President Reagan may have struck out in trying to get Congress to go along with drastic cuts in farm-program spending, but he might end up a winner anyway if the Gramm-Rudman-Hollings budget-balancing bill is enacted.

A House Agriculture Committee staff report prepared for Chairman E (Kika) de la Garza (D-Tex.) says that if the bill's spending-cut requirements were triggered, the administration could reshape the farm programs any way it wished -- no matter what current farm law might provide.

An irony, the report hinted, is that the harsh farm-policy changes and spending cuts proposed this year by Reagan and pronounced as "dead-on-arrival" by most members of Congress, could become a reality through Gramm-Rudman-Hollings.

"The same administration that gave you that proposal could implement it by fiat," said Howard (Chip) Conley, a staff economist and coauthor of the report with counsel Phillip L. Fraas. "The same administration . . . could do any kind of thing it wanted under Gramm-Rudman."

Although there is dispute on Capitol Hill over the precise meaning of Gramm-Rudman-Hollings for agricultural programs and uncertainty about how the bill will emerge, there is agreement that the mushrooming costs of farm programs would be natural targets for administration budget-cutters.

Congress and the administration continue at loggerheads over the direction of the farm programs. The House has passed a bill that reduces price-support loan rates for commodities, as Reagan wanted, but retains the higher income support subsidies, known as deficiency payments, that the president opposed.

The Senate Agriculture Committee has approved a version that also keeps the income supports higher and that apparently is far more expensive than the House bill. The measure is caught in a political tangle, with the Republican leadership unable to muster enough floor support to cut the program's costs.

During House debate on the budget-balancing bill two weeks ago, de la Garza expressed concern that triggering Gramm-Rudman-Hollings could cause widespread uncertainty among farmers, and he suggested guidelines that should be followed to assure fair treatment for all types of farmers.

De la Garza and other farm-state legislators have expressed fears that the department will make farmers sign price-support loan and subsidy payment contracts with provisions allowing the government to reduce payments if the Gramm-Rudman-Holling plan were invoked.

"That might be neat and clean," Conley said, "but it would introduce all manner of new uncertainty into the programs . . . . They could try to make the farm programs sufficiently unattractive that participation would decline. And they might not have to cut that much to shake people out of the programs.

"One of the purposes of these programs, after all, is to minimize the uncertainty that farmers face."

Without the income protections provided in current programs, Conley and other congressional experts theorize, some farmers might give up because of an inability to survive with the lower market prices the administration seeks as a way of making U.S. agriculture more competitive abroad.

The administration is giving no hints of what it might do to USDA spending under Gramm-Rudman-Hollings, although Secretary John R. Block recently told reporters that the legislation would give the department an important boost in its budget-reduction efforts.

At a committee hearing to explore the agricultural implications of Gramm-Rudman-Hollings, department witnesses were noncommittal, although they talked in a general way about cuts being good for an out-of-control, farm-program budget.

Farm-belt legislators who vigorously opposed Reagan's farm-policy changes, yet are just as vigorously in favor of Gramm-Rudman-Hollings, could have some explaining to do at reelection time if the budget-balancing scheme becomes law and is applied to agriculture.