The Maryland General Assembly today approved a $22 million grant for the renovation of Baltimore's Memorial Stadium, a measure designed to please Robert Irsay, owner of the Baltimore Colts, and dissuade him from moving his football team elsewhere.

Approval of the grant was assured early in the day when the committee chairman in control of the stadium bill won a long-sought victory of his own on another matter: enactment of a bill raising the allowable load limit for trucks on Maryland highways.

"This is the year of the trade," said one legislator after the stadium-truck weights bargaining had been accomplished. "Everybody's trading everything."

The trcuk weights bill, favored by Gov. Harry Hughes and puchsed hard by Appropriations Committee Chairman John Hargreaves -- who owns stock in a major Maryland Trucking firm -- was approved this morning on a 77-57 vote in the House of Delegates.

When the House reconvened after lunch, the Appropriations Committee immediately sent the stadium bill to the floor for a final vote. After a few objections from rural delegates, the stadium bond bill was approved by a margin of 89 to 42. The measure now go to Gov. Hughes, who has promised to sign them.

Passage of these two measures and another bill for construction of a new prison near Jessup marked the resolution of almost all the most difficult issues facing this year's legislature.

By a 79-0 vote, the House tonight enacted a measure to place a 500-bed prison adjacent to the old House of Correction near Jessup and to limit the total numer of prisoners in this area of the state. With the exception of one more authorizing constrution of a new prison in Baltimore, few items of statewide importance remain to be decided on Monday, the session's final day.

With the state's commitment to Memorial Stadium, Irsay will not get the 13,400 new upper deck seats and the "VIP lounges" he requested for nothing. Before the state will sell bonds to finance the project, Irsay must agree to sign a 15-year lease on the stadium.

If he reneges on the lease, the legislation requires Irsay to pay all the remaining interest and principal on the $22 million bond issue.

Irsay has told Baltimore City officials that he cannot sign such a lease until he knows if Baltimore Orioles Owner Edward Bennett intends to keep his baseball team at the stadium. And Williams, who says the planned renovations do little for him and take away part of the baseball outfield, has consistently refused to sign a lease at the city-owned stadium.

What Williams has said is that he will keep the pennant-winning Orioles in Baltimore as long as the city "supports" the team. He has not defined what he means by support.

Passage of the stadium bill was an important victory for Hughes and Baltimore Major William Donald Schaefer, who had both stressed the sports team's economic value to the region.

The success of the truck weights bill was a coup both for the governor and some of the state's more powerful business interest, who argued that the measure would bring Maryland into conformity with the regulations in neighboring states.

The controversial measure, which raises the maximum allowable truck weight on Maryland Highways from 73,000 to 80,000 pounds, has been one of the most heavily lobbied measures in Annapolis during the past two years.

In the closing hours of the 1979 session, committe chairman Hargreaves, who has a $140,000 interest in Preston Trucking Inc., held all state construction projects hostage while state senators across the hall were talking the truck weights bill to death.

Hargreaves finally relented, but the bill and the trucking industry's lobbyists were back again this year.

This year, Senate opponents of the bill threatened another fillibuster, arguing that the increased weights bill will cause highway and bridge damage costing the state millions in future repair bills.

But the opponents backed down after the bill's supporters agreed to permit Baltimore City officials to determine which city streets the trucks could travel on, and also agreed to an increase in truck registration fees that will bring the state an additional $1.6 million in annual revenue.

The bill also won substantial support from Anne Arrundel County delegates today after they were assured by one House Speaker Benjamin L. Cardin's lieutenants that their support of the truck weights bill would probably guarantee the approval of a $4 million bill for construction of a school in Crofton.

"(Cardin) didn't exactly assure us of (passage of the bond bill) but he said it had a better chance if the (truck weights) bill passed," said Del. Tyras B. Athey, a member of the Anne Arundel County delegation.

In other action today, the assembly:

Approved the centerpeice of Montgomery County executive Charles Gilchrist's legislation package, a measure authorizing a four percent tax on sales of apartments being converted to condominiums. The Montgomery Council must still pass legislation implementing the tax. The measure is expected initially to raise $4.8 million. Gilchrist said he plans to use the money for a program of low interest loans to developers building new rental housing.

Enacted emergency legislation banning the manufacture, distribution and sale of certain specified types of drug paraphernalia designed for use with marijuana, cocaine and hasish. A more all-inclusive measure banning drug paraphernalia was enacted on Thursday.

Enacted a measure establishing a seven-member judicial compensation commission to make reports every two years on proposed salary increases for the state's judges. These proposals must then be approved by the legislature. t