With every few inches the Mississippi River drops this summer, Billy Joe Ragland and thousands of farmers just like him lose money.

The drought that is causing the Mississippi to dwindle started in the spring of 2005 and hasn’t loosened its grip yet.

It’s bad enough that the dry conditions are hurting his yields of soybeans, corn and cotton. But now low water is beginning to affect the fragile transportation system relied upon by farmers and factories in America’s heartland.

And there isn’t much chance anything will change for months. Little rain is in the forecast and little hope is in Ragland’s heart.

“This is going to be the year that puts a lot more of us out of business,” said Ragland, a Bentonia, Miss., farmer who serves on the Mississippi Farm Bureau board of directors. “I hope it’s not going to be me, but I can see right now it’s not going to be good in the end.”

Low water on America’s largest river has already caused a reduction in the size and draft depths of the giant barge flotillas that carry more than 310 million tons of grain, petroleum, steel, ore and Ragland’s soybeans and corn along the Mississippi every year.

Last week, the Coast Guard said parts of the river were closed temporarily due to a series of towboat groundings.

And hydrologists at the Lower Mississippi River Forecast Center expect the marine highway to continue to drop rapidly. There is no significant rain in the forecast and extreme drought conditions are expected to worsen in the basins of most of the Mississippi’s mammoth northern tributaries.

One forecast, a 28-day, worst-case scenario based on the unlikely idea that no rain will fall in the basin, calls for the lower Mississippi to drop 2 to 3 feet in most areas. While the river is not at historic lows, it is 8 to 10 feet below normal in most areas. Scientists and forecasters warned that with another month or two of similar conditions, the Mississippi could start to bottom out.

It would take weeks of substantial showers to reverse the trend. Even heavy-water storms lasting a day or two would have little impact on river levels. Drought-stricken vegetation and soils quickly absorb any moisture, leaving little to make the journey down the watershed.

“The long-range impacts on river flow, especially the Mississippi River, will be virtually nil,” Louisiana state climatologist Barry Keim said of occasional showers in the basin. “If it’s problematic now, it’s not likely to get any better. In fact, it’s more likely to get worse.”

In times of low water, the draft — or depth to which a barge sinks in the water when it is loaded — must be reduced. Ideally, barges would sit at a depth of 12 feet. But the Lower Mississippi River Committee, the industry group that regulates traffic in times of high and low water, has limited draft depth to 9 or 9 1/2 feet along most sections of the river. Some ports are requiring draft levels of 8 feet.

And because the main channel of the Mississippi narrows in times of low water, the committee also decreased the width of floats by one string of barges. On the lower Mississippi, a string usually consists of as many as eight barges tied nose to stern.

Under normal conditions, barges — each typically measuring 35-by-200 feet — are lashed together five wide and eight long. An optimal float measures 175 feet wide by 1,600 feet long, the equivalent of five football fields.

The required draft decrease of 3 feet means each barge can carry only 900 tons of grain instead of the usual 1,500. A reduction of eight barges per float means another 12,000 tons has to be left in port.

It then costs barge owners and tow companies significantly more money to get the same amount of grain to the mouth of the river.

And there are only so many towboats around.

“That’s when the ol’ supply and demand kicks in and everything gets more expensive,” said David Choate, vice president of Oakley Barge Line Inc.

“I haven’t seen much reason for optimism. I would say we’re at the point where we need to be concerned.”

That’s because there is no soaking rain in the forecast and the late-summer dry season doesn’t usually end till November.

About 70 percent of the water that flows into the lower Mississippi comes from the Ohio River valley, which gathers water from eight states. The area has gotten enough rainfall recently to remove the drought designation, but much of it has either traveled the wrong way into the Great Lakes or is greatly reduced on its way south.

Other tributaries are also in trouble along the Mississippi, which is a simple system — water in, water out. “It’s not rocket science,” Rosedale port director David Work said.

The Mississippi watershed is immense, draining 41 percent of the continental United States, according to the National Park Service. Its tributaries originate in 31 states and two Canadian provinces, reaching from western Montana to western New York.

The river is less than 3 feet deep and 20 to 30 feet wide near its headwaters in Lake Itasca, Minn. By the time it reaches New Orleans, it is 200 feet deep and flowing at a rate of 600,000 cubic feet per second.

The river has been used for trade since prehistory. The first European shipment, of bear and wolf pelts, came down the river in 1705.

The flow of goods hasn’t stopped since.

It has occasionally slowed, however. High water and flooding in the spring have most often been the culprits. But low water can have a major impact. In 1988, the lowest year in memory for most, barges became stuck and severe limits on tonnage were required.

Most try to remain optimistic, but August, September and October are traditionally the river’s dry months.

The long-range precipitation forecast for the Ohio River valley calls for rainfall 30 percent to 40 percent below normal. And the U.S. Drought Monitor shows the Mississippi’s other major tributaries — the Missouri, Arkansas and Tennessee rivers — are deep in the grip of drought.

“Clearly the entire central part of the county is in pretty dire straits droughtwise,” Keim said.

Ragland said a drop in water levels might easily eat 15 percent to 20 percent of his price per bushel. He’s already bypassing the Yazoo River port at Yazoo City and trucking his soybeans to Vicksburg — at five miles per gallon. The Yazoo River is so low, the elevator is full of grain waiting to be shipped down to the Mississippi, then south. He expects the same thing to happen soon on the Mississippi.

“The only way we could unload (in 2005) is if another truck came in and took a load out,” he said. “It’s going to be that way this time. It would already be this way but the crops are coming up short because of the drought.”