The five-month-old boycott by black students of South Africa's secondary schools appears to have ended this week after student leaders called for return to classes.

Although the government has not met black students' demands for fundamental changes in their educational system, boycott organizers reversed their earlier calls for students to stay away from classes when the school opened for the new year last Wednesday.

In the black township of Soweto near here, where 27,000 secondary students began the boycott last August, officials reported that schools were receiving increasing number of applications.

The Soweto protest had quickly spread to primary schools and to other urban black areas eventually involving more than 20,000 children.

The Soweto Students League, after urging students to return to classes, said this week that its opposition to the government's educational system for the blacks was not ended.

Three factors seem to have influenced the students to end their boycott.

There has been pressure on student leaders by many children who want to continue their educations. Thousands of students have missed almost two years of schooling because of sporadic unrest, riots and the boycott.

Sources close to the students also say that student leaders are hoping that the daily contact at school will help reorganize and revitalize the student movement, which has fallen into disarray and confusion since the boycott and the Oct. 19 government crackdown on dissenters that put many of their leaders into jail.

Finally, Soweto students and their parents were greatly influenced by Zulu Chief Gatsha Buthelezi who last Sunday called on students to end their boycott saying. "There is a time in any struggle when the best form of attack is retreat."

The students were protesting what they see as the poor quality of teaching and the inadequate funding of black education by the white minority government. They also demanded that the black educational system be merged with that of white children.

In response, the governmentpromised to upgrade the quality of teachers and to close the gap between spending on white education and black educations.

It has not, however, set a time table for closing this gap as black students and teachers have been demanding. The government also refused to merge the two systems.