harvesters

Harvesters are devices and personnel used to gather mature crops from agricultural fields. In farming, the term commonly refers to mechanical harvesters—machines designed to cut, thresh, and in some cases clean or separate grain from the plant in a single pass.

Types include combine harvesters, which perform cutting, threshing, and cleaning; specialized harvesters for sugar cane, potatoes, onions, fruits, and other crops; and picking machines that carefully remove fruit without significant damage. Some harvesters are self-propelled; others are tractor-drawn or mounted.

History: Before mechanization, harvesting was done by hand with sickles and scythes. The mechanical reaper, developed in the 19th century, enabled more efficient harvesting. The 20th century saw the rise of the self-propelled combine harvester, uniting cutting, threshing, and winnowing. Later developments added automation, GPS guidance, yield monitoring, and other digital controls.

Operation: A typical combine uses a header to cut the crop, a threshing drum or rotor to separate edible parts from chaff, and a cleaning system to separate grain from unwanted material. The processed grain is stored in a tank or bucket, while straw or chaff is expelled from the rear or side. Advances include headers optimized for particular crops and autonomous or remotely controlled units.

Impact: Harvesters have increased agricultural productivity and reduced seasonal labor demand, enabling larger-scale farming. They can raise energy and maintenance costs and may contribute to soil compaction and energy use. For delicate fruits, specialized picking mechanisms aim to minimize damage.

Global use: Mechanical harvesters are common in many temperate regions and for large fields of cereals, corn, and sugar cane. In smallholder and labor-intensive farming systems, manual or semi-mechanized harvesting remains common for certain crops and locales.