Hiram Moore (1801-1875) If you look back at the US employment statistics for the late 1700s, about 90 percent of the workforce was employed in agriculture. Nearly the entire population spent their time growing food. Then engineers got involved in food production, and agriculture took off in terms of efficiency. The combine harvester, which was first developed by Hiram Moore in 1835, was one huge innovation that led the charge. Today, America produces all the food it needs (and then some) with about 1 percent of the workforce. Chemical engineers produce pesticides and fertilizers. Mechanical engineers produce machinery and tools. We produce far more food per acre of land and per person than ever before. Harvesting grain used to be labor intensive and time consuming. People with scythes would cut a swath of wheat or oats and tie the stalks into sheaves. The sheaves would be transported to a threshing floor where feet or flails would separate the grain from the stalks. Then winnowing would separate the wheat from the chaff. Harvesting a big field could take dozens of people many days. A modern combine does all this work quickly and efficiently in one step. The machine has a cutting bar up front. The stalks are ingested into the body of the machine on a conveyor. Inside the body, a threshing drum separates the grain, and a series of sieves and fans winnows the grain. The straw and chaff fall back to the field while the grain moves to a holding tank. A truck pulls up and offloads the grain from the tank periodically. A big combine harvester like this with a single driver can handle one hundred or more acres per day of grain, beans, or corn. A person with a scythe might do one acre a day, with several people following behind to make the sheaves. The work of transporting, threshing, and winnowing took even more people. That improvement in human productivity shows the power of engineering. It drastically reduces costs. Similar improvements in plowing, planting, cultivating, and fertilizing, not to mention center-pivot irrigation and, later, drip irrigation, make today's farmers incredibly efficient.