LAB 3: SOIL SAMPLING – PART 1 – SOIL PROPERTIES

OBJECTIVE

To develop a basic understanding of the classification and properties of various types of soils by conducting a series of soil tests.

INTRODUCTION:

This lab provides for an introduction to the properties of soil and soil analysis including:

· sieve analysis;

· texture;

· particle density;

· bulk density;

· porosity; and

· permeability.

PROCEDURE

This lab is to be completed in pairs. The write-up for this lab is to be completed individually and is due the week following the lab. Use either your standard laboratory notebooks (carbon copy) or field notebook to record the experimental data. Please upload your final report to DC Connect. Submit your carbon copies or field notebook at the end of the lab period. You must wear a lab coat and safety glasses at all times. Experiments A-G in this lab can be completed in any order.

A. Sieve Analysis

A maximum of two groups can be conducting the sieve analysis at the same time. Each group will require approximately 30 minutes to complete the sieve analysis.

1. Weigh out each empty sieve and bottom pan to be used in the sieve analysis. Duplicate the table on the next page (first four (4) columns only) in your laboratory notebook.

2. Accurately weight out about 500 grams of one of the mixed soil samples.

3. Using a set of nested sieves, place the sieve with the largest openings on the top and the solid pan on the bottom. A typical range of sieve sizes is shown in the following table.

Sieve #	Sediment Description	Size of Opening (mm)
325	Silt or Clay	0.044
230	Silt	0.063
140	Fine Sand	0.105
60	Medium Sand	0.25
30	Medium Sand	0.60
10	Coarse Sand	2.00
4	Very Fine Gravel (granule)	4.76

4. Dump the sample into the top of the set of sieves.

5. Place the sieve stack in the mechanical shaker and shake for 5 minutes.

6. Remove the stack from the shaker and carefully weigh and record the weight of each sieve and the bottom pan with its retained soil.

7. Before discarding the soil, verify your results by ensuring the initial weight of the soil is consistent with the total mass of the soil retained in the sieves.

Sieve size (#)	Mass of Empty Sieve (g)	Mass of Sieve + Soil (g)	Mass of Soil (g)	% of total mass	% Retained1	% Passing2
4
10
30
60
140
230
325
pan
total	–	–			–

Notes: 1

% Retained
is cumulative. For example if 3% of the total mass of the soil is collected on size 4 sieve and an additional 5% of the total mass of the soil is collected on the size 10 sieve, the % retained is 8% (5%+3% =8%).

2

% Passing
is the opposite of the % Retained. In this example, 92% of the soil passed through the sieve (100% – 8% = 92%).

(Steps 8, 9 and 10 are to be done after lab and included in your report under “Calculations”).

8. Make a graph of percent passing versus grain size (mm) on semi-log paper for the soil sample

9. Identify the percentage of gravel, sand, silt and clay for the sample. For calculation purposes, assume that 20% of the silt/clay mixture is clay and 80% is silt.

10. Excluding the percentage of gravel in the sample, recalculate the percentage of sand, silt and clay. (The total of sand, silt and clay should now be 100%)

11. Use the texture triangle to determine the soil type for the sample based on percentages of sand, silt and clay calculated in step 10.

B. Texture

1. Obtain small amount (about a tablespoon) of each of the five (5) soil samples (clay, fine sand, medium sand, coarse sand and gravel).

2. Observe and feel each sample and describe the texture (gritty, smooth, powdery, sticky, etc.) and colour of each.

3. Add a few drops of water to each soil sample and try to knead the sample into a ribbon (e.g., snake) by rolling it between the thumb and forefinger.

4. Record which samples would form a ribbon, a partial ribbon or a good ribbon.

5. Classify the soil according to the following three groupings:

· does not form a ribbon – coarse textured (sandy loams, sands)

· forms a partial ribbon – medium textured (loams, silt loams and silts)

· forms a good ribbon – fine textured (clay loams, clay)

6. Dispose of the soil into the dry soil bucket.

C. Bulk Density (g/cm3)

1. Weigh out about 50 grams of each of the four (4) soil samples (medium sand, coarse sand, gravel, mixed soil) on the top loading balance.

2. Pour each of the samples into a separate graduated cylinder and measure the volume for each of the samples.

3. Calculate the bulk density for each sample using the following formula:

Bulk Density = weight of soil

volume of soil and air

4. Reuse these soil samples for Part D.

D. Particle Density (g/cm3)

1. Weigh out 50 grams of each of the four (4) soil samples (medium sand, coarse sand gravel, mixed soil).

2. Fill a 100 mL graduated cylinder to the 50 mL mark with distilled or deionized water. (The water must be added to the cylinder first.)

3. Add 50 grams of each of the soil samples to separate graduated cylinders (use a powder funnel if necessary).

4. Allow to stand for 10 minutes.

5. Record the volume of the water plus soil mixture.

6. Record the difference between this volume and the initial volume of 50 mL. This is the volume of soil particles.

7. Dispose of the wet soil into the bucket supplied, not down the sink.

8. Calculate the particle density for each sample using the following formula:

Particle density = weight of solid

volume of soil particles

E. Soil Permeability

1. Fill four 100-ml graduated cylinders to the 50 ml mark each with one of each the four (4) soil samples (medium sand, coarse sand, gravel, mixed soil).

2. Measure the height of the cylinder (cm) from the bottom to the 50 ml mark (or the top of the sediment if you are slightly off. Record this value.

3. One person should start timing as another begins pouring the 50 ml of deionized water into each of the sediment-filled 100 ml cylinder. When water reaches the bottom of the cylinder, stop the watch and note the time. If the water has not reached the bottom in 10 minutes you may stop the test. Be sure to record the distance that the water did travel.

4. Calculate the velocity of the water permeating the soil in centimetres per second (cm/sec).

F. Sample Quartering

1. Weigh out about 200 grams of the mixed soil sample using the top loading balance.

2. Spread the sample out evenly on a piece of paper and divide into four quadrants with a ruler.

3. Combine two of the diagonal quadrants and reject the other two.

4. Repeat steps 2 and 3 until a sample size of about 50 grams is obtained.

5. (Sample quartering is used to reduce the size of a sample to avoid bias as fines preferentially go to the bottom of a container.)

6. Return the soil back to its original container.

G. Porosity (Pore Space)

1. Calculate the porosity for each of the four samples using the following formula:

Porosity (%) = [ 1 – Bulk Density ] x 100%

Particle Density

REPORT (Total 20 marks)

1. Objective/Introduction: Provide an objective and introduction for this experiment. Minimum of 4-5 sentences. (3 marks)

2. Method: Refer to this handout for the detailed method. (0.5 marks)

3. Observations: Provide in tabular format, the data collected during the experiment. (3 marks)

4. Calculations: Based on the lab data, calculate the bulk density, particle density, porosity and permeability of the four soil samples. (3 marks) Complete the calculations for the sieve analysis including the graph on the semi-log paper and the determination of the soil type using the texture triangle. (3 marks)

5. Conclusion: Provide a concluding statement regarding your findings. Minimum of 3-4 sentences. (2 marks)

6. Laboratory Work Book: record all lab work as the lab progresses. (2.5 marks)

7. Questions: Include the answers to the question below. (3 marks)

QUESTIONS

1. Provide definitions for the following (minimum three (3) sentences each): (2 marks)

a. Pedogenesis

b. Soil horizons

c. Eluvial

d. Luvisolic

e. Brunisolic

2. Provide references (properly cited) for the above, Wikipedia is not an acceptable reference. (1 mark)

Lab 3 – Part 1 – Soil Properties (___∕20) (Part 1)

Objective/ Criteria	Performance Indicators
	Level 4	Level 3	Level 2	Level 1	Not Submitted
Introduction/ Objective	(3 points) Provided background on the soil testing and soil properties. Included what tests were conducted and how they were conducted. Contained a minimum of 4-5 sentences. Clearly stated using proper scientific terms without any grammatical or spelling errors.	(2.4 points) One of the required elements was not included.	(1.8 points) Two to three of the required elements were not included.	(1.2 points) Four or more required elements were not included.	(0 points)
Method	(0.5 points) A reference was made to the lab procedure that included the title of the lab.	(0.4 points)	(0.3 points) The reference did not include the full title of the lab or contained grammatical or spelling errors	(0.2 points)	(0 points)
Observations	(3 points) Results of all tests were provide typed in the report in tabular format with clear headings. The results were consistent with the experiments being conducted according to the instructions.	(2.4 points) One test was not conducted according to the directions.	(1.8 points) One test was not conducted or included in the observations. Results were not provided in tabular format. Results were difficult to follow.	(1.2 points) Two or three tests were not conducted according to the directions or not included in the observations.	(0 points)
Calculations – Part A	(3 points) Accurately completed the calculations for the sieve analysis including the graph on the semi-log paper and the determination of the soil type using the texture triangle. Results were provided neatly.	(2.4 points) One error in the calculations. Results clearly reported.	(1.8 points) Two errors in the calculations. Results difficult to follow. Semi-log paper not used.	(1.2 points) Three or more errors in the calculations or calculations incomplete. Soil type not determined.	(0 points)
Calculations – Parts D – G	(3 points) Calculations for bulk density, particle density, porosity and permeability of the four soil samples were all done correctly. Example calculations clearly provided. Values were provided to an appropriate number to significant figures.	(2.4 points) One error in the calculations. Results clearly reported.	(1.8 points) Two errors in the calculations. Results difficult to follow. Example calculations not provided.	(1.2 points) Three or more errors in the calculations.	(0 points)
Conclusion	(2 points) Concluding statement was a minimum of 3-4 sentences. The conclusion included the results for each soil type as well as the soil type determination. The conclusion was consistent with the stated objectives. Clearly stated using proper scientific terms without any grammatical or spelling errors.	(1.6 points) There was a minor deficiency in the conclusion.	(1.2 points) Student provided a vague conclusion with some reference to the data. Conclusion was not consistent with the stated objectives.	(0.8 points) Student provided a conclusion without reference to the data.	(0 points)
Laboratory Notebook	(2.5 points) All data was recorded fully and neatly in the laboratory notebook. Laboratory notebook was dated and signed.	(2.0 points) Laboratory notebook was missing minor item (e.g., signature, balance no., etc.). Notebook did not use headings for each element of testing.	(1.5 points) Data missing for one element of the testing. Notes taken were sloppy and/or difficult to follow.	(1.0 points) Notes were poorly/partially recorded or were illegible.	(0 points) Notes were not recorded during the lab or not submitted at the end of the 3rd lab period.
Questions	(2 points) Definitions provided were scientifically correct and each a minimum of three sentences. Definitions were grammatically correct and had no spelling errors.	(1.6 points) There was a minor deficiency in the definitions.	(1.2 points) One or two definitions were less than three sentences. Definitions were not grammatically correct or were poorly stated. One definition incorrect.	(0.8 points) Three or more definitions were less than three sentences.	(0 points)
References	(1 points) References were properly cited. Credible scientific references were used.	(0.8 points) Minor formatting or style issues	(0.6 points)	(0.4 points) A non-scientific reference was used (e.g., dictionary.com)	(0 points) Wikipedia was included in the reference list.