Quantifying Soil Sustainability on Habitable Worlds.

So, you want to farm on Mars? On Asteroids, the moon, distant planets or other habitable worlds? The movie, The Martian, made it look pretty cool on the big screen and our collective popular imagination sure makes the image of moving to another planet to escape overpopulation and climate change seem appealing and practical. But, at the most basic level, we need soil to farm. Here on Earth, we can all recognize sensational images of erosion: the Dust Bowl of the 1930’s, dust plumes spreading east from China, the brown Amazon reaching far into the Atlantic Ocean, and our own haboobs in Phoenix. What we generally don’t recognize or think about is how and whether this dramatically lost soil is replenished through soil production. There’s a simple truism underlying this relationship: if erosion exceeds soil production, then soil is stripped and the landscape is laid bare. It is, therefore, rendered non-farmable. To predict what will happen across any landscape, here or on another planet, we must therefore know rates and processes of erosion and soil production for that landscape. My research group focuses on the science underlying the quantification of these processes on Earth. How do we quantify rates and processes of soil production and erosion on a planet that we don’t live on? This talk explores those challenges through the lens of a Mars analogue, the Atacama Desert of Chile. We have quantified rates and processes of soil production and erosion there and have learned a great deal about the challenges of applying conceptual frameworks developed for more typical Earth environments. I will briefly review these conceptual frameworks before elaborating on how and why they don’t apply to the landscape of the Atacama, as well as how we arrived at a new conceptual framework that may be applicable beyond Earth.