Soil Properties
That can be observed and measured to predict soil quality
Color
• The most obvious property when looking at soil is its color. The color of
soil can tell scientists a lot about it.
• Geologist officially recognize over 170 different soil colors. Most of
these are shades of black, brown, red, gray, and white.
• Generally speaking, the darker a soil is, the more nutrient rich it is. The
darker color often indicates an increase in decomposed organic matter
known as humus.
• Gray soils often indicate poor drainage, while red soils can indicate very
poor soils.
• These general rules about soil colors can, however, be misleading.
Under certain conditions, a very poor soil can appear as dark black,
while a rich healthy soil can appear as red.
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Temperature
• Soil temperature is even more important than air temperature in your
greenhouse, particularly if you're growing in beds.
• When soil temperatures are below 45°F, roots grow more slowly and
are less efficient at taking up water and nutrients.
• Warm soil is particularly important for germinating seeds or rooting
cuttings. 65 to 75°F is recommended for germinating most types of
seeds.
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Texture
• Another easily experienced
property of soil is texture. Pick up
a pinch of soil between your
fingers and rub it back and forth.
You will quickly notice that the
soil is made up of many different
sized particles. These particles
give the soil its texture.
• Some soils have more large
particles and fewer small
particles, while other soils have
an abundance of small particles
with few large particles. Other
soils have an equal balance
between small and large
particles. These well balanced
soils are the most healthy for
plant life and are called loam.
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Particle Size/Infiltration
• Remember: gravel is 2mm
and larger; sand is less than
2mm; silt is less than
1/16mm; and clay is less
than 1/256mm
• Infiltration is the amount of
water that passes through
the soil surface in terms of
depth (inches) in a given
time period (usually 1 hour).
• Water Retention Experiment
Video
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• Lighter textured soils
(such as sands or sandy
loams) have desirable
infiltration rates.
• 'Heavy' textured soils
which have a lot of clay
and/or silt often have
poor infiltration, because
the space that the soil
occupies is relatively
dense.
Soil Moisture
• Soil water is particularly
important in nutrient
management.
• In addition to sustaining all life
on Earth, soil water provides a
pool of dissolved nutrients that
are readily available for plant
uptake.
• Therefore, it is important to
maintain proper levels of soil
moisture.
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• Soil water is important for three
special reasons:
1. The presence of water is essential
for the all life on Earth, including
the lives of plants and organisms
in the soil.
2. Water is a necessary for the
weathering of soil. Areas with high
rainfall typically have highly
weathered soils.
3. Soil water is the medium from
which all plant nutrients are
gotten by plants. Soil water
contains dissolved organic and
inorganic substances and moves
dissolved nutrients, such as
nitrogen, phosphorus, potassium,
and calcium, to the plant roots for
absorption.
pH – How acidic is the soil?
• In order for plants to obtain the
nutrients they need to survive, these
nutrients must be carried into them
by being dissolved into the ground
water that the plants absorb
through their roots.
• If a soil has too much acid in it, the
nutrients in the soil will be dissolved
too quickly, and washed away as the
water drains. If a soil is too alkaline
(basic), or in other words, if there is
not enough acid, then nutrients will
not dissolve quickly enough.
• Thus, a neutral soil, which is neither
too acidic nor too alkaline, is the
preferred type of soil for plant life to
thrive.
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Fertility
• Fertile soil is crucial for our
existence!
• Soil plays an essential part in our
survival since it is connected to our
food supplies.
Here’s why:
• Fertile soil ensures plant survival.
Fertile soil holds plants in place
while providing them with the lifesupporting nutrients that they need
to survive.
• Plants ensure our survival. The
food (nutrients) that all living
organisms, including humans need
in order to survive comes
immediately or indirectly from
plants.
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• So, soil fertility is important.
Without fertile soil we would
have no plants. Without
plants we would have no
food. And without food,
there is no us, since we need
food to survive.
• Fertile soil helps plants take
up the ingredients required
for photosynthesis.
• Fertile soil provides plants
with lots of additional "food"
that supports plant life.
Soil Property Video
• Soil Properties Video
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