Soil: A mixture of minerals, organic matter, living organisms, air, and water that together support plant life.

45% inorganic mineral matter, 25% water, 25% air, 5% organic matter (microorganisms and macroorganisms)

Burrowing animals (prairie dogs, ground squirrels and badgers burrow; owls, snakes, lizards and rabbits use holes made by other animals) mix soil, facilitates water movement and reduces flooding.

Living organisms

(arthropods: ants, termites, spiders, mites, centipedes, millipedes) aerate soil, breakdown organic matter and disperse microbes.
(Nematodes: round worms) Mix and aerate soil, breakdown organic matter and disperse microbes.
(Protozoa) eat bacteria and release nutrients.
(Bacteria) Releases nutrients through nitrogen-fixation and decomposition.
(Fungi) release nutrients though decomposition, mutualistic associations with plant roots and help hold soil together.
(Earthworms) Aerate soil, break down organic matter and disperse microbes.
(Mollusk: slugs, snails) Break down organic matter and disperse microbes.
(Plants) Reduce soil erosion.

Organic matter provides food, water, shelter, and air for the living soil.

	Created by Inayah Munaf over 4 years ago

Biology Note on Plant Biology Unit 1, created by Inayah Munaf on 19/01/2020.