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

Il suolo, chiamato spesso la pelle del Pianeta,
&#xE8; molto di pi&#xF9; che porco.

&#xC8; un complesso ecosistema che include

fattori abiotici come minerali inorganici, aria

e acqua.

Contiene anche numerosi
fattori biotici, come batteri

funghi e altri organismi.

I minerali inorganici rappresentano il 40-45%

del volume del suolo e
arricchiscono l&#x27;ecosistema

con sostanze nutrienti come nitrati,
fosfati e potassio.

Aria e acqua insieme fanno il
50-55% del volume del suolo.

L&#x27;aria arricchisce il suolo con gas
come ossigeno, azoto e

anidride carbonica,

mentre l&#x27;acqua aiuta le sostanze
nutrienti a penetrare nel suolo.

Gli organismi che comprendono
il 5-10 % del volume del suolo

interagiscono tra loro e
con fattori abiotici

per la nutrizione.

Il suolo &#xE8; compreso tra
livelli, o strati.

Lo strato superficiale del suolo &#xE8;
il pi&#xF9; importante per la crescita della pianta,

perch&#xE9; &#xE8; ricco di humus&#x2014;materiale
organico formato dalla

decomposizione microbica di
materia vegetale e animale morta.

L&#x27;humus arricchisce il suolo con
sostanze nutrienti,

migliora la ritenzione di umidit&#xE0; e acqua,

e attira organismi come i lombrichi,

che contribuiscono ad una tessitura
soffice e porosa del suolo.

La tessitura e composizione
dello strato superiore

&#xE8; il substrato ideale per la
germinazione dei semi e la crescita

della pianta.

Un suolo sano &#xE8; considerato fertile

e una risorsa preziosa per l&#x27;agricoltura.

Tuttavia, le piante in crescita utilizzano
le sostanze nutrienti del suolo

e ne impoveriscono la fertilit&#xE0;.

L&#x27;ecosistema del suolo ripristina
le sostanze nutrienti in maniera naturale

mediante processi come la decomposizione

di materia organica.

Tali funzioni ecologiche vitali sono

conosciute come servizi di ecosistema.

A causa dell&#x27;aumento dell&#x27;attivit&#xE0;
l&#x27;inquinamento supera

di gran lunga il tasso
di auto-rigenerazione del suolo.

Per esempio, la microplastica originata

dalla frammentazione dei rifiuti plastici

&#xE8; tossica per gli organismi
e colpisce la tessitura del suolo,

alterando il riciclaggio
delle sostanze

nutrienti e il funzionamento dell&#x27;ecosistema.

Con il cambiamento climatico,
che colpisce sempre pi&#xF9;

gli ecosistemi del suolo, e
la crescente domanda di cibo,

la gestione e conservazione del suolo
sono diventate essenziali per sostenere la vita

nel nostro pianeta.

l'ecosistema del suolo

Le piante ottengono minerali inorganici e acqua dal suolo, che agisce come un mezzo naturale per le piante terrestri. La composizione e la qualit&#xE0; del suolo dipendono non solo dai costituenti chimici, ma anche dalla presenza di organismi viventi. In generale, i suoli contengono tre componenti principali:

<ol><li>Materia minerale inorganica, che costituisce circa il 40-45 per cento del volume del suolo.</li>
 <li>Materia organica, conosciuta anche come humus, che costituisce circa il 5 per cento del volume del suolo.</li>
 <li>Acqua e aria, coprendo circa il 50 per cento del volume del suolo.</li>
</ol>Il suolo sano ha una quantit&#xE0; adeguata di aria, acqua, minerali e materia organica per promuovere la crescita delle piante.

Sulla base della sua struttura fisica, il terreno &#xE8; composto da quattro strati distinti:

<ol><li>O-horizon o terreno</li>
 <li> A-horizon </li>
 <li>B-horizon o sottosuolo</li>
 <li>C-horizon o base</li>
</ol>L&#x27;o-horizon comprende la materia organica appena in decomposizione - il risultato della decomposizione di piante, animali o microrganismi. E &#x27;noto anche come top-soil. Questo strato di humus &#xE8; significativo nel migliorare la fertilit&#xE0; del suolo, umidit&#xE0;, e ritenzione d&#x27;aria. Anche se l&#x27;humus &#xE8; una percentuale minore del volume complessivo del suolo, &#xE8; comunque essenziale.

L&#x27; A-horizon &#xE8; una miscela di componenti organici e inorganici ed &#xE8; l&#x27;inizio del vero terreno minerale formato dagli agenti atmosferici della roccia.

Il B-horizon, o sottosuolo, &#xE8; uno strato di argilla fine che &#xE8; meno fertile del suolo superiore. &#xC8; ricco di umidit&#xE0; e mostra meno attivit&#xE0; biologica rispetto al suolo superiore.

Il C-horizon comprende la roccia intemperie sottostante. Sotto &#x22;l&#x27;orizzonte C&#x22; si trova generalmente la roccia che funge da materiale genitore nella formazione del suolo.

Formazione del suolo

Forme del suolo come conseguenza dei processi fisici, chimici e biologici di meteorologo che agiscono sul materiale roccioso principale. Nel caso di agenti atmosferici fisici, la terra si forma da azioni meccaniche come il cambiamento di temperatura, il vento, il gelo, l&#x27;abrasione o i terremoti, uno o tutti i quali possono causare la rottura della roccia. Negli agenti atmosferici chimici, la roccia reagisce con acqua, acido o altri componenti chimici. La materia biologica, al contrario, &#xE8; influenzata da animali scavatori e radici vegetali che crescono nelle fessure della roccia, facendola dividere.

Nel complesso, il tipo di terreno che verr&#xE0; prodotto &#xE8; governato da cinque fattori di interazione principali: la composizione del materiale genitore, il tipo di organismi viventi presenti, le condizioni climatiche, la topografia e il tempo. L&#x27;interazione tra questi fattori produce una variet&#xE0; infinita di terreni in tutta la terra.

L'ecosistema del suolo

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

Didattica

JoVE Core

Biology

Biologia

Plant Biology

Biologia vegetale

Plant Structure, Growth and Function

Struttura, crescita e nutrizione delle piante

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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...

introduction to seed plants

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

Plant flowering and organ identity shape a plant’s form and structure. These changes depend on growth and cell differentiation, which work together during plant morphogenesis. Precursor cells become specialized cell types, and those cells are organized into tissues and organ systems that support the whole plant. Plant growth and cell differentiation are controlled by hormones. Plant hormones regulate gene expression, often in response to environmental stimuli. Temperature and day length are...

light acquisition

How Plants Maximize Sunlight Capture

Plants need light energy to make glucose, so leaf shape and plant structure help determine how well they capture sunlight. Many modern plants have evolved leaves that are specialized for light capture. Leaf size can vary from just a few millimeters wide to tens of meters wide, depending on the environment. Competition for sunlight has pushed evolution toward larger leaves and taller plants. These changes help plants avoid being shaded by nearby competitors. They also depend on root systems...

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

Soil microbes help plants get nutrients, water, and protection. Plants can make their own food by photosynthesis, but they still depend on organisms in the soil to get the nutrients they need to work properly. Bacteria and fungi form symbiotic relationships with plants, which helps both partners survive in many environments. The bacteria living in and around plant roots are called the rhizosphere. This community is very diverse. Some bacteria can cause disease, but most help plant health. In...

epiphytes, parasites, and carnivores

Plant Nutritional Adaptations in Nature

Plant nutritional adaptations help some species survive by using fungi, bacteria, or other plants and animals. Many plants also rely on mutualistic partners in the soil. Root-colonizing fungi, such as mycorrhizae, increase root surface area and improve nutrient absorption. Nitrogen-fixing bacteria, such as rhizobia, convert atmospheric nitrogen (N2) into ammonia (NH3), which plants can use to build essential molecules like chlorophyll. These relationships benefit both sides. The plant gets...

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

JoVE Core Biologia illustra i concetti chiave della biologia grazie a oltre 300 video-lezioni animate, concise e di facile comprensione. Inoltre, negli oltre 150 video di "scienziati in azione", i concetti scientifici vengono applicati e dimostrati da ricercatori attraverso esperimenti in laboratorio.

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

HS-ESS2-1

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Physical Geology

Plate Tectonics

Structure of Earth

Earth's Resources

Soil and sediment

Virginia  Standards of Learning

HIgh School

ES.5

ES.5.a

ES.5.b

ES.8

ES.8.a

Life Science

LS.7

LS.7.a

LS.9

LS.9.c

Next Generation Science Standards

ecosystems-interactions-energy-and-dynamics

Ecosystems: Interactions, Energy, and Dynamics

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

Threats to Biodiversity

There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species ...

The Carbon Cycle

Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among ...

Energy Dynamics

The Food Chain
Energy is one of the most important abiotic factors in an ecosystem and organisms in an ecosystem are connected by the flow of energy and ...

What is Climate?

Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, &#8220;Climate is what you expect. ...

Sustainable Development

As the human population continues to grow and use resources, we must be mindful of our planet&rsquo;s natural limits. Sustainable development provides a ...

Global Climate Change

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global ...

Extinction

The History of Life on Earth
Fossils of organisms that were different from anything alive today had been documented as early as the 17th century, but it ...

Ecological Disturbance

An ecological disturbance is a temporary disruption in the environment resulting from abiotic, biotic, or anthropogenic factors, causing a pronounced ...

Climate Change

The certainty of climate change remains a public controversy despite the consensus among approximately 97% of active climate researchers, who not only ...

Habitat Fragmentation

Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land ...

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

ESS.EES.5.1

water-quality-analysis-via-indicator-organisms

Water Quality Analysis via Indicator Organisms

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba -The University of Arizona
Demonstrating Author: Luisa Ikner
Water quality analysis monitors ...

Nutrients in Aquatic Ecosystems

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Nitrogen and phosphorus are essential plant nutrients found in aquatic ...

turbidity-and-total-solids-in-surface-water

Turbidity and Total Solids in Surface Water

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Turbidity and total solids are related measurements addressing clarity of ...

environmental-applications-of-microorganisms

Environmental Applications of Microorganisms

Microorganisms play a pivotal role in maintaining ecosystem balance by recycling essential elements such as carbon, nitrogen, and phosphorus, as well as ...

Dissolved Oxygen in Surface Water

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Dissolved oxygen (DO) measurements calculate the amount of gaseous oxygen ...

The Water Cycle

The Earth&rsquo;s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, ...

Biodiversity and Human Values

Human civilization relies on biodiversity in many ways. Sudden changes in species biodiversity result in environmental changes that can modify weather ...

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

Measuring Tropospheric Ozone

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Ozone is a form of elemental oxygen (O3), a molecule of three oxygen atoms ...

determination-of-nox-in-automobile-exhaust-using-uv-vis-spectroscopy

Determination Of NOx in Automobile Exhaust Using UV-VIS Spectroscopy

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
In the troposphere, ozone is naturally formed when sunlight splits nitrogen ...

What is Weather?

Overview

Weather refers to the current state of atmospheric conditions at a specific time and place. Weather is temporary and is influenced by the ...

The Sulfur Cycle

Sulfur, an important element in the chemical makeup of proteins, is recycled through the atmosphere and aquatic and terrestrial environments. Found in the ...

Construct an argument to evaluate the ways that human activities influence atmospheric composition.

ESS.EES.5.3

Evaluate how human consumption patterns impact Earth's systems.

Soil Layers and How Soil Forms

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