South Africa's black 'homelands' sink deeper into poverty, instability

South Africa's ''homelands'' policy is backfiring. These tribal territories established by Pretoria to isolate blacks from ''white'' South Africa are becoming pockets of economic and political instability.

The latest turmoil has erupted in the Ciskei, the most recent so-called homeland to be granted ''independence'' by Pretoria. Over the past week that desperately poor territory has witnessed a convulsive power struggle that resulted in a dozen top officials being detained, including the commander general of state security, Charles Sebe, brother of Ciskei President Lennox Sebe.

The turmoil will not gain much attention internationally, since these independent homelands are not recognized by any other country in the world.

The significance of the upheaval is as an indicator of how far awry South Africa's homelands policy has gone from its original intention. South Africa's white minority government once forecast that by the late 1970s this country's black majority would be streaming back to these mostly rural territories, drawn by the economic prosperity and political sovereignty offered in the homelands.

The reality is quite different. These homelands have for the most part become economic disaster areas. The exception may be Bophuthatswana, which is reasonably prosperous and is stable.

But the plight of inhabitants of most homelands is vividly clear, with malnutrition and a threat of starvation rising during the current recession and drought in southern Africa.

Rather than streaming to the homelands, huge numbers of blacks have been forced into the destitute territories by Pretoria. Some 3.5 million forced removals have occurred since 1960, according to a recent report.

In addition to trouble in Ciskei, Pretoria cannot be happy with the drift of events in some of the other homelands.

In a rebuke to the government, the leader of the first homeland to take independence, the Transkei, joined with five other homeland leaders in a pledge to work for the establishment of a ''greater South Africa.'' It was a marked switch in attitude by Transkei Chief Kaiser Matanzima and one that runs counter to Pretoria's aim of partitioning South Africa in a way that would ultimately deprive all blacks of South African citizenship.

South African law has made all blacks citizens of 1 of the 10 homelands. And when these territories take ''independence,'' as four have, all the blacks associated with the homeland, whether they live there or not, lose citizenship rights in South Africa. More than 8 million blacks have lost citizenship this way.

In another homeland development, the gulf between Pretoria and KwaZulu Chief Gatsha Buthelezi is widening. Buthelezi is regarded as one of the few black politicians still moderate enough to deal with the white-minority government while retaining black respect. But his growing ire at Pretoria has led him to refuse to participate in coming elections in some black townships. His participation would have given some credibility to the local councils, regarded as puppet bodies by many blacks.

Ciskei, an impoverished region on the Indian Ocean, became ''independent'' in 1981 and was regarded as ''least likely to succeed.'' It has lived up to that billing. Most of its 669,000 inhabitants live hand to mouth.

President Sebe and his brother have ruled with an iron fist. The government has repeatedly harassed black trade union officials.

Ciskei authorities have frequently clashed with students at Fort Hare University. The university is in Ciskei, although many of its students reject the territory's legitimacy. Last year a motorcade of Ciskei ministers attending graduation was attacked by students.

Security chief Sebe projected a dangerous but, some say, a comical image. In his bemedaled uniform he ranted about his battle against communism and detained scores of people to that end. His departure will no doubt be welcomed by many in Ciskei.

The nature of the power struggle in Ciskei is unclear. But last week President Sebe hurriedly returned from overseas and announced a restructuring of the security apparatus.

South Africa evidently played a role in the security clampdown, although Pretoria has denied this. On-the-scene reports say white officials in cars with South African license plates were present during security operations in the territory.