Layers of Soil | Soil Profile Formation

soil is a living breathing organism that feeds everything on the planet a vast Hidden World of biodiversity so what is soil and where did it come from what type of soil is in your yard in your neighborhood we will answer these questions and conduct some experiments together and this episode all about soil a quarter of our planet's biodiversity is made up of soil organisms living in the ground small animals tunnel and redistribute soil earthworms aerate and improve soil microorganisms break down

organic material hold nutrients and bind soil particles together what is soil soil is composed of roughly 45 percent minerals that's sand silt and Clay 20 to 30 percent air and 20 to 30 percent water the rest of that is five to ten percent of organic material now that's anything that is currently or formally alive and all the microbes the mineral parts of soil the sand silt and Clay are categorized by size now you roughly know about how big a grain of sand is now silt particles are about the thi

ckness of a strand of hair and Clay particles are too small to even be seen hmm so in this experiment what you need to do is first collect your soil sample [Music] here are the soil samples that we've collected so hopefully because we've collected them in three different places each composition will be different but we have to wait and see you want to place it in a clear container my containers are plastic just because we're going to shake them in a minute and I don't trust myself with glass the

n you're going to fill it up about halfway with water put the lid on Shake it really good and then you need to wait a little bit let it settle and then observe so let's do it okay we already have stuff floating on the top let's put the lids on and shake each one [Music] okay now we wait I think I'm gonna go make a sandwich we're back our soil sample has been mixed up settled now we can see the composition of each one let's start with this one this one is mostly sand you can see that here at the

bottom and then there's a thin layer of silt it's the darker layer here on top and then there's a very fine layer of clay at the very very top it's light so when you do your soil sample the sand is always going to be at the very bottom because it's the biggest particle and it's the heaviest so when you're shaking everything around it all comes loose and then the heaviest particles are going to settle first then the silt then the clay remember the clay is the finest particles that we can't even s

ee and then always at the top will be floating organic material this one barely has any sand at all you can see that it's a darker color most of the way through that's silt then you see that very defined layer right here that's clay so so here we have a very thin layer of silt it's mostly sand here on the bottom then a thin layer of silt and then mostly clay actually I bet if we let this one settle for like 24 hours we would find that it was even more clay because the water is still so cloudy tr

y this experiment at home and then comment down below and let me know what kind of soil you have how is soil made soil is created when Nature has its way with the coating of minerals on the earth weathering that's rain heat freeze thaw Cycles gradually turn rock into sand silt and Clay particles this creates something a little more workable than rocks but it's the living organisms that do all the heavy lifting as microbes lichen plants and animals move in an enrichment cycle is created that make

s the soil more hospitable to plants Waters rule soil wouldn't even be possible without precipitation as water is absorbed into the ground it collects all the surrounding minerals and becomes soil water it carries nutrients further down so plants can absorb them with their Roots but the soil water doesn't stop at plant roots it can filter down to the deeper levels and keep leaching and depleting the nutrients from the topsoil soil layers if you were to slice down into the Earth you would see sev

eral different layers or Horizons this is called a soil profile let's go find some soil layers here in this Creek bed is a great example of our soil layers we can see all of the layers represented right here at the very top are all the plant roots invisibly darker organic matter then we move down to more Sandy and Clay type soil full of minerals and other nutrients leeched down then we get to the rocky parent material and the Bedrock you can see a cut out here into the Rock to see how it's solid

so here we have a paper model of all of those soil layers in the description below there is a link to this exact resource so let's look at these layers and go over what we can find in each one if you're still here liking this video and getting some benefit from it please show your support by hitting that like button leaving a comment below saying slow rocks and most importantly Please Subscribe this top layer is what we can see when we go outside and look around this top layer is the organic la

yer or the O Horizon this layer has humus which is rich in organic material below this is the a horizon commonly called topsoil lots of nutrients decomposed in organic material mixed in the plant's roots and burrowing animals are found here next is the B horizon or subsoil think of this as the storage center containing all of the silt and minerals that have been leached down by that soil water we were talking about earlier then there's the sea horizon or parent material this layer is full of par

tially broken rock then finally we have the r horizon or the Bedrock this is a bunch of unbroken parent material this is just an example soil profiles are different in every ecosystem climate vegetation topography all influence how soil is formed and its composition if you want to try another experiment with soil check out the soil pH experiment next