Best 17 what does organic matter do in soil

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what does organic matter do in soil

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Soil organic matter

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  • Summary: Articles about Soil organic matter Organic matter is an important source of nitrogen, phosphorus and sulfur. These nutrients become available as the organic matter is decomposed by microorganisms …

  • Match the search results: Waterlogged organic matter breaks down very slowly because microorganisms necessary for decomposition cannot exist where there is no oxygen. Soils formed from waterlogged organic matter are known as peats, and contain a high percentage of organic matter.

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What Is Organic Matter in Garden Soil? – The Spruce

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  • Summary: Articles about What Is Organic Matter in Garden Soil? – The Spruce Active organic matter consists of fresh plant and animal residues that take from a few months to a few years to decompose. This type of organic …

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    Generally speaking, organic matter comes from living materials that fix and store carbon and deliver it as a source of energy to the soil. More specifically, organic matter is divided into three types, depending on the time it takes for the organic matter to fully decompose. Active organic matter c…

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Five Benefits of Soil Organic Matter | Mosaic Crop Nutrition

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  • Summary: Articles about Five Benefits of Soil Organic Matter | Mosaic Crop Nutrition Organic matter causes soil particles to bind and form stable soil aggregates, which improves soil structure. With better soil structure, water infiltration …

  • Match the search results: Increasing levels of O.M. improve the physical, chemical, and biological functions of the soil. The benefits of O.M. are summarized into the following five functions:1. Biological FunctionThere are many benefits to O.M., most of which begin with enhancing the biological diversity and activity in the…

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Soil organic matter – Wikipedia

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  • Summary: Articles about Soil organic matter – Wikipedia Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal detritus at various stages of decomposition, …

  • Match the search results: Vegetal detritus in general is not soluble in water and therefore is inaccessible to plants. It constitutes, nevertheless, the raw matter from which plant nutrients derive. Soil microbes decompose it through enzymatic biochemical processes, obtain the necessary energy from the same matter, and produ…

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Compost and soil organic matter: The more, the merrier?

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  • Summary: Articles about Compost and soil organic matter: The more, the merrier? Soil organic matter: What is it and why is it important? · Provides essential nutrients for plants (such as nitrogen, phosphorus and sulfur) as …

  • Match the search results: Now, let’s take it one step further to ensure that your beautiful soil organic matter remains a benefit and not a liability to plants or to the environment. After all, it is possible to have too much of a good thing — even soil organic matter. But first, let’s look at what makes soil organic matter …

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Ch 2. What Is Organic Matter and Why Is It So Important – SARE

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  • Summary: Articles about Ch 2. What Is Organic Matter and Why Is It So Important – SARE However, char does not provide soil organisms with readily available food sources as do fresh …

  • Match the search results: Carbon and organic matter. Soil carbon is sometimes used as a synonym for organic matter, although the latter also includes nutrients and other chemical elements. Because carbon is the main building block of all organic molecules, the amount in a soil is strongly related to the total amount of all t…

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Soil Organic Matter Does Matter — Publications

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  • Summary: Articles about Soil Organic Matter Does Matter — Publications Hydrogen, oxygen, nitrogen, phosphorus and other nutrients make up the remaining mass. If you see a report that lists soil organic carbon (scientists often do …

  • Match the search results: Many different materials in soil fall under the definition of organic matter; however, not all organic matter is created equally. For example, a mouse carcass and a rotten log are considered organic matter, but they are very different in their chemical nature and how fast they decompose. While diffe…

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Function of organic matter in soil

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  • Summary: Articles about Function of organic matter in soil growth. In addition to serving as a source of N, P, S through its mineralization by soil microorganisms, organic matter influences the supply of nutrients from …

  • Match the search results: biological function in that it profoundly affects the activities of microflora and microfaunal organisms physical and physico-chemical function in that it promotes good soil structure, thereby improving tilth, aeration and retention of moisture and increasing buffering and exchange capacity of soils…

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What Does Organic Matter Do In Soil? – Nico Orgo’s

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  • Summary: Articles about What Does Organic Matter Do In Soil? – Nico Orgo’s What Does Organic Matter Do In Soil? · Nutrient Supply. Organic matter is a reservoir of nutrients that can be released to the soil. · Water- …

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Soil Organic Matter- enhancing soil health and soil nutrient …

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  • Summary: Articles about Soil Organic Matter- enhancing soil health and soil nutrient … Soil organic matter is the foundation for healthy and productive agricultural soils, and is central to a range of soil functions and …

  • Match the search results: The quantity and quality of organic matter can be influenced by management. Some management practices can build soil organic matter, such as, the use of cover crops and crop rotations, diversification of grassland species, maintenance of good soil structure and porosity, balancing soil fertility, an…

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Soil Organic Matter – an overview | ScienceDirect Topics

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  • Summary: Articles about Soil Organic Matter – an overview | ScienceDirect Topics Soil organic matter (SOM) is the substrate and habitat of soil microorganisms and fauna. These biotic pools, along with inorganic soil components, contribute to …

  • Match the search results: The discovery that much of the organic matter in soil has a microbial signal (rather than plant; Bird et al., 2008) indicated that the residues and metabolic by-products generated through the processing of organic matter by fungi and bacteria are important sources of organic matter, including stable…

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Increase soil organic matter – GOV.UK

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  • Summary: Articles about Increase soil organic matter – GOV.UK Soil with more organic matter can absorb and keep in more water. This can improve crop productivity and reduce: … Soils with lower organic …

  • Match the search results: Soils with lower organic matter are at higher risk of wind erosion, especially sandy soils. Increasing organic matter will bind topsoil to help prevent wind blow and associated pollution from airborne particles.

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Soil Organic Matter: The Living, the Dead, and the Very Dead

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  • Summary: Articles about Soil Organic Matter: The Living, the Dead, and the Very Dead What is it? Soil organic matter is made up of plant and animal residues in different stages of decomposition, cells of soil microorganisms, and substances that …

  • Match the search results: Living organisms are also considered to be part of soil organic matter,
    and they play a big role in contributing organic residues to the soil and
    in formation of more stable types of organic matter. Plant roots and various
    soil animals (rodents, earthworms, mites, etc.) all provide…

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Soil Organic Matter, Soil Structure, and Bacterial Community …

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  • Summary: Articles about Soil Organic Matter, Soil Structure, and Bacterial Community … For example, the stock of soil organic matter represents the long-term balance between input of plant residue to the soil and decomposition of …

  • Match the search results: For example, the stock of soil organic matter represents the long-term balance between input of plant residue to the soil and decomposition of that residue by soil microorganisms. Agriculture has been shown to upset this balance, largely by increasing the rate of organic matter decomposition (Magdof…

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Soil Organic Matter, Soil Structure, and Bacterial Community …

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  • Summary: Articles about Soil Organic Matter, Soil Structure, and Bacterial Community … For example, the stock of soil organic matter represents the long-term balance between input of plant residue to the soil and decomposition of …

  • Match the search results: For example, the stock of soil organic matter represents the long-term balance between input of plant residue to the soil and decomposition of that residue by soil microorganisms. Agriculture has been shown to upset this balance, largely by increasing the rate of organic matter decomposition (Magdof…

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Organic matter: how to use in the garden – RHS

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  • Summary: Articles about Organic matter: how to use in the garden – RHS Soil organic matter is also present as free organic matter derived from plant or animal remains or from recently added manures and composts. This decays quickly …

  • Match the search results: Under natural conditions in cool climates organic matter accumulates in natural soils to fairly high level where gain balances losses, but upon cultivation soil organic matter falls as man made vegetation usually supplies less organic residues then natural vegetation, and the effects of ti…

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Organic matter: what is it? / RHS Gardening

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  • Summary: Articles about Organic matter: what is it? / RHS Gardening The term ‘organic matter’ is used for both organic matter in the soil (better called soil organic matter), and the many manures, composts (garden and green …

  • Match the search results: The term ‘organic matter’ is used for both organic matter in the soil (better called soil organic matter), and the many manures, composts (garden and green waste) and other organic materials added to the soil to increase the organic matter content.

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Multi-read content what does organic matter do in soil

Adhering to the propriety of the season, carefully considering the nature and condition of the soil, then and only then with the least amount of work will yield the greatest success. Relying only on one’s own ideas, and not on the dictates of nature, all efforts will be in vain.

—Jia Sixie, 6th century, China

As we will see at the end of this chapter, organic matter has a major influence on most soil properties, although it is generally present in relatively small quantities. Typical agricultural soil contains 1-6% organic matter by weight. It is made up of three distinct parts: the living body, the fresh pulp and the molecules from the well-decomposed residue. These three parts of soil organic matter have been described asthe life, thedeceasedanddefinitely dead.This three-tier classification may seem simple and unscientific, but it is very useful for understanding soil organic matter.

The life. Soil organic matter includes a variety of microorganisms, such as bacteria, viruses, fungi, protozoa and algae. This even includes plant roots and insects, earthworms and larger animals, such as moles, mantises and rabbits that spend part of their time in the ground. The living part represents about 15% of the total organic matter of the soil. The number of organisms in the soil is so large that it is estimated that they represent around 25% of the total global biodiversity. Microorganisms, earthworms and insects feed on plant debris and manure to provide energy and nutrients and in doing so mix organic matter with mineral soil. Plus, they recycle phytonutrients. Sticky substances on the skin of earthworms and other materials produced by the fungus help hold the particles together. This helps stabilize soil aggregates, which are the clumps of particles that give soil good structure. Root adhesions as well as the growth of fine roots and their associated mycorrhizal fungi promote the development of stable soil aggregates. Organisms such as earthworms and certain fungi also help to stabilize soil structure (for example, by creating channels that allow water to seep through) and thus improve the state of water and soil. soil aeration. . Plant roots also interact significantly with various microorganisms and animals that live in the soil. Another important aspect of soil organisms is that they are always at war with each other (Figure 2.1). A more in-depth discussion of the interactions between soil organisms and roots, and between different soil organisms, is provided inChapter 4.

Countless microorganisms, earthworms and insects obtain energy and nutrients by breaking down organic matter in the soil. At the same time, most of the energy stored in the residues is used by organisms to create new chemicals as well as new cells. How is energy stored inside organic remains in the first place? Plants use energy from sunlight to bind carbon atoms into larger molecules. This process, known asphotosynthesis, is used by plants to store energy for respiration and growth, and most of this energy will be converted to soil residues after the plant dies.

Death. Fresh residue, or “dead” organic material, includes microorganisms, insects, earthworms, old plant roots, crop residues and recently added manure. In some cases, looking at them is enough to determine the source of the fresh residue (Figure 2.2). Soil organic matter is the active or biodegradable fraction. This fraction of soil organic matter is the main source of food for the various organisms – microorganisms, insects and earthworms – that live in the soil. When organic matter is broken down by “life”, it releases many nutrients needed by plants. The organic chemical compounds produced during the decomposition of fresh residues also help to bind the soil particles together and give a good structure to the soil.

Certain organic molecules released directly from the cells of the fresh residue, such as proteins, amino acids, sugars and starches, are also considered part of this fresh organic matter. These molecules generally do not last long in the soil. Their structure makes them susceptible to decomposition as many microorganisms use them as food. Some cellular molecules such as lignin are broken down, but organisms take longer to do so. This can accumulate a lot of soil organic matter in poorly drained soils, such as peat and silt, as well as wetlands that are already in agricultural production. These contain large amounts of organic matter that do not break down due to waterlogging, but they do not provide the same benefits as fresh residues.

DEAD MAN.This includes other organic matter in the soil that is difficult for organisms to break down. Some use the termhumusto describe all soil organic matter. We will use this term to refer to the relatively stable part of soil organic matter that resists decomposition. Humus is protected from decomposition mainly because its chemical structure makes it difficult for soil organisms to use.

Identifiable fragments of undigested or partially decomposed residues, including microbial remains, may be retained within aggregates in spaces too small for organisms to approach. In a way, they behaved as if they were “very dead” because they were inaccessible to creatures. As long as the organic matter is physically protected from microbial attack, it will be part of the “very dead part”. When these aggregates are decomposed by freezing and thawing, drying and composting, or by plowing, organic debris is entrained and the simple organic matter adsorbed on the clay can be accessible to microorganisms and easily decomposed. Since most soil organic matter is so well protected from decomposition, it can physically and chemically age in the soil for up to hundreds of years.

But although humus is protected from decomposition, its chemical and physical properties make it an important part of soil. Humus contains certain essential nutrients and stores them for slow release in plants. Some medium-sized molecules can also surround certain potentially harmful chemicals, like heavy metals and pesticides, and prevent them from harming plants and the environment. Similar types of molecules can also make certain essential nutrients more available to plants. A good amount of humus and crop residues can reduce drainage and compaction problems that occur in clay soils. They also improve water retention in sandy soils by promoting clumping, reducing soil density, and retaining and releasing water.

Figure 2.1. A fungus-eating roundworm, part of a system of checks and balances. Photo by Harold Jensen. Figure 2.2. Partially decomposed fresh residue removed from the soil. Stem fragments, roots and mycelium are all readily utilized by soil organisms.

Carbonize.Another class of organic matter, which has received a lot of attention recently, is commonly calledblack carbonWherecharacters.Many soils contain small pieces of charcoal, the result of past natural or human-caused fires. Some, such as the black soils of Saskatchewan, Canada, may contain relatively high amounts of charcoal, possibly due to natural grassland fires. However, the increased interest in soil charcoal has mainly come from the study of so-called dark soils,indian terracottalocated on the sites of long-occupied villages in the Amazon region of South America that were destroyed during colonial times. These dark soils contain 10-20% carbon black at the base of the soil surface, giving them a much darker color than the surrounding soils. Soil charcoal is the result of centuries of cooking fires and the burning of crop residues and other organic matter in the fields. The way combustion occurs – burning slowly, perhaps due to the humid conditions common in the Amazon – produces more charcoal and not as much ash as with more complete combustion at higher temperatures. These floors were widely used in the past but were abandoned for centuries. However, they are still much more fertile than the surrounding soils, partly due to the high nutrient inputs in the animal and plant residues that were originally taken from the nearby forest, and they provide a better energy yield than surrounding soils typical of tropical regions. forests. Some of this higher fertility – the ability to supply plants with nutrients with very low leaching losses – is attributed to the large amount of black carbon and the large amount of biological activity in the soil (even old several thousand years). ). Charcoal is a very stable form of carbon that maintains a relatively high cation exchange capacity and supports biological activity by providing suitable habitat. However, charcoal does not provide soil organisms with readily available food sources as well as fresh residues and compost. People are experimenting with adding biochar to soil, but it doesn’t seem to be economical on a large scale. The amount needed to make a big difference to the soil is obviously very large – several tons per acre – and may limit the usefulness of this method for small plots, gardens and potted plants, or as a targeted additive coated with cereals. Additionally, the benefits of adding biochar must be considered against what could be achieved using the same feedstock source as wood chips, crop by-products, or food waste added directly to the soil. , after composting or even after complete combustion to ashes.


The exceptionally productive “dark soils” of the Brazilian Amazon and other parts of the world are believed to be produced and stabilized by long-term association with charcoal. Black carbon, produced by wildfires as well as human activity and found in many soils around the world, is the result of burning biomass at around 600 to 900 degrees F under oxygen conditions. . This incomplete combustion results in about half or more of the carbon in the starting material being retained as charcoal. Charcoal, which also contains ash, tends to have a high negative charge (cation exchange capacity), liming the soil, retaining certain nutrients from burnt wood or other combustible residues, stimulating microbial populations and being very stable in the soils. Although several yield increases have been reported following the use of biochar – perhaps in part due to increased nutrient availability or increased pH – yields are sometimes affected. Legumes did particularly well with the addition of biochar, while grass was often nitrogen deficient, suggesting that nitrogen may be deficient for some time after fertilization.

Biochar is a variable feedstock because a variety of organic materials and combustion methods can be used to produce it, perhaps contributing to its inconsistent effects on the environment, soil, and plants. The economic and environmental impacts of biochar production and use depend on the source of the organic matter converted into biochar, and whether the heat and gases produced in the process are used or only allowed to dissipate, the amount of available oxygen during biochar production, and the distance between where it is produced and the field where it is applied. On the other hand, when used as a seed mulch, much less biochar is needed per acre and it can still stimulate seedling growth and development.

Note: The effect of biochar in raising soil pH and immediately increasing calcium, potassium, magnesium, etc., is likely largely the result of the ash rather than the carbon black itself. same. These effects can also be achieved by using materials that burn more completely, contain more ash, and less carbon black.

Carbon and organic matter. Carbon in the soilsometimes used as a synonym fororganic material, although the latter also includes nutrients and other chemical elements.Because carbon is the primary building block of all organic molecules, the amount in the soil is closely related to the total amount of all organic matter: living organisms plus fresh residue plus decomposed residue. When people talk about soil carbon instead of organic matter, they are usually referring to organic carbon or the amount of carbon in organic molecules in the soil. The amount of organic matter in the soil is twice as high as the level of organic carbon. However, in many soils of glacial and semi-glacial regions, it is common to find another form of carbon in the soil – limestone, either as a circular concrete or evenly dispersed throughout the soil. Lime is calcium carbonate, which contains calcium, carbon and oxygen. This isInorganic(mineral) carbon form. Even in humid climates, when limestone is found very close to the surface, some may be present in the soil. In such casestotal carbon in soilincludes both inorganic and organic carbon, and organic matter content cannot be estimated simply by doubling the total carbon percentage. The normal decomposition of organic matter in soil is similar to the process of burning wood in a kitchen. When burning wood reaches a certain temperature, the carbon in the wood combines with the oxygen in the air and forms carbon dioxide. When this happens, the energy stored in the carbon-containing chemicals in the wood is released as heat in a process called oxidation. The living world, including humans, animals and microorganisms, also uses the energy contained in carbon-containing molecules. The process of converting sugars, starches, and other compounds into a directly usable form of energy is also a type of oxidation. We usually call itRespiratory. Oxygen is used and carbon dioxide and heat are released in the process.

Why is soil organic matter so important?

Fertile, healthy soil is the foundation for healthy plants, animals and people. And soil organic matter is the foundation of healthy, productive soil. Understanding the role organic matter plays in maintaining healthy soil is essential to developing ecologically sound agricultural practices. But how can organic matter, which makes up such a small percentage of most soils, be so important that we spend three chapters in this section discussing it? The reason for this is that organic matter positively affects or alters the effects of virtually all soil properties, and it is what makes soil fertile. That’s why it’s so important to understand the health of our soils and how to better manage them. Organic matter is essentially at the heart of the story, but, as we will see later, certainly not the only one. In addition to playing many important roles in promoting soil processes and plant growth, soil organic matter is an important part of a number of global and regional cycles.

It is true that you can grow plants in soil that has little organic matter. In fact, you don’t need to have any soil at all. Although hydroponic gravel and sand systems, and even aeroponics (where a nutrient solution is sprayed directly on the roots of plants) without soil can still grow good plants, large-scale systems This large variety can have ecological problems and only makes economic sense for a limited number of high-value crops grown close to their market. It is also true that there are other important issues besides organic matter when considering soil health. However, as soil organic matter decreases, it becomes increasingly difficult to grow plants due to problems with fertility, water availability, compaction, erosion, pests, diseases and insects. Increasingly high levels of inputs – fertilizers, irrigation water, pesticides and machinery – are needed to maintain yields in the face of organic matter depletion. But with attention to the proper management of organic matter, the soil can sustain a good harvest with few costly repairs.

The organic matter content of agricultural topsoil is generally between 1 and 6%. A Michigan soil study demonstrated a potential increase in crop yield of about 12% for every 1% increase in organic matter. In an experiment in Maryland, researchers found an increase of about 80 bushels of corn per acre when organic matter went from 0.8% to 2%. The tremendous influence of organic matter on so many soil properties—biological, chemical, and physical—makes it vitally important to healthy soil (Figure 2.3). Part of the explanation for this effect is the small particle size of well-decomposed organic matter, humus. Its large surface area to mass ratio means that the humus is in contact with a significant part of the soil. The close contact of humus with the rest of the soil allows many reactions, such as the release of available nutrients into soil water, to occur quickly. However, the many roles played by living organisms make soil an essential part of the history of organic matter.

Changes caused organic matterFigure 2.3. Adding organic matter causes many changes. Modified from Oshins and Drinkwater (1999).

plant nutrition

agricultural nutrient cycleFigure 2.4. Phytonutrient cycle.

Plants need 17 chemical elements to grow: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium ( Mg), iron (Fe), manganese (Mn), boron (B), zinc (Zn), molybdenum (Mo), nickel (Ni), copper ( Cu), cobalt (Co) and chlorine (Cl). Plants acquire carbon in the form of carbon dioxide (CO2) from the atmosphere (part diffusing from the ground below as organisms break down organic matter). Oxygen is mainly obtained from air in the form of gaseous oxygen (O2). The remaining essential elements are obtained mainly from the ground. The availability of these nutrients is affected directly or indirectly by the presence of organic matter. Elements needed in large amounts – carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulfur – are called macronutrients. Other elements, called micronutrients, are essential elements needed in small amounts. Sodium (Na) and Silica (Si) help many plants grow better but are not considered essential for plant growth and reproduction.

Nutrients from the decomposition of organic matter. Most of the nutrients in soil organic matter cannot be used by plants as long as these nutrients are part of large organic molecules. As soil organisms break down organic matter, nutrients are converted into simpler inorganic (mineral) forms that plants can easily use. This process, called mineralization, provides much of the nitrogen plants need by converting it from organic forms. For example, protein is converted to ammonium (NH4+) then to nitrate (NO3-). Most plants absorb most of the nitrogen from the soil in the form of nitrates. Organic chemical mineralization is also an important mechanism for supplying plants with nutrients such as phosphorus and sulfur, and most micronutrients. This release of nutrients from organic matter by mineralization is part of a larger agricultural nutrient cycle (see Figures 2.4 and 10).Chapter 7).


Having a good amount of topsoil is very important. But what gives topsoil its beneficial properties? Is it because he is at the TOP? If we bring in a bulldozer and scrape off some of the soil, is the exposed soil now topsoil because it’s on top? Of course, everyone knows that there is more to topsoil than its location on the surface. Most of the properties we associate with topsoil – good nutrient supply, slope, drainage, aeration, water storage, etc. – is there because the topsoil is rich in organic matter and contains a lot of life. These characteristics decrease as you dig lower, making topsoil a unique and integral part of the soil structure.

Nitrogen supplement.Bacteria living in legume root nodules convert nitrogen from atmospheric gases (N2) in forms usable directly by the plant. Some free-living bacteria also fix nitrogen.

Store nutrients on soil organic matter.The decomposition of organic matter can provide food directly to plants, but it can also indirectly benefit plant nutrition. Some essential nutrients are found in the soil as positively charged molecules called cations (pronounced cat’s eye). The ability of organic matter to retain cations so that they are always available to plants is called cation exchange capacity (CEC). Humus has many negative charges, and because it attracts opposite charges, it can contain positively charged nutrients, such as calcium (Ca++), potassium (K+) and magnesium (Mg++) (see Figure 2.5a). This prevents them from being washed away (washed through the soil) deep into the ground below. The retained nutrients can be gradually released into the soil solution and made available to the plant throughout the growing season. However, keep in mind that not all phytonutrients are present as cations. For example, the nitrate form of nitrogen has a negative charge (NO3-) and is actually repelled by the negatively charged CEC. Therefore, nitrate is easily washed away as water enters the soil and exits the root zone.

model of cations in organic matterFigure 2.5. Cations cling to organic matter and negatively charged clay.

Clay particles also have a negative charge on their surface (Figure 2.5b), but organic matter can be the main source of negative charge for medium to coarse textured soils. Some clays, such as those found in the southeastern United States and the tropics, tend to have a low negative charge. When this clay is present, organic matter is even more important because it is the main source of negative charge that binds nutrients.

Protect nutrients by chelating iron. Soil organic molecules can also retain and protect certain nutrients. These particles, calledchelate(pronounced key-lates) are by-products of the active breakdown of organic matter or are secreted by the roots of plants. In general, chelated elements are held more tightly than by the binding of positive and negative charges. Chelates work well because they bind nutrients to multiple sites on the organic molecule (Figure 2.5c). In some soils, trace minerals, such as iron, zinc, and manganese, will be converted to an unavailable form if not chelated. It is not uncommon to find soils with low organic matter content or subsoils deficient in these micronutrients.

Other Ways to Keep Nutrients Available.There is some evidence that soil organic matter can inhibit the conversion of available phosphorus to forms not available to plants. One explanation is that the organic matter that coats the surface of minerals may be closely related to phosphorus. Once these surfaces are coated, available forms of phosphorus are less likely to react with them. Additionally, some organic molecules can form chelates with aluminum and iron, both of which can react with phosphorus in the soil solution. When stored as chelates, these metals cannot form an insoluble mineral with phosphorus.

Beneficial effects of soil organisms

Soil organisms are essential for keeping plants supplied with nutrients as they break down organic matter, including other dead organisms. These organisms make nutrients available by releasing them from organic molecules. Some bacteria fix nitrogen gas from the atmosphere, making it available to plants. Other organisms break down minerals and make phosphorus more available. If there are not enough food sources, the organisms in the soil will not be abundant and active, so more fertilizer will be needed to provide nutrients to the plants.


To live

  • When organic matter is broken down, nutrients are converted into forms that plants can use directly.
  • CEC is produced during decomposition, which increases the soil’s ability to hold calcium, potassium, magnesium and ammonium.
  • Organic molecules are designed to retain and protect certain micronutrients, such as zinc and iron.
  • Some organisms produce more soluble mineral forms of phosphorus while others fix nitrogen, converting it to forms that other organisms or plants can use.


  • Substances produced by microorganisms promote better root growth and healthier roots. With bigger and stronger roots, plants can absorb nutrients more easily.
  • Organic matter improves soil structure, leading to increased water infiltration after rainfall and increased soil water holding capacity; It also improves root growth in more permeable soil. This leads to better plant health and allows greater movement of mobile nutrients (such as nitrates) to the roots.

A diverse biotic community is your best defense against major pest outbreaks and soil fertility issues. Soils rich in organic matter and constantly fed with different types of fresh residues, through the use of cover crops, complex crop rotations and fertilized organic materials such as compost or animal manure, constitute the habitat of a much more diverse group of organisms than soils that have been depleted of organic matter. The remains provide a sufficient food source to sustain large populations of soil organisms. There are two dimensions to biodiversity, both aboveground and belowground: 1) the number of different organisms present and 2) their relative populations (called uniformity). It’s good to have a variety of species, but it’s a richer environment when there’s a similar population size. For example, if there is a population of moderately diseased organisms, we don’t just want a small population of beneficial organisms; Soils would be biologically richer if there were a moderate population of beneficial organisms. Well-diversified organism populations help ensure that fewer potentially harmful organisms can grow in sufficient numbers to reduce crop yields.

Soil loam

When the soil is in a favorable physical condition for plant growth, it is said to haveso far. These soils are porous and allow water to easily penetrate, rather than run off the surface (Figure 2.6). More water is stored in the soil for plants to use between rains and less erosion occurs. A good slope also means that the ground is well ventilated. The roots can easily absorb oxygen and eliminate carbon dioxide. Porous soil does not limit root growth and exploration. When the soil has a low slope, its structure deteriorates and soil structures are disturbed, causing increased compaction and decreased aeration and water storage. The soil layer may be so compacted that roots cannot develop. Soils with excellent physical properties will have many channels and voids of varying sizes.

Diagram of water flow patterns in soilFigure 2.6. Changes in land surface and water flow patterns as seals and crustaceans develop.

Studies on farmland and undisturbed land show that as organic matter increases, the soil tends to be less compact and has more room for air to pass through, helping to guide water into the ground and store it for the used tree. Sticky substances are created during the decomposition of plant residues. Together with plant roots and mycelium, they bind mineral particles into clusters or aggregates. Additionally, the sticky secretions of mycorrhizal fungi—beneficial fungi that penetrate roots while growing into thin filaments in the soil that help plants get more water and nutrients—are important binders in the soil. The arrangement and aggregation of individual particles into aggregates and the degree of soil compaction have a great influence on plant growth.(see chapters 5 and 6). Overall growth is desirable in all soils as it promotes better drainage, aeration and water storage. An exception is some wetland crops, such as rice, where you want a dense layer of soil that keeps the field flooded. (Although new rice cultivation systems have shown that high yields can be obtained with less flooding, thus saving water.)

Organic matter, either as deposits on the soil surface or as a binding agent for near-surface aggregates, plays an important role in reducing soil erosion. As with the leaves and stems of living plants, surface residue blocks raindrops and reduces their ability to separate soil particles. These surface residues also slow down water as it flows through the field, giving it a better chance of soaking into the soil. Aggregates and large channels greatly improve the soil’s ability to transport water from the surface to the ground. Larger pores form in several ways. Old root canals may remain open for some time after the root has broken down. Larger soil organisms, such as insects and earthworms, create channels as they move through the soil. The mud that earthworms secrete to keep their skin from drying out also helps keep their ducts clear for a long time.

Most farmers can tell that one soil is better than another by looking at it, seeing how it works when plowing, or even feeling how it feels when walking or touching it. What they see or feel is really good so far. And digging a little deeper into the ground can reveal its porosity and degree of clumping.

Since erosion tends to remove the most fertile part of the soil, it can significantly reduce crop yields. In some soils, just a few centimeters of topsoil loss can reduce crop yields by up to 50%. The surface of some organic-poor soils can become sealed or scaly as precipitation breaks down clumps and voids near the surface fill with solids. When this happens, water that cannot penetrate the soil flows out of the field, washing away valuable topsoil (Figure 2.6).

Protects the soil against rapid changes in acidity

comparing corn growthFigure 2.7. In an experiment by Rich Bartlett, adding humic acid to a nutrient solution increased tomato and corn growth and root number and branching. Corn grown in nutrient solution with (right) and without (left) chelating agent (soil extract). Photo by R. Bartlett

Acids and bases are released when minerals dissolve and organisms perform their normal functions of breaking down organic matter or fixing nitrogen. Acids or bases are removed by plant roots and acids are formed in the soil from the use of nitrogen fertilizers. It is best for plants that the acidity of the soil, called pH, does not fluctuate too much during the season. The pH scale is a way of expressing the amount of free hydrogen (H+) in soil water, but in the soil is closely related to the availability of phytonutrients and the toxicity of certain elements such as aluminum. It is a logarithmic scale, so a soil at pH 4 is very acidic and its solution is 10 times more acidic than a soil at pH 5. A soil at pH 7 is neutral: the more bases there are in the water . acid. Most plants do best when the soil is slightly acidic and the pH is between 6 and 7, although there are some acid-loving plants like blueberries. More essential nutrients are available to plants in this pH range than when the soil is more acidic or basic. Soil organic matter can slow or buffer pH changes by removing free hydrogen from solution when making acids or releasing hydrogen when making bases.(For a discussion of acid soil management, see Chapter 20.).

Stimulates root growth

Soil humic substances can stimulate root growth and development by improving the availability of micronutrients and altering the expression of certain genes (Figure 2.7). Soil microorganisms produce many substances that stimulate plant growth. These include a variety of phytohormones and chelating agents. The stimulation by the chelators (helper cells) is mainly due to a greater availability of micronutrients for the plant, which makes the roots longer and branched. Additionally, free-living nitrogen-fixing bacteria provide plants with an additional source of essential nutrients, while certain bacteria help break down phosphorus from minerals, making it easier for plants to supply.

darken the earth

Organic matter tends to blacken the soil. You can easily see this in coarse-textured, sandy soils containing bright quartz minerals. In well-drained conditions, a darker soil surface allows the soil to warm up a little faster in the spring. This gives a slight advantage in seed germination and early stages of seedling development, which is often beneficial in cold regions.

Protection against harmful chemicals

Certain chemicals naturally present in the soil can be harmful to plants. For example, aluminum is an important part of many minerals in the soil and therefore poses no danger to plants. As soil becomes more acidic, especially at pH below 5.5, aluminum becomes soluble. Some soluble forms of aluminum, if present in soil solution, are toxic to plant roots. However, under conditions where there is a significant amount of organic matter in the soil, the aluminum is tightly bound and will not cause much damage.

agriculture carbon cycleFigure 2.8. The role of soil organic matter in the carbon cycle. Illustration by Vic Kulihin.

Organic matter is the most important soil property that reduces pesticide leaching. It adheres strongly to some pesticides. This prevents or reduces the leaching of these chemicals into groundwater and gives the bacteria time to detoxify. Microorganisms can alter the chemical structure of some pesticides, industrial oils, many petroleum products (gas and oil), and other potentially harmful chemicals, rendering them useless and harmful.

Organic matter and natural cycles

carbon cycle

Soil organic matter plays an important role in several global cycles. People are more interested in the carbon cycle because the accumulation of carbon dioxide in the atmosphere is the main cause of climate instability.

Figure 2.8. Carbon dioxide is extracted from the atmosphere by plants and used to make all the organic molecules necessary for life. Sunlight provides the energy the plant needs to carry out this process. Plants, like herbivores, release carbon dioxide into the atmosphere as they use organic molecules to produce energy. Carbon dioxide is also released into the atmosphere when fuels such as gas, oil, coal and wood are burned.


In Illinois, a portable chart was developed to allow people to estimate the percentage of organic matter in the soil. Their darkest, almost black soil contains only 3.5-7% organic matter. Dark brown soil only 2-3% and yellow brown soil only 1.5-2.5% organic matter. (Color may not be clearly related to organic matter in all regions, as the amount of clay and mineral types also affects soil color.) good for rough estimates.

Soil stores carbon that accumulates and captures nutrients from plant production, and most of the carbon available on the soil is not in living plants but stored in soil organic matter. It took a while, but this idea is now finding its way into carbon cycle discussions. More carbon is stored in the soil than all plants, animals and the atmosphere combined. Soil organic matter contains about four times more carbon than living plants, and in fact two to three times more carbon is stored in all the soils of the world than in the atmosphere. When soil organic matter is depleted, it becomes a source of carbon dioxide for the atmosphere. Additionally, when forests are cleared and burned, large amounts of carbon dioxide are released. A secondary, often larger, amount of carbon dioxide is released from the soil due to the rapid depletion of soil organic matter following the conversion of forests to agricultural activities. There is as much carbon in seven inches of soil containing 1% organic matter as there is in the atmosphere above a field. If organic matter is reduced by 3-2%, the amount of carbon dioxide in the atmosphere can double. (Of course, wind and diffusion will move carbon dioxide to other regions of the globe, and it can be taken up by the ocean and taken up by plants during photosynthesis.)

Climate change and soil

Climate change has had profound effects on the planet by warming the oceans, melting glaciers and sea ice, melting land ice (permafrost) and increasing extreme weather events: more waves, higher temperatures warmer weather, increased rainfall intensity in many places and more frequent droughts in other places. . As of this writing, the past 5 years (2015, 2016, 2017, 2018, and 2019) have been the hottest since record keeping began in the 1880s. The 2018 and 2019 heat waves in America North, Europe, Southeast and East Asia, as well as during the next Australian summer (from December 2018 and again in the summer of 2019-2020, this time accompanied by historic bushfires of history), is particularly severe. July 2019 was the hottest month on record. Cultivation has been affected in many parts of the world, with rising night temperatures reducing grain yields, as much of the energy produced by plants during the day is used by respiration, more at night, and drought in the region caused crop failures. TO HAVE2), methane (ONLY3) and nitrous oxide (N2O) traps heat in the atmosphere, leading to a warming of the Earth, the so-calledGreenhouse effect.

The concentration of carbon dioxide in the atmosphere has risen from about 320 parts per million (ppm) in the mid-1960s to 415 ppm at the time of this writing, and it is increasing at a rate of about 2 to 3 ppm per year. The historic transition from forests and grasslands to crops is responsible for transferring large amounts of carbon (from accelerated degradation of soil organic matter) to the atmosphere in the form of CO2. This agricultural transition ranks second only to the burning of fossil fuels because it is the largest contributor to the increase in atmospheric CO.2concentration (remember that fossil fuels are derived from carbon stored in ancient plants). When forests are burned and land is plowed for crops (increased use of organic matter by soil organisms), CO2emitted into the atmosphere.

But soils that are managed in such a way that organic matter accumulates can become net carbon sinks to store carbon and possibly promote soil health at the same time. Increasing soil organic matter isn’t a magic bullet to fight climate change, but it can help slow it downto augmentin CO2for some time if done on a large scale around the world. Several NGOs in the United States, as well as several international efforts, encourage farmers to increase soil organic matter content as payment for carbon sequestration. (Large-scale “geo-engineering” programs have been proposed to obtain CO.2out of the atmosphere or throw particles into the atmosphere to reflect some of the incoming radiation from the sun. The costs and possible negative side effects of these recommendations have not been determined. Therefore, for now, drastically reducing the use of fossil fuels by switching to renewable energy sources and reducing total energy consumption is the only sure way we know to stop or reverse climate change. ) Matter certainly has a role to play in the fight against climate change. . It has win-win outcomes because higher organic matter content also increases the resilience of soils to more intense storms and dry spells as the planet heats up with increasingly unstable weather patterns. Learn more about the role of soil health in climate resilience in the SARE newsletterCultivating climate resilience on the farm and on the farm(

Nitrogen cycle

profit.Another important global process in which organic matter plays a major role isnitrogen cycle. It is of direct importance in agriculture because often there is not enough nitrogen available in the soil for better crop growth. Both nitrate and ammonium can be used by plants, but most of the nitrogen used by plants is used as nitrate, with a small amount being ammonium. A small amount of several small amino acid and protein sources can be absorbed. Figure 2.9 illustrates the nitrogen cycle and how soil organic matter enters the cycle. Almost all nitrogen in the soil is part of organic matter, in forms that cannot be used by plants as their main source of nitrogen. Each percent of organic matter in the topsoil (up to 6 inches deep) contains about 1,000 pounds of nitrogen. Each year, bacteria and fungi convert some organic nitrogen into ammonium, and different bacteria convert ammonium into nitrate. Depending on the level of organic matter in the soil, a typical plant can get 20-50% of its nitrogen from mineral organic matter.

Animal manure can also make an important contribution to the availability of plant nitrogen in the soil. They often have a high content of organic nitrogen which is made available when microorganisms convert the organic form to ammonium and nitrate. Most of a crop’s nitrogen requirements can be met with manure on livestock farms where large amounts of manure are produced.

In addition to breaking down organic matter and manure, nitrogen is derived from certain soil bacteria that can “fix” nitrogen, converting nitrogen gas into a form that other organisms, including plants, can use. This may be a modest amount of nitrogen in typical cereal growing systems, but it is a large amount when growing legumes. Additionally, inorganic forms of nitrogen, such as ammonium and nitrate, exist naturally in the atmosphere and are sometimes enhanced by air pollution. Rain and snow deposit these inorganic forms of nitrogen on the ground, but usually in modest amounts compared to the needs of a typical crop. Inorganic nitrogen can also be added as a commercial nitrogen fertilizer, with most grain crops (except legumes such as soybeans) typically being the largest nitrogen addition. These fertilizers are derived from atmospheric nitrogen by industrial fixation which requires a lot of energy.

nitrogen cycle in agricultureFigure 2.9. The role of organic matter in the nitrogen cycle. Illustration by Vic Kulihin.

Losses. Nitrogen can be lost from the soil in several ways. Soil conditions and agricultural practices govern the extent and manner of nitrogen loss. When crops are removed from the field, nitrogen and other nutrients are also removed. When uncomposted manure or some forms of nitrogen fertilizers are deposited on the soil surface, gas loss (evaporation) can occur, which can lead to losses of up to 30%. Nitrates (NOT3-) a form of nitrogen that easily escapes from soil and can end up in groundwater at undrinkable levels or enter surface waters, where it causes low oxygen “dead zones”. Leaching losses are greater in sandy soils and soils with tiled drainage. The organic forms of nitrate, as well as nitrate and ammonium (SM4+), can be lost to runoff and erosion. When released from soil organic matter, nitrogen can be converted back into final forms in the atmosphere. Bacteria convert nitrate to nitrogen (N2) and nitrous oxide (N2O) gas in a process known as denitrification, which can be an important route of loss from saturated soil. Nitrous oxide (also a potent greenhouse gas) is a strong contributor to climate change and is, in fact, estimated to be the largest contributor to greenhouse gas emissions (more than carbon dioxide and methane) . Additionally, when it reaches the upper atmosphere, it reduces ozone levels, which helps protect the earth’s surface from the harmful effects of ultraviolet (UV) rays. So if you need another reason to use fertilizers and nitrogen fertilizers efficiently – beyond the economic cost and contamination of ground and surface water – then you have to be careful.

Water cycle

Organic matter plays an important role in local, regional and global water cycles due to its role in promoting water infiltration and storage in soil. The water cycle is also calledhydrologicalBicycle. Water evaporates from the surface of the earth and the leaves of living plants, as well as from oceans and lakes. The water then returns to the earth, often far from where it evaporated, as rain and snow. The soil is rich in organic matter, has an excellent inclination, promotes the rapid infiltration of rainwater into the soilandincrease the water storage capacity in the soil. When we consider the increasing occurrence of major floods in many parts of the world, especially in the United States grain belt, we draw attention to climate change. But this is certainly aggravated by the progressive degradation of the soils in the area which are mainly used for intensive agricultural production.

Water that has entered the soil may be available for plant use, or it may seep into the subsoil and help replenish the groundwater supply. Since groundwater is often used as a source of drinking water for housing and irrigation, groundwater recharge is very important. When soil organic matter levels are depleted, it becomes less able to receive and store water, leading to high levels of runoff and erosion. This means less water for plants and less groundwater withdrawal.


It is difficult, if not impossible, to put a meaningful monetary value on the value of organic matter in our soil. This positively affects so many different assets that looking at them all and determining their dollar value is a huge task. One percent organic matter in the top 6 inches of an acre of soil contains about 1,000 pounds of nitrogen. At around 45 cents per pound, this alone is worth around $450for each percentage of organic matterin your country. Plus a value of 100 pounds each for phosphorus, sulfur and potassium, for a total of $500 per acrefor each percentage of organic matter. But we also need to consider the other nutrients present and the beneficial effects of organic matter in reducing other inputs and increasing yields. And what are the monetary benefits of reducing flooding, water pollution and climate change? We know this is truly an invaluable resource, but it’s hard to put an exact price on it.

Summary of Chapter 2

Soil organic matter is essential for building and maintaining healthy soil as it has major positive effects on all soil properties – synthesis, nutrient availability, soil tilt, soil and water availability , biodiversity, etc. – help grow healthier plants. Organic matter consists primarily of soil organisms (“living people”), fresh residues (“dead people”), and well-decomposed (or burnt) matter that is physically or chemically protected. Residues trapped inside aggregates (parts of “dead” organic matter), especially small organic matter, are also protected from decomposition because organisms cannot reach the matter. Each of these types of organic matter plays an important role in maintaining healthy soil. The transformation of soil organic matter is an important part of plant nutrition and the ability to achieve good crop yields. Soil organic matter is also an integral part of local and global carbon, nitrogen and water cycles, influencing many aspects that determine the sustainability and future viability of life on earth. .

Chapter 2

Allison, F.E. 1973.Soil organic matter and its role in agricultural production. Scientific publishing house: Amsterdam, Netherlands.

Brady, North Carolina and R.R. Well. 2008.The nature and properties of the soil, 14th edition, Prentice Hall: Upper Saddle River, NJ.

Follett, R.F., J.W.B. Stewart and C.V. Cole, eds. In 1987.Soil fertility and organic matter are important components of a production system.Special Publication No. 19. American Soil Science Association: Madison, WI.

Lal, R. 2008. Review of atmospheric CO2 sequences in global carbon sinks.Energy

Lehmann, J., D.C. Kern, B. Glaser, and W.I. Wood, editor. 2003.Amazonian Black Earths: Origins, Properties, Management.Kluwer Academic Press: Dordrecht, The Netherlands.

Lehmann, J. and M. Rondon. 2006. Biochar soil management on heavily weathered soils in the humid tropics. InBiological approaches to sustainable soil systems,ed. N. Uphoff et al., p. 517–530. CRC Press: Boca Raton, FL.

Lucas, R.E., J.B. Holtman, and J.L. Connor. 1977. Soil carbon dynamics and agricultural practices. InAgriculture and energy, ed. W. Lockeretz, p. 333–451. Publisher: New York, NY. (See this resource for the Michigan study on the relationship between soil organic matter levels and crop yield potential.)

Manlay, R.J., C. Feller, and M.J. Rapide. 2007. Historical development of soil organic matter concepts and their relationship to the fertility and sustainability of cropping systems.Agriculture, Ecosystems and Environment119: 217–233.

Oliveira Nunes, R., G. Abrahão Domiciano, W. Sousa Alves, A. Claudia A. Melo, Fábio Cesar, S. Nogueira, L. Pasqualoto Canellas and F. Lopes Olivares. 2019. Evaluation of the effect of humic acids on maize root architecture by unlabeled proteomic analysis.Scientific reports (NatureReports)9, Article Count: 12019. Accessed September 14, 2019, at

Oshins, C. and L. Drinkwater. 1999.Introduction to soil health.The slide deck has not been published.

Authority, R.F. and K. Van Cleve. 1991. Long-term ecological studies in temperate and montane forest ecosystems.Journal of Agronomy83: 11–24. (This benchmark compares the relative amount of carbon in soil with the amount of carbon in plants.)

Stevenson, F.J. 1986.Soil cycle: Carbon, Nitrogen, Phosphorus, Sulphur, Trace elements.Jean Wiley

Strickling, E. 1975. Planting sequence and tillage in efficient agricultural production.Summary of Meetings of the Northeastern Branch of the American Agronomist Association 1975: 20–29. (See this source for an experiment in Maryland that linked soil organic matter to corn yield.)

Tate, R.L., III. In 1987.Soil organic matter: biological and ecological impact. Jean Wiley

US Environmental Protection Agency. 2019. Greenhouse Gas Emissions and Sinks Inventory in the United States. EPA 430-R-19-001. Available at Weil, R. and F. Magdoff. 2004. Importance of Soil Organic Matter for Soil Quality and Health. InSoil organic matter in sustainable agriculture,ed. F. Magdoff and R. Weil, p. 1–43. CRC Press: Boca Raton, FL.

Before Chapter 1. Healthy Soil
Continued Chapter 3. Amount of organic matter in the soil

Popular questions about what does organic matter do in soil

what does organic matter do in soil?

CHEMICAL: Soil organic matter significantly improves the soil’s capacity to store and supply essential nutrients (such as nitrogen, phosphorus, potassium, calcium and magnesium), and to retain toxic elements. It allows the soil to cope with changes in soil acidity, and helps soil minerals to decompose faster.

How organic matter improve the soil?

Organic matter causes soil to clump and form soil aggregates, which improves soil structure. With better soil structure, permeability (infiltration of water through the soil) improves, in turn improving the soil’s ability to take up and hold water.

What are the four 4 benefits of soil, organic matter?

Enhances aggregate stability, improving water infiltration and soil aeration, reducing runoff. Improves water holding capacity. Reduces the stickiness of clay soils making them easier to till. Reduces surface crusting, facilitating seedbed preparation.

Why organic matter is important?

CHEMICAL: Soil organic matter significantly improves the soil’s capacity to store and supply essential nutrients (such as nitrogen, phosphorus, potassium, calcium and magnesium), and to retain toxic elements. It allows the soil to cope with changes in soil acidity, and helps soil minerals to decompose faster.

How does organic matter affect soil pH?

With an increase in organic matter, the soil recovers its natural buffer capacity; this means an increase in pH in acid soils (Figure 19).

How organic matter in soil is decomposed?

During the decomposition process, microorganisms convert the carbon structures of fresh residues into transformed carbon products in the soil. There are many different types of organic molecules in soil. Some are simple molecules that have been synthesized directly from plants or other living organisms.

Does organic matter improve soil texture?

Soil texture

Soil organic matter tends to increase as the clay content increases. This increase depends on two mechanisms. First, bonds between the surface of clay particles and organic matter retard the decomposition process.

What defines organic matter?

Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals.

What is organic matter for plants?

Organic matter includes plants and animals that are alive, dead, or in some stage of decomposition. Organic matter is a major contributor to soil health. Most garden and landscape plants benefit from increases in soil organic matter.

What does organic matter do in soil class 7?

It absorbs and holds the water useful for growing plants. It provides food for various plants and animals present in the soil. Humus is rich in minerals; hence, it provides optimum conditions for plant growth. Good humus count also reduces water and wind erosion of soil.

What causes loss of organic matter in soil?

A decline in organic matter is caused by the reduced presence of decaying organisms, or an increased rate of decay as a result of changes in natural or anthropogenic factors. Organic matter is regarded as a vital component of a healthy soil; its decline results in a soil that is degraded.

How does organic matter affect plant growth?

Organic matter improves soil structure, which results in increased water infiltration following rains and increased water-holding capacity of the soil; it also enhances root growth into more permeable soil. This results in better plant health and allows more movement of mobile nutrients (such as nitrates) to the root.

Can you have too much organic matter in soil?

Although it may seem unlikely, particularly given how often gardeners are told to add organic materials to their gardens, it is possible to have too much organic matter in your soil.

How does soil organic matter positively affect soil properties?

The addition of organic matter to the soil usually increases the water holding capacity of the soil. This is because the addition of organic matter increases the number of micropores and macropores in the soil either by “gluing” soil particles together or by creating favourable living conditions for soil organisms.

Which soil is poor in organic matter?

Arid Soils

These soils are poor and contain little humus and organic matter.

Video tutorials about what does organic matter do in soil


keywords: #Oklahoma, #Oklahomastateuniversity, #extension, #research, #teaching, #agriculture, #Oklahomagardening, #kimtoscano2014

9/06/14-Not all soil additives are created equal. Organic materials differ significantly in their nutrient content as well as the ratio of carbon to nitrogen. In this segment, Dr. Jason Warren joins host Kim Toscano to discuss why these characteristics are very important as they impact the amount of nutrients available in soils for plant use.

keywords: #FrancescaCotrufo, #NatureGeoscience, #ResearchSquare, #videosummary, #SoilOrganicMatter, #decomposition, #plantlitter, #microbialdigestion, #TallgrassPrairie(Location), #MicrobialEfficiencyMineralStabilization, #nitrogenstabilization, #carbonstabilization


Cotrufo et al. “Formation of soil organic matter via biochemical and physical pathways of litter mass loss” Nature Geoscience (2015). doi:10.1038/ngeo2520

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