The nine-week sabotage trial of six white Air Force officers ended today with the defense calling for acquittal on grounds that the defendants had been tortured into making false confessions.

Judge Enoch Dumbutshena said he will render a verdict late next month.

The officers are accused of participating in the destruction of 13 aircraft--about one-quarter of the planes in the Zimbabwean Air Force--last July 25. The charges and allegations of torture have reopened racial wounds in this black-ruled southern African nation.

The alleged mistreatment of the officers, including Air Vice Marshal Hugh Slatter, the former second-in-command of the Air Force, has shattered the morale of white officers, many of whom have resigned, and has greatly lessened the Air Force's effectiveness.

As a result of the exodus, the Air Force is now in fact commanded by a Pakistani, acting Air Marshal Azin Daudpota, although the government has not announced the appointment. There no longer are enough pilots and mechanics to fly and maintain all the aircraft, and the government has had to bring in trainers and technicians from Pakistan.

The crux of the sabotage case is the defendants' contention that they were tortured. If Judge Dumbutshena throws out the confessions and the men are acquitted, as expected, the government will have to decide whether to rearrest the officers under emergency regulations. as it has done with other acquitted defendants.

"If Zimbabwe gets a reputation for torturing prisoners and then detaining them after acquittal, the government will find it difficult to get what it wants" out of some Western benefactors, a diplomat said.

The case has been closely followed in Britain, especially since three of the six defendants have dual British-Zimbabwean citizenship.

British Prime Minister Margaret Thatcher discussed the case with Zimbabwean Prime Minister Robert Mugabe in London last month and reportedly made it clear she hopes the government will abide by the court ruling.

Several members of Congress have voiced concern about the case. Three senators wrote to Mugabe about it last year.

The United States and Britain are the two principal sources of foreign aid to Zimbabwe. They have provided $400 million in assistance since 1980.

Funds have been raised in the United States and Britain to help pay for the defense, the cost of which is now estimated at $150,000--a staggering amount in this country. The chief defense counsel is British attorney Harry Ognall, who in 1981 prosecuted Peter Sutcliffe, the so-called "Yorkshire Ripper" accused of 13 murders.

In summing up the nine-week court proceeding, the longest trial in Zimbabwe's history, Ognall charged that "the trial has revealed abuse of the state's investigative processes on a grand scale."

"The conduct of the interrogators," he said, "involved protracted and wholly unscrupulous violations of the defendants' legal rights and we submit that this has been backed up in this court by dishonest evidence from the police."

During the trial the defendants testified that they had been subjected to electric shock, beatings and deprivation of sleep.

Ognall said the confessions "don't bear scrutiny; they are false and these are innocent men."

Legal experts generally agree that the government has no case without the confessions.

Government officials, speaking privately, acknowledge that it is unlikely that the men will be convicted, but say the purpose of prosecuting the widely covered case has been to demonstrate to Zimbabweans the seriousness of the threat from neighboring white-ruled South Africa.

The case stems from the destruction of 13 planes at the Thornhill Air Force Base in central Zimbabwe. Damage was estimated at more than $7 million. The government does not charge that the six officers actually blew up the planes, but accuses them of helping three unidentified South African agents who cut through the security fence and placed explosives in 12 jet fighters and a light plane.

Prosecuting attorney Honour Mkushi said "there was nothing improbable" about the confessions of Slatter, 41, and his codefendants, Air Commodore Philip Pile, 43; Wing Commanders Peter Briscoe and John Robert Cox, both 36, and Lts. Barrington Lloyd, 31, and Neville Weir, 24. Mkushi accused them of permitting security at the base to run down to allow the sabotage.

"It is satisfactory for the court to determine that the accused assisted in the sabotage," he said. "It is not necessary to determine who actually perpetrated the sabotage."

In two major trials earlier this year the government used its emergency powers to rearrest defendants after they were set free.

Home Affairs Minister Herbert Ushewokunze called the white judges in the two cases "colonial hangovers," out of step with the government's policy of "building a new socialist order."

As a result of prosecutors' setbacks, some analysts fear that the government may seek to change the judicial system or may simply bypass the courts and detain opponents indefinitely, as permitted by the emergency regulations.

One reason the prosecution has lost so many cases is that many new policemen lack adequate training, an official said. Under pressure to make arrests and get convictions, they reportedly have tortured suspects.

Mugabe was known to be furious over the sabotage, one of several such incidents since independence. He was understood to have been stunned to learn of Slatter's arrest because Slatter was expected to be the next Air Force commander.

Many analysts noted that the country's enemies got a double benefit from the sabotage: the destruction of the planes and the virtual disintegration of the Air Force, a white bastion during the war because of racism and the lack of technical training for blacks. More than half the Air Force helicopters are grounded because of the shortage of mechanics. Six of the seven group captains, a rank equivalent to colonel in the Army, have resigned. The Thornhill base is now commanded by a Ghanaian.