: What is soil?

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I understand what water and air are composed of and I more or less understand how fire works. But what is soil? If you put your hands in your garden, you will take out very heterogenous stuff, you will get some twigs and bugs which of course are organic matter, but what’s the general brown stuff? Is it organic? Were does it come from and how is it produced? Also collateral question, if earth is organic matter, when the first living organisms came out of the ocean, which were plants, how did they find nutrients?

In: Planetary Science

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Anonymous 0 Comments

It is a mix of things. A lot of it is minerals. A mixture of sand, silt, clay, pebbles, etc. Typically more then half of the soil is minerals. The rest is organic. Of course you can see the bugs and the twigs. But most of the organic matter is bacteria which are so tiny you can only see them as tiny specs on a microscope. Some of these bacteria even produce glue to keep the soil together. In addition to the bacteria there are lots of other microscopic microbes like amoeba and nematodes. These are single celled organisms which eat bacteria. And of course they poop out what they don’t eat so there are lots of free proteins, amino acids, fats, etc. in the soil as well. As for the larger structures there are almost always a few big fungal networks in the soil. These are made of thin strands that you might sometimes see when digging. They stretch on for large areas, typically through the entire biome. So a single mushroom might be the size of your neighborhood connecting all your gardens together. And it may go down into the bedrock for miles.

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