Principles of Soil Science – Chapter I: Soil as a Natural Body

Vocabulary flashcards covering fundamental terms, disciplines, components and key historical concepts from Chapter I of the Principles of Soil Science lecture.

A living, dynamic three-dimensional system that develops at the interface of atmosphere and lithosphere under the influence of climate, organisms, relief, parent material and time, and supports plant growth.

Soil

The branch of soil science that studies the origin, classification and description of soils as natural bodies, without primary concern for their practical use.

Pedology

The branch of soil science that studies soils in relation to higher plants, focusing on properties affecting crop production and ways to conserve or improve productivity.

Edaphology

A scientist who examines and classifies soils in their natural environment from a pedological perspective.

Pedologist

A soil scientist who evaluates soil properties for plant production and works to enhance soil fertility and conservation.

Edaphologist

The global scientific organization of soil scientists; a full member of the International Council for Sciences.

International Union of Soil Science (IUSS)

The science that deals with soil as a natural resource, encompassing its genesis, classification, physical, chemical, biological and fertility properties, and their management for crop production.

Soil Science

The discipline concerned with the nutrient-supplying capacity of soils.

Soil fertility

The study of soil’s chemical constituents, properties and reactions.

Soil chemistry

The study of the physical properties and processes of soils.

Soil physics

The branch that investigates soil microorganisms, their populations, classifications and roles in biochemical transformations.

Soil microbiology

The practice and study of protecting soil against physical erosion and chemical deterioration.

Soil conservation

The inorganic solid portion of soil, comprising about 45 % of soil volume.

Mineral matter

Plant and animal residues in various stages of decomposition, making up roughly 5 % of soil volume.

Organic matter

The voids between soil particles, about 50 % of soil volume, occupied by air and water.

Pore space

The air within soil pores; lower in oxygen and higher in carbon dioxide than atmospheric air due to microbial respiration.

Soil air

Water held in soil pores, generally richer in dissolved solutes than surface waters; its entry displaces pore air.

Soil water

Soil separate with particle diameters 2.0–0.05 mm; low surface area, high drainage and aeration, but low water-holding capacity.

Sand

Soil separate with particle diameters 0.05–0.002 mm; smooth feel, little stickiness, minor contribution to fertility.

Silt

Soil separate < 0.002 mm; high surface area, sticky when wet, high nutrient and water adsorption, often plate-shaped and negatively charged.

Clay

Minerals that have persisted with little chemical alteration since rock formation; dominate sand and silt fractions (e.g., quartz).

Primary minerals

Minerals formed by weathering of primary minerals; common in clay fraction and include many nutrient-adsorbing clays.

Secondary minerals

A fundamental principle of soil physics, formulated by Henri Darcy, describing water flow through porous media.

Darcy’s law

Von Liebig’s principle stating that plant growth is limited by the scarcest essential nutrient.

Law of Minimum

H. Jenny’s equation expressing soil as a function of climate, organisms, relief, parent material and time.

Factors of Soil Formation (s = f (cl, o, r, p, t))

The system introduced by V. V. Dokuchaev to designate major soil layers: A (topsoil), B (subsoil), C (parent material).

ABC horizon nomenclature

Key roles include anchoring plants, mediating air and water circulation, storing water and nutrients, housing microorganisms, regulating ecosystems, supporting engineering works and preserving cultural heritage.

Functions of soil