soil: the nexus

the "solid ground" we walk on is only about 50% solid — made mostly of minerals and 1-10% organic matter. the remaining 50% is open, pore space — filled with either air or water.


ecosystem services

soils are the foundation of nearly every ecosystem on the planet, providing important services that give rise to healthy plants, healthy people, and a healthy planet!

1. climate regulation2. medium for plant growth3.water filtration4. nutrient cycling5.water storage6. historical record7. habitat/biodiversity8. carbon storage9. engineering medium

"essentially, all life depends upon the soil... there can be no life without soil and no soil without life; they have evolved together." -charles kellogg

soil formation

rock weathering

through a combination of physical, biological, and chemical processes, rocks break down into smaller and smaller pieces.

physical chemicalbiologicalfaunarootsOHOCH3microbesAe-e-ABBe-e-dissolutionhydrolysisCO-O-O-+H+Hcarbonic acid weatheringroot expansionwind abrasiongravityfreeze/thaw

parent material


- rocks either weather in place or are deposited in one of the following ways:



- rocks are composed of different types of minerals that weather at different rates