Aim
To study soil samples from two different sites and analyse their properties such as texture, moisture content, water-retaining capacity and pH. Also, the study aims to correlate the plants found in such soil.
Necessary Materials & Apparatus
For this experiment, soil collected from the roadside and garden are to be used. Apart from the soil samples, other required materials are:
- Tile.
- Beaker.
- Funnel.
- Burner.
- Dropper.
- Crucibles
- Petri dish.
- Glass rods.
- Test tubes.
- Wire gauze.
- Filter Paper.
- Distilled water.
- Mortar and Pestle.
- pH paper booklet.
- Measuring cylinder.
- Universal pH indicator solution.
- Tin Box with a perforated bottom.
- Weighing scale or Electronic balance.
Procedure
The following are the steps taken to prepare the soil samples for experiments to analyse various properties.
To study the pH of the Soil Samples
- Take the collected roadside soil and garden soil into two different beakers containing water.
- Mix the test tubes with the soil solution slowly
- Now into a clean and dried two test-tube, arrange a funnel spread covered with a filter paper.
- Now gently pour the soil solutions into the test tubes separately.
- Let the water to completely filter off from the filter paper.
- Take the collected filtrates (soil) into the two different test tubes for testing the pH values.
- With the help of a dropper, add a few drops of universal indicator solution to both the test tubes.
- Observe the changes.
Observation
When the universal pH indicator is added to the test tube containing the soil solution, the colour changes. These colour changes can be tracked using the pH colour chart. Roadside soil has a pH level of 7 while garden soil has a pH level of 6. Most crops grow between pH levels of 6.0 and 7.0.
To study the texture of Soil Samples
- Collect 50 gm of any soil sample in a beaker.
- Take a clean and moisture-free measuring cylinder and the collected soil sample into it.
- Now pour little water into the same measuring cylinder and shake well.
- Keep the apparatus undisturbed for a few minuted and wait for the particles to settle down.
- After a while, observe the changes in the measuring cylinder.
- The soil particles in the measuring cylinder will start to settle down in layers.
- Record the thickness of these layers.
Observation
Using a soil textural triangle, draw the corresponding percentage of the soil components (silt, clay & sand). The resultant lines which, intersect indicate the type of soil.
To study the Moisture Content of Soil Samples
- Collect two different soil sample in two different crucibles.
- Weight the soil samples using a weighing balance.
- Make a note of the reading.
- Place the two crucibles over the bunsen burner and heat it until it becomes dry.
- Now again weigh the soil samples and record the weight of the dry soil samples.
- The samples are now ready to be used to determine the moisture content of the soil.
- Calculate the two different readings to know the moisture content of soil samples.
Observation
The sample where the initial and final weight is the larger indicates a higher moisture content. Lower values mean the moisture content is quite low.
To study the Water Holding Capacity of Soil Samples
- Collect a garden soil sample in a beaker.
- To a clean and dried mortar pestle add the collected soil sample.
- Now slowly grind the soil sample into a fine powder using a pestle.
- Place a filter paper at the bottom of the tin box.
- Weigh the entire contents of the tin box.
- Now, add the powered soil into the tin box.
- Use the glass rod to press and tap the box, so that the soil is uniformly layered.
- Now, the weight of the tin box is measured and to be recorded.
- Next, take two glass rods and place them parallel to each other. Ensure that the distance between the two is not long.
- Position the tin on the two glass rods in such a way that the bottom is in contact with the water.
- The complete setup should be left undisturbed until the water seeps through the upper surface of the soil.
- Now, remove the tin and allow all the water to flow out from the bottom.
- Wait until no more water percolates from the tin.
- Now wipe the bottom dry and use the weighing machine to note down the weight.
- Calculate the two different readings to know the water holding capacity of the given soil samples.
Observation
The water holding capacity of the soil is determined by the quantity of water held by the soil sample versus the dry weight of the soil sample.
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