Agriculture Secretary Richard E. Lyng, responding to a wave of complaints about race and sex discrimination in USDA programs, has warned the department's top officials that they will be held responsible for violations of equal rights requirements.

"Do not take this matter lightly," the secretary told officials and agency heads this week. "I expect you to assume personal responsibility and accountability . . . . I expect you to correct any program or management practice that results in inequitable treatment."

Lyng also announced the appointment of Peter C. Myers, the new deputy secretary, as his civil rights monitor and chief enforcer. He said Myers' first report and recommendations for action are due in 60 days.

Lyng said his strongly worded statement was "stimulated" by recent charges, from inside and outside the department, about discriminatory practices at USDA. At least two congressional subcommittees are investigating various allegations.

"I will not tolerate discrimination in any form, and I expect you to make equality of opportunity and respect for civil rights an integral part of all decisions and processes affecting your work force and programs," Lyng said.

"You have an obligation to assume and maintain direct and personal responsibility for the way the work force and program constituents are treated. Unless you do this, you place the credibility and integrity of this department at risk."

Civil rights and affirmative action programs at USDA, the subject of previous congressional inquiries, have been in turmoil since 1982, when the department's civil rights overseer was fired for proposing the dismantling of equal rights protections as a centerpiece of the Reagan administration's "New Federalism."

Recent criticism has focused on personnel practices in the Animal and Plant Health Inspection Service and the Extension Service here, and the Soil Conservation Service in Arkansas, where discrimination complaints have led USDA to launch a full-scale review of its major agencies in the state.

Lyng told his managers that he expected them "to communicate, educate and train all managers and supervisors on their critical performance requirements in this area. I want civil rights clearly reflected in the performance decisions you make regarding their future employment with this department."

Lyng said that all officials should "immediately" review the needs of the civil rights staffs in their agencies and told them "to mandate that their counsel and advice be accepted and acted upon. I will not condone harassment, reprisals or violations of the spirit or intent of the law."

The secretary also reaffirmed the role of USDA's personnel office and its Office of Advocacy and Enterprise (OAE) in monitoring civil rights, equal opportunity and personnel policies.