Bart. R. Lindsey gestured toward the sign displayed prominently near the tellers' cages in the First National Bank of Phillips County.

"Look at that sign," said the 35-year-old vice president of Helena's biggest bank. "It tells our problem."

The sign reads simply: "Our Six-Month Money Market Certificate Pays You 14.956 percent." Similar signs sit in lobbies of banks -- large and small -- across the United States.

It didn't used to be that we worried much about what went on in New York. Now we do," said Lindsey.

Unlike big banks -- which "buy" most of the funds they lend to their customers on the open market and adjust their business lending rates in tune with those fund-raising costs -- small banks rely mainly on their own customers to supply the deposits from which they make loans to consumers, merchants, small businesses and farmers.

Bankers and their business customers are accustomed to fixed-rate loans -- those based on the relatively stable cost of funds to the bank -- not on the rates New York or Chicago banks must pay for their big certificates of deposit or commercial paper.

But with the advent of the consumer-size certificate of deposit -- sold in minimum denominations of $10,000 with rates tied to the interest the Treasury pays each Monday when it auctions bills on the open market -- small rural banks have discovered New York.

When farmers begin to come in for loans to finance their spring plantings, they will come face to face as well with New York interest rates.

"We had $2.8 million of our deposits shift to money market certificates in one week in February alone," said William H. Brandon Jr., president of the $42-million-asset bank. All of that $2.8 million came out of either passbook savings accounts which cost the bank 5.25 percent, or long-term certificates which depositors bought months or years ago at interest rates of about 6 percent or 7 percent. Brandon said that depositors are cashing in those certificates despite the heavy interest penalties federal regulations require when a certificate is redeemed prior to maturity.

He said a year ago the bank had $11 million in checking accounts (which pay no interest but cost the bank the equivalent of 4 percent), $9.5 million in 5 percent passbook accounts, and $12 million in certificates, which cost an average of about 6.5 percent.

Today, the checking accounts run about the same, but passbook savings deposits (which now pay 5.25 percent) have declined to $7 million. About $16.5 million is in "expensive, hot money," Brandon said, mainly the short-term consumer-sized certificates that have been yielding close to 15 percent in recent weeks.

The bank actually gained a temporary, if perverse, earnings boost last year because of the popularity of the new certifications. Brandon said that so many customers cashed in their old, low-interest certificates early and paid the interest penalty that the bank did not have to pay out thousands of dollars of interest as it had expected.

Of course this year "we'll be paying 15 percent on those funds compared to about 6 1/2 percent last year," he said.

"Remember 10 years ago when everyone was talking about how smart corporate treasurers had become in taking advantage of the earning power of their money? Well, consumers in small towns are just as savvy today.They don't leave their money at 5.25 percent when they can earn 15 percent," Lindsey said.

Federal regulators dreamed up the money market certificates so that banks and savings and loan associations would be able to compete for their depositors' money during periods of high interest rates. In earlier high-interest-rate periods, consumers often withdrew their funds from bank accounts -- where interest ceilings were set by law -- and used the proceeds to buy investments such as Treasury bills.

During those periods (although the interest rates then pale by comparison), big-city consumers were more prone to withdraw their funds, or disintermediate as the economists call it, than were their rural counterparts. But with the bank-offered money market certificates, depositors have to be no further than the nearest teller to triple their interest yields.

As a result, however, First National or Phillips County has money to lend its customers, especially the farmers who will need loans soon to finance their spring planting.

But that money is going to cost the farmers a lot more than it did last year.

John King, who farms about 4,000 acres in the county found out last week that he will have to pay at least 16 percent for the $200,000 he thinks he will need to borrow between now and next fall's harvest. Last year he paid 10 percent.

"I'm happy to have the money. Price matters, but I've got to have the money," the 47-year-old farmer said. "There is no way a farmer can go without borrowing unless he goes out of business."

But King said he is being squeezed: All his costs are rising at the same time that the price he expects to get for his soybeans is down 25 percent because of the president's embargo on further grain shipments to the Soviet Union. Interest is not an inconsequential cost to King, reportedly one of the most successful independent farmers in this old Mississippi River town, about 65 miles southwest of Memphis.

Last year he paid an interest rate of about 8 percent, and this ate up 10 percent of the $700,000 he grossed, King said.

Although King will get the money he needs to finance his current harvest, bank officials told him he can just about forget borrowing any money if he wants to buy more land. King has been adding to his land holdings steadily for the last 25 years, but is resigned to buying no more in 1980.

If current customers cannot expect to have any new ventures financed by First National -- there might be some limited exceptions to the general policy, Lindsey said -- new customers might as well forget it, especially those who need to borrow small amounts of money.

Arkansas bankers face more strictures on the amount they can charge customers than do their counterparts in other states. The 100-year-old state constitution sets a usury ceiling of 10 percent that cannot be corrected by an act of the legislature as it has been in other states.

Nationally chartered banks such as First national use a loophole in the National Banking Act to charge one percentage point more than the Federal Reserve discount rate (now 13 percent). But state-chartered banks such as Farmers and Merchants here cannot use that loophole for loans of less than $25,000.

"We're turning down a lot of their customers," said Lindsey.

All Arkansas banks can charge up to 5 percentage points more than the discount rate on loans of more than $25,000 because Congress passed a special law to override the Arkansas constitution. That law expires at the end of the year.

"We'll have the money for our regular customers," said Brandon, who is bracing now for the big seasonal upsurge in farm lending. He expects farm loans to balloon from about $3.7 million to $8 million in the summer.

"Right now, we've got a long-to-deposit ration of 61 percent. We'll go close to 80 percent this summer. But 'we'll fight loans as much as we can. We're going to shoot for liquidity. We're a little scared," Brandon said.

This is just what the Federal Reserve wants the banking system as a whole to do: lend less money in order to restrain spending and fight inflation. But bankers such as Brnadon say that rural banks do not make the speculative types of loans that fuel inflation.

Instead, he said, the loans, his banks make go mainly from local depositors to local borrowers (usually the same people) who use the money to grow crops, buy necessities and finance inventories.

Indeed, Phillips County is fighting for its economic life. Agriculture, the backbone of its economy, has mechanized over the years, throwing thousands on the unemployment and welfare rolls and convincing many to leave for good. The county's population has shrunk in half in the last 30 years. More than 30 percent of its 35,000 citizens are on welfare, and its unemployment rate runs close to 13 percent, according to John Gatling, head of the newly organized Economic Development Council.

One victim of high interest rates and scarce money in Phillips County is Al Willinger, who heads a new barge building company that so far has put 50 Phillips County residents to work. Willinger needs $500,000 to finance steel and salaries for the $2.4 million worth of barges he has on order. His life is further complicated because Brandon is on his board of directors and First National could not make him a loan even if it were possible otherwise because of the interlock in directors.