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In this lesson we are going to discuss about the properties and characteristics of soils

Answer Text:
Properties and
Characteristics of Soil
a) Texture

- Composition of soil in terms of its particles.
- Can be coarse/gritty (sand), medium (loam) or fine (clay).
Importance
a) Determines soil water retention by that coarse grained soils have poor retention while those fine
grained have high water retention.
b) Influences ease of root penetration into the soil whereby it is easy on coarse textured and difficult in fine textured.
c) Determining soil fertility in that clay content prevents humus from being washed down the soil by water.
b) Structure
- Arrangement of soil particles into aggregate compound particles.
Types
i) Crump soil structure - soil made of small, soft, groups of particles of irregular shape.
ii) Granular structure - soil made of porous groups of particles of irregular shape called granules.
iii) Plate structure - soil made of plate like flat particles arranged in horizontal manner.
iv) Prismatic structure - soil made of vertical prism like particles with rounded tops.
v) Blocky structure - soil made of irregular pieces of soil with sharp corners and edges.

c) Soil PH
- Basicity or acidity measure of a soil.
- Sulphate/phosphate - acidity
- Calcium/magnesium - Basicity
Importance
i) Influences the activity of soil micro-organisms and hence decomposition of organic matter.
ii) Influences rate at which roots absorb minerals.
iii) Determines the types of crops to be grown e.g. tea acidic.
iv) Determines availability of different nutrients to the plants e.g. phosphorous is not available at low PH while
potassium and iron not available at high PH.
d) Soil Colour
- Visible quality of soil.
Dark brown or black – considerable amount of organic matter.
Grey - poorly drained or water logged.
Whitish - lacks organic matter, iron oxides and has soluble salts concentration.
Importance
i) Influences soil temperature in that light coloured soils have low temperature and hence low organism activity.
ii) High temp destroy humus, increase organism activity and provide warmth required for germination.
e) Soil Porosity

- Amount of pore spaces in a soil sample.
Importance
i) Influence soil water retention. Clay has high retention and is water logged because it doesn’t allow
drainage due to many tiny pore spaces while sand has poor water retention due to rapid percolation caused by large pore spaces.
f) Soil Permeability
- Ability to allow the water to pass through.
- Depends on texture and porosity.
Clay is impermeable due to being fine textured and tiny pored while sand is permeable due to being coarse textured and very porous.