todd dejong soil report
TRANSCRIPT
Soil Analysis Soil Science
By Carolyn Stevens, Mohammed Taha, Todd De Jong, Marissa Cleroux
12/9/2011
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Table of Contents
Introduction................................................................................................Page 2
Soil Forming Factors.................................................................................Page3
Classification of Soil...................................................................................Page4
Conclusion..................................................................................................Page 8
Appendix.....................................................................................................Page9
References...................................................................................................Page19
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Introduction
Soil samples were taken from Milford, Nova Scotia on September 29, 2011. The area is
located approximately 56 km North East of Halifax in a rural, primarily farmland setting. The
purpose of sampling, field analysis, and subsequent laboratory testing was to characterize and
name the soil according to the Canadian Soil Classification System. This report will detail field
and laboratory work related to the project and present the analytical results in a manner that will
facilitate an understanding of soil horizons and soil composition.
The soil samples were taken beside a pasture at the edge of a forest in Milford, Nova Scotia
(+45° 2' 8.86", -63° 26' 27.89"). It was a clear, sunny day and the temperature was around 17° C.
In the days leading up to the sampling, many rain
events had occurred leading the soil to be
moistened. At the location, a hole was dug with
the dimensions 1 meter wide, by 1 meter in
length, and 0.56 meters deep. Any further depth
was prevented due to the tough clay, inhibiting
the equipment from digging any further. Despite
this, representative samples were able to be
obtained from the Ah horizon and B horizon, as
well as two core samples, but not from the C
horizon due to the limitation in depth. Proper
procedure and protocols were followed
throughout the sampling and laboratory analysis.
Brown sandstone from the sample site was
obtained from the sample site, which gave clues as to the original parent material of the soil. The
parent material was a dusky red clay loam till from red shales and mud stone, with numerous red
and brown sandstone fragments (refer to Figure 8).
Figure 1: Site Sketch
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Soil Forming Factors
Parent Material: Milford sits atop the Windsor Group formation (refer to Figure 7) which it
mainly comprised of siltstone, sparse gypsum, and shallow marine limestone bedrock. This
bedrock is of a reddish brown clay loam, with a lighter shade sitting above a darker shade of red.
This coincides with the parent material, which was a dusky red clay loam till from red shales and
mudstone, with numerous fragments of red and brown sandstone.
Topography: The location where the soil was formed consisted of gently rolling drumlins left in
the wake of the last ice age with generally moderate slopes. In this area, the surface drainage rate
is moderate while the internal drainage is much slower due to the higher amounts of clay (refer
to Table 9). Water movement through the Ah horizon was found to be at a rate of 2.68 m/day,
whereas the water movement results from the B horizon are still pending. This suggests a very
poor hydraulic conductivity due to an increase in clay particles in that horizon.
Climate: The climate for Elmsdale, Milford is determined based on its inclusion in the Atlantic
Maritime region where the Atlantic Ocean has a strong influence on this area’s climate. The
presence of an ocean causes the area to produce cooler summers, yet warmer winters all with a
humid climate. The winter temperatures average around -4°C while the summer temperatures
have an average around 17°C (refer to Table 9). Annual precipitation for this area averages
around 1453 mm (refer to Table 10). High precipitation and a humid climate also indicate that
the region is prone to storm events. This type of climate facilitates good soil forming conditions.
Biota: The soil was sampled on the boundary between a forested area and a farmer’s field where
cows were led out to graze (refer to Figure 4). The first few centimeters of the soil had grass,
causing fixation reactions that contributed decayed organic material, organics acids, and
structure to the soil provided by the roots. In addition to providing structure, these roots provide
a barrier to slow the natural processes of erosion. Within the horizons, 23.3 mg/g of organics
were found in the A horizon while 1.31 mg/g were present in the B horizon. This contributes to
water retention, adds structure by acting as a gluing agent, supplies acid through decay, and
serves as a nutrient reserve for the soil.
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Time: The soils in the Milford area have been forming under these conditions since the last ice
age occurred, approximately 11,000 years ago.
Soil Classification
Based off of the various analyzed criteria, it was determined that the soil at the designated
sampling site was of the Humo-ferric pdozol great group. The soil has a reddish B horizon with
an Ah horizon (refer to Figure 1). The B horizon was at least 10 centimetres thick (refer to
Figure 1) and the organic carbon within the Ah horizon was found to be 2.33%. This is within
the 0.5-5% range stated in the Canadian System of Soil Classification. The cation exchange
capacity (CEC) was found to be 7.5 cmolc/kg in the B horizon which borders the 8 cmolc/kg for a
Humo-ferric podzol. With all of these attributes taken into account, it can be said that the soil
sample obtained from Milford is a Humo-ferric podzol.
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Figure 9: Caparisons of Horizons, Milford Soil
Ah Horizon
B Horizon
Ah Horizon
B Horizon
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Field Capacity Description (refer to Tables 5 and 6):
The original field moist capacity for the Ah horizon (54%) was more than that of the
disturbed soil (35.1%). In addition, the original field moist capacity for the B horizon (28%) was
only slightly higher than that of the disturbed soil (26.6%).
The disturbed Ah horizon soil was below field capacity by approximately 18.9% while
the disturbed B horizon soil was only 1.4% less than the original field moist capacity.Overall, the
Ah horizon holds more water due to the humic and organic compounds in the soil. In addition, as
the porosity decreases in a soil so too does the field capacity. The porosity in the B horizon is
much less, causing it to be able to hold far less water than the Ah horizon. In regards to texture,
the Ah horizon has a larger field capacity due to the larger aggregate size creating larger, more
open pores due to the reduced clay content. The higher clay content of the B horizon caused the
Ah horizon to have the larger field capacity.
Hygroscopic Water Content (refer to table 7):
In the soil sample, the Ah horizon had a larger hygroscopic moisture content than the B
horizon due to the presence of more organic material. The concentration of organics within the
Ah horizon is 23.3 mg/g or organics while the B horizon contained only 1.31 mg/g of organics.
This allows for the organic material to retain more water than the soils in the B horizon, causing
the hygroscopic content to be larger. The hygroscopic water content of the Ah horizon was
2.58% while the content of the B horizon was just 0.6%.
Bulk Density Explanation (refer to Table 1):
Bulk density is the weight of a given volume of soil in its natural, undisturbed condition.
It depends on the structure, size, pores, and the make-up of the soil horizon mineral content.
Typically, organic soils have lower bulk densities than the more compacted soils below. In the
soil samples that were taken, the Ah horizon bulk density was 1.04 g/mL and the B horizon was
1.46 g/mL.
Particle Density is similar to bulk density; however, where the bulk density includes the
volume of air, water, and solids content of a soil, the particle density is simply the volume of the
solids content. Solids content includes the minerals and organic matter. For the Ah horizon, the
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particle density is 2.26 g/mL whereas the B horizon had a value of 2.70 g/mL. According to
these values, the B horizon had the greater solids content.
Porosity is another important parameter in regards to bulk density, and is defined as the
amount and size of pores and the total amount of water that a soil can hold. In the Ah horizon
where the clay content was less, there was a porosity of 52% while the B horizon, which had
greater clay content, had a porosity of 46%. The Ah horizon had the greater porosity because of
the greater uniformity in particles size and shape.
Organic Carbon (refer to Table 8):
Organic Carbon levels in the Ah horizons were measured to be 2.33% whereas the B
horizon contained a meager 0.131%. The increased organics in the Ah horizon is due to the
increased proximity to the organic layer at the surface, in addition to the roots of plants and
decaying material that reach into the horizon itself. The sparse organics content in the B horizon
is a reflection of the minute amount that managed to leach from the Ah horizon down to the B
horizon.
Cation Exchange Capacity (refer to Tables 2 and 3):
The cation exchange capacity (CEC) Is higher in the Ah horizon with a value of 12.028
cmolc/kg than in the B horizon with 7.5 cmolc/kg. Once more, this is due to the higher organic
content in the Ah horizon. In addition, this higher CEC allows for more hydrogen ions to be
exchanged and retained, as well as the roots contributing increased hydrogen through root
microbe respiration. This is reflected in the pH value of 6.63 in the Ah horizon as opposed to the
6.74 in the B horizon.
Soil Water Movement
Soil water movement is the measure of the rate at which water can pass through the soil
horizon and is related to the porosity in the given horizon. For this sample, the Ah horizon had a
hydraulic conductivity of 2.68 m/day. On the other hand, the B horizon results are still pending
as the water has not moved in over a week. Based off of this data, it can be said that the water
movement through the Ah horizon is much greater than the B horizon, but there is currently no
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way to give a direct ratio. Slower water movement through the B horizon can be attributed to the
higher clay content plugging up the larger pores in the aggregates.
Soil Structure
The soil sample exhibited a spherical aggregate shape in both the Ah horizon and the B
horizon, which tends to be common in soils containing an Ah horizon. In addition, the shape is
granular in both with a bit of a crumb structure for the Ah horizon. This structure is typical of
surface horizons prone to biological activity, such as that provided by the adjacent forest and
cow pasture. Finally, the aggregate size was approximately 3 mm to 1 cm in the Ah horizon and
less than 1 mm in the B horizon.
Soil Mineral Content
In the soil horizons, the sand content was relatively the same in both horizons, valued at
67.87% and 68.53% for the Ah and B horizons respectively. The Ah had a higher silt content
compared to the B horizon (29.33 % to 19.67 %), while the B horizon had larger clay content
(11.8 % to 2.8 %). There is more clay in the B horizon and less silt because of illuviation, which
is the removal of a material from one layer to another. So while the clay from the Ah horizon is
illuviated into the B horizon the Ah horizon silt content increases due to deposited material.
Conclusion
On September 29, 2011, soil samples were taken from Milford Nova Scotia. The purpose
of this soil project is to learn how to take a representative sample of soil and interpret the results
to characterize the soil and its genesis. This is done through laboratory determination of several
important physical, chemical and biological properties. The soil sampled at Milford was of the
Humo-ferric podozol great group, with Ah and B horizons. Due to organic inputs and differences
in clay content, the characteristics of the two horizons greatly differed and added their unique
properties to the soil landscape in Milford.
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Appendix A
Table 1: Bulk Density, Particle Density and Porosity
Ah Horizon B Horizon Weight of the cylinder plus soil 157.7 g 167.1 g
Weight of the cylinder alone 130.6 g 130.6 g
Soil weight 27.1 g 36.5 g
Volume of soil 25mL 25mL
Bulk Density 1.04 g/mL 1.46 g/mL
Volume of soil solids and water
mix
62 mL 63.5 mL
Volume of water added 50 mL 50mL
Volume of soil solids 12 mL 13.5 mL
Particle Density 2.26 g/mL 2.70 g/mL
Pore volume 13 mL 11.5 mL
Porosity 52 % 46 %
Table 2: Cation Exchange
Horizon: Ah Recorded Dilution Conversion Ca
++ 4.2-2.95 = 1.25mg/L x
20 = 25 mg/L as
CaCO3
X 10
250mg/L as CaCo3 x .400
(to convert to Ca++
)=
100mg/L as Ca++
Mg++ Total Hardness – Ca
++
Hardness = 280 –
250= 30mg/L as
CaCO3
N/A 30 mg/L as CaCO3 x .243
(to convert to Mg++
) =
7.294 mg/L as Mg++
Na+ N/A N/A N/A
K+ 2.5 mg/L as K + X 100 250 mg/L as K
+
Al+++ 0.013 mg/L as Al
+++ X 10 0.13 mg/L as Al
+++
pH 6.63 N/A
Total Hardness 0.7 x 20 = 14mg/L as
CaCO3
X20 280mg/L as CaCO3
Horizon: B Recorded Dilution Conversion
Ca++
0.6 x 20= 12 mg/L as
CaCO3
X 10
120 mg/L as CaCO3 x
.400 (to convert to Ca++
) =
48 mg/L as Ca++
Mg++ Total Hardness – Ca
++
Hardness = 222 – 120
= 102 mg/L as CaCO3
N/A 102 mg/L as CaCO3 x .243
= 24.79 mg/L as Mg++
Na+ N/A N/A N/A
K+ 1.10 mg/L as K + X 100 111 mg/L as K
+
Al+++ 0.08 mg/L as Al
+++ X 10 0.80 mg/L as Al
+++
pH 6.74 N/A
Total Hardness 0.555 x 20 = 14mg/L
as CaCO3
X20 222mg/L as CaCO3
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Table 3: Total Cation Exchange Capacity
Ah Horizon B Horizon Ca++ (cmolc) 5 2.4
Mg++ (cmolc) .604 2.32
Na+(cmolc) 0 0
K+ (cmolc) 6.41 2.82
Al+++ (cmolc) .014 .008
H+ (cmolc) .00024 .00018
Total Cation Exchange(cmolc) 12.028 7.5
Table 4: Moisture Content of Field Moist Samples: Gravimetric Method
Ah Horizon B Horizon
Weight of tin 1.30 g 1.30 g
Weight of soil 20.0 g 20.0 g
Weight of soil + tin 21.3 g 21.3 g
Oven dry weight of soil + tin
19.0 g 15.8 g
Weight of Water 2.30 g 5.50 g
Percent moisture by dry weight
13.0 %
37.9 %
Percent moisture by volume
13.5 % 53.3 %
Cm water/ meter of soil
13.5 55.3
Table 5: Soil Water Holding Capacity
Ah Horizon B Horizon Volume of water used (mL) 10 10
Volume of Leachate (mL) 1.9 5.8
Volume retained by Soil (mL) 8.1 4.2
Oven dry weight of soil used (g)
15 15
% moisture by weight at 100% water holding capacity
54 % 28 %
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Table 6: Field Capacity of Disturbed Soil
Ah Horizon B Horizon Weight of tin 1.2 g 1.2g
Weight of soil 10 g 10 g
Weight of soil + tin 11.2 g 11.2 g
Oven dry weight of soil + tin 8.6 g 9.1 g
Weight of Water 2.6 g 2.1 g
Field Capacity 35.1 % 26.6 %
Table 7: Hygroscopic Water Content
Ah Horizon B Horizon Weight of tin 1.3 g 1.3 g
Weight of soil 15.9 g 15.9 g
Weight of soil + tin 17.2 g 17.2 g
Oven dry weight of soil + tin 16.8 g 17.1 g
Weight of Water 0.4 g 0.1 g
Hygroscopic moisture content 2.58 % 0.6 %
Table 8: Organic Carbon Content
Ah Horizon B Horizon Sample Weight (g) – Hydroscopic water
1.169 1.192
FeSO4 titrant Standard (mL) 10.1 10.1
FeSO4 titrant Sample (mL) 3.1 9.7
Organic Carbon (mg/g) 23.3 1.31
Organic Carbon % 2.33% 0.131%
Table 9: Mineral content percentages by horizons
Ah Horizon B Horizon
Silt Content 29.33 % 19.67 %
Sand Content 67.87 % 68.53 %
Clay Content 2.8 % 11.8 %
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Table 9: Elmsdale Average Temperature
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average high -1.2 -1.1 3 8.4 15 20.3 23.6 23.3 18.8 12.7 6.9 1.4
Average low -10.7 -10.2 -5.8 -0.5 4.5 9.6 13.5 13.5 9.3 3.8 -0.7 -7.1
Average -6 -5.6 -1.4 4 9.8 15 18.6 18.4 14.1 8.3 3.1 -2.8
Table 10: Elmsdale Monthly Precipitation (mm)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Monthly rainfall (mm) 101 69 96 96 106 98 102 93 104 126 133 115
Monthly snowfall (cm) 55 50 41 21 3 0 0 0 0 2 14 44
Monthly precipitation
(mm) 149 114 135 118 110 98 102 93 104 129 146 155
Table 101: Aggregate size, shape and structure
Ah B
Aggregate shape Spherical aggregates Spherical Aggregates
Size 3 mm- 1 cm <1 mm
Structure Granular/crumb Granular
Table 112: Soil Water Movement
Soil Water Movement Horizon Ah B
Per Rate 2.68 m/day N/A*
Minimum Area Required for a discharge of 6.5 m3/day
2.43m2 N/A*
*Results pending
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Appendix B
Figure 2: Texture Triangle Describing Each Soil Horizon
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Figure 3: Sampling Site. Photo taken by: Alex Königseder on September 29, 2011
Figure 4: Grazing Cow. Photo taken by: Alex Königseder on September 29, 2011
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Figure 5: Sample Site Location
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Figure 6: Contour Map of Sample Site
X= Sample Site
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Figure 7: Soils Bed Rock, Milford
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Figure 8: Parent Material, Milford
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References
1. Agriculture and Agri-Food Canada. Agriculture and Agri-Food Canada Publication, (1998). The canadian
system of soil classification (third edition). Retrieved from Agriculture and Agri-Food Canada website:
http://sis.agr.gc.ca/cansis/references/1998sc_a.html
2. Globe. (2002). Bulk density protocol. Retrieved from: http://globe.gov/sda/tg/bulkden.pdf
3. H. Conley, R. Stea, Y. Brown. "Surficial Geology Of The Province Of Nova Scotia Map 92-3".1:500
000.1992. http://www.gov.ns.ca/natr/meb/download/mg/map/htm/map_1992-003.asp
4. Nova Scotia Department of Natural Resources (2011, February 8). Reading room 1: The story of glaciers in
maritime canada. Retrieved from http://www.gov.ns.ca/natr/meb/field/glacier.asp
5. Sandor, F. (2008, February 8). Soil testing. Retrieved from:
http://www.rootsofpeace.org/assets/Soil%20Testing%20Manual%20V6%20(Feb%208).pdf
6. The Canadian Biodiversity Web Site. (n.d.). Atlantic maritime. Retrieved from
http://canadianbiodiversity.mcgill.ca/english/ecozones/atlanticmaritime/atlanticmaritime.htm
7. WARD's Natural Science Establishment INC. (n.d.). Porosity and permeability of soils model. Retrieved from:
http://www.spegcs.org/attachments/committees/8/Porosity Model_Users Guide_040607.pdf