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1. Determine 5 outdoor sites (each
20 cm in diameter) with different amounts of sunlight exposure
(100%, 75%, 50%, 25%, and 0%). Use a densitometer to determine
the amount of sunlight exposure in each site. Also, make sure
that each site contains the same species of plants as the other
sites and the same plant density (e.g a meadow)
The densiometer we used:
2.
Label the 5 locations accordingly. For example using
flags where each
flag's label corresponds to the amount of sun exposure in its
individual site. Then place flag in the direct center of its
corresponding site.
3.
In each location on the same day at the same time,
uproot one entire plant sample (see figure 2).
Place each collected plant sample in an appropriately labeled
bag, making sure that the label includes the amount of sun exposure in
that particular site and the day the sample was collected. Make sure
that you are uprooting the same kind of plant from each
location.
(See
Trouble Shooting
1)
Figure 1
Figure 2
4.
Immediately after uprooting the plant and placing it in the bag,
extract a sample of soil, 15 centimeters deep and 2 centimeters
in diameter, from each site at the point directly underneath the
previously uprooted plant.
(See
Trouble Shooting
2).
Steps to our
extraction:
a. We hammered
the soil extractor 15 centimeters into the correct area of soil
b. We then twisted the
soil extractor clockwise and pulled it out of the ground.
C. We then put the extracted soil into the appropretely
labeled bag.
5.
On the same day as the plant
and soil samples were collected from each site (to avoid plant decay), test for
the amount of both iron
(ppm) and
manganese (ppm) in each of the plant and soil samples.
(See
Trouble Shooting 3)
Steps we took to test for iron and
manganese:
a. Put on gloves
and goggles for safety!
b.
Extract both the soil and plant samples.
Cutting the leaf material to prepare it for the extraction.
Cutting the leaf material to prepare it for the extraction.
Putting the soil into tubes for extraction.
The extraction process
Adding Universal Extracting solution to the cut up leaf
material
The filtering proccess of a soil extraction
c. We then tested for both
ferric iron and manganese.
 
Adding the soil extraction solution to a spot plate for ferric iron testing Adding Manganese Buffer powder to the spot plates for the
manganese tests
In the proccess of performing the ferric iron test
Looking at iron testing samples
Comparing the color of the manganese solution in the
spot plate to the color standard on the Manganese in Soil Color
Chart
6.
Record your results.
7.
Repeat steps 3-6 once a day for several days. Make sure
you collect your samples at roughly the same time everyday.
8.
Analyze all your data by comparing the amount of sun
exposure to the iron and
manganese levels that were found in the soil and plant samples.
9.
Compute four sets of T-tests (to find the p-values) for
each of the four independent variables (Fe in the soil samples,
Mn in the soil samples, Fe in the plant samples, and Mn in plant
samples). In each set, determine the p-values between sun
exposure combinations (0% and 25%, 25% and 50%, 50% and 75%, 75%
and 100%, 0% and 50%, 0% and 75%, 0% and 100%). Then examine and
determine what your p-values tell you.
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