101 Questions answered
Microbial Hotspots: Where Soil Life Thrives
Soil microbes hang out near their food, which is mostly around:
Plant roots. The rhizosphere is the small area (2-3 mm) of soil immediately around plant roots. Bacteria feed on the protein and sugars roots excrete, and broken-off root cells. Nematodes and protozoa that eat the bacteria tend to stay here too.
Soil organic matter. It contains carbon, water, nitrogen, and other nutrients microbes to feed on.
Decomposing crop residues. They’re only decomposing because soil biology is at work. Also a favourite for bigger soil life like mites, termites and earthworms.
Microbes also like to live on the edges of soil particles, in pores, and sometimes inside soil aggregates.
Most microbial life is in the top 0–15 cm of soil. The deeper you go in the soil, the less food there is, and fewer microbes.
Most microbes also need to be in contact with water, either in water in pores, aggregates, or a water film on the surface of an aggregate. They don’t move much unless they can travel through water. Bigger life like worms and insects can move about as they please.
