soil sampling technique

7/28/2019 Soil Sampling Technique

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Experiment 1: Soil Sampling Technique

Aim

To collect the soil sample from the research spot.Apparatus

Metal cylinder (Tin can), hammer, nail and piston (for digging out the soil).

Procedure

1. An empty metal cylinder (tin can) is poked with few holes at its bottom, using a hammer and a

nail.2. The metal cylinder is then pressed into the soil.

3. The soil sample is removed from the cylinder by using a piston.

IntroductionThe most common method that used to take the soil sample without change its natural properties

and condition is by using metal cylinder and piston.

a) Piston consists of a cylinder with a narrow and quite sharp end. Firstly, the cylinder is pressed

into the soil and turns it around to break the soil under the end of the cylinder.b) By using the piston, the soil sample in the metal cylinder can be removed. Then without changethe shape or natural content of soil, take it to science laboratory for further investigation.

Metal Cylinder with few holes at its bottom Metal cylinder is pressed into the soil


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Discussion

1. The types of particles in a soil sample are determined by using a filter or soil sieve withdifferent mesh sizes.

2. To determine the ratio (%) of sand, silt and clay particles of a soil type, a soil sample is

initially dried in the oven, then weighed and sifted using a sieve with a 2 mm mesh size toremove gravel.

3. The product of this first sifting is sifted again using a sieve with a very fine mesh (0.02

mm) to separate sand, which is then collected and weighed so that the particles that are able topass through the fine mesh of this sieve are then collected in a fairly large evaporating dish of

known weight. The dish and its contents are then weighed.

4. Distilled water is added to the contents of the evaporating dish after weighing. The

contents are stirred and then left for hours to settle. The cloudy supernatant liquid that isobtained is the strained. This step is repeated until the filtrate is clear.

5. Silt left in the evaporating dish is then dried and weighed to obtain its weight and the

percentage of silt in the soil sample understudy. From the percentage of sand and silt obtained,the percentage of clay can be determined by subtraction of these percentages from 100%.

6. Based on the percentage of sand, silt and clay, the texture of the soil sample can bedetermined by referring to the texture triangle. For example, if the percentage of sand is 30%,silt 40% and clay 30%, and then the texture of the soil being studied is peaty clay in character.


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Experiment 2: Determination of Texture of Soil

Aim

To determine the texture of soilApparatus

500cm3 measuring cylinder, 100 cm3 soil sample, 300 cm3 water

Procedure

(1) Add the soil sample to the measuring cylinder and cover with water.

(2) Shake the contents vigorously.(3) Allow the mixture to settle out, according to density and surface area of particles, for 48 hours.

(4) Measure the volume of the various fractions of soil sample.

Explanation1. 100 cm3 sample of the soil that collected from research area is added into a 500 cm3 measuring

cylinder and followed by 300 cm3 of water(distilled water or rainwater is the best if water

comes from a source that is hard or produces lime scale). The amount of soil depends on thesize of the container. It needs to be about half full of soil.

2. The soil is put in the container and filled to three quarters full with water and the top is closedwith a lid or cork for shaking vigorously for a minute to make sure all the soil particles arebroken down into suspension in the water. Then the mixture is put somewhere to settle where it

wont be disturbed at all for 48 hours.

ObservationThe heaviest particles sink to the bottom followed by the fine clay particles are the last to settle out

of suspension. Organic matter, which is not decomposed, either floats or sinks to the surface after

the clay particles. Occasionally it will settle as a band before the clay.

The percentage of stone, sand and clay components of the soil sample is calculated by using the

formula below:-

Formula


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Result

Types Sample I Sample II Sample III Average Percentage

( % )Height ( cm )

Humus 0.30 0.40 0.30 0.33 1.69

Water 10.10 10.00 10.20 10.10 51.88

Clay 0.50 0.60 0.60 0.57 2.93

Silt 1.70 1.70 1.60 1.67 8.58

Fine sand 1.80 1.90 1.80 1.83 9.40

Coarse sand 5.00 4.90 5.00 4.97 25.53

Total 19.40 19.50 19.50 19.47 100.00

Discussion

1. Soil texture is the weight proportion of the separates for the less than 2 mm as determined from

a laboratory particle-size distribution.

2. Field estimates should be checked against laboratory determinations and the field criteria

should be adjusted as necessary. Some soils are not dispersed completely in the standardparticle size analysis.

3. For these, the field texture is referred to as apparent because it is not an estimate of the resultsof a laboratory operation. The field texture is a tactile evaluation only with no inference as to

laboratory test results.

4. Field criteria for estimating soil texture must be chosen to fit the soils of the area.5. The texture classes are :

Sands

Loamy sands

Sandy loams

Loam

Silt loam

Silt

Sandy clay loam

Clay loam

Silt clay loam

sandy clay

Silt clay

Clay

Sands are subdivided into coarse sand,sand,fine sand, and very fine sand.

Subclasses of loamy sands and sandy loams that are based on sand size are named

similarly.

ConclusionThe soil sample settle down in 6 fractions that is coarse sand at the lowest fraction for 4.97cm

high, 1.83cm for fine sand, 1.67cm for slit, 1.57cm for clay, 10.10cm for water and 0.33cm for

humus at the highest.


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Experiment 3 : Determination of Water Content of Soil

AimTo determine the water content of soil

Apparatus

Aluminum foils pie dish, balance, oven, desiccators, tongs, thermometer.Material

80 gm soil

Procedure

1. The empty aluminum foil pie dish is weighed and its mass [A] is recorded.

2. A broken-up soil sample is added to the pie dish and weighed. Mass [B] is recorded.

3. The pie dish containing the soil sample is placed in the oven at 1100C for 24 hours.4. The sample is then removed from the oven and cooled in desiccators.

5. When the sample is cool, the mass is again weighed and recorded.

6. The sample is returned to the oven at 1100C for the further 24 hours.7. Steps 4 and 5 are repeated until a consistent weighing (constant mass) is obtained.

The mass [C] is recorded.8. The percentage of water content is calculated as follow:

9. The soil sample is retained in the desiccators for experiment 4.10. The experiment is repeated on soil samples from different area.

The soil sample is put into the oven at 1100C.

Result

Calculate the percentage water content of the soil sample by using the formula


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Discussion

1. Soil sample evaporate to lose its water in the experiment but this process cannot lose

the water content in crystallized chemical compound of soil so that the soil sample isdried in the oven at 110C to fasten the process of evaporation.

2. This can be done by repeating several times of the heating and cooling process and

followed by measurement until a constant weigh achieved.

3. Water form a thin layer around every soil grains. It is among the few minerals neededfor living and the growth of plants. The water in the thin layer was pulled by

strengthening forces of plants are the forces that can release water from strengtheningforces of soil grains.

Ground water can be divided into 4 important groups, that is:

1. Gravity waterGravity force will cause the rain water flows downward. Hence, dissolving of

water will occur where water that carried with mineral salts will flow to the

bottom of soil until the roots of plants cannot penetrate to this level. This watercannot stay longer in the soil after thunderstorm.

2. Water combined chemicallyWater also can be a part of soil structural with the existing of the soil grains to bepart from it structural. However, this water cannot be used by the soil.

3. Capillary water

Water can be maintained in the spaces between the soils grains, so that the plantscan absorb it. Quantity of water in the soil depends on size of soil grains where

size of soil grains decreases, water content of capillary in the soil increases. Clay

contains more capillary because the size of soil grains in clay smaller than sand.

4. Hygroscopic waterThis water is the water that formed as a layer of water molecule on the surface of

soil grains. It exists due to strongly adhesive forces on the soil grains and plants

cannot use it.

Conclusion

The average water content of the soil is 18.21%. The size of soil grains determines theability of soil to support water. The size of soil grains decreases the ability to support

water increases because there are many spaces that can be used to store water. Therefore,

clay can support more water than sand or loam.

No Title Soil Sample Average

Sample I Sample II Sample III

1 Mass of pie dish, (g) 1.20 1.23 1.22 1.22

2 Mass of pie dish + soil, (g) 80.10 79.95 80.05 80.03

3 Mass of soil, (g) 78.90 78.72 78.83 78.82

4 Mass of pie dish + soil (dry), (g) 66.88 67.05 66.95 66.965 Mass of soil (dry), (g) 65.68 65.82 65.73 65.74

6 Mass of water, (g) 12.01 11.98 12.02 12.00

7 Percentage of water in soil (%) 18.28 18.06 18.29 18.21


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Experiment 4: Determination of Organic Matter Content

AimTo determine the organic content of soil sample

Apparatus

Desiccators and lid, tripod, Bunsen burner, asbestos mat, fireclay triangle tongsMaterial

Dried soil sample

Procedure

1. The crucible and lid are heated strongly in the Bunsen Flame to remove all traces

of moisture and placed in the desiccators to cool. The mass (A) is weighed and

recorded.2. The dried soil sample from experiment 3 is added to the crucible and weighed.

The mass recorded (B).

3. The soil sample is heated in the crucible, covered with lid, to red-heat for 1 hourto burn off all the organic matter. Allow cooling for 10 minutes and removing to

the desiccators.4. The crucible and sample are weighed when cool.5. Step (3) and (4) are repeated until constant mass (C) recorded.

6. The percentage of organic content is calculated as follow:

A = weight of empty crucible

B = weight of dried soil sample + crucible before heatedC = weight of dried soil sample + crucible after heated

7. The experiment is repeated on soil samples from different areas.

the soil is burned the soil is weighted


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Result

Calculate the percentage of organic matter of the soil sample by using the Formula

No Title Soil sample Average


1 Mass of crucible (g) 21.76 21.48 22.23 21.82

2 Mass of crucible + soil ( dry with

organic matter ) (g)

43.99 44.78 45.64 44.80

3 Mass of crucible + soil ( dry

without organic matter ) (g)

42.48 42.38 44.02 42.96

4 Mass of soil used (g) 22.23 23.30 23.41 22.98

5 Mass of organic matter (g) 1.51 2.40 1.62 1.84

6 Percentage of organic matter (%) 6.79 10.30 6.92 8.00

Discussion

1. The temperature of 110 0C is the most suitable temperature for drying process of the soil

samples.2. Soil samples must be heated until red heat so that the organic substance in the soil burned

completely to ensure more accurate data.

3. Steps must be taken in order to ensure the oxidization process of organic component in

the soil sample is complete.i. The lid must be opened and closed frequently to allow entrance of oxygen for

burning purpose.

ii. Heating, weighing and cooling process must repeat until a constant result isobtained.

iii. The soil is heated in oven to evaporate the humidity of soil.

4. Humus, as the end result of this process, is less valuable for plant growth than are the

products formed during active decomposition.

5. Humus has a profound effect upon the physical properties of mineral soils with regard toimproved soil structure, water intake and reservoir capacity, ability to resist erosion, and

the ability to hold chemical elements in a form readily accessible to plants.

Conclusion

The average percentage of organic matter in the soil sample is 8.00%.


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Experiment 5: Determination of Air Content of Soil

AimTo determine the air content of soil

Apparatus

Tin can of volume about 200 cm, 500 cm beaker, metal seekerMaterial

Water

Procedure

1. The empty can is placed with its open end uppermost into the 500 cm beaker and

the beaker is filled with water above the level of the can. The water level in the beaker is

marked.

2. The water in the can is carefully removed and the volume of water is measured by

using a measuring cylinder. The volume (a) obtained is recorded. The water level in the

beaker fell by an amount corresponding to the volume of the water in the can.

3. The base of the can is perforated using a drill, eight small holes is made.

4. The open end of the can is pushed into the soil from which surface vegetation has

been removed until soil begins to come through the perforations. The can is then gently

dug out, turned over and the soil from the surface is removed until it is level with the top

of can.

5. The can of soil, with open end uppermost, is placed gently back into the beaker of

water and the soil in the can is loosen with seeker to allow air to escape.

6. The water level in the beaker was lower than the original level because water will

be used to replace the air which was present in the soil.

7. Water is added to the beaker from a full 100 cm measuring cylinder until the

original level is restored. Volume of water added (b) is recorded.

8. The percentage of air in the soil is calculated. The percentage air content of the soil

sample can be determined as follows:

9. The experiment is repeated on soil samples from different area.


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Result

The percentage volume of air in the soil sample can be calculated by using the formula asshown as below:Volume of soil used = 410 cm

Volume of water added to soil sample = 500 cm

Total volume of water + soil sample = 500 + 410 cm= 910 cm

Total volume of water + soil sample (after shaking) = 740 cm

Volume of air = 910 cm - 740 cm

= 170 cmPercentage of air in the soil = (170/410) cm 100%

= 41.5% (3 significant places)

Title Soil samples Average


Volume of soil sample used (cm3) 410.00 410.00 410.00 410.00

Volume of water used (cm3) 500.00 500.00 500.00 500.00

Volume of mixture water and soil (cm3) 740.00 710.00 720.00 723.33

Volume of air in soil sample (cm3) 170.00 230.00 200.00 200.00

Percentage of air in soil sample (%) 41.46 48.78 46.34 45.53

Discussion

1. The soil sample collected must be taken out from the ground by pressing a tin can against the

soil to make sure the natural content in soil sample can be preserved and the arrangement ofsoil will not be loose and air from atmosphere will not occupy the empty spaces in soil as these

conditions will affect the result of experiment.

2. After the soil sample was placed into the measuring cylinder containing water, it is then

shaken vigorously so that all the spaces between soils particles were filled up with water.

3. The air can be found in the spaces between soil particles. Air in the soil is essential to

provide oxygen for aerobe organisms that live in soil and plants roots to precede respiration.

4. If compared with air in atmosphere, air in the soil has higher percentage of carbon dioxide

gas because of the respiration of soil organism, roots system of plants and limited air in the


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ground. Concentration of carbon dioxide increases with depth of soil. However gas exchange

occurs through diffusion process between air in soil and air from atmosphere.

5. For instance, air will be push out when rainwater diffuses into the spaces in the soil but at the

same time air from atmosphere will be suck into the soil with the rainwater. If there is too

much water in the soil, volume of air in the sand is bigger than volume of air in clay that both

have equal weight because the arrangement of clay and soil particles are closer than sand that

has loose arrangement and bigger particles. Small spaces between soil particles can maintain

water to undergo capillary action and prevent the entrance of air. Besides, aeration of soil can

be improved by the soil fertilization and organisms activities in soil such as earthworms which

can loosen the soil by burrowing in the soil.

Conclusion

The average percentage of air content in the soil sample is 45.53%.

Experiment 6: Determination of Soil pH

Aim

To determine the soil pHApparatus

Long test tube, test tube rack, spatula, 10cm pipette

MaterialUniversal indicator

Procedure

1. Add about 1cm of soil to the test tube and 1cm of barium sulphate, which ensuresflocculation of colloidal clay.

2. Add 10cm of distilled water and 5cm of BDH universal indicator solution. Seal the testtube with the bung as shown in the figure below. Shake vigorously and allow contents to

settle for 5 minutes.

3. Compare the colour of liquid in the test tube with the colours on the BDH reference colour

chart and read off the corresponding pH.4. The experiment is repeated on soil samples from different areas.


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Result

The colour of the universal indicator remains unchanged. The pH of the soil is pH 7 which isneutral.

Discussion

1. The pH value is used to measure acidic and alkaline of soil. Besides that, pH is to indicate the

concentration of hydrogen ions in a solution.

2. Acidic soil will show a small value of pH. Meanwhile, pH is one of the main factors that affect

plants growth. The pH value in the range of 6.0 to 7.5 is the most suitable condition for most

of the plants.

3. However, there are certain plants that needed acidic or alkaline soil for better growth. For

example, plants like tea tree, potato tree, pineapple tree, oil palm tree and orchid needed acidic

soil with value of pH 4.5 while other plants like groundnut, carrot vein needed alkaline soil.

4. Generally, acid is released by bacteria and fungus that decompose organic substance to yield

humus. Other than that, there is carbonic acid formed by the dissolving of carbon dioxide gas

that is released from the respiration of soil organisms, with water in the soil. Therefore, soil

that contains many humus and soil that carries water always acidic.

Conclusion

From the result, we can notice that the properties of the soil sample. The soil sample is neutral.


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Experiment 7: Determination of the Type of Soil Organisms

Aim

To determine the type of soil organisms

Apparatus

Tullgren funnel, Retort stand, beakers, Magnifying glass, Microscope, Glass slide, Bearmann funnelMaterial

4% formalin solution or alcohol solution 70 %

Using Tullgren Funnel To Extract Soil Organisms

Introductions

The Tullgren funnel technique is based on the negative respond of animals towards bright light,

high temperature and low moisture. The bright light force the soil organism downwards and they

eventually fall into the formalin.

Procedure

1. Tullgren funnel is set up as shown in diagram below.2. The soil sample is prepared and placed to the filter in Tullgren funnel.

3. The filament light is fixed, switched on and let the instrument for 24 hours.

4. The organisms collected in the beaker are identifying by using microscope.


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An example of the Tullgren funnels arrangement

Result

Macroorganisms collected from Tullgren Funnel

Precaution

1. All pebble in soil sample must smashed before put on the rough net to make sure there are noorganisms hide in a pebble and the soil become loosen because pebble might cause

organisms cannot move freely.

2. Bigger soil organisms need to be taken out before the soil is put on the net because bigger

soil organisms cannot be removed through the rough net in Tullgren Funnel.3. Surface of funnel should be dark in colour and able to prevent condensation so that water will

trap tiny organism before it drops into the beaker.

Discussion

1. Basic principle Tullgren Funnel is based on environment factors that affect the soilorganisms is temperature, moisture, and light.

2. Light will decrease the moisture and increases soil temperature in Tullgren Funnel.

3. Soil organisms will keep themselves away from a light, hot and dried place.

4. These organisms need to be drop down into alcohol solution 70 % or formalin 4% so thatembalmed organisms which drop into the beaker can be killed.

Conclusion

From the results, organisms collected are sensitive to the light, high temperature and lowmoisture. Soil mesofauna such as ant, termite, and small insects can be collected by using

Tullgren Funnel.


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Using Bearmann Funnel To Extract Soil Organisms

Introduction

The Baermann Funnel is used to isolate mesofauna living in the soil at the bottom of ponds andcanals. This technique is based on the fact that aquatic soil organisms such as nematodes and

Tubifex which are denser than water. The higher temperature and light intensity in the upper

water layer when compared to the base of the funnel, causes these aquatic soil organisms tomove downwards and gather at the stem of the funnel. When the clip opened, these organisms

fall into the beaker containing formalin and can be identified.

Procedure

1. Bearmann funnel is set up as shown in diagram below.

2. The soil sample is prepared and placed to the filter in Bearmenn funnel.

3. The filament light is fixed, switched on and let the instrument for 24 hours.4. The organisms collected in the beaker are identifying by using microscope.

An example of the Bearmann funnels arrangement

Result

Microorganisms collected from the Baermann Funnel

Summary of soil analysis

Experiment Object Result

2 Percentage of Humus 1.69 %


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Percentage of Water 51.88 %

Percentage of Clay 2.93 %

Percentage of Silt 8.58 %

Percentage of Fine sand 9.40 %

Percentage of Coarse sand 25.53 %

3 Percentage of water in soil 18.21%

4 Percentage of organic matter 8.00 %

Percentage of air in soil sample 45.53 %

6 pH 7 ( neutral )

7 Organism found in soil Ant, mites, paramesium

soil sampling technique

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