Name: soil layers and how soil forms
Uploaded: 2026-08-26T08:21:04.082Z
Duration: 3 min 6 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Earth and Environmental Science

Earth and Human Activity

ESS.EES.6.1

The Soil Ecosystem

De bodem, de huid van de aarde, is meer dan alleen grond.
 Het is een complex ecosysteem met abiotische factoren zoals anorganische mineralen, lucht en water.
 Het bevat ook biotische factoren zoals bacteri&#xEB;n, fungi en andere organismen.
De anorganische mineralen zijn 40 tot 45% van het bodemvolume en verrijken het ecosysteem met nutri&#xEB;nten als nitraten, fosfaten en kalium.
 Lucht en water samen zijn 50 tot 55% van het bodemvolume.
 Lucht verrijkt de bodem met gassen zoals zuurstof, stikstof en koolstofdioxide.
Water helpt nutri&#xEB;nten de bodem te penetreren.
 De organismen die 5 tot 10% van het bodemvolume beslaan zijn in interactie met elkaar en met abiotische factoren voor voeding.
 De bodem bestaat uit verschillende horizonten of lagen.
De bovenlaag is het belangrijkst voor plantengroei omdat het rijk is aan humus&#x2014; organische materie gevormd door microbi&#xEB;le afbraak van dode materie van plant en dier.
 Humus verrijkt de bodem met nutri&#xEB;nten, verbetert het behoud van vocht en lucht en trekt organismen aan zoals wormen, waardoor de bodemtextuur zacht en poreus wordt.
 De textuur en samenstelling van de bovengrond maken het een ideale substraat voor zaadkieming en plantengroei.
Een gezonde bodem is vruchtbaar en is belangrijk voor de agricultuur.
 Maar groeiende planten verbruiken bodemnutri&#xEB;nten, zodat de vruchtbaarheid daalt.
 Het bodemecosysteem vernieuwt bodemnutri&#xEB;nten natuurlijkerwijs door processen als de afbraak van organische materie.
Deze belangrijke ecologische functies heten ecosysteemdiensten.
 Vanwege toegenomen menselijke activiteit overstijgt vervuiling de snelheid waarmee de bodem zijn ecosysteem kan herstellen.
 Bijvoorbeeld: microplastics, afkomstig van de fragmentatie van plasticafval, zijn toxisch voor organismen en tasten de bodemtextuur aan, waardoor het recyclen van nutri&#xEB;nten en het functioneren van het ecosysteem worden gewijzigd.
Klimaatverandering be&#xEF;nvloedt bodemecosystemen steeds meer en de vraag naar voedsel stijgt snel, dus bodembeheer en -behoud zijn cruciaal voor het leven op onze planeet.

het bodemecosysteem

Planten halen anorganische mineralen en water uit de bodem, die als natuurlijk medium voor landplanten fungeert. De samenstelling en kwaliteit van de bodem zijn niet alleen afhankelijk van de chemische bestanddelen, maar ook van de aanwezigheid van levende organismen. Over het algemeen bevatten bodems drie hoofdcomponenten:

<ol>
	<li>Anorganisch mineraal materiaal, dat ongeveer 40 tot 45 procent van het bodemvolume uitmaakt.</li>
	<li>Organische stof, ook wel humus genoemd, vormt ongeveer 5 procent van het bodemvolume.</li>
	<li>Water en lucht, die ongeveer 50 procent van het bodemvolume bedekken.</li>
</ol>

Een gezonde bodem heeft voldoende lucht, water, mineralen en organisch materiaal om de plantengroei te bevorderen.

Op basis van zijn fysieke structuur bestaat de bodem uit vier verschillende lagen:

<ol>
	<li>O-horizon of bovengrond</li>
	<li>Een achtergrond</li>
	<li>B-horizon of ondergrond</li>
	<li>C-horizon of basisgrond</li>
</ol>

O-horizon omvat vers ontbindend organisch materiaal - een gevolg van de afbraak van planten, dieren of micro-organismen. Het wordt ook wel bovengrond genoemd. Deze humuslaag is belangrijk bij het verbeteren van de bodemvruchtbaarheid, het vocht en het vasthouden van lucht. Hoewel de humus een kleiner percentage van het totale bodemvolume uitmaakt, is het toch essentieel.

A-achtergrond is een mengsel van organische en anorganische componenten en is het begin van echte minerale grond, gevormd door de verwering van gesteente.

De B-horizon, of ondergrond, is een laag fijne klei die minder vruchtbaar is dan de bovengrond. Het is rijk aan vocht en vertoont minder biologische activiteit dan de bovengrond.

De C-horizon omvat het onderliggende verweerde gesteente. Onder de C-horizon ligt doorgaans het gesteente dat als moedermateriaal fungeert bij bodemvorming.

Bodemvorming

Bodem ontstaat als gevolg van fysische, chemische en biologische verweringsprocessen die inwerken op het oorspronkelijke gesteentemateriaal. In het geval van fysieke verwering ontstaat de aarde door mechanische acties zoals temperatuurverandering, wind, vorst, slijtage of aardbevingen, die allemaal of allemaal de afbraak van het gesteente kunnen veroorzaken. Bij chemische verwering reageert het gesteente met water, zuur of andere chemische componenten. Biologische verwering wordt daarentegen be&#xEF;nvloed door gravende dieren en plantenwortels die in de scheuren van de rots groeien, waardoor deze splijt.

Over het geheel genomen wordt het type bodem dat zal worden geproduceerd bepaald door vijf belangrijke op elkaar inwerkende factoren-de samenstelling van het moedermateriaal, het aanwezige type levende organismen, de klimatologische omstandigheden, de topografie en de tijd. De interactie tussen deze factoren levert een oneindige verscheidenheid aan bodems over de hele aarde op.

Het bodemecosysteem

Plants obtain inorganic minerals and water from the soil, which acts as a natural medium for land plants. The composition and quality of soil depend not ...

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Education

JoVE Core

Biology

Biologie

Plant Biology

Plantenbiologie

Plant Structure, Growth and Function

Plantstructuur, groei en voeding

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

soil layers and how soil forms

Soil supplies plants with water and inorganic minerals. It is the natural medium for land plants, and its quality depends on both chemical makeup and living organisms in the soil. Healthy soil contains enough air, water, minerals, and organic matter to support plant growth.

Soil is made of three major components. Inorganic mineral matter makes up about 40 to 45 percent of soil volume. Organic matter, also called humus, makes up about 5 percent. Water and air fill about 50 percent of the volume.

Soil also has four distinct layers based on its structure. The O-horizon, or topsoil, contains freshly decomposing material from plants, animals, and microorganisms. This humus layer helps improve soil fertility, moisture, and air retention. The A-horizon is a mixture of organic and inorganic material. It is the start of true mineral soil formed by rock weathering.

The B-horizon, or subsoil, is a layer of fine clay. It is less fertile than topsoil, but it is rich in moisture. It also has less biological activity than the upper layers. The C-horizon is the weathered rock below the subsoil. Under the C-horizon is bedrock, which serves as the parent material for soil formation.

Soil forms through physical, chemical, and biological weathering of bedrock. Physical weathering includes temperature change, wind, frost, abrasion, and earthquakes. Chemical weathering happens when rock reacts with water, acid, or other chemical components. Biological weathering is caused by burrowing animals and plant roots that split rock as they grow into cracks.

The kind of soil that develops depends on five interacting factors: parent material, living organisms, climate, topography, and time. These factors work together to create many different soils across the Earth.

Soil Layers and How Soil Forms

introduction to plant diversity

Plant Adaptations for Life on Land

Plant adaptations for life on land explain how Kingdom Plantae moved from water to land about 410 million years ago. This shift happened when green algae began colonizing a new environment that had not been widely occupied. Land offered more light and carbon dioxide for growth, but it also created major challenges for early plants. One key adaptation was the cuticle, a waxy outer layer that helps prevent water loss. It traps moisture inside the plant. But it also limited direct gas exchange...

non-vascular seedless plants

Nonvascular Plants and Their Life Cycle

Nonvascular plants include some of the earliest plants on Earth. Today, this group includes liverworts, mosses, and hornworts. These plants are also called bryophytes. They have no true roots, leaves, or stems because they lack extensive vascular tissue. Bryophytes reproduce with spores instead of seeds. Their life cycle is dominated by the haploid gametophyte stage, which produces eggs and sperm. The sporophyte stage makes haploid spores that can grow by mitosis into new gametophytes. In many...

seedless vascular plants

Fern Life Cycles and Vascular Tissue

Seedless vascular plants include ferns, horsetails, whisk ferns, and lycophytes. Ferns are the most common example. Whisk ferns and their relatives, along with horsetails, are monilophytes. Lycophytes include club mosses, spikemosses, and quillworts, and none of these are true mosses. Seedless vascular plants differ from nonvascular plants because they have vascular tissue. This tissue includes xylem and phloem, which move water and nutrients through the plant. Most seedless vascular plants...

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Seed Plants: Cones, Flowers, and Fruits

Seed plants are land plants that make seeds, use pollen, and have reduced gametophytes. This group includes gymnosperms and angiosperms. Gymnosperms include cycads, Ginkgo biloba, gnetophytes, and conifers. Gymnosperms usually form cones. Pollen cones contain the male gametophytes. Ovulate cones contain the female gametophytes and produce exposed seeds after fertilization. Angiosperms are the most diverse and widespread land plants. They form flowers and fruit, and both structures support...

basic plant anatomy: roots, stems, and leaves

basic-plant-anatomy-roots-stems-and-leaves

Plant Organs and Their Specialized Roles

Plants are built from roots, stems, and leaves, but each organ can change to fit a plant’s environment. These structures may look very different from one species to another. They still carry out the main jobs needed for growth and survival. Roots are usually underground, but that is not always true. Aerial roots grow aboveground. Epiphytic plants, such as orchids, can live without ever touching soil. In strangler figs and banyans, aerial roots begin aboveground, grow downward, and later reach...

plant cells and tissues

Plant Growth and Support Tissues

Plant growth and support tissues help plants grow, protect themselves, and move materials through the body. Plant tissues are groups of similar cells that do related jobs. These tissues combine to form organs such as flowers, fruit, stems, and leaves. Two major kinds of plant tissue are meristematic tissue and permanent tissue. Meristematic tissue is the main growth tissue in plants. It can keep dividing and renewing itself, and every plant cell begins in a meristem. Meristematic tissue is...

meristems and plant growth

Plant Growth from Root and Shoot Tips

Plants grow throughout their lives, and that pattern is called indeterminate growth. This trait sets plants apart from most animals. Some plant parts stop growing, such as leaves and flowers, but roots and stems can keep growing for a long time. Meristems make this ongoing growth possible. A meristem is a plant tissue that contains undifferentiated cells called meristematic cells. When these cells divide, some daughter cells stay in the meristem. That keeps a supply of cells that can keep...

primary and secondary growth in roots and shoots

primary-and-secondary-growth-in-roots-and-shoots

Root and Shoot Growth: Length vs. Width

Root and shoot growth in vascular plants happens in two main ways: primary growth and secondary growth. Primary growth makes roots and shoots longer. Secondary growth makes them thicker. Many woody plants show both kinds of growth, and the two can happen at the same time. Primary growth happens in newer parts of the plant. Secondary growth happens in regions that have already finished primary growth. In roots and shoots, the process starts in apical meristems, which are areas of actively...

morphogenesis

Plant Flowering and Organ Identity

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light acquisition

How Plants Maximize Sunlight Capture

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water and mineral acquisition

How Roots Absorb Water and Minerals

Roots absorb water and minerals from the soil using specialized tissues. Their branching patterns help them reach more soil, and root hairs on the outer cells increase surface area for contact with the ground. Water enters roots passively because the water concentration in the soil is higher than in root tissue. Minerals move in a different way. They are taken up actively by root cells, which requires energy and transport proteins. Soil particles carry a negative charge, so positive ions...

short-distance transport of resources

Plant Cell Membranes and Water Balance

Plant cell membranes control how water, ions, and other solutes move over short distances. This transport can happen across just 2 to 3 cells, and it begins at the plasma membrane. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse through the membrane on their own. Ions and larger molecules need transport proteins because of their charge or size. Membrane transport also happens inside plant cells. The central vacuole stores resources and helps manage the cell’s...

xylem and transpiration-driven transport of resources

xylem-and-transpiration-driven-transport-of-resources

How Xylem Moves Water in Plants

Xylem moves water and dissolved minerals from the roots to the rest of the plant. The cells that carry xylem sap are dead when mature, so the flow is passive. Xylem transport depends on special tracheary elements, which connect directly with the extracellular space in the apoplast. There are two main tracheary elements: tracheids and vessel elements. Tracheids are long cells with lignified walls and small pits. These pits let xylem sap move from one cell to the next where the walls overlap.

regulation of transpiration by stomata

How Guard Cells Open Plant Stomata

How guard cells open and close plant stomata controls gas exchange in leaves. A stoma is a tiny opening in the leaf epidermis. The word comes from the Greek word for “mouth.” These openings let plants take in carbon dioxide for photosynthesis and release oxygen into the air. Each stoma is surrounded by two guard cells. When these cells take up water, they create an opening. Ion transport controls how much water stays in the guard cells. A trigger causes pumps to move hydrogen ions out of the...

adaptations that reduce water loss

Plant Features That Limit Water Loss

Plant features that limit water loss help plants survive in dry or hot environments. Water is needed for photosynthesis and other cell processes, so plants have evolved several ways to slow evaporation from their leaves. One major barrier is the cuticle, a waxy layer on the leaf epidermis. The epidermis is the outer cell layer, and it makes cutin and other plant waxes that form this hydrophobic coating. The cuticle helps stop water from escaping and also keeps out unwanted solutes. Its...

phloem and sugar transport

How Phloem Moves Sugars in Plants

Phloem moves sugars and other materials through plants. In angiosperms, sugar production is mostly limited to photosynthetic cells in the leaves. These leaves act as sugar sources because they make more sugar than they use. Roots, shoots, flowers, and fruits are usually sugar sinks because they need more sugar than they can make. This movement is called translocation. It carries sugar, hormones, amino acids, and some signaling molecules from source tissues to sink tissues. The transport...

the soil ecosystem

Soil supplies plants with water and inorganic minerals. It is the natural medium for land plants, and its quality depends on both chemical makeup and living organisms in the soil. Healthy soil contains enough air, water, minerals, and organic matter to support plant growth. Soil is made of three major components. Inorganic mineral matter makes up about 40 to 45 percent of soil volume. Organic matter, also called humus, makes up about 5 percent. Water and air fill about 50 percent of the volume.

key elements for plant nutrition

Plant Nutrients: Macro and Micro Needs

Plants need both organic and inorganic nutrients to survive, grow, reproduce, and keep normal cell function. Researchers use hydroponics to study these essential nutrients. In hydroponic culture, plants grow without soil in water-based nutrient solutions. At least 17 nutrients are known to be essential for plants. Plants get these elements from the atmosphere, the soil around their roots, and water. Nine of them are macronutrients, which plants need in larger amounts. These macronutrients are...

the roles of bacteria and fungi in plant nutrition

the-roles-of-bacteria-and-fungi-in-plant-nutrition

How Soil Microbes Help Plants Get Nutrients

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epiphytes, parasites, and carnivores

Plant Nutritional Adaptations in Nature

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the apoplast and symplast

Plant Water Transport Pathways

Plant water transport pathways help roots absorb water and dissolved minerals from the soil. These pathways move materials through plant tissues that support growth and nutrient uptake. The main tissue regions involved are the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells. It contains cell walls, extracellular spaces, xylem, phloem, and tracheids. The symplast is the cytosol of all living plant cells, along with the plasmodesmata that...

key terms and concepts

Explore soil layers, soil composition, and the weathering processes that form soil. Learn how humus, subsoil, and bedrock support plant growth.

Soil Layers and How Soil Forms | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

Earth's Systems

ESS.EES.2.4

ESS.EES.2.5

ESS.EES.4.1

ESS.EES.4.2

Pennsylvania State Academic Standards

Earth and Space Science

3.3.9-12.N

Louisiana Student Standards for Science

High School

Earth Science

Earth’s Systems

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ohios-learning-standards-and-model-curriculum

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Virginia  Standards of Learning

HIgh School

ES.5

ES.5.a

ES.5.b

ES.8

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LS.7

LS.7.a

LS.9

LS.9.c

Next Generation Science Standards

ecosystems-interactions-energy-and-dynamics

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HS-LS2-6

HS-ESS2-2

HS-ESS2-6

HS-ESS3-1

Florida Department of Education

SC.912.L.14

SC.912.L.14.7

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

Earth and Space Science (ESS)

E-ESS3-1.

E-ESS3-2.

Georgia Standards of Excellence

Entomology

SEN1.

SEN1.a

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Extinction

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Analyze and interpret data to explain the impacts of land use on Earth's systems.

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Turbidity and Total Solids in Surface Water

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Analyze and interpret data to evaluate how human use of ground and surface waters impacts water quality and availability in river basins, wetlands, estuaries, and aquifers.

ESS.EES.5.2

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ESS.EES.5.3

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Soil Layers and How Soil Forms

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