An estimated 70 percent of the earth’s surface is covered with water, while the remaining 30 per cent constitutes land. The layer of the earth that is composed of soil and is influenced by the process of soil formation is called pedosphere. But what exactly is soil and what is soil made of?
What is Soil?
Technically, the soil is a mixture that contains minerals, organic matter, and living organisms. But broadly speaking, soil can refer to any loose sediment. Moreover, there are many types of soil that are distributed around the world and these are generally classified into the following:
- Clay Soil
- Sandy soil
- Loamy Soil
- Silt Soil
Typically, the soil consists of 45% minerals, 50% empty spaces or voids and 5% organic matter. Furthermore, soil performs many important functions such as:
- Providing a growth medium for the plants
- Acts a modifier of the earth’s atmosphere
- One of the most crucial components of the biosphere
- Provides habitat for organisms
Also Read:Soil Teeming
How is Soil Formed?
Soil is formed by weathering of rocks. Solid rock can weather away in one of the three ways into the soil, namely:
- Mechanical Weathering
- Chemical Weathering
- Biological Weathering
Mechanical Weathering
This is commonly observed near the surface of the earth. Also called physical weathering, as this process is influenced by physical forces such as wind, water and temperature.
Chemical Weathering
As the name suggests, chemical weathering occurs when rocks are broken down by chemical reactions. Often, such types of weathering can change the chemical composition of the soil.
Biological Weathering
Though not an actual weathering process, living organisms weaken and subsequently disintegrate rocks, often by initiating mechanical or chemical weathering. For instance, tree roots can grow into cracks in the rock, prying them apart and causing mechanical fractures. Microorganisms can secrete chemicals that can increase the rock’s susceptibility to weathering.
Also Read:Soil Profile
Composition of Soil
The soil is composed of different components: 5% organic matter, 45% minerals, 20-30% different gases and 20-30% water. Therefore, the soil is known as a heterogeneous body. Given below is the composition of soil in detail:
Organic Matter
Organic substance is found in very small amounts in the soil. Plants and animals are the main sources of organic matter. Depending upon the decomposition stage, the organic matter is of the following three types:
- Completely decomposed organic matter
- Partially decomposed organic matter
- Undecomposed organic matter
Minerals
Minerals are an important element of the soil. These are solid components composed of atoms. These occur naturally and have a fixed chemical composition. Olivine and feldspar are the main minerals present in the soil.
Gaseous Components
The air-filled pores of the soil contain the gaseous components. Nitrogen and oxygen present in the pores is generally the atmospheric air fixed by the microorganisms. However, the composition of carbon dioxide is higher due to the gas produced by microorganisms present in the soil.
Water
The soil dissolves the minerals and nutrients in the water and transports it to different parts of the plants. These are essential for the growth and development of the plant.
Importance of Soil
Soil is an important element essential for the survival of living organisms. The importance of soil is mentioned below:
- The fertile soil helps in the growth and development of the plants. The plants thus produced are healthy and provide food, clothing, furniture, and medicines.
- It supports many life forms including bacteria, fungi, algae, etc. These microbes, in turn, maintain environmental balance by retaining the moisture and decaying the dead organisms.
- The topsoil supports certain life activities such as reproduction, hatching, nesting, breeding, etc. of a few organisms.
- The organic matter present in the soil increases the fertility of the soil which is responsible for the growth of the plants. It also contains certain minerals and elements that are necessary for the plants to carry out their cellular activities.
- Soil is used for making cups, utensils, tiles, etc. The contents in the soil such as gravel, clay and sand are used in the construction of homes, roads, buildings, etc.
- Useful mineral medicines such as calcium, iron, and other substances such as petroleum jelly for cosmetics are extracted from the soil.
- The soil absorbs the rainwater. This water is evaporated and released into the air during sunny days, making the atmosphere cooler.
Also Read:Mineral Riches In The Soil
Thus we see how the soil is formed, what it is composed of and how it is importantto different life forms.
To know more about soil, its formation, composition and importance (along with other important concepts such as soil pollution), download BYJU’S – The Learning App.
FAQs
Typically, the soil consists of 45% minerals, 50% empty spaces or voids and 5% organic matter. Furthermore, soil performs many important functions such as: Providing a growth medium for the plants. Acts a modifier of the earth's atmosphere.
What is the importance of soil and composition of soil? ›
Soil is the loose surface material that covers most land. It consists of inorganic particles and organic matter. Soil provides the structural support for plants used in agriculture and is also their source of water and nutrients. Soils vary greatly in their chemical and physical properties.
What is the composition of the soil answer? ›
The basic components of soil are minerals, organic matter, water and air. The typical soil consists of approximately 45% mineral, 5% organic matter, 20-30% water, and 20-30% air. These percentages are only generalizations at best.
What is it about soil that makes it so important to us? ›
Soil helps produce our food and unearth life-saving medicines and vaccines. Soil also filters and purifies our water, reduces flooding, regulates the atmosphere and plays a crucial role in driving the carbon and nitrogen cycles.
What are the most important things about soil? ›
Soils are not only the resource for food production, but they are the support for our structures, the medium for waste disposal, they maintain our playgrounds, distribute and store water and nutrients, and support our environment. They support more life beneath their surface than exists above.
Why is the soil important? ›
Soil provides a host of crucial services for both people and the planet. Soil puts food on our plates, purifies our water, protects us against flooding and combats drought. It's also key to tackling climate change as it captures and stores vast amounts of carbon. There is no food security without healthy soils.
What is the importance of good soil structure answers? ›
A good soil structure is important to allow air and water into the soil which are vital for healthy plant growth. It will improve drainage and reduce soil erosion caused by excess surface run-off.
How to determine soil composition? ›
Through in-field testing (such as rolling soil together to determine how well the soil sticks together) or through lab testing for properties such as pH levels, chemical composition, and other factors, the composition of soil can be easily determined.
What is the composition of the perfect soil? ›
The perfect soil is a 40-40-20 percent mix of sand, silt and clay. This is what is known as loam. You get the best of the three soil types from loam: moisture retention with good drainage, good airflow and decent nutrient retention. There are two simple tests you can do yourself to determine your soil type.
Why is soil important essay? ›
For one, it is vital for plants to grow as it holds and supports the roots as well as provides the adequate minerals and nutrients for the plant to thrive. It also holds and maintains carbon dioxide and other atmospheric gases as well as helps to filter surface water ("Importance of Soils").
Healthy soil is foundational to human health. Healthy soil is needed to grow crops, provides food, and sustains populations. It supports diverse ecosystems and critical ecological services such as pollination. It stores water and prevents floods.
What is the healthiest soil? ›
Loam: Loam is an ideal garden soil for many types of plants. It's crumbly, full of organic matter, retains moisture, and drains well. For most plants, this is "healthy" garden soil.
Why is soil quality important? ›
Healthy soil gives us clean air and water, bountiful crops and forests, productive grazing lands, diverse wildlife, and beautiful landscapes.
Which is the most important in soil? ›
The key to healthy soil
Biological – organic matter provides food for microorganisms. Chemical – increases cation exchange capacity in soils. It buffers the soil environment and stabilises against heat and cold extremes and pH fluctuations. Physical – a strong physical component builds a better soil structure.
What are 5 things we need soil for? ›
Just like how a foundation for a home is critical, healthy soil acts as a foundation for plants by supporting plant roots and keeping plants upright for growth. Soil acts as a pantry for plants, storing and cycling essential nutrients and minerals that plants need to grow. Soil stores water for plants.
What is the most important factor of soil? ›
Climate: This is probably the most important factor that can shape the formation of soils. Two important climatic components, temperature and precipitation are key.
Why is proper soil composition important for plants? ›
The relative amounts of pore space and mineral and organic matter vary greatly among different soil types. But for plant growth, most soil scientists agree that 50% pore space, 45% mineral matter, and 5% organic matter make up an ideal ratio.
What is the most important factor that affects soil composition? ›
Climate: This is probably the most important factor that can shape the formation of soils. Two important climatic components, temperature and precipitation are key. They determine how quickly weathering will be, and what kind of organic materials may be available on and inside of the soils.
What is soil the most important component of? ›
Soil is a vital part of our environment. It allows plants to grow, holds and cleans water, recycles nutrients and provides a home for a multitude of organisms on Earth.
Why is it important to understand the particle composition of soils? ›
Soil texture, defined by the composition of particle size, namely sand, silt, and clay, is an important land environmental variable because it plays a key role in soil degradation and water transport processes, controlling soil quality and its productivity (Hillel 1980; Blume et al., 2010).
