1. Soil moisture, percent organic matter and soil texture calculations

2. Soil Moisture Procedures
1. Weigh the soil when it is taken out of the ground. 2. Dry it in the oven. 3. Weigh the soil after it is dry. 4. Consider drying the soil more and reweighing the soil to be sure it is dry.

3. Soil moisture calculation
Percent moisture = mass water x 100 mass original soil

4. Calculate the percent of soil moisture
Masses of soil and the pan +/ Mass of original soil + pan Mass of dry soil + pan Mass of empty pan 20.00

5. Percent water
Percent water =
30.00/ x 100
= 19%

6. Percent organic matter in the soil
Grind dry soil into small particles
Put a sample into a dry, weighed crucible
Weigh the crucible and the soil
Heat to burn the soil
Let it cool
Heat the crucible and the soil
Reweigh
Repeat until the mass no longer change

7. Percent Organic Matter

8. Percent Organic Matter
Why must the soil be dry before heating?
Why is the soil heated in a crucible?
Will the mass of the soil increase or decrease?

9. Percent organic
Why does the soil need to be heated repeatedly until the mass no longer changes?

10. Percent organic equation
Percent organic = mass organic matter x 100 mass of original, dry soil

11. Percent organic calculation
Masses of crucible and soil +/ g Mass of crucible and soil Mass after first heating Mass after second heating Mass after third heating Mass of dry empty crucible 5.00

12. Percent organic calculation
Percent organic = 2.00/20.00 x = 10.0 % organic matter

13. Soil Texture
Soil texture depends on the amounts of sand, silt and clay.
Sand is the largest type of particle
Silt is intermediate in size
Clay is the smallest
Gravel is removed first..

14. Soil texture
Soil texture depends on the amounts of sand, silt and clay in the soil.
Size description Diameter in mm
Clay < 0.002
Silt
Sand

15. Sand – the largest particles

16. This is also sandy soil

17. Silty soil

18. Clay soil – the smallest particles

19. Porosity The amount of space between the particles.
More porous soils have space for more air.

20. Soil Permeability: The ability of water to flow through soil.

21. Water holding capacity: the ability of the soil to hold water
Clay stores too much water
Sand does not hold water very well

22. Water logging: Clay soils easily become water logged

23. A heavy clay soil when dry

24. Water logging When the soil becomes too wet
Plants can die from growing in water logged soils
Clay soils can become waterlogged easily.

25. Water logged field

26. Compare sand, silt, clay Which is the most porous?
Which has the highest water-holding capacity?
Which is the most permeable?
Which has the best drainage?
Which has the most air space?

27. Workability: Workable soil is good for agriculture and gardens

28. Loam Soil Loam soil is a mixture of sand, silt and clay
It is good for agriculture because it has a range of properties from all of the particle types.

29. Loam
A mixture of 40% sand, 40% silt and 20% clay

30. Soil Texture test

31. Compare the sand, silt and clay

33. Soil texture calculations
Percent sand: 15%
Percent silt: 60%
Percent clay: 25%
Determine the soil texture
Silty Clay Loam

34. Soil Texture calculations:
Percent sand: 70
Percent silt: 20
Percent clay: 10
Determine the texture of the soil.

35. Soil Texture calculations:
Percent sand: 70
Percent silt: 20
Percent clay: 10
Determine the texture of the soil.

36. Soil Texture calculations:
Percent sand: 70
Percent silt: 20
Percent clay: 10
Determine the texture of the soil.

37. Soil Texture calculations:
Percent sand: 70
Percent silt: 20
Percent clay: 10
Determine the texture of the soil.
Sandy loam

38. Sandy Loam

39. Soil texture calculations
Percent sand: 20%
Percent silt: 30%
Percent clay: 50%
Determine the soil texture

40. Soil texture calculations
Percent sand: 20%
Percent silt: 30%
Percent clay: 50%
Determine the soil texture

41. Soil texture calculations
Percent sand: 20%
Percent silt: 30%
Percent clay: 50%
Determine the soil texture

42. Soil texture calculations
Percent sand: 20%
Percent silt: 30%
Percent clay: 50%
Determine the soil texture
Clay

43. Clay Soil

44. Properties of clay, sand, silt and loam
Texture
Porosity
Water flow
Water holding
Aeration
Workability
clay
low
poor
Good
(too much?)
silt
medium
sand
high
good
loam
Best

45. Soil Texture Experiment
Grind the soil sample with a mortar and pestle.
Weigh the sieves and put them together correctly.
Shake the soil sample to separate the particles.
Pull the sieves apart.
Weigh the sand, silt and clay.
Add to find the total mass.
Calculate the percent of sand silt and clay
Use a soil texture triangle to classify the soil texture.

46. Soil Texture Lab Report
Data collection:
Data TABLE with a descriptive title, units, ranges of uncertainties for the units
Qualitative Observations! (colour…)
Data Processing:
The equation used and a sample calculation
Data Presentation:
A labelled table with the results.