Properties of Soils Notes Sheet
Name: ___________________________________________
Date:
1. Most people take soil for granted
a.
b.
c.
d.
2. Scientists recognize five main factors that influence soil formation.
a. 1.
b. 2.
c. 3
d. 4.
e. 5.
3. Parent Material
a. Refers to both the _____________________ and __________________ material in
which soil formation takes place.
b. Mineral can include:
c. Soil formation will happen more ___________________ in material that are more
permeable to water.
4. Climate
a. Climate influences the amount of _________________________available for weathering
the parent material and the ________________________ at which it occurs.
b. A warm, moist climate fosters _____________ growth and speeds up
___________________________, both of which contribute to faster soil formation.
5. Living Organisms
a. ___________________ supply soil with organic material and help prevent erosion.
b. Deep-rooted plants have a ____________________ impact on soil formation than
shallow-rooted plants because they create ________________ channels for
_________________ movement.
c. Insects, ________________________, fungi and bacteria are important because they
help decompose organic material releasing plant _______________________.
d. Erosion:
6. Topography
a. The three dimensional shape of the land influences ___________________ movement
and therefore the _________________ of soil formation.
b. Since water flows downward due to gravity, _____________ on slopes are prone to
erosion.
c. Areas that are very wet or very dry may not be __________________ and the resulting
lack of plant growth can slow the rate of soil formation.
7. Time
a. The ______________________ of rock slowly produces soils. Constant exposure to wind
and rain cause the rocky crust to break slowly down into smaller particles.
b. It can take _____________________to produce fertile topsoil.
c. As rainwater __________________ into cracks, temperature extremes cause the water
to freeze. The ______________ expands, contracts and fractures.
d. ______________________ that live on and in the soil help these weathering actions
along.
8. Humans
a. Of course, in addition to these five factors, ______________________ activity also can
influence soil formation.
b. _________________________ practices and urban development especially can interfere
with the naturally occurring process of soil formation.
9. The gradual process of soil formation produces a series of ______________________________.
a. A ____________________________: is a layer generally parallel to the soil surface,
whose physical and chemical characteristics differ from the layers above and beneath.
b. A given type of soil usually has ___________________ or ___________________
horizons.
c. _________________________ are characterized by the obvious physical characteristics
of ________________________ and ________________________.
d. The formation of soil horizons is influenced by factors such as ______________,
_______________, _____________________and ____________________________.
e. The weathering of parent material occurs first at the _____________________ and then
works its way ____________________.
1. The uppermost layers are changed (weathered) the
____________________, while the deepest layers are the most similar
to the _______________________ parent material.
10. Soil Horizons
a. The major components of soil (in addition to the
organic matter) are _____________, silt and
_________________.
b. Each horizon is labeled with its own capital letter
that identifies its place.
i. O:
ii. A:
iii. B:
iv. C:
v. R:
11. Sand, Silt and Clay
a. Gravel:
b. Sand:
c. Silt:
d. Clay:
e. Every soil type is a
mixture of sand, silt and
clay.
12. Sand
a. Too _______________________
b. Soils with lots of _____________________ have big spaces between the particles.
c. They don’t hold water or ____________________________.
d. Sandy soils don’t stick together very well. _____________________________________
can’t hold onto this soil but the big spaces do allow air into the soil.
e. There are some plants that are able to grow in sandy topsoil by putting their roots deep,
through the sand to the subsoil
13. Silt
a. Too _____________________
b. This is material which is finer than sand, but still feels gritty.
c. Silt is commonly found in floodplains and is the soil component that makes mud.
d. Soils with a lot of silt make excellent __________________ land, but erode easily.
e. This is the soil blown away in dust storms and carried downstream in floods.
14. Clay
a. Too _____________________
b. Lots of clay makes the soil ______________________ and dense. The spaces between
soil particles are very tiny. When clay is dry, it’s almost as hard as concrete.
c. Plant roots can’t push through it. No air can get in from the surface.
d. Most _______________________ and other soil organisms that need oxygen can’t
breathe. But clay is important because it can change the soil chemistry.
15. Loam
a. Just __________________
b. The perfect soil for plants and soil organisms has about the same amount of sand and silt
plus a small amount of clay. This soil has enough large and small spaces for air and water
to flow in.
c. It also has enough clay to let it ______________________ together and hold humus.
1. The dark organic material in soils produced by the decomposition of
vegetable or animal matter and is essential to the fertility of the earth.
d. These clumps make another size of space. Plant roots can easily grow through these
spaces.
16. Surface area and particle size
a. Calculating surface area of a cube is simpler than calculating surface area of a sphere.
i. Formula:
17. Soil Texture
a. During soil formation, _______________________ material is broken down by
weathering into particles of various sizes.
b. Soil Texture:
c. Scientists classify soil particles into three categories: Sand, silt and clay.
18. Soil Triangle
a. Soils vary in their proportions of clay, silt and sand
b. Soil scientists classify different soil types using the
______________________________________.
c. Each side of the soil triangle represents the __________________________ of a particle
of a certain size – clay silt and sand.
d. The relative amounts of these three soil components intersect within the triangle and
determine to what type of soil those proportions correspond.
e. The soil triangle diagram is divided into __________________ soil classifications based
on the amount of sand, silt and clay in the soil.
f.
A ___________________ includes an ideal mix of sand, silt and clay for many crop plants.
19. Properties of soil particles
a. The ability of a soil to accept and retain water is largely determined by the relative
amounts of:
b. Porosity:
c. Permeability:
d. Loamy soils typically contain about __________________ air space which allows root
systems to “breathe”
e. The organic material is composed of living organisms, plant roots and plant and animal
residue.
f.
1 gram of healthy topsoil contains: