Kansas Agland has a report on how much wheat combines have evolved over the last century. According to the ag website, harvesting wheat a century ago involved cutting wheat stalks with a horse drawn binder and gathering them in bundles. The bundles were then stacked into windrows to dry, after which a giant steam-powered threshing machine separated the wheat kernels from the straw. The entire process was extremely labor intensive. But all of that changed in 1917 with the invention of the self-propelled combine by the Baldwin Brothers of Nickerson, Kansas.
These days the Gleaner Combine, manufactured by AGCO in Hesston, has come a long way from those first Baldwin Combines. While a 1927 Baldwin Combine could cut 30 acres a day, a 2015 Gleaner can thresh 22 acres per hour.