A novel plan by Poland's Roman Catholic Church to obtain Western agricultural goods for Polish farmers has become entangled in a web of erroneous reports about the plan's dimension and design. This has complicated the church's efforts to raise funds and support for it in the West.

In an interview that he requested with The Washington Post, a senior Polish church official today sought to clarify details of the project, in hopes that enough U.S. and West European money can be raised by the fall to begin pilot programs.

The official disclosed that Polish leader Wojciech Jaruzelski had confirmed to Polish Cardinal Jozef Glemp in a letter dated June 27 that the Warsaw government is ready to approve a church-sponsored agricultural foundation.

Earlier, Jaruzelski was reported to have agreed to the project in principle during private talks in June with Glemp and Pope John Paul II.

Creation of the foundation would be revolutionary by Soviet Bloc standards. The organization is expected to use money raised by Catholic bishops in Western Europe, North America and Australia to purchase fertilizers, seeds, farming implements and machines, which will be distributed to private farmers. The Polish church wants to tap Western industrial and private sources as well as the European Community and the American government for funds.

"In sum, this is a kind of Marshall Plan for Polish agriculture," the church official said, referring to the U.S. effort to help Europe rebuild after World War II.

The official emphasized that the project calls for the establishment of a foundation, not a bank, and foresees a five-year budget of about $2 billion.

If realized, the plan would provide a huge boost to Poland's ailing farm industry, once a primary European food supplier. In contrast to land ownership practice in other Soviet Bloc countries, where state-run collectives are dominant, about three-fourths of Poland's vast arable land area is privately owned and farmed. Polish farmers are short of everything, however, making do with half the tractors they say are needed and with only a sprinkling of the necessary fertilizer.

Some key food items are now rationed in Poland, so a surge in farm productivity could well help to strengthen Jaruzelski's position.

The government would like some of the proposed aid to go to Poland's state-run farms, but the church is insisting that all supplies be earmarked for private farmers and craftsmen.