Although it's not certain who first said it, the proverb, "necessity is the mother of invention" has been translated in Plato works and was used in England as early as the 1500s. Over 500 years later, that expression still rings true, especially among farmer-inventors. Farmers know it's not always practical to have a mechanic fix a broken piece of equipment, and with a little bit of farmer's ingenuity, many opt to fix these issues themselves. The same philosophy applies to creating a new piece of machinery.
Numerous pieces of farm equipment throughout history fall under this category. An example Randy Leffingwell points out in his book, The American Farm Tractor, is the first portable grain cleaner, invented by Daniel Best, who, like many farmers in the mid-1800s, moved out west to prospect for gold. Like many, he wasn't successful, and after working in the lumber industry in both Oregon and Washington, he moved to Marysville, California to farm with his brothers.
It was here that this proverb came into play. After he found out they had to haul grain into Marysville and pay $3 a ton to have it cleaned, Best began to designing portable cleaners, and built three cleaning machines in the following year. He soon started manufacturing them on a mass scale, and went on to build combines, steam-powered tractors and combines, and earn numerous patents on his inventions. He became a major competitor with another inventor at the time, Benjamin Holt, who would acquire Best's company in 1908, before Holt Manufacturing Company became known as Holt Caterpillar Company.
This kind of innovation is still around today of course, whether it's making a proven piece of machinery a little better by adding to it to suit the farmer's needs, or building a brand new implement altogether. While a lot of inventions are made by the manufacturer to meet the specific needs of farmers, the number of farmers with patents on their own inventions never ceases to amaze me.