School Papers

Most that surrounds soil particles (, n.d.). There

soil comes from rocks after the rocks have been weathered (, n.d.).
Soils are made from complex structures of solid grains which are separated by
pores, channels and cavities (, n.d.). The solids are chemically
active and are always gradually changing in structure and shape (,
n.d.). The pores contain a mixture of air and water which are changing and many
microscopic organisms (, n.d.). Animals that live in soil are consumers
and decomposers (, n.d.). One animal that lives in the soil
are worms, one type of worm is Earthworms, they live off plant material and
organic matter, and excrete worm castings in the soil as food for other
organisms that live in the soil, n.d.). microscopic worms
called nematodes, or roundworms also live in soil, they live in the water that
surrounds soil particles (, n.d.). There are numerous
different types of nematodes, some eat dead materials, some eat living roots,
and some eat other organisms (, n.d.). There are also many
arthropods in the soil, that have exoskeletons and jointed legs. These include
millipedes, springtails, and centipedes, n.d.). Bacteria are
the most abundant organism in the soil, with there being billions per gram
(, 2005). There are different types of bacteria, decomposers
are involved in the initial steps of decomposition of organic materials,
Nitrogen fixers convert nitrogen from the atmosphere into substances that
plants can use e.g. Rhizobium bacteria found on root nodules of legume plants,
Disease suppressors release antibiotic substances that will suppress certain
competitors, Actinobacteria assistance in slowly breaking down humates and
humic acids in soils, Sulphur oxidisers like Thiobacillus bacteria convert
sulphides (which in this form can’t be used by plants) into sulphates (form
plants can use), Aerobes and anaerobes, Aerobic bacteria dominate in well-drained
soil where there is oxygen present but anaerobic bacteria do not need oxygen
and favour waterlogged soil, they can produce toxic compounds causeĀ