Soil

Soil

Soil contains
1. Rock particles
2. Humus (dead materials)
3. Living organisms (fungi, protozoa, nematode, earthworms, snails, and bacteria)
4. Air containing oxygen
5. Water containing dissolved minerals (e.g. magnesium)
Soils differ in various ways
1. pH
2. water content
3. mineral content
The best soil is
1. not waterlogged - prevents oxygen getting to the roots. This is needed for earthworms + bacteria also
2. has a neutral pH
3. rich in minerals
Ways to improve soil
1. Add lime to neutralise acidic soild
2. Add sand to waterlogged ground - separates soil particles which creates spaces for water to drain through
3. Aerate the soil with a pitchfork to allow oxygen to get in for respiration in plants and soil animals
Earthworms improve soil by
1. Burrowing = aerates soil, improves drainage
2. Mixing layers in soil
3. Moving dead, organic material from the surface down to allow decomposers bacteria and fungi) to work
4. Adds chalk as it eats the soil to neutralise it
Sandy soil has the biggest particles - the water and air can move through as it has has spaces between particles
Separating soil
1. 1. Weigh, evaporate water, re-weigh
  1. 2. Water displaces the air, measure volume
    1. 3. Weigh, heat to high temperature e.g. 550 degrees celcius, re-weigh - burns off the humus
Organisms living in the soil need water for photosynthesis and oxygen for respiration
Humus increases fertiliity of soil (as it provides more minerals)
It is important to neutralise soil because a lot of plants will not grow in acidic conditions so this will provide the optimum pH for growth
Herbivores = eat plants only
1. Detrivores = eat dead/decomposed material only
  1. Carnivores = eat meat only

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	Created by alice.finlay over 11 years ago