• Harvesto Group

What is Soil?

Updated: Dec 2, 2020

What is soil?

Soil is a natural body developed by natural forces/ weathered biochemically as a synthesized product of nature and it is a natural habitat for plant growth and other living organisms composed of minerals, organic material.


Why is soil important?

  1. Soil is the basic foundation and vital part of our ecosystem.

  2. Soil is the most important factor for the plant as it supports roots, keeping plants upright for growth.

  3. Soils are also habitat for living organism these are nature hidden helpers for plants because they provide the essential nutrients and minerals to grow.

  4. Healthy soils protect the land from erosions such as Grill Erosion and Gully Erosion.

  5. Soils provide better crop yields protects plants from biotic stress.

  6. Soil keeps adequate aeration for plants for gaseous exchange provides oxygen for living microbes and stores water for plants.

  7. Soils help in regulating the earth’s temperature protect plants from climate change such as removal of CFC’S, Greenhouse Gases, Fossil fuel emission.

  8. Soil is a non-renewable natural resource.

  9. The process of capturing and storing carbon dioxide from the atmosphere is called Carbon sequestration and it is a method of reducing the amount of carbon dioxide in the atmosphere.

  10. Soil helps in water purification and soil contamination is reduced.


Importance of soil, how is soil formed and why do plants need soil?
Importance of Soil

How is soil formed?

  • Soil is the uppermost thin layer of the earth’s surface. Soil is formed by a process known as Weathering and Soil Formation.

  • Soil is mainly made up of Solid Space (50%): Mineral particles 45%, Organic particles 5%, Pore Space(50%): Water 25%. Air 25%.

Weathering Process:

  • The disintegration of decomposition of rock and rock minerals known as the Weathering process.

The process can be 3 types:

Physical Weathering: Breakdown of parent material through the mechanical way as temperature changes and abrasion.

Chemical Weathering: Breakdown of parent material through the chemical way as parent material reacts with air, water, or other chemicals in the atmosphere.

Biological Weathering: Breakdown of parent material through the natural way as cracks in the rock, splitting and making soil mineral into true soil.


Soil Formation:

  • Accumulation of material through the action of water, wind gravity contributes to Soil Formation. The Process is very slow takes thousands of years.


Factors for the formation of soil:


There are 5 main factors that affect the formation of soil by Passive and Active Process.

Active Process: Climate and organisms.

Passive Process: Parent Material, Relief/ Topography, and Time.

  • Parent Material: Soil minerals form the basis of soil produced from parent material known as Rock through weathering.

  • Organisms: Soil formation is influenced by organisms and microorganisms.

  • Climate: Temperature and rainfall affect the weathering and decomposition of the parent material.

  • Topography: Flat, Undulating, Depression and Exposure are the slope affects drainage, type of vegetation and amount of rainfall.

  • Time: The soil formation process depends on how long the soil has been weathered.

Why do plants grow in soil?

Soil is the natural habitat for plant growth so plants growth occurs because of:

  1. Soil supports plant growth by root anchorages and balance of the plant.

  2. Soil provides essential nutrients and minerals for a plant to grow also provides water to plants for its metabolic process.

  3. Soil provides good microclimatic conditions for microorganisms growth so that the breakdown of complex molecules into elements the plant can absorb easily.

  4. Soil supports to withstand any climatic conditions such as heavy rainfall, heavy winds etc, for plants.

  5. Soil provides aerobic conditions for photosynthesis, respiration process.

What is Soil Quality?

Soil quality is the measure of the condition of a soil performs related to productivity, the solubility of nutrients and salts, water percolation, fertility, nutrient cycle, organic matter content, biological activity, soil tilth and texture of the soil.

This functioning capacity of a soil to perform within a natural or managed ecosystem and varies from soil to soil. Soil quality relates to soil functions. Soil quality can be evaluated by using soil management assessment framework.

What is Healthy Soil?

Soil which meets all its range of ecosystem functioning known as Healthy Soil. Soil health is defined as a soil’s ability to function and sustain plants, animals and humans as part of the ecosystem.

Factors that impact the health of soil are Soil structure, Soil texture, Soil chemistry, Soil biology, Organic matter content and Water infiltration.

How can we protect the soil?

Soil is protected by using conservational practices in soil. Soils are protected in Agronomic measure, Mechanical measure and Biological measure.

Agronomic Measures:

  1. Contour Ploughing: The farming practice of planting across a slop in elevated contour lines. It reduces soil erosion, runoff water and enhances soil quality.

  2. Agroforestry: Management of land by trees, shrubs, palms, bamboos with agricultural crops and animals in form of spatial and temporal arrangement. It helps in nutrient cycle availability to roots, make to store carbon in the soil, maintain soil moisture, soil physical properties and also reduces weeds.

  3. Strip cropping: Farming involves the cultivation of the crop in a long, narrow strip in an alternated crop rotation system.

  4. Inter-cropping: Farming involves the cultivation of two or more agriculture crops on the same field to produce a good yield by using making use of resources.

  5. Mixed cropping: Farming involves the cultivation of more agriculture crops on the same field in a mixed way or making different strips for different crops.

  6. Grazing management: Management of animal grazing in planning, implementation and monitoring way for sustained animal, land.

Mechanical Measure:

  1. Graded bunding: Bunding is suitable for lands having slopes from 2-10 % and recommended in an area where rainfall of more than 800mm per year.

  2. Sub-Soiling: The technique used for adverse effects of soil compaction to improve soil physically in cropping and pastoral agriculture. Break up the soil profile up to a certain depth and produce vertical cracks.

  3. Broad Bed and Furrow: This furrow is suitable for managing rainwater in deep black soils where surface drainage during the monsoon period is a problem.

  4. Bench Terracing: This type of terracing is adopted in lands where steep slopping and undulating land.

  5. Vegetative Barriers: The barriers which are closely planted usually in a few rows of grasses or shrubs along the field for controlling soil erosion.

  6. Vertical Mulching: The placing of crop residues or straw in narrow trenches across the slop at intervals.

Biological Measures:

  1. No-Tillage: Tillage is an agricultural technique for growing crops or pastures with disturbing soil through till but in No-Tillage soil is not disturbed.

  2. Crop Rotation: Planting different crops on the same plot of land helps to improve soil health, nutrients, minerals, pest and weed pressure.

  3. Wind-breaks: Planting of trees and shrubs to break the wind flow and reduce wind speed and help crops to sustain from those.

  4. Leguminous Crops: Crops that belong to Leguminous groups such as groundnut, cowpeas and soya which have Nitrogen fixation bacteria in roots in root node fixes nitrogen in the soil.

  5. Reforestation: The process of re-growth of plants in the forest which have been cut down for a purpose.

  6. Mulching: Mulch is a layer of crop residues applied to the surface of the soil for the conservation of moisture in the soil, reducing weed growth.


How is soil degraded?

Decrease in soil quality by physical activities, chemical activities and biological activities.


Physical Activities:

  • Soil structure

  • Soil erosion

  • Desertification/ Deforestation

  • Increase flooding.

  • Environmental Pollution.

Chemical Activities:

  • Acidification

  • Leaching

  • Salinization

  • Cation retention capacity

  • Fertilizers

Biological Activities:

  • The decline in land biodiversity

  • Loss of organic matter

  • Overgrazing

  • Reduce soil disturbance

  • Overexploitation

Soil Regeneration is important
Soil Regeneration is important

How can soil be regenerated?

The particular form of regeneration of soil within the field of restoration ecology.

  1. Integrated Nutrient Management: Management of crop residues for the production of compost and the use of fertilizers and manures for soil fertility and provides nutrients for plants.

  2. Organic agriculture: Cultivation of crops in a sustainable way with using natural resources to crop obtain good health of the soil and maintain ecological balance prevents pest problems.

  3. Crop Rotation: Planting different crops on the same plot of land helps to improve soil health, nutrients, minerals, pest and weed pressure.

  4. Mixed Cropping: Farming involves the cultivation of more agriculture crops on the same field in a mixed way or making different strips for different crops.

  5. Biochar: Charcoal like substance made from burning agricultural waste like crop dry residues called Biochar which improves plant growth and increases yield without depleting soils.

  6. Mulching: Mulch is a layer of crop residues applied to the surface of the soil for the conservation of moisture in the soil, reducing weed growth.

  7. Compost and Manure: Compost is the organic matter decomposed from organic matters such as leaves, humus, grass and food scraps and decomposed by fungi, earthworms. Manure is the organic material such as animal faeces, crop residues, leaves are decomposed and used as a fertilizer and it provides nutrients for plants.

  8. Biosolids and wastewater: Solid nutrient-rich organic matter obtained from sewage treatment and wastewater treatment are beneficially used as fertilizer to improve soil properties, plant growth and reduces the use of inorganic fertilizers.

  9. Legume Crops: Crops that belong to Leguminous groups such as groundnut, cowpeas and soya which have Nitrogen fixation bacteria in roots in root node fixes nitrogen in the soil.

  10. Agroforestry: Management of land by trees, shrubs, palms, bamboos with agricultural crops and animals in form of spatial and temporal arrangement. It helps in nutrient cycle availability to roots, make to store carbon in the soil, maintain soil moisture, soil physical properties and also reduces weeds.


Healthy Soil Healthy Crop
Healthy Soil Healthy Crop

Is soil a renewable resource?

Soil is a valuable resource and slowly renewable resources take a long time to become productive once the soil is used for cultivation it loses its nutrients and minerals in form of food, feed, fibre and fuel but we can restore them by conservational practice. But for human purposes soil is a non-renewable resource because of careless use, erosions, salinization, acidification, usage of inorganic chemicals, management practices, unsustainable land uses forms different economic and ecological imbalance. The current rate of soil degradation causes severe problems to a capacity of future generations to meet the most basic needs.

So, the soil is not a renewable resource.