Pic Courtesy – http://eschool.iaspaper.net/wp-content/uploads/2018/02/Soil.jpg
Let us consider this world and the life on this planet. What makes the earth a great place to live. Today, the four basic things required by us are Food, Water, Shelter, and Clothing. With a little more thought, Air and Energy. Amazingly all are not only related, but dependent on a single source, and that is SOIL. Humans despite their artistic pretensions, their elevating sophistication, and their many accomplishments owe their existence to a 20 cm. layer of TOPSOIL only. When we go out in the field and walk over to a patch of soil, we will find it to be reddish-brown, dark grey, or even the color of rich dark chocolate. But as we generally perceive, it is not an inert growing medium. This piece of earth is throbbing with life. It is a living and life-giving resource. All life on the Earth depends on the top 20 cm. of soil.
Soils are amazing. Soil can be defined as the top layer of the earth’s crust. It’s formed by mineral particles and organic matter. water, air, and living organisms. Soil is a biologically active and breathing porous medium that has developed in the uppermost layer of the earth’s crust. Soil is one of the principal substrata of life on Earth, serving as a reservoir of water, nutrients, and carbon. In a water filtration system, as water drains through soil, soil microorganisms and minerals act upon it to remove pollutants and toxins. It occurs through a physical, biological, and chemical process. It is also an important participant in the cycling of carbon and other nutrients through the global ecosystem. It interfaces with the lithosphere, the hydrosphere, the atmosphere, and the biosphere.
Soils are extremely complex, variable, and living medium. Life as we know, it would not exist without them. They provide countless services that benefit all humans. It can be difficult to say when some soils are born. But we can say that while some are young, many are very old. The oldest soil on Earth may be in Australia, where stable landforms have allowed some soils to age several million years. New soils are born with every landslide, volcanic eruption, or glacial retreat. Soils change over time through a host of biological, chemical, and physical processes. The formation of soil occurs at an extremely slow rate. One inch of topsoil can take several hundred years or more to develop. And we take only a few years to destroy it completely. As per data available, the slowest rates occur in cold dry regions (1000s+years). The fastest rates are in hot wet regions ( 100s+years).
Soils differ from one part of the world to another. Even it differs from one part of the backyard to another. They differ because of how and where they were formed. Five major factors control how soil is formed. They are Climate, Organism, Relief (landscape), Parent Material, and Time, (CLORPT). As soil formation is an extremely slow process, it can be considered essentially a non-renewable process, because they are constantly forming. Soil is the most diverse habitat of all. Up to 1.5 kg. of living organisms live beneath one square meter of healthy soil. They can be threadworms, earthworms, springtails, mites, insects larvae, and myriads of microorganisms. Soil organic matter is one of the largest carbon reservoirs that are in rapid exchange with atmospheric CO2. It is a critical source and sinks of greenhouse gases.
In 2010 “Earth Microbiome Project” was launched. This was related to genome sequencing of soil to identify, characterize, and analyze microbial communities across the world. It aims to collect samples from all possible environments. The result tells us that “Soil is teeming with life. It is made up of a vibrant, thriving population of bacteria, archaea, and fungi”. The number of microscopic organisms that live in a shovelful of rich garden soil exceeds the number of plants and animals inhabiting the entire above-ground Amazon rainforest. Soil is what supports life on Earth. It looks static, but it hosts plenty of activities. Its earthworm may be excavating tunnels when we are sleeping. Where earthworms are active, they can turn over the entire top 15 cm. soil in 10 to 20 years. They are not the only ones that are making changes. Other creatures below the ground (maybe too tiny to be seen with the unaided eyes) are also on the job of formation of soil.
Only about 7.5% of the earth’s surface provides the soil, we rely on for agriculture. Topsoil is used to grow 95% of our food and it is disappearing ten times faster than it is being replaced or formed. Soil is in direct contact with the plant root. The plants communicate with the ecosystem in the soil with a perfect mechanism. The Rhizosphere is the place where the plants absorb water and nutrients. It is also where they release compounds that can control the activity of organisms in the soil. Plants and microbes communicate in the Rhizosphere and help each other. It takes thousands of years to create an inch of fertile topsoil, but it can be destroyed in days. Soil has been called the fragile skin of the earth.
What humans are doing with their (only) own habitat? “No creature, not even swine, fouls its nest with abandon as does home sapiens. A morass of rotting human flesh awaits us all unless the antidotes are rapidly applied”, said Peter Tompkins. Around 24 billion tonnes of fertile soil are lost worldwide every year. Soil erosion is a serious concern in all parts of the globe. Over the past 150 years, 50% of the planet’s topsoil has been lost due to erosion. At least 16% of African land has been affected by soil degradation. And globally 50000 square kilometers of soil is lost every year. Overall erosion of soils is significantly higher than rates of soil formation. This represents a substantial long-term threat to the world’s soil. Eventually, all forms of life depend on soil and there can be no life without soil, and no soil without life. They have evolved together. Franklin D. Roosevelt once said, “The nation that destroys its soil, destroys itself”.
Soil is the basis of our nation’s agroecosystem which provide us with FEED, FIBRE,
FOOD and FUEL. The best way to support the soil is by limiting the amount of food that ends up in our garbage. This way we will prevent valuable nutrients from ending up in a landfill. The second is food diversity. When land is used to grow multiple crops, it helps keep biodiversity and soil fertility intact. Also “Eating A Rainbow” helps the body get a green assortment of nutrients. By using the, method of terrace and contour farming, we can prevent water flow from gathering speed and washing soil, away from farmlands. One of the most effective ways of preventing soil erosion is the restoration of welt lands. They act as natural sponges absorbing rainwater and preventing it from carrying the soil away. Tree plantation on a war footing will be an effective effort to prevent erosion of soil. While it may be easy to dismiss the importance of dirt, it’s a fact that SOIL IS VITAL TO HUMANKIND. Let’s stop soil erosion and conserve it to save life on Earth.