Soil Analysis Lab
Purpose
 Analyze a soil sample and remediate soil based on analysis
Introduction
Collect a soil sample by digging a small hole at least 2 inches deep. Remove
any stones, roots, grass, or thatch from the sample and place it in a plastic
sealable bag. Make notes on the surroundings where you collected your
sample. Factors such as plant life, buildings, walkways, and paved areas may
influence some of your tests and give clues about why you got the results
you measured.
(DAY 1) Part One: General Observation
Take some of your sample and carefully place it on a tray or large piece of paper towel.
Look closely, at your soil sample. What did you see? Record the forms of organic
matter, such as worms, insects, plant roots, etc. Observe and comment on the various
particle sizes. Do any sizes dominate? Use a hand lens and draw what you see.
1. General Observation:
2. Abiotic component of your sample:
3. Biotic components of your sample:
(DAY 1 & 2) Part Two: Soil Texture
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 Centimeter Ruler
 Soil Sample
 Wooden Stir Stick
Soil is made of mineral particles belonging to three size categories: clay, silt, and sand.
The size of soil particles is important. Large particles of sand allow empty space for air
and water to enter the soil. Smaller silt and clay particles help hold the water in a soil so
that it does not drain away too quickly to be of use to plants. The ratio of these materials,
or texture, can be determined qualitatively and quantitatively.
Water
100-mL Graduated cylinder
(DAY 1) Qualitative Test Take a small moist wad of your sample and squeeze it
between your thumb and forefinger. If it feels gritty, then you have mostly sand. If it
feels sticky, then you have mostly clay. It is feels neither gritty nor sticky, then you have
mostly silt.
If you can squeeze out a long, unbroken ribbon of soil from your finger, you have clay.
If you can squeeze out a short ribbon, you have silt or loam. If you cannot form a ribbon,
then you have sand or sandy loam.
1. What type of soil do you think you have? Why?
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Quantitative Test In a 100-ml graduated cylinder, place about 60 mL of your soil sample. Add
enough water to saturate the soil completely and then keep adding water until the level gets to
about the 100-mL mark. Now place your hand tightly over the open end of the graduated
cylinder to seal it and shake the whole aparatus until the soil and water completely mix to make a
free moving slurry. Be sure to break up any lumps in the soil. Do this for at least one minute.
Now place the graduated cylinder in a safe place for 24 hours, to let the soils settle out. The
denser, larger sand particles will settle out first and be on the bottom of the cylinder. A layer of
silt will settle out on top of the sand and finally, after 12 to 24 hours, the tiny clay particles will
settle out on top of the silt.
(DAY 2) For calculations, show all setups with proper units.
2. With a centimeter ruler, measure the height of each layer and the total height of the
sample. Calculate the percent or sand, silt, and clay in the sample.
Total Height: ______cm, _______ %
Silt:
Sand:
Clay: ______cm, _______ %
______cm, _______ %
______cm, _______ %
3. What type of soil do you have? Use the Soil Triangle.
4. How does your answer compare to the qualitative method?
5. Compare your soil texture to the results other in class have measured. Which sites
were the most sandy, silty, clay-like?
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6. Hypothesize why the soils are the way they are. How were they actally formed?
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7. If there were plants growing naturally in the area where you took your samples, do
they prefer a particular soil type (research)?
(DAY 1 & 2) Part Three: Soil Moisture
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Aluminum
Drying Oven
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.001 g Scale
Soil Sample
(DAY 1) You will now measure the amount of water in your soil sample. Make a small
tray of aluminum foil and record the mass. Write your name on you foil. Then put about
a cup of soil on the tray, spread it out on the aluminum (for quicker drying) and again
record its mass. Now put the tray with your sample into a drying oven for 24 hours, at a
temperature of 90-95o C.
(DAY 2) After 24 hours, remove the soil sample, let the sample cool and again record
its mass. Any mass loss will most likely be water.
1. Determine the percent water, by mass, in your sample. Show your work.
Mass of aluminum tray empty:
______ g
Mass of tray + soil sample before heating:
______ g
Mass of tray + soil sample after heating:
______ g
Mass loss due to heating:
______ g
______% mass loss
2. Compare the soil moisture of your sample to your soil texture results in Part Two.
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3. Is there a pattern or correlation between soil moisture and texture, based on results by
other members of the class? Describe it.
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(DAY 2) Part Four: Percent Organic Matter
*On Day 2, two partners should start this right away!
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Crucible
 Oven dried Soil Sample
Crucible tongs
 Ring stand and ring clamp
.001 g Scale
 Pipe Stem Triangle
Bunsen burner
 Lighter
To measure the organic matter, you will have to burn the soil at a high temperature to
convert as much of it as possible into CO2 and H2O. Since the general procedure
involves measuring mass loss, you must first ensure the dryness of the sample.
Record the mass of a clean, dry porcelain crucible and fill it about ¾ full of your oven
dried soil sample. Record the mass of the crucible plus the dry soil. Near the window,
place the crucible with the soil on a ring stand, using an iron ring and pipe stem triangle.
Heat it gently for a few minutes and then heat it as hot as you can for about 30 minutes.
(it may glow and/or smoke) Shut off the burner and allow the crucible to cool. Now
record the mass of the crucible and soil again.
1. Calculate the organic matter in the sample (the loss of mass). Show your work.
Mass of empty crucible: _______ g
Mass of crucible + dry soil: _______ g
Mass of crucible + soil after heating: _______ g
Percent organics in sample: _______ %
2. Why is it not necessary to measure the mass of the soil alone?
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3. Give at least three reasons why it is important to have organic material in soil.
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(DAY 2) Part Five: Soil Fertility Analysis
*You will have an assigned time to complete this section. Watch your time.
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Color charts
Floc-Ex, N, P, and K Tablets
0.5 g measuring scoop
Pipet
Plastic teaspoon
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30-mL Test Tube
10-mL Test Tube
Oven dried soil sample
pH indicator
Four variables are important in determining the fertility of soils. They are: pH and the
amount of nitrogen, phosphorus, and potassium. The values of each of these components
can serve as a limiting factor in the growth of plants.
pH: Fill the test tube with 4-ml of pH indicator. Use the 0.5 g scoop to add .15g of soil
sample to the test tube. Cap and shake gently for one minute. Allow tube to stand for 10
minutes to let soil settle. Match color of water with the pH Color Chart. Record the pH.
Extraction: Fill the round extraction tube to the 30mL line with distilled water. Add two
Floc-Ex Tablets (5504). Cap the tube and mix until the tablets have disintegrated.
Remove the cap. Add one heaping teaspoon of soil. Cap the tube and shake for one
minute. Let the tube stand until the soil settles out. The clear solution above the soil
will be used for the Nitrate, Phosphorus, and Potassium tests.
Nitrogen: Use the pipet to transfer the clear solution above the soil to a square test tube
until it is filled to the shoulder. Add one Nitrate WR CTA Tablet (3703). Cap and mix
until the tablet disintegrates. Wait 5 minutes for the color to develop. Compare the pink
color of the solution to the Nitrogen Color Chart. Record the amount of nitrogen.
Phosphorus: Use the pipet to transfer 25 drops of the clear solution above the soil to a
square test tube. Fill the tube to the shoulder with distilled water. Add one Phosphorus
Tablet (5422). Cap and mix until the tablet disintegrates. Wait 5 minutes for the color to
develop. Compare the blue color of the solution to the Phosphorus Color Chart. Record
the amount of phosphorus.
Potassium: Use the pipet to transfer the clear solution above the soil to a square test tube
until it is filled to the shoulder. Add one Potassium Tablet (5424). Cap and mix until the
tablet disintegrates. Compare the cloudiness of the solution in the test tube to the
Potassium Color Chart. Hold the tube over the black boxes in the left column and
compare it to the shaded boxes in the right column,
1. Record the values for each variable.
pH:
_______
Phosphorus: _______
Nitrogen:
_______
Potassium:
_______
2. Based on these test, which nutrients are low in your soil sample?
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3. Besides found in DNA, how do plants utilize phosphorus?
How do plants utilize nitrogen?
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How do plants utilize potassium?
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