People have been farming for centuries. In the beginning, work was done by hand with simple tools. As the world population continued to grow and people began living in cities, the market for food increased.
Crofters began inventing tools and small machines to do the work faster with less effort. This increased their output without having to hire as many hands to work the farm. The use of iron in the machinery added strength and longevity.
Below is a cultivator which was used in the early 1800s. It would have been pulled behind a horse, oxen or similar animal. The small wheel in the front would have helped get it from one place to another, but I wonder if it was left on once it was hooked into the harness gear. It would have easily fetched-up on stones and hard lumps of soil, making work more difficult than need be.