The House Agriculture Committee yesterday finished Round 1 of its work on a four-year farm bill that is far above spending limits set by the Reagan administration and the House budget resolution.

Round 2 probably will occur next week, when the committee reconvenes to confront the hard part: it will try to trim programs $2 billion to conform to the budget limits.

The bill approved yesterday follows along the lines of a measure adopted Wednesday by the Senate committee, rebuffing the administration in a number of areas.

The House dairy program, for example, is more generous than the administration wanted. Against administration wishes, a sugar price support program is to be established and a new support program for sunflowers.

The bill also would retain the target-pricing concept on commodities that Reagan has sought to end. Target prices are direct payments to farmers, covering their production costs, rather than loans.

House lawmakers would put limits on the power of the secretary of agriculture to set price-support loan rates and, contrary to administration wishes, would mandale support levels for the four-year term of the bill.

The Senate version is similar, but the two bills diverge on peanuts. The administration wanted to phase out the peanut acreage allotment system and hold the line on price supports. Both bills would continue allotments, but would set different support prices, although both are higher than the Reagan request.

The House committee yesterday added language to protect farmers from economic harm in the event of any future embargoes on exports, roughly doubling the price supports the government would have to pay them. Loan rates would be set at 90 percent of parity, about twice today's rate. The Senate adopted a 100 percent of parity approach.

One of the more spirited debates occurred over a losing amendment offered by Rep. James Weaver (D-Ore.) to set up a grain export system that would force overseas customers to pay higher prices to American farmers.

Weaver found wide support for his idea -- members agreed that it could give farmers a more realistic return -- but objected to the way he would have done it. Weaver's proposal would have empowered the secretary of agriculture to determine the prices for export grain.

Weaver said he will offer the proposal again on the House floor, using a theme set by Rep. Byron L. Dorgan (D-N.D.), who called the present export system "food stamps for the OPEC nations and the Soviet Union."