Midori Kirby
APES FORMAL LAB
Title: Soil Quality – Physical, Chemical, Biological Testing
Purpose: To observe and determine physical, chemical, and biological factors of a soil sample to
determine its quality and how it could be improved.
Procedure:
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Go to the area you will be taking your soil sample and remove a 6”x6”x8” sample from the
ground with a spade.
Spread the soil that was taken on a sheet of paper above a table and first perform the physical
testing to determine particle size and texture and estimate the type of soil obtained. You must
estimate your soil type by general observation, feel (through the flow chart), and
fractionalization.
Perform the chemical tests to find soil fertility based on pH, and values of nitrogen, phosphorus,
and potassium.
Perform the biological test by picking out organisms from your sample. Make sure to identify
each organism and look for biodiversity.
Data:
Individual data:
Physical Testing:
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Profile: some grayish pebbles in soil, but mostly light tan. Darker towards the top portion of the
soil.
There are many roots in our sample. It seems as if it has little color variation. The color indicates
that our soil is mostly clay and silt, meaning it had good water retention and is about 7.5 4/6
years old.
Sample is most likely sandy clay loam
Soil Components:
Sand
40%
Silt
16%
Chemical Testing:
Test
Nitrogen
Phosphorus
Potassium
pH
Result
Depleted
Adequate
Depleted
7.5 Alkaline
Clay
44%
Midori Kirby
APES FORMAL LAB
Biological Test:
From our sample there were 18 earthworms found. No other organism was able to be found. This may
have been because the sample was depleted in Nitrogen and Potassium, decreasing the soil quality and
fertility.
Data from whole class:
GROUP
Part 1
Soil Profile
1
Part 3
Soil
Texture
Part 4
Soil
Texture
Part 5
Fertility
Part 6
Biodiversity
Mostly sand, Gritty, light
clay on
brown color
bottom,
organic
material on
top
Sandy clay
loam
Sandy
loam
Ants: 9
Worms: 4
Spider: 1
2
lots of silt
and organic
material
Dark brown
color, very wet
and malleable,
neither gritty
nor smooth
Clay loam
silt
3
Some gray
patches in
soil, inside is
darker than
the outside.
Very clay-ish
and chunky
Mostly sand
& silt, easily
broken
apart
Lots of roots,
Sandy clay
dense clay, small loam
variation of
color
Clay
Clumps of clay,
dark brown soil
color, mainly
smaller
particles, slightly
damp and
crumbly
Reddish-Brown
chunks of clay,
in large
particles.
Sandy clay
loam
Loam
Silty Clay
Loam
Silty Clay
Loam
NitrogenDepleted
PhosphorousAdequate
PotassiumSufficient
pH- 7.5
Nitrogendepleted
Phosphorusdeficient
Potassiumsufficient
pH- 7.5
NitrogenDepleted
PhosphorousAdequate
Potassium:
Depleted
pH- 7.5
Nitrogendepleted
Phosphorousadequate
Potassiumadequate
pH- 6.5
NitrogenDepleted
PhosphorousDeficient
PotassiumAdequate
pH- 6.5
4
5
Mostly silt
and clay.
Easily
moldable
and damp.
Part 2
General
Observations
Millipedes: 2
Earthworms:
18
Pill Bugs: 2
Worms: 2
Beetle: 1
Millipede: 1
Ant: 1
Worms: 6
Millipede: 1
Midori Kirby
APES FORMAL LAB
6
Mostly silt
Dark brown with Loam
Loam
NitrogenNo
with small
lighter shades of
Depleted
organisms
amount of
clay. Held
Phosphorus- found
clay below.
together in
Depleted
Some
clumps. Several
Potassium clumps and
small roots in
Sufficient
damp.
soil.
Our group ( group 3 ) had less biodiversity than most of the other groups but had a large quantity of
earth worms. This may have been because our sample had very little decomposed material on the
surface which often times harvests organisms like ants and beetles.
Analysis:
1. Humus provides nutrients along with metals and minerals. It also contains microorganisms that
help breakdown waste and absorb nutrients from soil.
2. Top soil components are mainly minerals, organic matter, water and air. We are losing topsoil at
an alarming rate mostly because of agricultural reasons like frequent tilling of land. It is also
caused by deforestation and the decrease in vegetation that prevents erosion. A way to reduce
topsoil loss is to not till land between planting, leaving crop stubble to reduce erosion, and
planting new seeds between crop stubble.
3. Layers in a soil profile: HORIZONS
In the North Carolina Piedmont area, the surface layer is a dark gray sandy loam while the
subsoil layer contains red clay with clay loam.
4. pH is important because it will influence what kind of organisms that will live in the soil. pH
allows nutrients to become soluble in water and be absorbed by roots. When pH is too high or
too low, it becomes infertile because it cannot sustain life for organisms or gain certain nutrients
even if they are present in the soil because most nutrients are less soluble in basic soil
conditions.
5. Some natural sources of nitrogen, potassium, and phosphorus:
Nitrogen is found abundantly in the atmosphere. Potassium and phosphorus both are found in
decaying or decomposed organisms.
6. Atmospheric Nitrogen is converted into ammonia, a form that plants can easily absorb through
their roots by nitrogen fixation.
7. Living organisms use nitrogen, potassium, and phosphorus to produce complex organic
molecules and nucleic acid and cell energy generation. There nutrients also play a role in
nervous, circulatory, and neurological system processes.
8. Our sample soil was not very fertile because it was depleted in nitrogen and potassium, which
would stunt the photosynthetic process and cause vegetation to have yellowish leaves that die
off near the bottom. It also had a pH of 7.5 meaning those primary nutrients would not be able
to dissolve more readily as it would be able to in a more acidic condition.
9. Because our soil type was sandy clay loam or clay, and the pH was 7.5, it could probably only
sustain grasses and landscaping vegetation. Most fruit based plants need a more acidic soil type
to be able to flourish.
Midori Kirby
APES FORMAL LAB
10. Our soil sample had very little soil diversity and consisted of only earthworms. Because we took
our sample from an area that had very little to no vegetation, it may have been unhealthy,
infertile soil, which organisms would not want to live in.
11. What could have gone wrong in the experiment? We could have missed other organisms in the
soil which would affect our data of biodiversity. Also when taking the percentages of soil
composition we may not have allowed the sample to settle out completely in the graduated
cylinder, giving up an inaccurate description of the soil composition.
Conclusion:
What improvements should be made to your soil?
Fertilizer can be added to supplement the depleted nutrients of nitrogen and potassium. It is
also a pretty basic soil type so by increasing its acidity it would be able to support more acid loving
plants such as blueberries, azaleas, etc. We could also introduce a larger variety of organisms to the area
to help break down decaying organic material to increase the fertility of the soil.