Soil is the uppermost loose layer of the earth’s crust.
It is powdery material with different grades and sizes of soil particles.
Soil supports the growth and survival of the plants and trees.
Due to this, all the animals are dependent on plants for their survival in one or another way.
Most animals depend on plants for food while few for shelter (like birds, insects, and few animals like monkeys).
Besides humans are also dependent on clothing, furniture, medicines, etc.
Soil components that contribute to fertility are nutrients, soil water, and soil microbes.
Soil’s property to provide sustenance to plants is due to its fertility.
Soil fertility is the nutritive organic and inorganic component mixture that is suitable for the proper nourishment of plants.
This soil fertility includes major nutrients and minor nutrients and also mineral and non-mineral elements.
And these nutrients are available in organic form in a greater ratio than inorganic matter form.
With the presence of water, these nutrients are being absorbed into the plant.
♠ Major Nutrients in soil fertility: These are nutrients required in sufficiently large amounts like Nitrogen, Phosphorous, Potassium.
These elements are useful for plant growth as they are part of cell components like proteins, amino acids, adenosine triphosphate (ATP), nucleic acids like DNA, RNA, hormones, enzymes. Further, they also regulate plant cell physiology like buffering action, pH maintenance, etc. They are the actual building material of plants.
♠ Secondary Nutrients: These are nutrients required in sufficiently small amounts like Calcium, Magnesium, Sulfur.
These secondary elements participate in functions like buffering, pH maintenance, components of enzymes, some proteins, etc.
♠ Micro-nutrients: These are elements required in minute quantities but are absolutely essential for plants. They include zinc, Manganese, Iron, Copper, Boron, Molybdenum, Chlorine.
Most of these micro-nutrients form the components of co-enzymes. These co-enzymes are supportive of enzymes involved in photosynthesis, metabolism, detoxification, etc.
Without them, these reactions can stop leading to disruption of plant physiology.
Other nutrients involved in soil fertility:
These are nutrients available to plants in gaseous form in plenty but also to a small extent from the soil.
Carbon, oxygen, and hydrogen are present in a combined form with organic material of soil. but plants don’t require them through the soil.
Water: This is the primary factor which is an indicator of soil fertility. Soil’ s capacity to hold water in its pores i.e between the soil particles is advantageous because,
1. Nutrients mentioned above are all dissolved in soil water.
2. Water ad-mixed with all the above nutrients is taken up by plant roots by capillary action. So water acts as a medium to help plants take up nutrients.
3. Water facilitates the growth of soil bacteria which decay the organic matter. Hence, the decayed bulk of organic matter leaves behind only the nutrients in a form easily available to the plants through the soil.
This is the reason why the desert is lack of any fertility due to low water holding capacity.
4. Water from soil facilitates the distribution of nutrients to the entire plant as there is no circulatory system.
5. Soil water facilitates the germination of seeds by breakage of hard seed coat and also activation physiology.
6. Water in the soil also helps retain or hold essential nutrients.
Soil bacteria: This is another factor contributing to soil fertility.
Bacteria in the soil decays organic matter to provide nutrients into the soil. plants and animals dead are decayed leaving the organic waste which enhances soil fertility.
Some bacteria even absorb nitrogen from atmospheric air and fix in the soil making it available to plants in the form of ammonia.
Soil bacteria also remove organic toxic waste by decay. So soil with beneficial bacteria is considered to be fertile.
Air: Gases to some extent are present in soil pores and are available for plants during germination.
Thus fertile soil has water, nutrients, bacteria insufficient ratio and contributes to plant germination, growth, and survival.
Without the soil, it would be difficult for the survival of living organisms on the earth. So with this importance of soil in mind, we need to take steps to conserve the soil for the future.