Soil is a complex mixture of organic and inorganic materials, microorganisms, water and air.
During the last ice age (20,000 years ago) vast glacial sheets sed across Europe and the Americas, grinding substrates to produce new, fertile layers of soil rich in nutrients, especially nitrogen and phosphorus. However, because of Australia's latitude (where most deserts are located) the continent missed out on this episode of glacial-induced soil formation. Thus, Australia's soils today are the oldest and the most nutrient-poor soils. Nitrogen is particularly scarce, with numerous plants adapting to this condition by developing carbon-rich defenses and structures.
here we studied soil and soil horizons
Los suelos sin lugar a dudas es un factor indispensable para el desarrollo de la vida en la tierra, ya que estos permiten el establecimiento de las plantas que proveen aliemento y oxigeno natural para el resto de organismos
El perfil consiste de una sucesión de estratos más o menos diferenciados. Horizonte A: capa superior, posee mayor actividad biológica, generalmente está enriquecida con materia orgánica y es más oscura que el suelo subyacente. Horizonte B: algunos de sus materiales (ej. arcilla o carbonatos) son filtrados del A por agua percolada. Suele ser más grueso que el A. Horizonte C: es material parental del suelo. Un suelo residual C consiste de material rocoso fragmentado y erosionado.
es un aparte importante para los ecosistemas, la calidad de los suelos es un factor limitante para el crecimiento de la población, es una unión de varios materiales, inicia con la formación de roca madre, luego se mezclan con la materia orgánica. el agua, aire y otros también quedan atrapados, su formación es muy lenta. requiere muchos años. el suelo tiene capas, cada capa tiene una textura diferente debido a su composición. tiene diferentes componentes vitales para el crecimiento de plantas. el tipo de suelo depende de los tipos de materiales según la disposición del agua.
Soil profile is what defines that particular soil.
Soil is the cleanest material on earth because it support life for food through agriculture, mining what about cotton that gives us clothes that we wear today think about Louis Vuitton.
Do think soil support gravity?
How many types of soil are there in the world?
Soil plays an important role in land ecosystems. In order for a community of producers and consumers to become established on land, soil must be present. Furthermore, soil quality is often a limiting factor for population growth in ecosystems.
Soil is a complex mixture of inorganic materials, organic materials, microorganisms, water and air. Its formation begins with the weathering of bedrock or the transport of sediments from another area. These small grains of rock accumulate on the surface of the earth. There they are mixed with organic matter called humus, which results from the decomposition of the waste and dead tissue of organisms. Infiltrating rainwater and air also contribute to the mixture and become trapped in pore spaces. This formation process is very slow (hundreds to thousands of years), and thus soil loss or degradation can be very detrimental to a community.
Mature soils are layered. These layers are known as soil horizons, and each has a distinct texture and composition. A typical soil has a soil profile consisting of four horizons, which are designated: O, A, B and C.
The O horizon is the top layer at the earth's surface. It consists of surface litter, such as fallen leaves (duff), sticks and other plant material, animal waste and dead organisms. A distinct O horizon may not exist in all soil environments (e.g., desert soil). The O horizon protects the underlying topsoil from erosion and moisture loss by evaporation.
Below the O horizon is the A horizon, which is also known as topsoil. This layer contains organic humus, which usually gives it a distinctive dark color. The organic humus in the A horizon aids in holding water and nutrients, making it the most fertile layer. Therefore, plants with shallow roots are anchored in the A horizon.
The O and A horizons in typical mature soils have an abundance of microorganisms (e.g. fungi, bacteria), earthworms and insects. These organisms decompose the organic material from dead organisms and animal waste into inorganic nutrients useable by plants.
The B horizon, or sub-soil is the next layer down from the surface. It consists mostly of inorganic rock materials such as sand, silt and clay. Water seeping through the upper layers may dissolve water-soluble minerals and transport them to lower layers in a process called leaching. Very fine clay particles can also be transported by seeping water and accumulate in the subsoil layer.
The accumulation of clay particles and leached minerals can lead to compaction of the B horizon. This compaction can limit the flow of water through the layer and cause the soil above to become waterlogged. The B horizon is not as fertile as the A horizon, but deep-rooted plants can utilize the water and minerals leached into this layer.
The C horizon sits atop bedrock and therefore is made up of weathered rock fragments. The bedrock is the source of the parent inorganic materials found in the soil. The C horizon represents a transition zone between the bedrock and the soil. It lacks organic material, but may be saturated with groundwater that is unable to move deeper due to the solid barrier of bedrock below.
Different types of soil may have different numbers of horizons, and the composition and thickness of those horizons may vary from soil to soil. The type of soil depends on a number of factors including:
• the type of parent rock material,
• the type of vegetation,
• the availability of organic matter, water and minerals, and
• the climate.
Grassland and desert soils lack a significant O horizon as they generally have no leaf litter. Grassland soil may have a very thick, fertile A horizon, while desert and tropical rain forest soils may have very thin, nutrient poor A horizons. The A horizons in coniferous forests may be severely leached.
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