 against 60,000 tons in a normal year. The government has appealed for nearly 200,000 tons of food aid.

The capital city itself is threatened by the advancing desert. Sand dunes are on the point of engulfing the capital and a 12-mile-long by half-mile-wide ''green belt'' of trees and shrubs is being planted to hold them back.

But experts say that the growing desertification is caused more by overgrazing, overcultivation, and deforestation than by lack of rain.

Mauritania has some of the world's richest fishing waters, but they have brought the country comparatively little benefit. Illegal fishing by Soviet, Spanish, and other foreign fleets deprive Mauritania of several hundred million dollars of revenue annually.