Two weeks ago, the first four pages of this capital's only morning newspaper were taken up with pictures of Nicaraguan President Anastasio Somoza receiving the credentials of several new ambassadors.

The president owns the newspaper.

When Nicaragua's economy was devastated by a 1972 earthquake, one of the local companies that prospered during reconstruction, which was financed by hundreds of millions of outside aid dollars, was the country's one and only cement plant.

The president owns the cement plant.

These two not particularly isolated examples illustrate a basic truth in Nicaragua - that most significant events here end up contributing to the personal, or political gain of President Somoza.

Perhaps more than any other leader in a part of the world known for governments that successfully mix business with iron-fisted political power, Somoza controls a one-man empire.

In addition to the presidency, Somoza heads the Nicaraguan National Guard, the country's only armed military and police force.For more than 40 years, these two offices have, except for a new brief intervals been held by Somoza or his father or his brother.

As head of Nicaragua's majority political party Somoza, according to imformed sources here, appoints virtually every local public official and judge, elected or not.

The president's private business holdings are estimated at more than 100 companies, and while he is not the only rich man in Nicaragua, and may not have a direct hand in every sector of the economy, Somoza is believed to be the richest individual Nicaraguan.

Besides the newspaper and cement plant, Somoza controls or owns the contry's national airline, radio and television stations, a bank, and a textile firm.

Somoza interests run the Nicaragun Mercedes-Benz distributorship, freight transportation and shipping companies, farms and cattle ranches, meat packers, sugar and salt production facilities and a construction firm, along with controlling large tracts of real estate.

So pervasive is Somoza's hold over the National Guard and the economy that sources say he may not mind giving up the presidency when his term expires at the end of the decade. Somoza's presidential duties, the sources say, are beginning to interfere with his other activities.

While opposition leaders charge widespread corruption in the Somoza regime, Somoza partisans says that the president has managed to separate his various jobs.

"Nobody can claim that the government under Somoza, ever tried to mingle with business," said presidential aide Gen. Roger Bermudez.

Bermudez noted that all corporate ownership documents are public records in Nicaragua, and that any cursory check would show that the extent of Somoza control is small. Very few of those corporations, however, are listed under Somoza's name.

In any case, Bermudez said, "the president was born a rich man."

The staggering number of opportunities for Somoza to have conflicts of interest, however has made the State Department nervous about the United States' continuing strong association with Nicaragua. Allegations by international human rights organizations that the National Guard, under Somoza, has been responsible for inhuman treatment, illegal imprisonment and possible murder of several hundred Nicaraguan peasants over the past few years have added to the concern.

While few charge direct U.S. payments into Somoza's pocket, the extent of the president's private business holdings, according to one U.S. official, "makes it impossible for Somoza not to personally benefit from nearly every U.S. assistance program in Nicaragua.

In 1976, U.S. economic aid to Nicaragua, through bilateral and multialteral loans and grants, reached more than $100 million.

Although it has threatened to cut off all military and economic assistance to Somoza because of his human rights problems, the Carter administration may find it difficult to actually sever what for more than 60 years has been a "special" relationship between the governments began in 1914, when Nicaragua signed a treaty giving the United States a 99-year option to build a transoceanic canal through the country. That treaty, designed to protect U.S. control of the isthmus and shipping in the event of possible trouble in Panama, was abrogated during the Nixon administration.

The treaty set a precedent, however, for Nicaraguan political support of U.S. interests, making Nicaragua the United States' most dependable Central American ally. It also began a compensatory pattern of U.S. financial and military support for Nicaragua.

The unspoken agreement has paid off in many ways for U.S. policy, including the use of Nicaraguan shores to launch the 1961 Bay of Pigs invasion.

In 1912, two years before the signing of the canal option treaty. U.S. Marines began a 21-year occupation here - an ostensible attempt to insure political stability.

By the time the Marines left, they had insured a form of stability that has lasted until the present. With U.S. money and arms, they created and trained perhaps the most powerful military force in Central America - the Nicaraguan National Guard.

Installed as its commander was Anastasio Somoza, the father of the current president. Since then, virtualy every officer in the 7,500-man force that serves as both army and police here has been trained by the U.S. military - either at the Southern Command headquarters in Panama or in the United States.

Nicaragua, U.S. officals said, is the only country in the world where this is the case. Today, one National Guard general said proudly, in perfect English, no officeer is promoted without such U.S. training.

The national guard, which is still equipped almost entirely with U.S. weapons at a cost of $32 million in credits loans and grants over the past six years is considered here to be Somoza's personal army, and informed sources here say its loyalty to him is absolute.

"Somoza personally makes all the decisions on promotions," said one source. "If one of them gets sick, he needs a loan, he gets it from Somoza."

Recent attempts in Congress to bar Nicaragua from U.S. military assistance because of alleged human rights abuses by the guard have failed because of a combination of administration opposition and in some instances, support maintains with U.S. officials.

Such personal ties have been Somoza's salvation at several points when U.S. opposition to his government has grown.

According to Rep. Edward I. Koch (D.N.Y.), an ardent Somoza foe, former ambassador to Nicaragua James Theberge visited him personally shortly before a crucial House vote on military aid and assured Koch that "systematic violations of human rights were not occuring in Nicaragua."

Theberge's predecessor was Turner Shelton, whose friendship with Somoza is commemorated on one denomination of Nicaragua's currency with a picture of the two taken during ceremonies canceling the canal treaty.

But what are perhaps Somoza's best U.S. friendships were forged at West Point, where he graduated in the clans fo 1946. Somoza's West Point roommate, according to press aide Gen. Bermudez, was Jack Marnly currently a Democratic Congressman from NEW YORK.

Murphy, who Bermudez said has been to Nicaragua "at least 100 times" and stays at Somoza's house, helped lead last June's floor fight in the House that kept U.S. military assistance from being killed.

"What's wrong with Somoza's friends helping him?" Bermudez asked. On his desk was a roster of the West Point Class of '46 used, Bermudez said, "so that the president can kept track" of his classmates.