ST. LOUIS (AP) — While other corn growers already have knocked down their drought-ravaged crops to feed them to livestock, Nebraska farmer Doug Nelson still waits for his maize to mature, well aware it won't be a banner year.

On the day a new report suggested the nation's worst dry spell in at least a generation is deepening in America's breadbasket, Nelson said Thursday he expects to harvest anywhere from nothing to 43 bushels per acre on his unirrigated acreage, a far cry from the 120 to 140 bushels he'd typically get. On the irrigated land, he could see 150 to 200 bushels an acre; in previous years, Nelson would see a minimum of 180 bushels.

"For the most part, we haven't seen a hit like this since 1974, as far as my career goes," said the 61-year-old Nelson, who farms some 5,000 acres near Wayne. "But we'll have the combines going here in probably another month, and then we'll know for sure.

"You can walk these fields and run into good spots, then walk another part where there's a different soil and have nothing."

That's part of the growing frustration with an increasing drought in Nebraska and several other farming states, despite recently cooler temperatures that have, at the very least, given people a break from this summer's stifling heat.

The U.S. Drought Monitor's weekly map showed that, as of Tuesday, just over two-thirds of Iowa, the nation's biggest corn producer, was in extreme or exceptional drought — the worst two classifications. That's up more than 5 percentage points, to 67.5 percent, from the previous week.

Nearly all of Nebraska, Kansas, Missouri and Illinois are in extreme or exceptional drought, with Illinois showing the most dramatic climb, spiking 17 percentage points in one week to 96.72 percent, according to the map.

In neighboring Indiana, where 5 inches of rain fell in some parts over the past week or so, the area in exceptional or extreme drought fell 9 percentage points, to 37.09 percent.

Conditions cooled in the region, but little or no meaningful rain fell, said Mike Brewer, a National Climatic Data Center scientist who put together the latest map, which is released by the National Drought Mitigation Center at the University of Nebraska in Lincoln.

The lack of rain allowed exceptional and extreme drought conditions to continue expanding in the area from northern Missouri and into Kansas and Nebraska, he said.

On Wednesday, the USDA added 33 counties from eight drought-stricken states to its list of natural disaster areas, bringing that tally to 1,821 counties in 35 states over the past six weeks. That's more than half of all U.S. counties, and the vast majority received the designation because of drought.

Plains farmers have begun harvesting what corn managed to survive, although many growers cut their fields weeks ago, chalking the year up as a loss. Some ranchers have sold livestock because they had no grass for grazing or money to buy feed, the price of which has soared.

In the lower 48 states, there was a subtle increase in the overall area experiencing at least some drought, from 61.77 percent last week to 63.2 percent. There was little change in the overall area seeing exceptional or extreme drought, which went from 6.26 percent last week to 6.31 percent this week.

Rain is expected in the northern Plains in coming days, though it may be too late to save many withered crops.

The U.S. Agriculture Department twice has slashed its forecast for this year's corn and soybean output because of the drought. In the spring, it forecast the nation's biggest harvest, as farmers planted 96.4 million acres of corn — the most since 1937. But the agency now expects the nation to produce 10.8 billion bushels, the fewest since 2006.

If that estimate holds, the federal government says it will be enough to meet the world's needs and ensure there are no shortages. But experts say food prices will almost certainly climb — corn is widely used in products ranging from cosmetics to cereal, colas to candy bars.

While just 1 percent of the nation's corn crop is brought in from the fields by this time of year, the USDA said Monday in its weekly crop progress report that 4 percent of the harvest is complete. The reaping is farther along in Kansas, Missouri, South Dakota, Kentucky and Tennessee.

In an occupation that's at nature's mercy, "we've got to calculate we're gonna lose a crop once in a while and calculate that into our expenses," said Nelson, whose northeastern Nebraska farmland is about 60 percent corn, the rest soybeans. "Sometimes it's heat, drought, excessive rains, bugs, winds. I guess that's what keeps us coming back for next year."

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