Sen. Harry F. Byrd Jr. (I-Va.) said in a Senate speech yesterday that he will oppose ratification of SALT II because its implementation would "confirm Russia's strategic superiority" over the United States.

The independent, senior senator from Virginia thus became the first of the area's senators to announce a position on the pact.

All four area senators are members of committee that are conducting hearing on the treaty. Byrd and Sen. John W. Warner (R-Va.) serve on the Senate Armed Services Committee; Sen. Paul S. Sarbanes (D-Md.) is on the Senate Foreign Relations Committee, and Sen. Charles McC. Mathias (R-Md.) is a member of the Senate Intelligence Committee.

Sabanes, Mathias and Warner said yesterday that they plan to withhold judgment on the treaty at least until current hearings end.

Byrd said he asked himself the question, "Does approval of SALT II enhance the security of the United States and our free allies? . . . In my judgment, it does not."

Since the signing of SALT I seven years ago, Byrd said, "Russia has achieved a massive military buildup in both conventional and neclear weapons" while the United States is "much weaker."

The white-hired conservative, who won reelection as an independant but votes with Democrats when they organize the Senate, told his colleagues, "Frankly, I do not trust the Soviet leadership."

Byrd said his distrust of the Soviets dates back to 1939, when "as a young newspaper editor" he remembers the signing of a Soviet-Nazi pack and that "the Russians attacked an almost defenseless Finland." Adding to his distrust were the Soviet blockade of Berlin, the crushing of the Hugarian uprising in 1956 and Soviet tanks entering Czechoslovakia in 1968, Byrd said.

Among 14 reasons Byrd cited for opposing ratification was the fact that American foreign policy "rules out a first strike." That means that the United States must have the power to survive a Soviet nuclear assault and then retaliate.But under SALT II, American would have both fewer weapons and fewer survivable ones than the Soviets, as Byrd reads the agreement.

While Warner said he would wait until he has heard all of the testimony, he agreed with Byrd that "American can never enter into any agreement with the Soviet Union that is based on trust."

Therefore, Warner has said in speeches about SALT, the key to his spport is being convinced that the United States will have the ability to verify that the Soviets are living up to the agreement.

Again like Byrd, Warner said he "resented the statement by President Carter that the Senate should not amend the treaty -- that we should take it or leave it."

Mathias said he hopes to be able to support the treaty, and was encouraged by recent testimony that the United States would be "no worse off" by signing the treaty. Mathias said he would rely heavily on testimony scheduled to be given today by former secretary of state Henry Kissinger to the Foreign Relations Committee.

Sarbanes, who serves on that committee, has given little indication of his leanings in questions he has posed in recent weeks. As he did with the Panama Canal last year, Sarbanes is likely to wait until all testimony has been offered before taking a stand, an aide said.