In the 16th Century, Leonardo da Vinci said: "We know more about the movement of celestial bodies than about the soil underfoot." That still rings true today. Most of us give little thought to the earth beneath our feet, yet without it our planet would be as barren as the moon. Soil is essential for life on earth. It helps plants grow, stores water and nutrients and acts as a carbon sink. And while it may appear "dead," most of the land's biodiversity lives in the soil, not above it. Just a teaspoon of it contains more microbes than there are people on earth. But soil faces many threats ranging from climate change to unsustainable farming practices.