Nancy Cameron
Research Paper
7/1/07
SOIL RESPIRATION MEASURED IN MEADOW,
MATURE FOREST, AND STREAM SIDE
Abstract: Soil respiration was measured by calculating the difference of masses between
soda lime that absorbed carbon dioxide and anhydrous soda lime. A jar of anhydrous
soda lime was placed under an upside down bucket over soil at three different sites. After
24 hours, the soda lime was dried, and then weighed the second time. The difference in
mass is the amount of carbon dioxide given off by microbes, fungi, and root respiration
which was absorbed by the soda lime. Three sites were taken into consideration to see if
soil respiration would be at different amounts in reference to the amount of visible
biomass. Note: The study was not done over any photosynthetic plant or algae. The three
sites were meadow, mature forest, and stream side which consisted mostly of sand
showing little or no biomass. A control group was conducted over concrete, as to having
no biomass. All sites were in similar temperature conditions. The study found that the
forest site resulted in highest amount of carbon dioxide. Respectively, next came were the
amounts collected from meadow, stream side, and the control group produced the least
amount of carbon dioxide.
Introduction: Soil respiration is an important part of the carbon cycle within the
ecosystem. Microbes found in the soil break down plant debris releasing nutrients to near
by roots. The microbes release carbon dioxide to the atmosphere because of respiration.
Plants, in return, can absorb the carbon dioxide through photosynthesis, completing the
cycle. Roots of plants are able to absorb the available nutrients produced by the microbes
and fungi.(Bormann and Likens, 1979) Productivity of an ecosystem is dependent on the
amount of biomass in soil, if water and temperature are not the limiting factors.(Singh,
J.S.,1977) In this experiment, the amount of carbon dioxide produced by decomposers
will be measured and compared between three different sites having variation amounts of
biomass. The three sites will be: mature forest, meadow, and stream side.
Assuming that the amount of carbon dioxide generated from decomposers is directly
related to plant productivity, the mature forest will have the largest amount carbon
dioxide production from soil microbes. The biomass in the forest soil also has
mycorrhizae which helps release nutrients to roots and will also generate carbon dioxide.
Stream side will have the least amount, not counting the control group, because it has
practically no biomass. However, water is not the limiting factor for stream side.
Methods: In order to collect the carbon dioxide produced by detrivores in soil, 5 to 10
grams of soda lime is needed to collect the gas. Soda lime also absorbs water and will be
measured. Place a recorded amount of anhydrous soda lime in a jar. Place the jar on the
area to be tested. In this case, three areas will be tested for CO2 amount at each site:
meadow, forest, stream side, and on concrete –the control group. Each experimental area
needs to be free of any plants. Photosynthesis will absorb the carbon dioxide, also. Place
a plastic container up-side-down over the jar containing the soda lime. The rim of plastic
container needs to be edged into the ground to help seal any atmospheric leaks. Place a
laundry basket wrapped on outside with aluminum up-side-down over the plastic
container which is over the jar with the soda lime. The aluminum will help insulate and
reflect any sun rays. Temperature can be a limiting factor for microbial activity.
(Toland,D.E.,1994). This set-up at the three areas at each site will be done
simultaneously. Wait 24 hours and then collect the jars containing the soda lime from
each area. Record the mass of soda lime before placing it in 105 degree Celsius oven.
Wait another 24 hours. Record the mass of anhydrous soda lime. The difference between
the mass of soda lime at beginning of experiment, and mass of soda lime after oven is the
mass of CO2 produced by biomass per area of plastic container.
The T test will be calculated for statistical analysis. If p is less than .05, then there is 95%
or greater chance that the three sites, mature forest, meadow, and stream side are different
in CO2 amounts.