Experiment To Show The Presence Of Living Organisms In The Soil.

Before the experiment I shall briefly talk about soil and soil formation.

What Is Soil?

Soil can be defined as the upper region of the earth surface on which plant grows. Soil contains 45% of mineral matter (which are gotten most of the times from weathered rocks), 25% of water, 25% of air, and 5% of organic matter. Some of the important use of soil are;

1. It is essential for plant growth being that it anchors the plant and supplies the plant with all the basic necessities needed for it's growth.
2. It severs as a habitant for animals.
3. It is used for building constructions.

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Formation of Soil

The formation of soil as stated earlier on is as a result of weathering of rocks. The term weather is the breaking down of rocks into smaller pieces. Weathering can be of three forms; 1. Physical weathering. This is involves climatic actions such as temperature, wind movement, rain and other factors such as freezing water, ice movement. 2. Biological weathering. This involves the action of biological organisms such as plants root on rocks which can cause the rock to crack, due to the pressure exerted on it. Actions of man during cultivation and construction. 3. Chemical weathering. In this process, rocks are broken down by chemical processes such as hydrolysis, hydration, oxidation etc.

Soil Living Organisms.

Soil living organisms compromise from mammals (such as rats) to micro organisms (such as nematodes and protozoa). Soil organisms help in the modification of soil, and also in the decomposition of organic matter. However they can also pose as a treat to to some crops, as they are responsible for some plant diseases.

Experiment To Show The Presence Of Living Organisms

Apparatus;

two conical flask, rubber corks, two soil sample, two muslin bags, strings, lime water and heater.

Procedure;

Label the conical flask as A and B. Label the muslin bags A and B. Label the two soil sample A and B. Heat sample B well in other to kill living organisms found in it. Insert both samples into the muslin bag respectively. Attach a string to both bags. Pour into the conical flasks lime water. Suspend the bags into the conical flasks respectively and cork the flasks with the rubber corks. leave the experiment to stay up to 4 hours.

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Observation;

1. After 4 hours, the lime water in conical flask A turned milky. This is because when living organisms respire, they give out carbon (IV) as a by product. When carbon (IV) oxide dissolves in lime water, it turns it milky. 2. The lime water in flask B remained clear. This is because all the living organisms where destroyed during heating.

Conclusion

Soil contains living organisms.

reference

Teaming With Microbes by Jeff Lowenfels and Wayne Lewis. Encyclopedia of soil science by Rattan lar (Second Edition)