-Population density of bacteria in the soil
For a list of our materials, click the hyperlink.
1. Choose an area outside containing different concentrations of grass and annual plants
2. Within this area, find and mark seven circular plots, 40 centimeters in diameter, containing varying amounts of grass and annual plants. Record the number of grasses and annuals in each plot.
-One plot must contain no plants
-One plot must contain no grass or annual plants
-The five other plots must contain varying amounts of grass and annual plants
-If necessary, you can take plants out of the ground in order to have varied amounts of grass and annuals in your plots
3. Take a soil core sample that is 15 centimeters in depth and 2.5 centimeters in width from one randomly chosen location within each of the plots and place the soil into seperate, correspondingly labeled plastic bags. If you are having trouble getting the tool you are using into the ground, use a mallet!
-Important: All soil samples must be taken at the same time
4. In the lab perform all necessary serial dilutions and bacteria plating found in the bacteria protocol (follow the hyperlink to see the protocols we used to perform these tests)
-Bacteria plating must be performed directly after serial dilutions
-Nitrate testing and serial dilutions must be performed at the same time
-We only performed serial dilutions and plating up to 10-3 in order to conserve petri plates
5. Perform nitrate testing in parts per million (ppm) on the soil extractions taken on the corresponding day (follow the hyperlink to see what test kit we used in our experiment.
