Two Washington-based investment funds are holding significant amounts of Farm Credit System securities but have decided not to buy any more until they see an end to the crisis over agricultural loan losses.

The Fund for Government Investors, a $1 billion money market fund based in Bethesda, currently holds between $150 million and $175 million in Farm Credit discount notes. Those notes will be off the books in three weeks, however, said Richard J. Garvey, president of the fund.

"As of three weeks ago, we stopped buying all farm credits," Garvey said. The short-term Farm Credit notes represent about 15 percent of the fund's current portfolio.

The Calvert Social Investment Fund's Managed Growth Portfolio holds about $3.5 million in Farm Credit securities that come due in 1990 and 1994, reported Grace Parker, vice president of the fund. The long-term bonds represent about 14 percent of the fund's portfolio. Parker said that while the fund isn't buying any more Farm Credit paper, they are not worried about the safety of the bonds.

"We expect the government to honor them," she said.

Garvey voiced similar sentiments about the safety of the Farm Credit securities. "The government will bail them out," he said, noting that the government bailed out other large financial institutions that have run into trouble.

Instead of buying short-term Farm Credit notes, Garvey said, he would shift to Treasury bills, which offered a little less yield but more safety. Farm Credit System securities, unlike Treasuries, are not direct government obligations. The securities have no federal guarantees, but investors have generally regarded them as if there were guarantees.

Two other Washington-based funds, the Government Investors Trust and the Washington Mutual Investors Fund, reported no holdings of Farm Credit paper.

Washington Mutual president Harry J. Lister said his $750 million fund holds $5.5 million worth of stock in a bank that lends money in midwestern agricultural areas but said he did not know whether there were any loan problems.

Farm Credit Administration securities are sold as six-month and nine-month issues and longer term paper that runs from two to 20 years.

The short-term securities normally are sold monthly, the longer term paper goes on the market from four to six times a year. The next regular short term sale is scheduled for Sept. 23.