The First Discovery

Crop rotation makes for sustainable agriculture. Without it land loses the ability to sustain a population. The Romans understood crop rotation, but practiced a two field rotation. One field was used and the other was fallow. As a result, 50% of their agricultural land was producing food. In the Middle Ages three field crop rotation was discovered. By planting different types of crops in cycles, two thirds of the land was producing food while one third was fallow. This resulted in 32% more food being grown on the same amount of land. As such three field crop rotation makes my list of one of the top five.