ALTA, Iowa (AP) _ The farmer who found the 400-pound engine part suspected of causing a jet crash that killed 112 people learned today she will get a reward of more than $100,000 from General Electric Co.

''It's just a shock,'' said Janice Sorenson, who found the piece while harvesting corn Tuesday with a combine.

GE had offered a $50,000 reward for the titanium fan disk from the rear engine of United Airlines Flight 232, which crashed July 19 in Sioux City, killing 112 people of 296 people on board. GE manufactured the engine.

Investigators suspect the fan disk came apart, causing the engine to disintegrate and spew shrapnel that severed the jet's hydraulic system and made the plane virtually impossible to control.

GE spokesman David Lane said the company would not give the amount of the reward. But a source close to the matter said it would be about $130,000, and Mrs. Sorenson today said GE told her it would be more than $100,000.

''I'm just in shock. I can manage $20,000, but this?'' she said.

The amount being given is more than $50,000 because of all the fan blades and other parts still attached to the disk and because some other small parts found in the ground with the disk.

Mrs. Sorenson said she had no immediate plans for the money. She and her husband, Dale, have lived on the farm since 1953.

GE established a reward fund totaling $271,000 to pay for parts recovered from the crash, Lane said; less than half that amount has been paid.

The disk, which looks like a windmill, was flown to a GE plant near Cincinnati for analysis.

''We don't know yet whether this is the golden nugget we're looking for,'' said Jim Burnett, a member of the National Transportation Safety Board. ''But we're glad we found it.''

Mrs. Sorenson found about two-thirds of the fan disk assembly, and 100 searchers hired by GE will look for the rest of the disk and its hardware over the weekend.