Last fall, when students returned to Cambridge, they were greeted by 75-cent subway fares.

It was the second time in two years that Massachusetts Bay Transportation Authority (MBTA) officials tried to shore up a week budget by increasing the cost of transit service. But ridership has been dropping off, and officials are now considering calling back the price-hikes.

MBTA spokesman William Coughlin said yesterday that the Board of Directors will probably submit a request for additional local funding today, adding that fare cuts, as well as increased rush-hour service, could be implemented as soon as possible if the supplementary budget gains approval.

A decrease in fares to 60 cents--initially proposed in early February--may be implemented before the summer, but budget complications could prevent any change before July. MBTA officials said yesterday.

When fare hikes were approved last summer, the Legislature included a provision for reducing the increase if rider-ship fell more than 10 percent over the previous year.

Different studies completed in February concluded the number of commuters has dropped between 6 and 20 percent.

The MBTA Board of Directors on February 4 submitted their recommendation for fare reductions but made it contingent on a huge budget increase. Coughlin said yesterday that the cuts would therefore cost about $7 million. Not surprisingly, the transport system's Advisory Board--composed of representatives of cities and towns--has refused to provide the additional funds, claiming hardship from Proposition 21/2.

Lewjean Holme, chief budget analyst for the Advisory Board said that approved of the additional funds is unlikely. She added that the MBTA should look to funding sources other that the Advisory Board, which provides roughly 30 percent of the $344 million budget.

If the Advisory Board refuses to provide funds, riders will have to wait for action by the legislature or state courts. The New England Conservation Law Foundation has filed a suit with the Massachusetts Superior Court charging that the MBTA should have automatically implemented fare cuts because of the latest disappointing ridership statistics.

The fare cuts might also take effect when the legislature passes a 1982 budget. Gov. Edward J. King's proposed budget includes provisions for increased revenue for the transit system, including a cap on the share that cities and towns are obligated to contribute.