Congress settled a last-minute dispute over legislative language yesterday and gave final approval to a package of "technical corrections" in last year's farm law.

At the same time, President Reagan, who is expected to sign the farm law changes, announced that he had ordered a $750 million infusion into Farmers Home Administration (FmHA) direct loan accounts to help farmers meet spring planting costs.

The White House had been under growing congressional pressure in recent days as FmHA offices around the country reported running out of direct loan funds.

The farm law changes approved yesterday would alter formulas used for calculating farmers' federal benefits. The Senate and House finished work on the package last week, but administration objections to the wording of a "sense of the Congress" provision touched off new debate and forced reconsideration by both chambers.

The provision was authored by Sen. Tom Harkin (D-Iowa), who wanted to order the president to provide spring advances on crop loans that ordinarily would not be made until fall harvest.

Instead of the direct order, Harkin agreed to nonbinding language expressing the sense of Congress that the president "shall" make the advance loans. But the administration insisted on more lenient language. Lawmakers resolved the problem by dropping the "shall" and leaving the loan provision discretionary.

Also yesterday, a House-Senate Appropriations conference committee broke up deadlocked over the wording of an emergency $5 billion supplemental appropriation to replenish the Commodity Credit Corp., which has been unable to make farm loans and surplus food purchases since last week.

The conferees are scheduled to meet again today. Their dispute involves future funding for the new conservation reserve program, which will pay farmers to remove highly erodible land from production for 10 years.