Which natural resource takes 200 years to form per centimeter?

And the answer: soil.  
Photo credit: HolgerK

New soil is a valuable and limited resource. In ideal climate conditions, it takes between 200-400 years to form per centimeter. Once soil has taken on an excessive amount of water-soluble salt—a process known as salinization—it is difficult and sometimes nearly impossible to reverse the damage or repurpose the soil.

We may walk all over it every single day (ba dum tss), but soil is actually a very complex biome that is home to many different kinds of organisms. In fact, one tablespoon of soil has more organisms in it than there are humans on Earth! Interestingly, when soil organisms get energy for growth from organic molecules, they “respire,” just as plant roots do, by using oxygen and releasing carbon dioxide to the atmosphere. So, yes, in that sense the ground is actually “breathing”!

Organisms that depend on soil for survival range widely in size—from microorganisms like bacteria, to small animals like earthworms. The ability for one species to thrive in healthy soil greatly impacts the remaining organisms on the food chain, and so a soil can actually become “sick” in the sense that it struggles to support healthy plants. The interconnectedness of soil ecosystems can also be readily seen in these fascinating recent research findings, which discovered that the roots systems of trees are interconnected by a symbiotic (AKA mutually beneficial), underground network of fungi. The trees actually need this system of fungal networks—not only for the nutrients it helps deliver to their roots, but also for the chemicals that allow the plants to actually communicate with one another!

Did you know?

Yesterday was World Soil Day! Around 95% of all the food we eat comes from the soil, so it’s important that we do what we can to keep our Earth clean. Each year, World Soil Day helps to bring attention to the importance of healthy soil, as well as advocating for the sustainable management of soil resources. Learn more about this year’s event here.

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