Anticipating shortages of diesel fuel and home heating oil that could prove worse than the current gasoline crisis, the Department of Energy's Economic Regulatory Administration is considering reimposing rederal controls on them.

The agency has already taken the first step toward federal allocation of the two essentially identical fuels by issuing an emergency order to assure that farmers have enough diesel fuel for spring plantings.

The ERA issued the emergency order last Friday after the Department of Agriculture warned that shortages of diesel fuel had delayed planting so long that food production might fall. The order requires that suppliers meet all fuel needs of farmers.

Now mass transit systems are demanding similar treatment, saying at least 40 bus lines across the nation will have to cut back service unless they can get more diesel fuel. Moreover, railroads and long-haul truckers are preparing their own pleas for special consideration.

The DOE regulators are condsidering "imposition of a comprehensive system of allocation controls similar to the system that existed prior to the exemption" of the fuels from federal regulation three years ago, the agency said in a proposed rule.

Diesel fuel and home heating oil are chemically the same product, although diesel fuel is subject to state and federal highway user taxes. Both are part of a family of fuels known in the oil industry as middle distillates.

After the first three months of 1979, middle distillate supplies were 16.8 percent lower than a year earlier, said a spokesman for the American Petroleum Institute, an industry group.

Compared with 136.8 million barrels a year earlier, middle distillate supplies were down to 117.3 million the first week of May, API estimated. "That's low. We're bumping the danger point," said API executive Earl Ross.

He blamed the shortage on reduced Iranian oil production, unusually strong demand for gasoline and a need to build up heating oil supplies for next winter.

With farmers, commuter bus lines, truckers and railroads all claiming a high priority on available diesel fuel, the lowest priority falls to the individual drivers who bought diesel-powered cars to avoid shortages of gasoline.

DOE's 25-page proposal for allocation middle distillates makes no mention of the plight of the diesel auto driver.

Most diesel fuel users now are getting about 80 percent of their normal fuel allocations from suppliers. Under the DOE emergency order, agricultural users - including commercial fishermen - would get 100 percent of their needs until July 31. DOE is considering requiring a 100 percent allotment for mass transit as well.

With only 80 percent of their fuel needs met, users buying additional fuel on the open market are forcing up prices.

"At first the fuel was there if you were willing to pay for it, but in the last two weeks it's gotten tight regardless of price," said Rupert Welch of the American Trucking Associations. Welch said truck fuel prices have jumped from 40 or 50 cents a gallon to as much as 85 cents this week.

"As of last week it's up pretty much everywhere to around 75 cents per gallon," he added. About half of all trucks burn diesel fuel.

At the Transitruck Center in Laurel, manager Bob Schanlaub said the prices on his diesel fuel pumps "go up every time we get a new load.

"I can guarantee you it's been at least 10 cents in the last month," said Schanlaub. After a four-cent increase on the latest shipment from Texaco, the price on the pump went to 77.9 cents, he added.

With prices soaring like that and supplies tight, rival users of diesel fuel are pressing DOE to consider their needs, too.

"It makes no sense to allocate fuel to agriculture and not give it to the people who carry the products to market," complained Association of American Railroads spokesman Dan Lang.

"It doesn't make any sense to allocate fuel for agriculture industries if people can't get to work," countered Judy McCormally of the American Public Transit Association. CAPTION: Picture, Station on Old Dominion Dr. in McLdean did a brisk business yesterday. By Margaret Thomas - The Washington Post