Sample Lab
I.
Title: Soil Quality of William B.Travis High School Grounds
1/24/2012
Introduction:
Soil is the top layer of the Earths surface composed primarily of minerials, organic
matter, water and air. Soil is formed from rocks and decaying plants and animals.
Without soil plants could not grow and animals could not have a source of food.
Plants also provide us with the oxygen we need to breathe therefore making soil an
very important resource for life. Soil Composition can have a direct effect on the
growth of plants. In this lab we will be comparing the soil composition and quality
from various locations on the school campus. We will be testing for permeability,
texture, consistency, pH and nutrients. My soil sample was collected at the softball
field. This area of the school has a very red based soil. These areas tend to have a
higher yield of clay because of the need to hold onto or absorb moisture but also
higher sand to prevent the ground from being too hard. As a softball player I know
how important that is. My hypothesis is that our soil sample will contain higher
amounts of sand and clay compared to silt giving it a high permeability and gritty
texture. It may also be low in nutrients due to the lower silt concentration and pH
will be more alkaline due to this.
II.
Materials Used:
Spoons, baggies, soil samples, styrofoam cups, beaker, rulers, graduated cylinders,
nutrient test kit, pH kit
*** Safety Hazards – when collecting soil be aware of your surroundings for insects
especially ant beds.
III.
Procedures:
A. Soil Permeability
1. Fill styrofoam cup half full with soil and place three holes in bottom.
2. Add 50 ml water slowly to the soil and collect water in beaker and measure with in 1
minute. Repeat two times.
3. Record amount collected
B. Soil Texture
1. Place 25ml of soil into a graduated cylinder. Add 75 ml water and suspend allow
to sit for at least 30min.
2. Measure Layers of sand, silt and soil and use the texture triangle to determine soil
makeup.
Soil Texture by hand
1. Place a small amount of soil with water in your hand and roll into a ball.
2. Squeeze soil between thumb and forefinger until a ribbon forms and breaks.
3. Measure ribbon length and answer questions in soil texture flow chart.
C. Soil Nutrients
1. Place soil from graduated cylinder into a beaker and create a solution that is 1:5
dilution of soil sample.
2. Using a soil nutrient kit add the soil solution to the testing containers for
Sodium, Potassium, Nitrogen and pH.
3. Add the correct color tablet to each test container and read the color indicator to
determine nutrient concentrations and pH.
4. Record data and determine the type of fertilizer that is best to use on your soil
sample and two other class mates.
IV. DATA:
Soil Permeabiltiy:
Volume of Water
(mls)
Soil Sample 1
10ml
Group 1
Soil Sample 2
25
Group 8
Soil Sample 3
38ml
Group 5
Soil Texture: By hand soil is sticky yet smooth with a slit gritty ness =Clay
Loam
Soil Sample
1
2
3
Soil Texture
By Feel
Analysis
Clay loam
Silty clay loam
Group 8
Sandy clay
Group 5
Soil Sample
1
% Sand
20
% Silt
20
% Clay
60
2
60
20
10
3
90
5
5
Soil Texture
Clay loam
My group
Clay
Group 8
Loamy sand
Group 5
Soil Nutrients
SOIL
Group1
Group 8
Group 5
NITROGEN
depleted
depleted
sufficient
PHOSPHOROUS
depleted
depleted
deficient
POTASSIUM
pH
depleted
8.6
depleted
6.0
adequate
5
FERTILIZER
10-10-10
10-10-10
5-10-5
V. DATA ANALYSIS:
Soil Permeability
1. Could the size of the soil particles affect life of microorganisms living in the
soil? Yes size of the soil particles can affect microbes because sand is large and
causes air spaces which results in more oxygen for them in the soil.
2. Which soil sample contains the most clay? Sand? Sample one had the most
clay because the least amount of water passes through and sample five has the
most sand because there is more water which means more space.
3. Why would a farmer need to know the soil permeability on his land? Soil
permeability would help a farmer to know how much water to irrigate with.
4. Which of the soil samples held more water and why? Soil sample one
because it had the most clay content and least amount of water passed through.
Soil Texture – by touch indicated we had clay loam from the data collected
1. What is the relationship between soil texture and water?
The more water the soil holds it contains more silt and clay
2. Which types of soil can be mixed together to form the best loam?
40% sand 40% silt 20% clay
3. What are the causes of erosion? Soil loss and degradation due to water, wind
and human interactions like deforestation, irrigation, and agriculture
4. What can be done about erosion problems? Special farming techniques can
be used like conservation tilling, irrigation methods like center pivot and drip,
contour stripping.
5. Which soil sample would be more subject to erosion? Soil that is high in sand
because it will be more easily blown away.
Soil Nutrients
1. What do you think gardeners and farmers could do to minimize contamination
of groundwater from certain compounds in fertilizers? They could use more
organic fertilizer or change the irrigation methods they use to drip.
2. Do you think the plants in this soil sample are getting the essential nutrients
that they need? No our soil was depleted in all nutrients due to high clay content.
3. Is there a relationship between the elements found in your soil sample and the
pH?Yes the less nutrients the more alkaline the soil due to leaching of soil.
4. How would precipitation or irrigation affect the elements in the soil? The more
water could cause leaching of soil nutrients if the soil texture is low in humus or
clay and deplete the soil nutrients.
5. What environmental effects does adding the wrong type of fertilizer have?
By adding too much fertilizer this can run off into neighboring lakes, and rivers
and cause Eutrophication to occur more radiply killing the life that is there. It can
also cause a buildup of nitrogen in the water supply and soil a known
carcinogen.
VI. Conclusions:
Based on our findings the soil sample that we collected was high in clay and
texture was 60% clay 20% silt and 20% sand yielding clay loam. The
permeability of our soil also matched this with a low permeability due to high clay
content. Our nutrient results also supported this finding because our soil was
depleted in nutrients with a high pH which is indicative of a soil high in clay as
well. All of these findings do support the hypothesis that we generated in the
beginning. If this soil was to be used to grow plants I would as a farmer
recommend a 10-10-10 fertilizer. However since this soil is used for high traffic
and softball the current texture is the most ideal for a semi hard surface with
could water absorption. Our classmate’s soils varied in their nutrient needs in
relation to where they were collected around the school. Most of the soil was
high in clay. Living in Texas requires soil to have a high clay content due to the
lack of water. Clay tends to hold water in the soil and makes up a large amount
of the soil samples. There is no real error that could be reported except that
maybe the soil samples used in the nutrient lab were not diluted correctly or the
texture lab graduated cylinders were read incorrectly. Students should be aware
of the particle size and densities of the sand, clay and silt before doing the lab. I
found this lab very informative and will now have a better understanding of how
soil fertilizers are used, the makeup of soils and why they are necessary to grow
plants in different climates around the world. I want to thank you Mrs. Lomax for
allowing us this opportunity to learn about soil and its makeup.