Organic Matter:

Determine the amount of organic material (humus) in your soil samples!

Materials:

• 27 labeled (1A-3C) plastic bags

• 27 labeled (1A-3C) flags

• 27 labeled (1A-3C) Petri dishes

• Soil Core Extractor

• LaMotte Test Kit STH-14 (Code 5010-01) Humus test

Procedure:

• Collect three humus samples in each of your three plots using the soil core extractor, up to the 15cm mark, and store in labeled plastic bags. Mark where you took your sample from with a labeled flag.

• Inside, transfer into the labeled Petri dishes and allow to dry on a windowsill overnight

• Transfer eight 0.5 g measurements (0698) of soil to a soil extraction tube (0704)

• Add demineralized water (1155) to the tube up to the 14 ml mark. Cap and shake to mix.

• Use a 0.5 g spoon (0698) to add two level measurements of Humus Screening Reagent (5119) then cap and shake for one minute.

• Add 15 drops of Soil Flocculating Reagent (5643). Cap and mix, then let sit for several minutes.

• Use filter paper (0465) and a plastic funnel (0459) to filter the mixture into a second extraction tube.

• Compare filtrate in the second tube with the Hmus Color Chart (1384)

• Repeat the procedure for all three days

Bacteria:

Find the number of bacteria colonies within different dilutions of soil. 

Materials: 

• 9 labeled (1A-3C) plastic bags

• 9 labeled (1A-3C) flags

• 9 labeled (1A-3C) Petri dishes

• Trowel 

• 45 15 mL culture tubes with caps 

• 45 3M Petrifilm Aerobic Count Plates 

• Sharpie and tape (labeling)

• 1 cc scoop 

• 10 serological transfer pipettes (1 for each soil sample and 1 for distilled water) 

• Distilled water 

• P200 micropipette 

• Micropipette tips 

1. Label 45 3M Petrifilm Aerobic Count Plates (1A "10-1" 3C "10-4")* for each of the soil samples. 

2. Label 45 culture tubes (1A "100" 3C "10-4") for each of the soil samples. 

3. Using a new transfer pipette, add 10 mL of distilled water to each of the culture tubes labeled with "100" dilution

4. Use the same pipette to add 9 mL of distilled water to the rest of the culture tubes, labeled "10-1", "10-2", "10-3", or

or "10-4". 

5.  Add 1 cc of the soil sample into the culture tube labeled "100" with the corresponding sample labeled. 

6. Cap and shake vigorously. 

7. Using a new clean pipette, remove 1 mL of the soil/water mixture from the "100" tube into the tube labeled "10-1" of the corresponding soil sample 

8. Cap and shake vigorously 

9. Using the same pipette, remove 1 mL of the soil/water mixture from the "10-1" tube into the tube labeled "10-2" of the corresponding soil sample 

10. Cap and shake vigorously 

11. Using the same pipette, remove 1 mL of the soil/water mixture from the "10-2" tube into the tube labeled "10-3" of the corresponding soil sample 

12. Cap and shake vigorously 

13. Using the same pipette, remove 1 mL of the soil/water mixture from the "10-3" tube into the tube labeled "10-4" of the corresponding soil sample 

14. Cap and shake vigorously 

15. All five tubes of the first soil sample (1A) should now have a soil/water mixture 

16. Repeat steps 7-14 with all samples (1A-3C). 

17. Plate 100 ul samples from each dilution (from 1A "10-1" to 1A "10-4") onto their own separate, corresponding labeled 3M Petrifilim Aerobic Count PLate using the micropipette and tips. Use a new tip for each dilution. 

    1. Use the smoother to spread out the soil/water mixture on the plate. 

18. Repeat step 17 for each of the 9 soil samples (1A-3C). 

    1. Use a new clean tip for each dilution. 

    2. Clean out the cc scoop with every new soil sample to avoid cross-contamination. 

19. Once all soil samples are plated, allow them to sit in a dark place, away from sunlight, for 48 hours to 72 hours. 

20. After the plates have been sitting for at least 48 hours, examine each of the plates from "10-1" to "10-4". 

21. Find the number with the least number of colonies (but at least 5 colonies) and record it in your data table. 

22. To find the number of bacteria in a 1 cc soil sample, use this formula: 

#microbes in 1 cc of soil = colonies on sheet x 102 x 10|dilution # at which these colonies were found|

23. If there are no individual colonies, but there's still a lawn at the 10-4, repeat the dilution adding a 5th (10-5) and 6th (10-6) dilutions, etc. as necessary until individual colonies are observed. 

24. *Note: Dilution of "100" will not be plated. 

Moisture:

 Determine the moisture content of a soil sample based on weight!

Materials:

• 27 labeled (1A-3C) plastic bags

• 27 labeled (1A-3C) flags

• 27 labeled (1A-3C) Petri dishes

• 27 labeled (1A-3C) pieces of construction paper

• Trowel

• Scale

Procedure:

• Collect three moisture samples from each plot using the trowel. Store in labeled plastic bags and mark where you took the sample from with a labeled flag.

• Inside, first tare the scale to the weight of just the construction paper, then add all of the soil samples you took. Do not allow the sample to dry, weigh immediately. Record weight.

• After weighing, dry the samples in an oven at 105o C for 24 hours

• Remove from oven and allow to cool to room temperature

• Weigh the samples again and record the weights

• Calculate moisture content with this formula:

Moisture content          Wet weight – Dry weight

On wet basis    =         —————————          X  100

                                       Wet weight

• Repeat the procedure for all three days