Combine Harvester


The modern combine harvester, or simply combine, is a versatile machine designed to efficiently harvest a variety of grain crops.

The name derives from its combining four separate harvesting operations---reaping, threshing, gathering, and winnowing---into a single process. Among the crops harvested with a combine are wheat, rice, oats, rye, barley, corn(maize), sorghum, soybeans, flax(linseed), sunflowers and canola.

The separated straw, left lying on the field, comprises the stems and any remaining leaves of the crop with limited nutrients left in it; the straw is then either chopped, spread on the field and ploughed back in or bales for bedding and limited-feed for livestock.   

Combine harvesters are one of the most economically important labour saving inventions, significantly reducing the fraction of the population engaged in agriculture.

Combines are equipped with removable header are designed for particular crops. The standard header, sometimes called a grain platform, is quipped with a reciprocating knife cutter bar.

Some wheat headers, called “draper” headers, use a fabric or rubber apron instead of a cross auger. Draper headers allow faster feeding than cross augers, leading to higher through due to lower requirements.

While a grain platform can be used for corn, a specialized corn head is ordinarily used instead. The corn head is equipped with snap rolls that strip the stalk and leaf away from the ear, so that only the ear enter the throat.

Occasionally rowcrop heads are seen that function like a grain platform, but have points between rows like a corn head. These are used to reduce the amount of weed seed picked when harvesting small grains.

Self-propelled Gleaner combines could be fitted with special tracks instead of assist in harvesting rice. These tracks can be made to fit other combines by adding adapter plates. Some combines, particularly the pull type, have tires with a deep diamond tread which prevents sinking in mud.