How Do Combines Harvest Corn?

Modern combines are a far cry from the earliest, horse-drawn combines.

It wasn't so long ago when corn was harvested by hand. Early combines (a name referring to its ability to harvest, thresh and clean) were horse drawn, giving way to today's combines, which can process about 200 acres a day of America's 68 million acres of corn.

Corn Picker or Corn Combine?

Both a corn picker and combine harvest corn, but a combine removes the corn from the ear. Sweet corn requires specialized pickers to avoid damaging its soft (moist) kernels. A combine harvests dry field corn.

How It Works

A "header" spans the front, sweeping several rows of corn plants into a giant, wheel-shaped pickup reel. The reel pushes plants down into the teeth of the cutter, where scissor-like mowing fingers cut the plant at ground level. Augers resembling giant drill bits then grip the corn and propel it up a conveyor belt to the threshing drum.

Inside the Threshing Drum

The threshing drum spins and vibrates, removing the corn kernels, which drop into a collection tank. These will eventually offload from a chute in the side of the combine, into another tractor. The chaff (plant stalks and cobs) travel on conveyor belts (called straw walkers) to the back of the combine, where it is expelled as mulch or baled and used for animal bedding.

References

• Explain That Stuff!: How Combine Harvesters Work
• Living History Farm: Self-Propelled Corn Combines in the 1950's and 60's
• Iowa Corn: FAQs

Resources

• Discovery Channel: How Stuff Works: Corn Combine
• Magic Studio: Inside a Threshing Drum
• Cornways: The History of Combine Harvesters
• AG Classroom: A History of American Agriculture - Farm Machinery and Technology
• Living History Farm: Harvest Technology During the 1950's and 60's