Moray is composed of three groups of circular terraces (muyus in Quechua) that descend 490 feet (150 meters) from the highest terrace to the lowest. Each muyu has 12 levels of terraces with the largest depression having a diameter of 600-feet.
It is widely believed that the Moray ruins were used as an experimental farm by the Incas over 500 years ago. The place has an Inca irrigation system consisting of a series of channels fed by water from a reservoir located higher in the mountains.
The temperature difference from top to bottom orf a muyus can range an astonishing 27 degrees Fahrenheit (12 degrees Celsius).
Also the sun hit each terrace at different angles and intensities. Each terrace at Moray had its own microclimate. This allowed the Incas to study the effects of altitude, temperature, and sun absorption on crop growth to determine ecological niches suitable for crops to thrive.
Taken from Nana Geruni