Soil

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What is Soil?

Soil is a complex mixture of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. Soil provides the structural support and is the source of water and nutrients for the growth of plants used in agriculture. It is the top layer of soil in which plants can grown.



  Video on what soil is and the formation of soil :


Video on the layers of soil :

The Importance of soil

The following points are reasons why soil is so important:
  1. Medium for plant growth                                                                                                                                                                                  Soils support roots and keep them upright for growth. Soils provide plants with essential nutrients and minerals. Soils hold water and maintain aeration. Soils protect plants from erosion and other destructive physical, biological and chemical activity.                                                                                                                                                     
  2. Habitat for many insects and other organisms                                                                                                                                      Insects and microbes live in soils and depend on it for food and air. Soils are home to a diverse range of organisms such as worms or termites. They provide the needed moisture and air for the breakdown of organic matter. They provide a home for many insects and rodents  to lay and hatch eggs and produce offspring.                                                                                                                                                                                                          
  3. Carbon store and maintenance of atmospheric gases                                                                                                                                  Soils help regulate atmospheric carbon by acting as a carbon store. On a global scale, soils contain about twice as much carbon dioxide as the atmosphere and about three times as much as vegetation. This results in organic matter with high carbon content. Many other nutrients are cycled, stored and transformed in the soil.

By: Malick Majiet

Soil Practicals:

Practical 1: Soil Composition of our soil sample

Results:
Test Tube :
a)     Sand layer thickness = 3  cm

b)     Clay layer thickness = 2 cm

c)     Silt layer thickness = 2   cm

d)     Other = ____________cm

OBSERVATIONS AND INTERPRETATIONS:
1.         What have you discovered about the composition of your soil?
        Our composed very well. The water stayed brown and wasn't very translucent. This suggests that our soil contained a lot of nutrients.
2.         What is the importance of air and humus content in your soil?
            Humus determines how fertile the soil is. It traps oxygen which is essential for root development. Humus holds the nutrients of the plant. It also prevents soil erosion. Aeration of soil is very important. The plant needs air to grow. The air also allows for better water drainage, so the plant does not drown. Micro-organisms also need the oxygen to survive.
3.         What does the air and humus content mean for the plants your Window Garden?

            This indicates that our plants will have the necessary nutrients needed to grow well and will survive for a long time. The amount of air suggests that the soil will also drain the water very well and not drown the plant.
                                                                  PIC

Practical 2: Soil Classification and Texture of our soil

OBSERVATIONS AND INTERPRETATIONS:
1.         Describe the texture of your soil samples?
Soil sample 1 is very rocky with not many fine particles. There are many small  
pebbles and is very hard and gritty. It is also a brighter colour than sample 2.            
Soil sample 1 is much fluffier and softer. The particles tend to stick together for
sometime if pressure is applied. There are some hard sticks and tiny rocks in the
sample.                                                      
2.         How would you classify your soil sample1 and 2?

            Soil sample 1 – Sandy Soil
            Soil sample 2 - Loam Soil

3.         Explain the relationship between soil texture and soil water retention?

            Soil sample 1 is very coarse and has large particles. This allows the water to drain
            through much easier. Soil sample 1 does not retain the water very well and
            separates easily when pressure is applied to make it into a clump. This suggests
            that larger particles will not retain water very well. Soil sample 2 has finer particles
            and some organic matter. This increased the water retention and suggests the finer
            the particles, the better water retention the soil has. Soil sample 2 stuck together
            it was clumped together.

4.         What does this information about your soil texture mean for your window gardens?
            This suggests that our soil will have very good water retention and the plant will
            survive longer. Our soil particles are very fine which also decreases the aeration of
            our soil. This suggests that we need to add some sand soil to our soil so that the
            aeration of our soil increases.
Image result for sand soil
Soil sample 1
Image result for loam soil
Soil sample 2
                 














Practical 3: Determining the water retention capacity of your soil.

RESULTS:
Table 1: 
Soil sample Mass of soil (cm3
or g)		 Amount of water that drained into glass beaker (ml) Amount of water retained by the soil (ml)
1
7g
39
61
2
7g
51
49

OBSERVATIONS AND INTERPRETATIONS:

Questions:


  1. Which soil sample retained more water? How much more did it retain?

Soil sample number 1 ( which was ours ) retained quite a bit more than number 2 did by 11ml. our soil was quit thick and managed to absorb the water like a sponge.


  1. Which soil sample retained less water?

Soil sample 2 retained less water since it was more of a sandy-like texture it allowed the water to run straight through it.



33.      Can you explain why there may be differences in water content between the two soil samples?


Soil sample 1 was much more loamy and thick which managed to retain quite a bit more water because the particles are much smaller meaning that much less water can pass through.


While soil sample 2 was much more thin and grainy allowing the water to flow through much easier. The particles in this soil were much bigger meaning more space for the water to come through.


  1. Do you think that a high level of water retention in a soil is likely to be beneficial or harmful to plants growing in that soil? Suggest a reason.


            It depends how high the water retention capacity is and what type of plant it is too high can flood the plant but decent can allow the plant to flourish and grow.




  1. What advantage would soil with a high amount of organic matter have over soil with a low amount of organic matter, as suggested by the results of this experiment?


High organic matter is an incredible asset to soil it really provides a lot of the thickness and absorbsion that made soil sample 1 succeed.

     6.  What value is there in knowing the water content of your soil in your window
          garden?

It is very valuable because you can analyse what plants you are using and your filtration system to see if its beneficial or not.

CONCLUSION:
Can you identify your soil types based on the evidence of the experimental results?
What can you conclude about the different soil type’s water retention capacities?

You can definitely asses which soil it is just by looking at the water retention capacity sandier soils always have lower water retention capacity whereas thick rich loamy soils have a high water retention capacity.


Would our soil be suitable to grow vegetables?

Our soil would be suitable to grow vegetables based on the following information:
  • The composition practical suggested that our soil was high in nutrients. This means that our plants will grow very well and have a long lifespan.
  • The texture of our soil is perfect for the plants that we are aiming to grow. Our soil particles are also very fine. This suggests that it would retain water very well.
  • The water retention practical suggests that our soil retains water very well. This means that our plants will have good moisture for long periods of time. Our plants will not dry out easily and die.