Soil
Scientists think it takes 200-300 years for 1 cm of soil to form! Soil is made through the weathering of rocks, combined with living organisms, & decaying organic material Scientists think it takes 200-300 years for 1 cm of soil to form!
What sediments make up Soil? Sand – good drainage and aeration Silt – good for plant growth Clay – holds water well, doesn’t drain well.
Let’a try a few together on the handout: Texture Loam is best because it has equal distribution of all 3 sediments Let’a try a few together on the handout: 1. 40% sand 50% silt 10% clay 2. 30% sand 40% silt 30% clay
What soil type(s) do we have in Mecklenburg County?
Climate - provides sources of erosion How are soils formed? Climate - provides sources of erosion Relief or topography - affects the retention of soil Organisms: - breaks down to provide nutrients Parent Material - must have starting bedrock material to break down Time - nutrients accumulate until they are at a stable place BrainPop on Soil
Porosity
Soil Layers R Horizon Bedrock (parent material) In Piedmont of NC, this is Igneous and Metamorphic rocks For our model, let’s start with a bedrock of marshmallow igneous rocks!
Soil Layers Aquifer This is where our groundwater is For our model, let’s use pudding to replicate our aquifer! High porosity
Soil Layers C Horizon Broken down parts of bedrock; no roots or organic material For our model, let’s use Hershey’s kisses to simulate regolith!
Soil Layers B Horizon AKA subsoil; little organic matter, mostly clay from above layers For our model, let’s use big pieces of Oreo cookie to represent the subsoil!
Soil Layers E Horizon Mostly sand and silt; most of clay has leached down to B horizon For our model, let’s use vanilla wafer crumbs to represent the subsoil!
Soil Layers A Horizon Dark colored and most fertile; lots of organic matter For our model, let’s use graham cracker crumbs to represent topsoil!
Soil Layers O Horizon Where most organisms (plants and animals) exist For our model, let’s use gummy worms to represent decomposers!