Civil rights specialists at the U.S. Department of Agriculture have begun a review of a plan drawn up by a USDA agency to bring its equal-opportunity and affirmative-action programs into compliance with the law over the next three years.

The plan was submitted this week, almost two months overdue, by the Animal and Plant Health Inspection Service (APHIS) in response to a demand by the USDA's civil rights oversight office. The office uncovered deficiencies in equal rights protections at APHIS last fall.

The failure of APHIS to respond quickly to the oversight review during the winter prompted Rep. Don Edwards (D-Calif.) to announce that his House Judiciary subcommittee on civil and constitutional rights intended to conduct an investigation of the situation at APHIS.

Edwards' interest was piqued when a fight between APHIS and the civil rights enforcement office headed by Lawrence Bembry became public last month. Bembry said yesterday that he could not comment on the APHIS response until his office has reviewed it completely.

In other developments related to the dispute:

*Officials of the Federal Grain Inspection Service (FGIS) said that as a result of a review by Bembry's office they have abandoned a rule that allowed supervisors to receive "satisfactory" performance ratings if they had been found guilty of no more than three discrimination complaints.

The rule, which had been in effect at least since 1981, stirred a tempest among FGIS employes who complained that it officially sanctioned illegal discriminatory practices. Sources said the rule was applied in at least one case involv- ing an FGIS supervisor in New Orleans.

*Vertis Stovall Jr., an APHIS employe who participated in the review of his office by Bembry's team, was told this week that he will be cut from the agency's payroll at the end of next week. Stovall was charged with copying information from a commercial publication and representing it as his own.

Stovall denied the allegation and accused APHIS officials of retaliating against him for his role in the civil rights review. Stovall withdrew a forced resignation letter in February and was then put on administrative leave with pay and ordered to remain by his home phone during the day.

Stovall said that he plans to appeal his firing to the Merit Systems Protection Board.

*In an apparent effort to prevent leaks to the press, between 40 and 60 workers in the APHIS personnel division, mainly in its civil rights oversight office, have been required to sign unusual, vaguely worded "confidentiality certificates" in which they pledge to release no information without the approval of George Robertson, head of the division.

The certificates say, in part: "I understand the material and evidence entrusted to me either orally or in writing for investigation and/or processing is for OFFICIAL USE ONLY. I will not release its contents, either verbally or in writing, to any unauthorized individual unless specific permission is granted by the director . . . . "

Larry B. Slagle, deputy administrator of APHIS for management and budget, said that he and Robertson adopted the new procedure because of "a breach of some files." Slagle would not discuss the breach but he said it was intended to cov- er instances such as the Stovall case, in which file data became public.

"We ought to do this routinely with personnel people," Slagle said. "They often tend to talk too much . . . . This is not a denial of free expression."