San Salvador — In the coming year, El Salvador can expect to see continued fighting, little chance of a negotiated settlement, and an ever more critical battle over the country's economy.
This seems to be the consensus among a wide range of experts, both Salvadorean and foreign, both military and civilian.
In the year now ending, the leftist-led guerrilla forces showed considerable strength, but far from enough to win the war.
During the same period, according to experts on the subject here, the American-supported Salvadorean Army showed some small signs of improving its performance. But the progress has been slow. Of critical importance in the coming year will be an improvement in the Army's ability to protect vital communications and economic installations.
In order to do this, military observers say, the Army will have to abandon what is described as its ''herd instinct'' - an inclination to launch safe but ineffective large-scale sweeps - and begin to engage in more small-unit tactics.
Ideally, small patrols would be constantly on the move, keeping the guerrillas off balance and providing early warning of their movements. This is the approach that American military trainers have consistently urged. They are said to believe that without it, the guerrillas' sabotage operations against the country's economy could intensify.
''We're worried about the economy,'' said one military observer, speaking of the need for some Army officers to adopt a more positive attitude toward small-unit tactics. ''The question is: Can the economy hang on long enough for that attitude to pervade the military?''
Despite Army efforts aimed at countering sabotage, the guerrillas have blown up dozens of bridges, fuel trucks, railroad locomotives, and electrical transmission towers. They have destroyed nearly a quarter - about 700 - of the country's buses.
In recent weeks, the insurgents also have destroyed tens of thousands of dollars' worth of coffee being carried by truck from the current harvest. In one area, according to a US official, guerrillas have killed four of the coffee truck drivers.
The insurgents also have kept insecticide-spraying airplanes grounded. One pilot decided to stop flying after the guerrillas put eight bullet holes in his plane. This has been particularly hard on the production of cotton, which requires repeated spraying.
Guerrilla attacks on electrical installations have in some cases drastically cut the operations of cotton-drying machines. In one case, the guerrillas blew up a bridge, and thus prevented cotton farmers from moving their product to a refinery. The city of San Miguel, in the eastern part of the country, was without electricity for about half of 1982.
American economic aid to El Salvador, which came to more than $230 million in 1982, can only partially offset the damage from sabotage. Part of the aid goes to overcoming balance-of-payments deficits.
In October of this year, the guerrillas launched a new military offensive, and have tended to hold the battlefield initiative since then.
As seen from here, the aims of the October offensive seemed to be fairly clear: to show that the guerrillas can take and hold towns; to inflict casualties on the Army; to capture weapons; and to draw government troops into major operations, thus leaving economic targets more vulnerable to sabotage.
In some cases this year, however, the guerrillas were not interested so much in taking and holding a town as they were in ambushing the government forces sent to retake the town. This was the case last June when the guerrillas took Perquin and then struck hard at the government reinforcements.
According to a recent interview with one guerrilla chief, Joaquin Villalobos, ''It was not important to us whether we held or did not hold Perquin. . . . Our principal idea was to put the stress on encircling the enemy reinforcements. . . . The fundamental problem was to manage to annihilate an important unit of the Army while it was in movement.''
On this occasion, the guerrillas succeeded in inflicting severe casualties on the Army; took more than 40 prisoners, including a vice-minister of defense; and captured numerous weapons, including light artillery pieces.
In the interview, which was published in December, Villalobos said that in order to defeat the Army it was not necessary to wipe out all of its soldiers or to capture all of its arms, but to bring about a collapse in the morale of the Army. The guerrilla chief said that in the October campaign the guerrillas aimed at (1) destroying strategic points held by the Army, when possible; (2) sabotaging means of transportation, electrical energy, and the communications system; and (3) continuing to harass and ambush the Army.
One of the problems confronting Salvadorean Defense Minister Jose Guillermo Garcia, is a need to keep a certain number of military commanders in place because of their political loyalties. Some of those who are most loyal politically are the least competent militarily. Mr. Garcia, who is said to have presidential ambitions, faces a challenge from Roberto d'Aubuisson, president of the National Constitutional Assembly and a former National Guard officer who is regarded as a representative of the extreme right in politics, economics, and military affairs.
Younger officers complain about corrupt and incompetent senior officers. But General Garcia seems to feel the need to protect his political flanks. A few months ago, San Salvador was full of rumors about a possible d'Aubuisson-sponsored coup against Garcia and his allies, including President Alvaro Alfredo Magana. Recently, however, Salvadoreans have felt that Mr. d'Aubuisson was losing influence.
In one case where Garcia gave an aggressive military commander considerable authority, it seemed to make a difference. Col. Jaime Ernesto Flores, a stubby brigade commander placed in charge of military operations in the eastern part of the country, has been pursuing the kind of small-unit actions that the American trainers have advocated. As a result, Colonel Flores appears to be hurting the guerrillas more than some of his military colleagues are elsewhere in the country.
The guerrillas have been learning from experience as well. Over the past year , they have trapped the Army in several successful ambushes. In their October offensive, they captured as many as 400 automatic rifles from the Army.
Military observers say, meanwhile, that the Army and security forces in neighboring Honduras have become more effective at blocking supplies sent through that country to the Salvadorean guerrillas from Nicaragua. The small Salvadorean Navy attempts to block the sea route. But, the observers say, more supplies are now coming in by way of small fixed-wing aircraft as well as helicopters. The pilots are reported to prefer flying on moonlit nights. The aircraft carry explosives, medicines, and radio equipment.