essay to soil

Why are soils important?

Soil is our life support system. Soils anchor roots, hold water and store nutrients. Soils are home to earthworms, termites and a myriad of micro-organisms that fix nitrogen and decompose organic matter. We build on soil as well as with it.

Soil plays a vital role in the Earth’s ecosystem and without soil, human life would be very difficult.

Soil provides plants a foothold for their roots and holds the necessary nutrients for plants to grow. Soil filters the rainwater and regulates the discharge of excess rainwater, preventing flooding.  It also buffers against pollutants, thus protecting groundwater quality.

Soil is capable of storing large amounts of organic carbon. It is the largest terrestrial store of carbon. On average, the soil contains about three times more organic carbon than the vegetation and about twice as much carbon than is present in the atmosphere [ source ]. This is of particular importance in efforts to mitigate climate change. Carbon can come out of the atmosphere and be stored in the soil, helping to re-balance the global carbon budget.

Soil provides people with some essential construction and manufacturing materials: we build our houses with bricks made from clay and we drink coffee from mugs that are essentially baked soil (clay). Water is served in a glass made from sand (silicon dioxide).

Rocks and minerals come to mind as the basis of soil material, however the soil also hosts a great deal of living organisms. The biodiversity of visible and microscopic life which uses the soil as their home is vast. The soil is one of the planet’s great reservoirs of undiscovered microorganisms and therefore genetic material which can become the basis of other scientific research such as developing new medicines.

Soil is also an archive. It presents a record of past environmental conditions by storing natural artifacts from past ecosystems like pollen. Many artifacts from human history are also stored underground, which archeologists carefully uncover and use to understand how civilizations have evolved.

Soil functions are general soil capabilities that are important for many areas of life including agriculture, environmental management, nature protection, landscape architecture and urban applications. Six key soil functions are:

• Food and other biomass production
• Environmental Interaction: storage, filtering, and transformation
• Biological habitat and gene pool
• Source of raw materials
• Physical and cultural heritage
• Platform for man-made structures: buildings, highways

• ENVIRONMENT

Why soil matters (and what we can do to save it)

Soil is failing across the world: every five seconds a soccer pitch of soil is eroded, and it’s estimated that by 2050 around 90 percent of the Earth’s soils could be degraded. What does this mean for people and planet, and what can we do to restore a healthy balance to the soil we need to survive?

A worm burrows its way through the dark earth, ingesting particles of soil and expelling nutrient-rich casts in a constant forage for food. Charles Darwin described earthworms as one of the most important creatures on Earth. Worms are critical to soil health, and without soil Planet Earth would be little more than a lifeless rock. So why is it that most of us take the earth beneath our feet for granted?

We might imagine soil as endless and indestructible: it is neither. Only about 7.5 percent of the earth’s surface provides the soil we rely on for agriculture, and it is remarkably fragile. Topsoil is used to grow 95 percent of our food, and it is disappearing ten times faster than it is being replaced: America’s corn belt has already lost much of its topsoil, threatening livelihoods and communities as well as food supply. The reality is that it takes thousands of years to create an inch of fertile topsoil, but it can be destroyed in minutes.

Healthy soil is a dynamic living ecosystem: a complex combination of minerals and organic matter containing air, water, and life. Worms are not alone in the ground, just a gram of dirt can contain as many as 50,000 species, all interacting with each other to keep their soil habitat healthy and productive. The activity of these organisms, the type of rock particles, the volume of organic matter, and the proportion of air and water all combine to create hundreds of different types of soil. These range from loose sandy soils to waterlogged peats to the beautifully balanced loam that is so well suited to agriculture. But human activity is destroying the balance and one-third of the world’s soil is already degraded.

Soil degradation, where soil loses the physical, chemical, or biological qualities that support life, is a natural process but it is being accelerated by human activity. Pollution kills microbial life in the soil; deforestation and development disturb soil structure making it vulnerable to erosion; soil compaction associated with farming and urbanization squeezes the air out of the ground and prevents it from absorbing water. Meanwhile, climate change continues to dry the ground: three-quarters of Spain is at risk of becoming desert.

But perhaps the biggest threat to soil is intensive farming. The need to feed a growing population and drive greater efficiency has sacrificed natural balance for increased yields. Monoculture farming, where one crop is grown repeatedly on the same ground, drains the soil of specific nutrients and allows pests, pathogens, and diseases to thrive. The pesticides and fertilizers used to counter these problems come with significant drawbacks. Excessive use of pesticides reduces vital biodiversity; the addition of nitrogen fertilizer speeds up the breakdown of organic matter, starving the soil’s microbial populations.

Even the plow, often considered one of history’s great inventions, can be bad news for soil. Tilling breaks up compacted ground, controls weeds, and incorporates organic matter, but we now understand how it also damages soil structure, dries out topsoil, and accelerates erosion. Similarly, the age-old practice of irrigation, when overdone, increases the volume of salt in the soil, damaging its biodiversity, water quality, and productivity. As a result of such destructive practices, in Europe alone, around 70 percent of the soil is considered unhealthy.

For Hungry Minds

This matters, because without soil we cannot survive. Healthy soil is the root source of a livelihood that sustains farmers and communities all around the world: good soil produces good crops that deliver a good income that enables families to flourish. But it’s more than this. Soil filters the water we drink, grows the food we eat, and captures the carbon dioxide that causes climate change. Soil is the largest carbon sink after the ocean and holds more carbon than all terrestrial plant life on the planet. But when we damage the soil, water systems become disrupted, food production declines, and carbon is released into the atmosphere. Any one of these essential soil functions would be reason enough to preserve our soil: taken together they are a compelling argument for urgent action.

So, how can we save our soils? Many of the ways to reduce and even reverse the damage are reliant on changes to current agricultural practices. By not tilling the land and reducing our reliance on pesticides and fertilizers, soil starts to recover. Replacing our reliance on monoculture with a return to crop rotations gives soil time to replenish the nutrients needed by plants. Agroforestry could take this further, growing a variety of plants together in ways that their biological systems support each other and help soil to flourish. Similarly, promoting soil fungi helps plants extract nutrients from the soil while increasing resistance to disease and building healthy soil structure. These good practices could regenerate our soils which helps sustain livelihoods and local communities, and keep people and planet healthy: but they require big changes.

Inspiring a fundamental shift in the way we farm needs to be driven by both the consumer and the companies they buy from. Responsible companies, including Unilever, are making serious commitments to minimize the damage done to the soil, while actively working to regenerate degraded land. This includes encouraging and supporting suppliers to improve soil health through regenerative practices such as growing cover crops that protect and nourish the soil between harvests: in Iowa, a state that has lost half its topsoil in a hundred years, farmers using cover crops reported that their land weathered heavy spring winter rains better than their neighbors’ land.

Knorr, Unilever’s largest food brand, is looking to expand such practices. It has set a goal of growing 80 percent of its key ingredients following Unilever’s Regenerative Agriculture Principles by 2026. Already, Knorr has partnered with Spanish tomato growers to use cover crops to improve soil health and reduce the use and impact of synthetic fertilizers; in the US Knorr is working with its suppliers to grow rice in ways that will reduce its demand for water and cut methane emissions. These are two of the many ongoing and planned projects as Knorr expands and scales up such projects while sharing their knowledge and inspiring others to transform the way food is grown.

Soil needs all the help it can get. It is a priceless, irreplaceable resource and key to sustaining all life on earth. Soil is struggling for survival but there is still time to rebuild our soils as healthy, productive, sustainable ecosystems. As the world learns to work together to preserve our oceans, our forests, and our biodiversity, we now need to look to the ground. The humble earthworm can only do so much: it’s time for individuals, communities, companies, and countries to help save our soils.

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What Are Soils?

Soils are dynamic and diverse natural systems that lie at the interface between earth, air, water, and life. They are critical ecosystem service providers for the sustenance of humanity. The improved conservation and management of soils is among the great challenges and opportunities we face in the 21st century.

Soil is... a Recipe with Five Ingredients

Soil is a material composed of five ingredients — minerals, soil organic matter, living organisms, gas, and water. Soil minerals are divided into three size classes — clay , silt , and sand (Figure 1); the percentages of particles in these size classes is called soil texture . The mineralogy of soils is diverse. For example, a clay mineral called smectite can shrink and swell so much upon wetting and drying (Figure 2) that it can knock over buildings. The most common mineral in soils is quartz; it makes beautiful crystals but it is not very reactive. Soil organic matter is plant, animal, and microbial residues in various states of decomposition; it is a critical ingredient — in fact the percentage of soil organic matter in a soil is among the best indicators of agricultural soil quality (http://soils.usda.gov/sqi/) (Figure 3). Soil colors range from the common browns, yellows, reds, grays, whites, and blacks to rare soil colors such as greens and blues.

Soils are... Big

You may be surprised to hear " dirt " described as "big". However, in the late 1800's soil scientists began to recognize that soils are natural bodies with size, form, and history (Figure 4). Just like a water body has water, fish, plants, and other parts, a soil body is an integrated system containing soil, rocks, roots, animals, and other parts. And just like other bodies, soil systems provide integrated functions that are greater than the sum of their parts.

Soils are... Young to Very, Very Old

Soils are... diverse.

• Plinthite — which hardens irreversibly upon repeated wetting and drying (Figure 8a).
• Sulfidic — a horizon containing pyrite which, upon exposure to oxygen, can produce so much sulfuric acid that it kills plants and can cause fish kills (Figure 8b).
• Petrocalcic — in which so much calcium carbonate is accumulated that it literally forms a rock-like layer in the middle of a soil (Figure 8c).

Soils... Communicate

• O - Horizon containing a high percentage of soil organic matter.
• A - Horizon darkened by the accumulation of organic matter.
• E - Horizon formed through the removal ( eluviation ) of clays, organic matter, iron, or aluminum. Usually lightened in color due to these removals.
• B - Broad class used for subsurface horizons that have been transformed substantially by a soil formation process such as color and structure development; the deposition ( illuviation ) of materials such as clays, organic matter, iron, aluminum, carbonates, or gypsum; carbonate or gypsum loss; brittleness and high density; or intense weathering leading to the accumulation of weathering-resistant minerals.
• C - A horizon minimally affected or unaffected by the soil formation processes.
• R - Bedrock.

These master horizons may then be further annotated to give additional information about the horizon. Lower case letters can be placed as suffixes following the master horizon letter to give additional information about soil characteristics or soil formation processes. For example, the lower case "t" on the B horizon in Figure 9 indicates that the horizon is characterized by illuvial clay accumulation. Multiple letters can be used — Figure 8c depicts a Bkm horizon meaning that it is cemented (m) by illuvial carbonates (k). Numbers placed before the master horizon name (e.g., 2Bt) indicate a difference in parent material; numbers placed at the end of a horizon name are used to subdivide horizons that have the same designation but are different in some way (e.g., a red Bt1 over a yellow Bt2).

Soils are... Biological Bliss

Soils are... fertile.

Soils are the primary provider of nutrients and water for much of the plant life on earth. There are 18 elements considered essential for plant growth, most of which are made available to plants through root uptake from soils (Brady & Weil 2007). Soils retain nutrients by several mechanisms. Most nutrients are dissolved in soil water as either positively or negatively charged ions; soil particles are also charged and thereby are able to electrically hold these ions. Soils also hold nutrients by retaining the soil water itself.

Arguably the greatest of all the ecosystem services provided by soils is the retention of water — without soils our land would be little but rocky deserts. Plants use much more water than one might think because they are constantly releasing water into the atmosphere as a result of transpiration, which is a component of the process of photosynthesis. Clay and silt particles are the primary mineral components in soils that retain water — these small particles slow the drainage of water and, like a sponge, physically hold water through capillary forces. Clay provides such strong force that plants can't pull all the water away from it, which makes silt particles the ultimate ingredient for plant-available water storage — they hold large quantities of water but also release it to plant roots (Figure 3).

Soils are... Clay Factories

Soils are... service providers, soils are... degrading and polluted, soils are... home, soils are... a profession.

activity - A general term used to describe how chemically reactive a particle is with ions, water, and other particles.

clay - A mineral particle smaller than 0.002 mm.

clay synthesis - Clays are formed in soils through the transformation of existing clays or through the generation of entirely new clay particles from ions precipitating from solution.

desertification - The transformation of a non-arid landscape to an arid landscape, usually through a combination of climate changes and human-induced soil degradation.

dirt - 1. synonym for soil material; 2. soil out of place; 3. unclean material of any composition.

eluviation - The removal of materials such as clays, organic matter, iron, or aluminum from a horizon.

erosion - The surface removal of soil material from soils by the action of water or wind.

eutrophication - A process of excess algal growth that leads to oxygen depletion; often caused by excess nutrient inputs.

factors of soil formation - Factors from which soil scientists are able to predict the end result of soil formation processes: climate, organisms, topography, parent material, and time.

gas regulation - The absorption and release of gases that mediates the levels of these gases in the atmosphere.

illuviation - The deposition of materials such as clays, organic matter, iron, or aluminum into a horizon; generally the materials come from an upper horizon in the soil body.

leaching - The removal of dissolved ions from a soil.

natural bodies - Systems that form in nature with size, form, and history that act as in an integrated fashion to provide functions that differ from the sum of their parts.

remediate - To transform a chemical from a toxic form or state to a non-toxic form or state.

salinization - A build up of salts in soils to the point that they destroy the soil's physical and chemical properties and plants are not able to take up water due to the high salt concentration; often associated with improper irrigation.

sand - A mineral particle ranging in size from 0.02 to 2 mm.

silt - A mineral particle ranging in size from 0.002 to 0.02 mm.

soil - 1. A material composed of minerals, living organisms, soil organic matter, gas, and water. 2. A body composed of soil and other parts such as rocks, roots, and animals that has size, form, and history and provides integrated functions that are greater than the sum of its parts.

soil horizon - Layer present within soil bodies that are distinguishable from other layers; often generated through soil formation processes.

soil organic matter - Plant, animal, and microbial residues, in various states of decomposition.

soil texture - The percentages of sand, silt, and clay particles in a soil.

soil quality - The capacity of a soil to provide desirable ecosystem services.

transpiration - Evaporation of water from openings in plant tissues called stomata; associated with photosynthesis.

weathering - Physical, chemical, and biological processes that breakdown and transform rocks and minerals.

References and Recommended Reading

Ahrens, R. J. & Arnold, R. W. "Soil taxonomy," in Handbook of Soil Science , ed. M. Summer (CRC Press, 2000) E117-E135.

Brady, N. C. & Weil, R. R. T he Nature and Properties of Soils, 14th ed. Upper Saddle River, NJ: Prentice Hall, 2008.

Food and Agriculture Organization of the United Nations (FAO). Guidelines for Soil Description, 4th ed. FAO, Rome, 2006. ftp://ftp.fao.org/docrep/fao/009/a0541e/a0541e00.pdf

Haygarth P. M. & Ritz, K. The future of soils and land use in the UK: Soil systems for the provision of land-based ecosystem services. Land Use Policy 26S:S187-S197, 2009.

Jenny, H. The Factors of Soil Formation: A System of Quantitative Pedology . New York, NY: Dover Press, 1941.

Soil Survey Division Staff. Soil Survey Manual . Soil Conservation Service, United States Department of Agriculture, Handbook 18, 1993. http://soils.usda.gov/technical/manual/

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ENCYCLOPEDIC ENTRY

Soil composition.

Soil is one of the most important elements of an ecosystem, and it contains both biotic and abiotic factors. The composition of abiotic factors is particularly important as it can impact the biotic factors, such as what kinds of plants can grow in an ecosystem.

Biology, Ecology, Chemistry, Earth Science, Geography, Physical Geography

Soil Layers

Soil is composed of both biotic—living and once-living things, like plants and insects—and abiotic materials—nonliving factors, like minerals, water, and air.

Photo from Getty Images

Soil contains air, water, and minerals as well as plant and animal matter, both living and dead. These soil components fall into two categories. In the first category are biotic factors—all the living and once-living things in soil , such as plants and insects. The second category consists of abiotic factors, which include all nonliving things—for example, minerals , water, and air. The most common minerals found in soil that support plant growth are phosphorus, and potassium and also, nitrogen gas. Other, less common minerals include calcium, magnesium, and sulfur. The biotic and a biotic factors in the soil are what make up the soil ’s composition. Soil composition is a mix of soil ingredients that varies from place to place. The Natural Resources Conservation Service (NRCS)—part of the U.S. Department of Agriculture—has compiled soil maps and data for 95 percent of the United States. The NRCS has found that each state has a “state soil ” with a unique soil “recipe” that is specific to that state. These differing soils are the reason why there is such a wide variety of crops grown in the United States. Consider the soils of three states: Hawai'i, Iowa, and Maine. Hawai'i’s deep, well-drained state soil contains volcanic ash that makes it perfect for growing sugar cane, as well as ginger roots, papaya, and macadamia nuts. Iowa, which is in Midwest region of the United States, has a state soil that is good for farming because it is made up of a thick layer of organic matter from the decomposition of prairie grasses. Corn and soybeans are the primary crops grown in these soils . The state soil of Maine, located in the northeastern part of the country, is made from materials left behind after local glaciers melted. This soil is perfect for growing trees—specifically, red spruce and balsam fir. Many of the trees being grown today in Maine are harvested for timber or for making paper. Soil scientists conduct various tests on soils to learn about their composition. Soil testing can identify the amounts of biotic and a biotic factors in the soil . The results of these tests can also reveal if the soil has too much of a specific mineral or if it needs more nutrients to support plants. Scientists also measure other factors, such as the amount of water in the soil and how it varies over time—for instance, is the soil unusually wet or dry? The tests can also identify contaminants and heavy metal in the soil and determine the soil ’s nitrogen content and pH level (acidity or alkalinity). All of these measurements can be used to determine the soil ’s health.

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ENZO PÉRÈS-LABOURDETTE / YALE E360

How the Loss of Soil Is Sacrificing America’s Natural Heritage

A new study points to a stunning loss of topsoil in the Corn Belt — the result of farming practices that have depleted this once-fertile ground. Beyond diminished agricultural productivity and more carbon in the atmosphere, it is a catastrophic loss of an irreplaceable resource.

By Verlyn Klinkenborg • March 1, 2021

Geologically speaking, I grew up in a small farm town on the Des Moines lobe, a huge tongue-shaped remnant of glacial activity that reaches south across central Iowa. All around us were mollisols with a deep A-horizon — a type of rich black topsoil visible in farm fields for miles in every direction. In school we were taught only one thing about that soil: to be proud of it. It was a given, a blessing, a moral fact. In a sense, it seemed to have no history. Yet when I was very young, I surely must have met old people — relatives from northwest Iowa — whose elders had helped break the prairie in the late 19th century, using heavy sod-plows and the great teams of animals needed to pull those plows through tenacious tallgrass. The way I was taught, it felt, somehow, as though the prairie’s providential job had been to keep the soil ready for a time when we would need it. By the time I was in school it was hard to find living prairie anywhere in Iowa. It had nearly all been turned.

You hear many different numbers regarding that black Iowa soil. It’s often repeated that the topsoil — the nutrient-rich A horizon — was some 14 to 16 inches deep when the prairie was first broken, a fantastic depth of fertility rivaled only by some regions in the Ukraine . By the mid-1970s — roughly a century after the prairie was broken — it was reported that, in places, half of that topsoil had already been lost to erosion from wind and runoff . There was a lot of talk about soil conservation, of course — about contour plowing and set-aside programs that paid farmers to keep marginal land out of cultivation. Yet year by year, the soil loss went on. There were also large-scale erosion events, like the floods of 2008 and 2013, in which parts of Iowa lost in a week what experts maintained was a sustainable yearly loss: 5 tons of soil per acre. It was possible to get a local sense of how much topsoil was being lost — in particular fields and drainages. But it’s been hard to get a region-wide, landscape-scale sense of the extent of Midwestern soil erosion — until now.

At best, 24 percent of Corn Belt topsoil has been removed by farming. At worst, 46 percent has been lost.

In late February, three geoscientists from the University of Massachusetts — Evan Thaler, Isaac Larsen, and Qian Yu — published a paper called, “ The extent of soil loss across the U.S. Corn Belt .” Using high-definition satellite imagery, a recent soil carbon index, and soil spectral data, they were able to show that across the Corn Belt — which includes all of Iowa and parts of Minnesota, Wisconsin, North Dakota, South Dakota, Missouri, Illinois, and Indiana — A-horizon soil was essentially no longer present on convex slopes. What they found on those slopes was B-horizon soil — subsoil in other words, with minimal fertility, which is only exposed after A-horizon soil has been removed. What does that look like? The paper includes a satellite photo of a bare field near Clear Lake, Iowa. The low areas in the field are medium to dark brown — an indicator of A-horizon soil. But the high spots are tan and beige — the color of B-horizon soil. By calculating the exposure of B-horizon soils across the region, the scientists were able to estimate the overall loss of A-horizon soil.

The number they arrived at is shocking. “We predict,” they wrote, “[that] the A-horizon has been completely removed from 35±11% of the cultivated area of the Corn Belt.” Plus or minus 11 percent is a large range of uncertainty. But its meaning is plain. At best, 24 percent of the topsoil in the Corn Belt has been completely removed by farming. At worst, 46 percent has been lost.

It’s worth being clear here. The authors aren’t talking about reduced soil fertility or loss of mineral nutrients. They’re talking about the complete removal of the medium in which crops are grown — the utter bankruptcy of the organic richness that lay for centuries under the tallgrass prairie. The authors argue, in a sense, that we’ve been farming in the dark, though they’re never quite that blunt. Previous estimates of erosion, they write, “may have greatly underestimated the extent of A-horizon loss, and therefore the thickness or mass of soil that has been eroded from hillslopes in the Corn Belt.”

A corn field being planted in Hull, Sioux County, Iowa. Melina Mara/ The Washington Post via Getty Images

Inevitably, the paper goes on to calculate the economic implications of these findings. And that’s how the agricultural press (which has scarcely noticed this study so far) has read it: The loss of topsoil on 30 million acres may result in a possible $3 billion annual loss “to Midwestern farmers.” I have to admire the narrowness of that interpretation, which is completely consistent with the economic assumptions that have governed industrial farming since World War II. The catastrophic loss of an irreplaceable resource — what you might call an essential part of our common earthly heritage — is construed as an annual loss of income to the farmers who operate those farms. The narrowness of these assumptions — driven by official U.S. Department of Agriculture policy and the shared economic interests of chemical and seed companies — has made it possible to farm in a way that is little more than slow strip-mining.

What drives the research behind this new study isn’t just geological or financial cost-accounting. It’s also carbon-accounting. The soils that have been eroded were once rich in organic carbon, which has also, of course, been sacrificed over time. Since World War II, the lost fertility once inherent in those carbon-rich soils has been replaced by chemical fertilizer, without adding carbonaceous material of any kind. It’s an old — and, in big ag circles, forgotten — maxim that good farmers don’t really think about raising crops: they think about improving the soil. But if all you add to soil is water and chemicals — nitrogen fertilizer (anhydrous ammonia) and glyphosate, that ubiquitous pesticide — erosion is all you can expect. We’ve been getting our food the wrong way. Industrial farming is like holding up the grocer at gunpoint for a head of lettuce — “efficient” in the short term, but eventually disastrous.

As practiced now, industrial farming is a major contributor to the global crisis of atmospheric carbon.

The good news in this study is the same old good news we’ve been hearing for years now. The main cause of soil erosion isn’t water runoff; it’s tillage — disturbing the soil in preparation for planting. The solution is a familiar one: no-till agriculture, which means direct seeding through the stubble of last year’s crops. No-till farming prevents erosion — because the soil is stabilized by last year’s roots — and it also adds carbon to the soil. As the authors note, however, long-term no-till farming (“for at least three consecutive years”) occurs on only 15 percent of the acreage in “the upper Mississippi watershed, the heart of the Corn Belt.”

Good farming should mean ongoing carbon sequestration. Agricultural land should be a carbon sink. But as practiced now — with massive reliance on fossil fuels, on soils stripped of organic carbon — industrial farming is a major contributor to the global crisis of atmospheric carbon.

It’s conventional to stop here — to look at a problem like soil erosion as a matter to be solved, or not solved, in the here and now and the immediate future. But I find it impossible — and unacceptable — to stop without looking back at the past, at what’s been lost since European settlement of the tallgrass prairie. No one alive has experienced, in its fullness, the web of life found in those Midwestern prairies, the plant and animal and insect — and, yes — human life. It seemed at one point — and would probably seem so even now — like an acceptable tradeoff, sacrificing that surface life for such rich, abundant tilth, capable of feeding so many people. But below the surface of the prairie lay a universe of soil organisms that has also been sacrificed, quietly and invisibly, over the years. Perhaps that too seems like an acceptable tradeoff, using a certain kind of calculus.

But what could possibly be acceptable about soil loss of the magnitude this study describes? It’s easy to blame the old farmers — the ones who broke the prairie and their immediate descendants — for not farming in a way that conforms to what we know now. But we ourselves aren’t farming the way we now know we should. Who do we blame for that?

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Introduction to Soils: Soil Quality

Collecting a soil sample to measure soil quality. Photo courtesy of Penn State Extension.

Soil health is the foundation of productive farming practices. Fertile soil provides essential nutrients to plants. Important physical characteristics of soil structure and aggregation allow water and air to infiltrate, and roots to explore. Soil health and soil quality are terms used interchangeably to describe soils that are not only fertile but also possess beneficial physical and biological properties. What is soil quality? Soil quality is how well soil does what we want it to do. Soil quality is the capacity of a specific kind of soil to function to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.

Soil fertility

Soil fertility is the ability of a soil to provide the nutrients needed by crop plants to grow. The primary nutrients plants take up from soils include nitrogen, phosphorus, potassium, calcium and magnesium. Frequently, we need to supplement soil nutrients by adding fertilizer, manure or compost, for good crop growth. Plants take up many other nutrients from soils, but there is usually enough of these secondary nutrients in the soil, so there is no need to add more.

Soil pH is another important aspect of soil fertility. pH is not a plant nutrient, but rather is a measure of the acidity of the soil. Most crops grow best when the soil pH falls between 6.2 and 6.8. This is the range in which plant roots can best absorb most nutrients from the soil.

Organic matter

Organic matter is composed of plant and animal residues, living and dead soil microorganisms, and substances produced through decomposition. Most agricultural soils contain only a small proportion of organic matter (usually less than 5%), but this small amount plays a very large role in soil quality. Soil organic matter tends to improve soil fertility, soil structure, and soil biological activity. Organic matter is added to soils through cover crops, manure, compost, and crop rotation.

Soil texture

Soil texture is an important soil characteristic that influences many aspects of soil quality. The textural class of a soil is determined by the percentage of sand, silt, and clay. Soils are usually made up of a mix of the three particle sizes. Sand particles are relatively large, clay particles are very tiny in comparison to sand, and silt particles are medium-sized. Clay and silt particles hold more water and plant nutrients along their surfaces than sand particles. Soil texture is an inherent property of a soil, and does not change under different management practices. Soils can be classified as one of four major textural classes: (1) sands; (2) silts; (3) loams; and (4) clays. These are based on the proportion of particle sizes found in each soil. 

Knowing the texture of a soil provides you with quite a bit of information about how well the soil holds water, holds and releases nutrients, and responds to different tillage practices. For example, a clay soil will hold more nutrients and more water compared to a sandy soil, but will be more susceptible to compaction from plowing and cultivating.

While soil texture is the proportion of the three soil particle types (sand, silt, and clay), soil structure refers to how those particles are arranged in space. We cannot change soil texture, but we can manage soils to improve soil structure. Soil with good structure has approximately 40-60% of its volume in pore space, or empty space between soil particles. Water and air can get into these pore spaces, and roots can grow into these spaces.

In a healthy soil, particles of sand, silt and clay aren't floating around by themselves. They are joined up with other particles, bits of organic matter, and small pore spaces into soil aggregates. Stronger, more stable aggregates stick together, even when hit by a raindrop or crushed by a footstep. A handful of healthy soil feels crumbly and light, due mostly to these stable aggregates.

Soil compaction occurs when soil aggregates are pushed closer together, and pore spaces shrink. This usually occurs when heavy tractors, trucks and other machines are driven over soil, particularly if soils are wet. Soils can become compacted at the surface, but also at the layer of soil just below the depth of tillage (subsoil compaction).  Plants have difficulty growing in compacted soil because the soil aggregates are pressed together, leaving little pore space for air and water, which are essential for root growth. 

Water holding capacity

Soil water holding capacity is the amount of water that a given soil can hold and then make available for crop use. Water holding capacity is largely determined by soil texture and by the amount of pore spaces in the soil, where water and air can be found. Sandy soils have lower water holding capacity, while silt and clay soils tend to have higher water holding capacity. A crop grown in a sandy soil will need to be irrigated more frequently, but with less total water, than a crop grown in a clay or silty soil. A clay or silty soil will hold more water for the crop to use, so can be irrigated less frequently. Compacted soils have less pore space for the water, and therefore have lower water holding capacity. 

Soil biological activity

Healthy soils are teeming with living organisms: bacteria, fungi, insects, earthworms, etc. As these living things go through their life cycles, they perform many functions that help improve the quality of soil. Soil organisms decompose fresh organic matter such as crop residues and animal manures. In the process, they help soil particles stick together into stable aggregates. They also create humus, a form of organic matter that doesn't decompose further, that helps soils hold water and nutrients. Soils with higher biological activity tend to have fewer plant disease organisms. Earthworms tunnel through soils, opening up pathways for air and water to move into the soil. 

Soil conservation

When water from rainfall or irrigation washes over bare soil, or wind blows over bare soil, soil particles may be washed or blown away, out of the field. This process is called soil erosion; the farming practices we use to stop erosion are known as soil conservation practices. Healthy soil is a very valuable natural resource, and we don't want to lose soil out of our fields. Soil particles that erode from fields can cause environmental problems, such as polluting creeks, rivers, lakes and even oceans. Airborne soil particles can lower air quality, and cause respiratory illnesses. Farmers can protect soils from erosion by limiting the time when there is bare soil in the field, improving soil structure, and by managing tillage, irrigation and crop rotation.

Funded by USDA Specialty Crop Block Grant Project ME#44166076 – "Sustainable Production and Pest Management Innovations for Next Generation Young and Hispanic/Latino Specialty Crop Growers"

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The Causes and Effects of Soil Erosion, and How to Prevent It

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• food security

Soil erosion is agriculture’s enemy: a major environmental threat to sustainability and productivity with knock-on effects on the climate crisis and food security.  

This is particularly true for places with the highest risk of erosion , such as watersheds in Indonesia, India, the Philippines and more. In these areas, protecting against soil erosion through sustainable land management can solve a multitude of problems.

Here’s a deeper look at the causes and solutions to soil erosion:

Why Is Soil Erosion Such a Big Problem?

Soil is a natural resource that may look robust and endless, but is in fact the fragile product of thousands of years of formation. Topsoil, which lies closest to the surface of the land, contains essential nutrients for crops. It is this layer of soil that is endangered by wind and water erosion. Soil erosion decreases soil fertility, which can negatively affect crop yields. It also sends soil-laden water downstream, which can create heavy layers of sediment that prevent streams and rivers from flowing smoothly and can eventually lead to flooding. Once soil erosion occurs, it is more likely to happen again.

This is a global problem. Soil is eroding more quickly than it is being formed, causing land to become unsuitable for agriculture – a particularly serious concern in a world where the population is expected to top 9 billion by midcentury. Smarter land management is a necessity.

How Does Soil Erosion Affect Climate Change?

Erosion degrades land, which means it can support fewer plants that can take in climate-warming carbon dioxide. Soils themselves could potentially sequester enough greenhouse gases in a year to equal about 5% of all annual human-made GHG emissions. Better land management can help keep soils intact so they can grow more carbon-sucking vegetation. This is already happening in China, where the Grain-for-Green project in the Yellow River basin conserved soil and water and reduced carbon emissions.     

On the flip side, unchecked climate change can worsen erosion. A report from the Intergovernmental Panel on Climate Change (IPCC) found that when cultivated without conservation practices, soil is currently eroding up to 100 times quicker than it’s forming.  The risk of erosion will become even higher in the future due to emissions-driven temperature changes, with resulting decreases in agricultural production, land value and human health.

What Are the Impacts of Soil Erosion?

We’re already seeing the risks of soil erosion play out around the world. Jakarta’s deadly floods earlier this year are a prime example. Eroded sediments from further upstream clogged Jakarta’s rivers and canals, causing them to overflow. Similar erosion-related floods have occurred in many other countries, such as Colombia , India , the Philippines and Democratic Republic of the Congo .

Soil erosion is not only an environmental issue; it also causes huge losses to the economy. One  study  estimated global economic losses from soil erosion to be around $8 billion, due to reduced soil fertility, decreased crop yields and increased water usage. In Java, Indonesia, soil erosion is responsible for a 2% loss in total agricultural GDP , taking into account the losses farmers face directly and the losses others face downstream. Another study showed that soil erosion in Sleman, a district located in Java, costs 17% of an average farmer’s net income per hectare of agricultural land.

The U.S. agricultural sector loses about $44 billion per year from erosion. This value includes lost productivity, along with sedimentation and water pollution. Lost farm income is estimated at $100 million per year. Soil erosion also costs European countries $1.38 billion in annual agricultural productivity losses and $171 million in lost GDP (about 1% of total GDP). South Asia loses $10 billion annually thanks to soil erosion.

What Solutions Exist to Prevent Soil Erosion?

1. use soil-friendly agricultural practices.

Terraced farming needs to be implemented to make hillside agriculture manageable. Terraces prevent erosion and allow more water to flow to crops. In addition, hillside farm fields need full crop cover to help keep the soil in place. This can be accomplished by intercropping, which means growing two crops together in the same field, such as planting rows of maize or soybean between rows of oil palm trees. For smallholders, agroforestry systems where a diverse set of crops, including trees, are grown together can be effective. Access to manure improves the organic matter of the soil, which inhibits erosion. Finally, alternating deep-rooted and shallow-rooted crops improves soil structure and reduces erosion at the same time.

2. Offer Incentives for Land Management

Although the science of sustainable land management has been gaining support, the socio-economic context often makes implementation difficult. Sustainable land practices need to be financially viable for farmers. Anti-erosion measures have a median cost of $500 per hectare , a considerable investment for a farmer. Governments and banks must help farmers get access to credit and support in implementing erosion prevention. This is not only a good deal for the farmer, but for the whole community. The cost of erosion prevention is far lower than the price of land restoration and rehabilitation, which one source estimated to be around $1,500–$2,000 per hectare . Another source found it could reach $15,221 per hectare.

3. Prevention AND Rehabilitation

The key to managing and reducing soil erosion is to rehabilitate already-damaged land , stop further degradation and put erosion-preventative measures at the core of land management policy. In this way, we can help prevent hunger and mitigate the climate crisis.

To learn more about WRI's work restoring eroded soils, click here .

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Essay on Soil: Meaning, Composition and Layers

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After reading this article you will learn about Soil:- 1. Introduction to Soil 2. Meaning of Soil 3. Composition 4. Soil Layers 5. Basic Properties 6. Testing of Properties.

• Essay on the Testing of Soil Properties

Essay # 1. Introduction to Soil:

Soil is the surface layer of earth on which the human civilization depends for its existence. Actually soil represents the loose upper crust of the earth surface distinctly different from the underlying bed rock.

Its depth, colour, and composition vary from place to place, but all soils are common in consisting of inorganic (mineral) and organic matter, water, and gaseous phases. Every soil is made up of a succession of layers, collectively known as soil-profile, reaching down to the parent material.

The soil-profile consists of two or more horizontal layers, called horizons. The soil horizon may vary in thickness, mineral composition, and structure; they are indicated by the letters A1, A2, A3, B1, B2, B3, C1, etc. A1 horizon is the uppermost or surface layer of the soil and its fertility level is very important from viewpoint of an agriculturist.

Soil fertility depends not only on the presence of inorganic and organic substances, but also on the presence of various species of microorganisms which influence the qualitative composition of the soil.

The existence of soil, the store-house of Nature, furnishing substances for all plants, animals, men, and other organisms, dates back to uncountable periods, even long before the man appeared on the scene. Vast number of plants, animals and finally the man populated the earth and the soil supported them all entirely without human assistance.

That, soil is vastly complex material on the face of earth is the fundamental truth to be understood in its study. Being a common commodity, it means a different thing to a different man in different pursuit. A geologist would preferably consider it to be the outer loose crust of the earth surface; quite distinct from the bed rock lying beneath.

To a farmer, it is a medium to grow his crops in and from which the plants obtain their mechanical support and many of their nutrients. Chemically, the soil is endowed with a magnitude of organic and inorganic substances not found in the underlying strata; indeed it functions as nature’s chemical laboratory in which various dissolutions and synthetic processes go on continuously in a hidden manner.

A lay man, however, is always of the opinion that soil is dust, essentially a dead material, sustaining nothing like life within it. With regard to origin and evolution of life, it can be considered that soil is the depository of all lives within which are carried out most of the transformations that enable life to continue.

Ecologically, soil is the most dynamic component (lithosphere) of the global environment encompassing distinct communities of organisms in its realm.

For a building engineer, the soil is a substratum on which structures can be built. But nothing could be farther from the truth, a microbiologist would say. For him, soil appears to be a dynamic body on the surface of the earth, pulsating with life due to presence of myriads of microorganisms.

Essay # 2. Meaning of Soil:

The word ‘soil’ is derived from the latin word ‘solum’ , which means floor or ground.

Soil is a natural formation resulting from the transformation of surface rock by combination of climate, plant and animal life with ageing.

Soil is formed through following steps:

(a) The formation of regolith by the breakdown of the bed rocks process is called weathering or disintegration.

(b) The addition of organic matter resulting from the decomposition of plant and animal residue and reorganization of these components by soil material of varying depths.

‘Petrology’ is the science of rocks which forms soil. ‘Pedology’ is study of soil which includes origin of soil, its classification and its description. ‘Edaphology’ is the study of various properties of soil in relation to growth, nutrition and yield of crops.

Soil can also be defined as natural body which is formed at the boundary between lithosphere and biosphere by inter-chains of all factors involved in Soil formation considering both living and dead.

So soil contains not only minerals but organic (humus) and organo-mineral (complex or chilate) compounds. The soil contains 13 elements in general out of 16 required by plants for growth. The soil becomes polluted when the quantity of 13 elements decreases or increases irregularly due to industrial effluents.

Several hazardous chemicals and the mountains of wastes are ultimately dumped on the lands. Dumping of industrial and municipal wastes causes toxic substances to be leached and seep into the soil and affects the ground water course.

Modern agricultural practices introduce numerous pesticides, fungicides, bacteriocides, insecticides, biocides, fertilizers and manures, resulting in severe biological and chemical contamination of land. Apart from all these, direct pollution of soil by deadly pathogenic organism is also of major concern. The properties of soil change with pollution and sometimes soil losses its fertility permanently.

Essay # 3. Composition of Soil:

The chemical composition of soil is much diversified and depends upon chemical composition of rock but in general the following elements are present in it.

In many soils of arid areas the following water soluble salts have also been examined:

Except CaCO 3 , MgCO 3 and CaSO 4 all other salts dissolve completely in water.

Essay # 4. Soil Layers of Earth:

Soil is made up of rock which has been transformed into other layers due to vegetation and various micro and macro-organisms.

Several factors contribute to the formation of soil from the parent material. This includes the mechanical weathering of rocks due to temperature changes and abrasion, wind, moving water, glaciers, chemical weathering activities, and lichens. Climate and time are also important in the development of soil.

In extremely dry or cold climate soils develop very slowly, while in humid and warm climates soils develop more rapidly. Under ideal climatic conditions, soft parent material may develop into 1 cm of soil within 15 years. Under poor climatic conditions, a hard parent material may require hundreds of years to develop into soil.

Mature soils are arranged in a series of zones called ‘soil horizons’ . Each horizon has a distinct texture and composition that varies with different types of soils. A cross-sectional view of the horizons in soil is called ‘soil profile’ .

The top layer or the surface litter layer, called the ‘O-horizon’ . It consists mostly of freshly-fallen and partially-decomposed leaves, twigs, animal waste, fungi and other organic materials. Normally, it is brown or black. The uppermost layer of the soil is called the ‘A-horizon’. It consists of partially-decomposed organic matter (humus) and some inorganic mineral particles. It is usually darker and looser than the deeper layers.

The roots of most plants are found in these two upper layers. As long as these layers are anchored by vegetation, the soil stores water and releases it in a trickle throughout the year instead of in a force like a flood. These two top layers also contain a large amount of bacteria, fungi, earthworms, and other small insects, which help to recycle soil nutrients and contribute to soil fertility.

The ‘B-horizon’ , often called the subsoil, contains less organic material and fewer organisms than the A horizon. The area below the subsoil is called the ‘C- horizon’ and consists of weathered parent material. This parent material does not contain any organic materials. The chemical composition of the C-horizon helps to determine the pH of the soil and also influences the soil’s rate of water absorption and retention.

Soil with approximately equal mixture of clay sand, slit and humus are called loams.

Essay # 5. Basic Properties of Soils:

I. acidity and alkalinity of s oils:.

The pH of a good soil should be about 7 but due to industrial effluents the pH increases or decreases causing pollution in soil.

Soils are characterized by the following pH values:

vi. Soil Air:

Good aeration of soil is important for maintaining its biological activity. Good soil aeration is also helpful for the growth of plant roots and other biota.

The soil contains the following gases:

Home — Essay Samples — Environment — Water Conservation — Soil and Water Conservation: Importance, Techniques, and Challenges

Soil and Water Conservation: Importance, Techniques, and Challenges

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Introduction, techniques for soil and water conservation, challenges to soil and water conservation.

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Home / Blog

Soil Conservation Guide: Importance and Practices

February 26, 2021 

Soils in all climates, including Arctic ecosystems , are essential to the global carbon cycle. The BBC reports that the thawing of permafrost — a type of soil in the Arctic that holds an estimated 1.5 trillion tons of carbon (more than Earth’s atmosphere and forests combined) — is releasing both carbon and poisons, such as toxins and diseases , into the atmosphere. As this Arctic soil continues to thaw, it further accelerates climate change, creating a harmful cycle that will impact future populations.

To help fight climate change, farmers committed to sustainable agriculture, scientists, and researchers champion soil conservation, which promotes healthy, fertile, productive, and resilient soils. Soil conservation is essential for:

• Reducing climate change’s destructive impact worldwide
• Maintaining a balanced climate cycle
• Providing healthy ecosystems where plants, trees, and animals can thrive
• Ensuring healthy agricultural yields through sustainable farming practices

What is soil conservation?

Soil provides the nutrients essential for plant growth, animal life, and millions of microorganisms. However, if soil becomes unhealthy, unstable, or polluted, the life cycle stops. Soil conservation focuses on keeping soils healthy through a combination of practices and techniques. Individuals committed to soil conservation help ensure that soil is fertile and productive, and protect it from erosion and deterioration.

Threats to soil conservation

The primary threats to soil conservation are climate change and traditional farming practices , according to the United Nations. Traditional farming practices include the overuse of harmful pesticides that contaminate soils, slash-and-burn methods, and land overuse. Soil conservation aims to mitigate these threats.

Chemical contamination

The use of pesticides can contaminate the soil, as well as nearby vegetation and water sources, with harmful chemicals. In addition to contamination, chemicals used on crops can be toxic to important beneficial insects, such as bees, as well as fish and bird populations. According to a recent study about bird biodiversity in the U.S. published in Nature Sustainability, the grassland bird population has declined by 53% since 1970. Among the causes reported for this decrease is the growing use of pesticides.

Slash and burn

Slash-and-burn farming is the practice of burning and clearing forests to make way for farmland. This method kills plant species and displaces wildlife from their natural habitats. Land cleared using slash and burn is only used while it’s productive for farming. Once it loses its fertility, another patch of forest is identified for clearing. This unsustainable process repeats endlessly, preventing soil from recovering sufficiently to support healthy ecosystems.

Land overuse

Overuse of land can limit soil’s ability to play its part in the global climate cycle. For example, overcutting forests and woodlands for timber and overgrazing pastures can far outpace the natural regrowth of vegetation, subjecting soil to increased exposure to erosion . As a result, land can lose its arability and become a desert.

Soil conservation is important for sustainability

For those working in sustainability, an understanding of soil’s role can create opportunities to develop new solutions and promote stewardship of our environment. Why is soil conservation important for sustainability? Simply put, without soil conservation, soil erosion would increase. Soil erosion impacts markets worldwide, including $8 billion in losses due to lower crop yields and increased water usage.

Why is soil important ? Soil is essential to food production. Crops need soil to grow, and farm animals need vegetation for feed. Conserving soil can help address food insecurity and promote healthy communities. Soil also helps to create a cleaner climate, absorbing about a third of the carbon dioxide that fossil fuels and industrial operations emit, according to the Climate Change and Land report from the Intergovernmental Panel on Climate Change (IPCC). Healthy stewardship of soil can help mitigate climate change’s impact.

Soil conservation resources

For more information about soil conservation, consider these resources:

• Conservation Institute, “Soil Conservation — What Do I Need To Know About It? Learn About Its Importance” : Information about soil conservation, from threats to techniques.
• Conservation International, “To Stop Climate Catastrophe, Look to Soil: Study” : Questions and answers about soil’s role in the carbon cycle.
• Earth Observing System, Soil Conservation Methods: Benefits of Implementation : A discussion of soil conservation highlighting strategies for sustainability.
• IPCC, “Chapter 2: Land-Climate Interactions” : Findings and statistics revealing climate’s impact on land and soil as well as mitigation strategies.
• World Resources Institute, “The Causes and Effects of Soil Erosion, and How to Prevent It” : A deeper look at soil erosion causes and solutions.

What makes soil so important?

Soils help meet societal needs, providing food, energy, and nutrients. They also help minimize the impact of climate change and promote healthy ecosystems. Below are three reasons why soil is so important:

Soil is home to many living things

Soil organisms ensure sustainable food systems and mitigate climate change. Plants and animals rely on soils for food, shelter, and more. Soil is also home to fungi, algae, and unicellular and multicellular organisms that are invisible to the naked eye, such as bacteria and protozoa. As they move through the soil, microorganisms help improve drainage and soil structure, making soil more fertile and productive.

Soil is key to the carbon cycle

Soil plays a critical role in the carbon cycle : the continuous process by which carbon atoms travel between the atmosphere and Earth. For example, in breaking down organic matter in the soil, microorganisms release carbon dioxide into the atmosphere and create nutrients and minerals that feed plants and crops. Soil also naturally absorbs carbon from the atmosphere in a process known as sequestration . Healthier soil absorbs more carbon, reducing the effects of greenhouse gases.

Soil’s essential roles

Farmers rely on soils to make food production possible, feeding people and livestock. Soil also acts as a purifier: As surface water travels through the ground to replenish aquifers, soil filters out toxins and impurities, making it drinkable. Soil also provides raw materials for infrastructure. For example, soil is an important element in making bricks for buildings.

Resources: Why soil is important

Consider these resources for insights into soil’s role in sustainability and creating a healthier world.

• Awe International, “Saving Our Soils for Future Generations” : An exploration of why healthy soils are essential for sustainable societies.
• Natural Resources Conservation Service, “The Heart of Soil: The Importance of Soil Health Principles” : An examination of healthy soil’s role in sustainable agriculture.
• Soil Science Society of America, “Soil Basics” : A deep dive into soil: what it is, its different types, and its function.
• Sustainable Agriculture Research and Education, “Why Soil Organic Matter Is So Important” : A comprehensive explanation of organic matter’s role as the foundation for healthy plants, animals, and humans.

Benefits of soil conservation

Soil conservation contributes to sustainability and offers the following benefits:

• Improves soil quality and productivity. Increased fertility improves crop yields, reduces the need for chemical fertilizers, and saves money.
• Optimizes water infiltration. Better filtration increases water storage, preventing soil from drying out.
• Provides food and shelter. Soil-producing vegetation provides nourishment to all types of animals and offers protection from the elements.

Soil conservation also helps to minimize the following:

• Loss of fertile and arable land, impacting crops and livestock production, as well as the economy
• Pollution and sedimentation flowing in streams and rivers, affecting fish and other species
• Erosion and environmental degradation and desertification of land , potentially increasing flooding and negatively impacting forest ecosystems

Soil conservation practices

Soil conservation is key to environmental sustainability : It helps protect natural resources and watersheds, restores habitats for plants and wildlife, improves water quality, and makes soil healthier. Soil conservation also creates economic opportunity. Productive and healthy soil helps farmers meet increased demand for agricultural commodities from a growing global population, driving economic growth.

No-till farming

Tilling turns over about 10 inches of topsoil and allows farmers to plant more seeds with less effort. A downside of tilling is that it removes the plant covering, potentially leaving the soil bare, decreasing the amount of nutrient-rich organic matter, and reducing its ability to absorb water and retain nutrients. Tilling can also make the soil more susceptible to erosion. In no-till farming, seeds are planted in narrow furrows, eliminating the need to plow.

No-till farming protects the soil from moisture loss due to high temperatures because cover crop residue remains on the surface of the soil. The residue layer also helps infiltrate water into the soil and increases organic matter and microorganisms , further enriching the soil.

Terrace farming

Terrace farming is an agricultural practice that uses terraces, or steps, built into the slopes of hilly or mountainous areas to create a water catchment system for crops and is commonly used in growing rice. Rainwater carries nutrients and vegetation from one terrace to the next, so the soil remains healthy. Terrace farming also reduces soil erosion and improves soil productivity in otherwise idle plots of land.

Contour farming

Like terrace farming, contour farming involves growing crops on hills, but instead of changing the structure of a hill, the farmer uses its natural slope. In contour farming , a farmer plows the soil parallel to the hill’s contours, creating rows of small dams that minimize runoff of essential nutrients, organisms, and plants, while increasing water infiltration in the soil. The U.S. Department of Agriculture (USDA) reports that contour farming can reduce soil erosion by as much as 50%.

Crop rotation

Instead of planting the same crop year after year on the same plot of land, crop rotation involves planning out growing seasons for different crops. This method of sustainable agriculture requires long-term planning, with crops changed every season. In addition to improving soil health and organic matter, crop rotation reduces the need for fertilizer and pesticides, lowering costs. It also helps prevent excess chemicals from entering water supplies, improving water quality.

Windbreaks are rows of trees and bushes planted between fields of crops, reducing the erosive power of the wind on the soil. Windbreaks also provide homes for living things. From an economic standpoint, using trees that produce fruits and nuts in windbreaks can diversify farm income.

Wetlands restoration

The U.S. Environmental Protection Agency (EPA) defines wetlands restoration and protection as “removing a threat or preventing the decline of wetland conditions.” Wetlands provide a habitat for living creatures of all types. They also act as buffers, protecting farmlands from floods.

Buffer strips

Like windbreaks, buffer strips are designated areas of land planted with trees and bushes. Instead of protecting soil from the wind, their purpose is to prevent water runoff and reduce erosion.

Forest cover reestablishment

In areas where soil has degraded, the reestablishment of forest cover can improve soil and restore ecosystem health. This method provides shade for crops and is particularly useful for forest farming , which cultivates high-value crops, such as those used for medicinal purposes.

Earthworms are among the most productive organisms in soil. They digest plant matter, releasing essential nutrients into the soil, and their tunnel networks create air channels that help water move through the soil.

Soil conservation: A key component of reducing climate change’s impact

Unsustainable agricultural practices can affect soil health, which in turn affects the global climate cycle. Poorly managed soil can release excess carbon dioxide, a greenhouse gas that contributes to climate change. Restoring degraded soil and using soil conservation practices in agriculture can effectively sequester carbon, helping build resilience to the effects of climate change.

Soil conservation also promotes sustainable and economic development to meet the U.N. Sustainable Development Goals (SDGs) : 17 goals focused on providing a “sustainable future for all.” According to the European Environment Agency, seven SDGs directly correlate to soil conservation practices , including the following:

• SDG 6 — Clean Water and Sanitation: Through drainage and purification, soil helps to provide clean water for drinking and farming.
• SDG 13 — Climate Action: Through sequestration, soil can play a pivotal part in combating climate change by reducing atmospheric carbon.
• SDG 15 — Life on Land: Healthy soils are essential for sustainable management of forests, fighting desertification, and reversing land degradation.

Building the resilience of our ecosystems is critical to addressing the challenges of a changing climate. One key factor sits right under our feet: soil. Through soil conservation, we can work to minimize the impact of climate change and support the long-term needs of society.

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• Biology Article
• What Is Soil?

What Is Soil

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:

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.

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.

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.

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 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.

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 important to 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.

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Study Today

Largest Compilation of Structured Essays and Exams

Essay on Importance of Soil

January 21, 2018 by Study Mentor Leave a Comment

The life supporting natural resource which is formed by mixing of weathered rock materials and   decomposed biomass consisting of organic matter is called soil. It is one of the important natural resources. Soil is the most essential element of existence of life on earth.

Soil is the living ecosystem. Without soil, there is no existence of life.  In our Vedas, it is said that life form on this earth consists of five elements and soil is one of them.

So, creation of life form belongs to soil, development of life form belongs to soil, destruction of life form belongs to soil.

“If a healthy soil is full of death, it is also full of life.”

Table of Contents

Formation of soil

Rocks are the chief sources for the parent materials over which soil formation takes place. Rocks are converted into parent materials by the weathering process. In other words, weathering process precedes the soil formation. Parent materials include rocks, loses, alluvium, sand etc.

Weathering process means the physical and chemical deterioration of rocks over time due to factors like temperature, heat, pressure, water, wind etc. It takes more than thousand years for the formation of just one-inch layer of soil.

Components of soil

Soil contains different kinds of components. The components are given below

Air- In between the spaces of soil particles air is present. Soil with loose surface allows air diffusion in to it. Air contains gases like carbon dioxide, nitrogen, oxygen etc. Concentration of carbon dioxide is more than other gases.

Water- Water is the solution of organic and inorganic compounds. Soil contains water as it contains both organic and inorganic materials. Soil with more number of pores contain more water as water is absorbed in those pores.

Minerals- During weathering process, disintegration of rocks occurs. At that time particles of minerals are formed inside the soil.

Organic matters- These are the decayed form of organic substances like plants, animals, micro-organisms on the soil. These kinds of substances increase the fertility of the soil.

Micro-organisms- Micro -organisms like bacteria, fungi, algae are present in high numbers in the soil. These organisms act as decomposers of plants, animals, other organisms.

The above all components make soil suitable for existence and development of life form.

Soil as life

“The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and   resurrect or, by which disease passes into health, age into youth, death into life. Without proper care for it we have no community, because without proper care for it we have no life”   -Wendell Berry

So, the existence of life form on this earth solely depends on soil. It forms the surface and ecosystem of the earth.

Image Credit: Source

As we early stated that soil is the living ecosystem. Soil is the habitat of all kinds of organisms. Different kinds of bacteria, fungi, algae, protozoa and undiscovered microbes acting as decomposes are found in high numbers in soil.

These micro-organisms decompose dead plant and animal bodies. As a result, pollution due to decaying dead bodies of animals decreases and it increases the quantity of organic matters in soil which makes the soil more fertile suitable for cultivation.

Soil is the natural medium for plant growth. Soil contains air which consists of gases like carbon dioxide, oxygen, nitrogen. For plant growth air ventilation is needed. So, soil provides oxygen, air ventilation for plant to grow. Water is also a major component of soil.

For plant growth water is important as it act as nutrient carrier and a main factor of plant life. Soil also contains minerals like silicon, aluminium, phosphorous, magnesium, carbon, iron, nitrogen etc. which are important elements.

Non-renewable resources like coal, petroleum, gold, copper, silver are found inside the earth. The modern world is standstill without these resources. These resources have become the integrated part of our life.

Soil holds the souvenir of our past and our cultural heritage buried in it. Soil plays a vital role as carbon reservoir as it absorbs most of the carbon dioxide gas and reduces the greenhouse gas concentration to some extent. Soil decomposes the dead bodies of plants and animals but it preserves their existence in the form of fossil.

For us food, cloth, and house are basic needs of life. Soil is the origin for all the three needs. When there is no soil, there is no food, no cloth, no house.

“Heaven is under our feet as well as over our heads.”    -Thoreau

Soil conservation

As soil is the origin of existence and development of life form on earth, conservation of it is must. Because without soil the whole living process is unthinkable. As earlier stated above that one-inch layer of soil formation takes more than thousand years.

Soil erosion mainly takes place due to water, wind, fertilizers etc. Heavy flow of water and heavy rainfall washes away the soil from one place to another. When there is no cover of plants, wind causes soil erosion. Loss of minerals, nutrients in soil as a result of utilization of fertilizers makes a steep erosion. Deforestation holds another cause.

Roots of trees hold the soil in a compact manner.  Litter of leaves resists soil erosion caused by wind and heavy rainfall. So, deforestation enhances the process of erosion.

Soil conservation includes following process

• Afforestation prevails erosion by reducing the velocity of wind and the roots held the soil in a strong manner.
• Growing of vegetation cover on the ground conserves soil.
• Crop rotation shoots up the productivity of the lands.
• Slowing down the water movement along the slope.
• Reduction in the usage of fertilizers, pesticides.
• Protection of soil from the strike of heavy water drops.

“Soil is a resource, a living, breathing entity that, if treated properly will maintain itself. When it has finally been depleted, the human population will disappear… project your imagination into the soil below you next time you go into the garden.

Think with compassion of the life that exists there. Think the drama, the sexuality, the harvesting, the work that carries on ceaselessly.”

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