On our farm we grow corn for grain. Unlike sweet corn our corn remains in the field until fall when the plant reaches maturity and the grain dries out. So what kind of equipment do we have to get it out of the field and into our grain bins or off to market?
The Combine Harvester
A combine harvester, or combine, is the tool of choice for harvesting corn and other grains. The reason this piece of equipment is called a combine is simply because it combines several jobs into a single machine. Combines cut the crop and separate the grain from the plant while processing and spreading the remaining material over the field. The invention of the combine was a major moment in human history (with some debate about who really invented it!) that revolutionized the way grain crops were harvested. Wikipedia has a really nice page on the history of the combine harvester.
How Do Combines Harvest Corn?
At the front of a combine is the corn head. Combines can switch between a variety of heads depending on the type of crop harvested. The inner workings of the combine itself don’t require a swap like changing heads from corn to another crop like soybeans, but adjustments in speeds, spacings, and more are made accordingly.
I discuss how a corn head works in the video below. Basically what happens is a pair of spinning rolls pull the corn stalks down through the head. Just above those rolls metal plates pop the ear off the stalk. Gathering chains push the ears to the back of the head where an auger funnels the ears to the center of the head and into the front of the combine to begin the grain separating process.
Inside the Combine
About 10 seconds after the head takes in the ears there will be clean, separated grain in the grain tank. In this short span of time a lot of activity happens inside the machine. Once the whole corn ears enter the combine they are introduced to a spinning rotor which threshes the grain from the cob. This is done both mechanically by the machine and by grain on grain threshing as material is flung around the rotor. After the rotor a series of cleaning mechanisms come into play. This short animation reveals the process much better than I can say in words.
Once the corn is clean it enters the clean grain elevator where it is transported up into the grain tank where it can be held until the tank is full. Our tank holds just over 400 bushels. Some grain may go through a secondary cleaning process via the tailings elevator. We routinely check samples of grain for damage and cleanliness, and make adjustments to the combine as needed. With today’s modern machines we can make nearly all the adjustments from the cab on the go with the push of a button.
What’s Left?
Once the kernels are in the grain tank all the material left behind must be dealt with. Bits of leaves and stalks along with the corn husks and cobs exit the rear of the combine. Combines are equipped to either spread the material evenly over the field or to drop a windrow of plant material that could be baled for livestock. We spread our chaff and let it sit for no-till or incorporate it into the soil with tillage.
To see our corn harvest in action check out the following video from my YouTube channel. Enjoy! And if you have any questions or comments about combines and corn please comment below!
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