❝ A reply to a comment on Hackernews “Farmers didn’t invent tractors. They didn’t invent any of the improvements. They were busy farming.”
Tractors are simply powering the business end of farming, harvesting. It is Farmers who invented the harvester.
In Melbourne, my home town we had a bloke called Hugh Victor McKay  who grew up in a farm in Drummartin, Victoria who got sick of the laborious inefficiencies of farming and decided to do something about it. He built a device eventually marketed as the Sunshine Harvester  which combined the following operations previously done by hand when harvesting grain: Cut, thresh, re-thresh, separate, cleaned & finally collect.  The machine was mass produced in Australia and exported across the world. 
This type of innovation in the field of farming is not unique. While MV McKay is credited with the "Combine Harvester", new historical evidence shows that many other Farmer/Inventors spurred on by financial gains and government prizes also experimented with new ideas and inventions. 
The farming world is full of inventions made by "Farmers" because they are by nature practical people who have to solve real problems. I could give more examples but I think I'm sufficiently making my point.
I've seen a photograph with this particular tractor, an early model Fordson pulling a combine harvester.
 Melbourne Museum, Hugh Victor McKay "Driven by frustration with the slow and laborious nature of farm work, and fueled by a persistent and inventive mind, McKay searched for a better and more efficient way of harvesting wheat" http://museumvictoria.com.au/sunshine/mckay.asp [Accessed Wednesday, May 27, 2009]
 Times Online, Bill Dunn, "Combine Harvester" http://www.timesonline.co.uk/tol/sport/related_reports/article377318.ece [Accessed Wednesday, May 27, 2009]
 Times Online, Bill Dunn, Ibid.
 Museum Victoria, "Sunshine Stripper Harvester Model, 1899" http://museumvictoria.com.au/discoverycentre/infosheets/sunshine-stripper-harvester/ [Accessed Wednesday, May 27, 2009]
 ABC Landline, Tim Lee, "New evidence casts doubt on harvester history" http://www.abc.net.au/landline/content/2005/s1320660.htm [Accessed Wednesday, May 27, 2009]