The Treasury announced yesterday that because of the growing budget deficit the government will borrow $50.5 billion during the three months that end Sept. 30 and another $44- to $49 billion by the end of the year.

The $100 billion in federal borrowing would be the most the Treasury has ever had to raise during a six-month period, according to Assistant Secretary Beryl Sprinkel.

Economists, Wall Street officials and investors are worried that the heavy Treasury borrowing needed to finance the federal deficit will reverse the recent decline in interest rates. The high rates in turn could dampen the expected economic recovery and plunge the nation back into a recession, many experts fear.

But Federal Reserve Board Chairman Paul A. Volcker, testifying before the Senate Budget Committee yesterday, said he thinks the Treasury can borrow $100 billion during the final six months of 1982 without causing a sharp rise in interest rates or preventing the beginning of a moderate recovery.

Sprinkel, at a press conference, told reporters that if Treasury borrowings were smaller, interest rates would be lower, but that even with the big borrowings there "can be further progress on interest rates."

The prospect of higher than anticipated Treasury borrowings drove short-term interest rates up this week. During the first three weeks of July, short-term rates--such as those on Treasury bills and on bank certificates of deposit--declined dramatically. On bank certificates that generally are sold in denominations of $1 million or more, the average rates fell more than 3 1/2 percentage points.

The $50.5 billion the government will borrow during the current quarter is sharply higher than the $32- to $37 billion it estimated three months ago it would need. Sprinkel said the need to replenish the Treasury's cash coffers coupled with a "modest" shortfall in tax receipts and a "very modest" increase in spending forced the Treasury to revise its borrowing requirements.

He said the Treasury, as part of its regular quarterly refunding operations, will raise $6.7 billion of new cash next week--selling $6 billion of a three-year note Tuesday and $5 billion of a 9 3/4-year note Wednesday. With the $11 billion it raises, the Treasury will pay off $4.3 billion of maturing debt.

Sprinkel said the Treasury's revised borrowing estimates are "consistent" with the new budget projections the administration will announce Friday as part of its delayed mid-year economic review. The administration is expected to project a deficit of $114 billion for fiscal 1983, which starts Oct. 1.

On Tuesday the Congressional Budget Office said it expected the federal deficit would be between $140 billion and $160 billion in each of the next three years, even if Congress makes all the spending cuts and tax increases called for in the current budget resolution.

Volcker, at the Senate hearing, said the budget office estimates "came as no surprise to us . . . They are in the general area of what I think is probable and in the general area of what the markets think is probable."

Volcker was repeatedly attacked by Democrats and some Republicans on the Budget Committee because of the high level of interest rates and the recession they have helped produce. Sen. Donald W. Riegle Jr. (D-Mich.) declared, "I think what the members of this committee are saying to you in a variety of ways . . . is that your monetary policy has failed, and I think it is time to change it."

"I do not agree that monetary policy has failed," Volcker replied, adding that most of the burden of fighting inflation has fallen on the Federal Reserve because fiscal policy has been stimulating rather than restraining economic activity.

Volcker said there seemed to be a sense that "all the rest of the world can be out of joint and monetary policy can solve all the problems . . . There is no magic in monetary policy."

Riegle shot back, "I think monetary policy is adding to the problem, not helping solve it."

"Well, I don't believe that," Volcker responded.

Earlier in the hearing, the Fed chairman said that at the central bank, "We are trying to conduct the most reasonable policy we can. The budget situation doesn't help."

Although he indicated the current large deficit does not threaten the expected recovery in the short run, the amount of money to be raised to finance it will mean that interest rates will be higher than they otherwise would be. Within some limit, he said, "the lower you make the deficit, the lower interest rates will be."A small reduction--say $10 billion out of $140 billion--would not "revolutionize the markets," he added.