Fundamentals of Soil Science: Soil as a Natural Body

Flashcards covering the fundamentals of soil science, including Earth's spheres, rock types, mineral classification, and the definition and components of soil.

Lithosphere

The solid zone of the earth consisting of continents, ocean basins, plains, plateaus, mountains, and the interior, accounting for $93.06\,\%$ of the earth.

Hydrosphere

The liquid sphere of the earth comprising the land covered by water forming seas and oceans.

Atmosphere

The gaseous envelope existing over the earth’s surface.

Earth's Crust

The outermost layer of the earth, $5-56\,km$ thick with a density of $2.6-3.0$, consisting of rocks built from minerals.

Oxygen

The most abundant non-metallic element in the earth's crust, comprising $46.60\,\%$ of its total weight.

Silicon

A non-metallic element that is the second most abundant in the earth's crust, accounting for $27.72\,\%$ of its composition.

Petrology

The science of rocks, derived from the Greek words 'petra' meaning rock and 'logos' meaning science.

Petrography

A branch of petrology that deals specifically with the description of rocks.

Petrogenesis

A branch of petrology that focuses on the study of the origin of rocks.

Igneous Rocks

Rocks formed by the cooling and crystallization of molten magma on or beneath the surface of the earth.

Intrusive Rocks

Igneous rocks formed from molten magma that cools within the earth’s crust.

Extrusive Rocks

Volcanic rocks that cool on the surface of the earth.

Sedimentary Rocks

Rocks formed from sediments derived from the breaking down of pre-existing rocks by wind, water, or ice.

Stratification

The most common feature of sedimentary rocks, leading them to be termed stratified rocks.

Clastic Sedimentary Rocks

A subgroup of sedimentary rocks composed of rock fragments, such as sandstone and shale.

Metamorphic Rocks

Rocks that have undergone chemical or physical changes from their original form due to water, heat, or pressure.

Hydrometamorphism

The change in rock form caused by the influence of water.

Thermometamorphism

The change in rock form caused by the influence of heat.

Dynamometamorphism

The change in rock form caused by the influence of pressure.

Gneiss

A metamorphic rock formed from granite.

Quartzite

A metamorphic rock formed from sandstone.

Minerals

Naturally occurring, homogeneous elements or inorganic compounds having a definite chemical composition.

Primary Minerals

The original components of an igneous rock.

Secondary Minerals

Minerals resulting from the decomposition or reprecipitation of the products of decomposition of primary minerals.

Dokuchaiev (1900)

Considered the Father of soil science, he defined soil as a natural body composed of mineral and organic constituents with a definite genesis.

Solum

The Latin word for 'the floor' from which the term soil is derived.

Solid Phase of Soil

The soil component consisting of inorganic mineral matter (approx. $45\,\%$) and organic matter (approx. $5\,\%$).

Liquid Phase of Soil

Commonly known as soil water, it is an aqueous solution of salts occupying $40-50\,\%$ of the bulk volume of soil pores.

Gaseous Phase of Soil

Known as soil air, it consists of air-filled pores where the concentration of carbon dioxide is much higher than in atmospheric air.

Land

The total natural environment of the areas of the earth not covered by water, including soil, organisms, air, water bodies, and rocks below.