The American Farm Bureau is sending a delegation of farmers to Europe next week to warn the European Community that its agricultural subsidy policy is inviting reprisals against farm products that it sends here.

Robert B. Delano, president of the country's largest farm organization, said yesterday that he and 20 state farm bureau presidents will visit four EC countries next week "to urge more open and fair trade of agricultural products."

Delano said the Farm Bureau is not displeased with the Reagan administration's efforts to open European markets to U.S. goods, but the organization thinks a people-to-people effort may help the cause.

"There are occasions when members of government ask how farmers feel, and that is one of our reasons for going," Delano said.

"We want to let the Europeans know that American farmers are solidly behind U.S. negotiators on these issues," he said. "Farmers are dead serious--the U.S. government is dead serious--that if duty-free bindings are interfered with, and if export subsidies don't cease, the EC will likely face retaliatory action against European products, either against agricultural products like cheese and wine, or against industrial items."

Delano said the trip was prompted in part by an EC decision to raise prices almost 11 percent.