How Does a Combine Work? Grain Harvest Prep 2014.

Dad is pictured above making a final check of all the settings on the machine before we test everything out.  Today's modern farm equipment is a modern marvel in itself.  We can harvest more grain in a day than my grandfather had for his whole crop when he bought his first self propelled combine.  When he was the age of my boys they cut wheat by hand, bundled it into shocks, loaded it on wagons pulled by horses or mules and took it to a steam powered threshing machine.  It's amazing to think of the advances that have been made during his lifetime.     

The harvest process starts at the front of the combine with the header.  We use a "stripper" header to gather the heads of grain into the combine.  The heads of grain are "stripped" off by the metal fingers in the rows above.  This header leaves the straw standing in the field.  You can also cut wheat with a platform header that cuts the straw off about 8 inches from the ground.  This type of header allows us to drive faster and cover more acres with the combine per day.  It also makes it easier to no-till our double crop soybeans into the standing residue without the ground being covered in chopped up straw.

Once the header strips the heads of grain it feeds the crop material into the Feeder House which is on the front of the combine.  It's job is simply to gather the crop into the machine and feed it through the feed accelerator.  The feed accelerator is a spinning row of bars that feeds the crop into the concaves at the front of the rotor.   

Our combine is a John Deere S680 "Rotary" combine.  This means there is a bullet shaped rotor behind the screens pictured above that threshes the crop after the feed accelerator feeds the crop into the machine in a "screw type" motion.  The grain and smaller particles of the fodder fall through the grates into the shoe augers below where it is moved further back into the machine for cleaning.

In the middle of the picture you can see the daylight where the door is open in the previous picture exposing the rotor and the shoe augers.  The augers move the grain back into the the pre-chaffer (the green fingers pointed up) where it is shook and the grain is separated from the chaff.  The combine is moving quickly and the rotor is full,  Sine of the crop material is pushed on back to the chaffer and shaker pan for cleaning (the silver fingers).  The clean grain falls down with gravity and is moved to the the clean grain elevator up to the grain tank on top of the machine.  In the very top of this picture is where the separated chaff and non-grain material is sent to the discharge beater to be discharged from the rear of the combine pictured below.

The spreader on the back of the machine (with the black cover) takes the non grain residue and crop material and spreads it evenly back onto the field.

All of the steps in the harvest process are controlled by the operator from a touch screen display inside the cab of the combine.  You make adjustments to the header or feeder house clearance and speed, rotor speed, concave clearance, auger and chaffer speeds according to the crop and the speed you are trying to run.  You want the crop material to feed evenly through the machine without bogging the machine down or running grain out the back of the combine onto the field.  We want grain in the tank not on the field!

Once all the settings are checked a field start is next.  We cut a small field of barley to fine tune the settings of the machine.  The barley crop looks to be about 100 bushels per acre.  Our barley is used in livestock and pet food rations.  Malting barley is grown in the western states where the soil is suitable to that type of grain.