Soil-science

Principles of Soil Science

• Understand the basic branches of soil science, including soil genesis, chemistry, mineralogy, microbiology, physics, and fertility.

Solar Nebular Hypothesis

• States that the solar system developed from an interstellar cloud of dust and gas (nebula) that collapsed and condensed.

Earth

• Earth's crust thickness ranges from 5–40 km, part of the lithosphere (average 100 km).

• Total distance from ground surface to Earth's center is approximately 6370 km.

• Soils form a thin, fragile skin on Earth’s surface, necessitating special care.

Atmosphere

• Mixture of gases surrounding Earth vital for life.

• Protects from UV radiation, traps heat, and regulates temperatures.

Biosphere

• Encompasses areas of the Earth where life exists, including various ecosystems from deep roots to ocean trenches.

Lithosphere

• The solid outer part of Earth, includes upper mantle and crust.

Hydrosphere

• Total amount of water on the planet (surface, underground, and air).

Pedosphere

• The interface where lithosphere, atmosphere, hydrosphere, and biosphere intersect.

Soil Definition

• Biologically active outer layer of Earth's crust, thickness varies from centimeters to decameters.

Soil as Natural Bodies in Ecosystem

• Forms on land, transition zones, and underwater, consisting of minerals and organic substances (humus).

• Minerals and humus create a specific soil structure with pores filled with water and air.

Functions of Soil in Ecosphere

• Populated surface area involved in cycles of energy, air, water, and substances.

Soil as an Open System Worth Protecting

• Nutrient pool for plants, acts as filter and storage, susceptible to degradation (erosion, compaction, etc.).

Soil Science Overview

• Studies the properties, functions, development, and distribution of soils; addresses soil contamination and damage.

Fields of Specialization in Soil Science

• Soil Genesis/Development (Pedology): Factors and processes of soil formation integrating various scientific fields.

• Soil Chemistry: Interactions of solid, liquid, and gaseous phases of soil.

• Soil Mineralogy: Structural chemistry of solid soil components.

• Soil Microbiology: Biochemical reactions by microorganisms in soil.

• Soil Physics: Study of soil characteristics and processes caused by physical forces.

• Soil Fertility: Quality and nutrients available for plant growth.

Approaches in the Study of Soil

• Edaphological Approach: Studies soil in relation to plant growth.

• Pedological Approach: Examines soil origins and classifications.

Soil Morphological Characteristics

• Focuses on observable attributes of soil profiles and horizon arrangements.

Observations in Soil Profiles

• Profile: vertical cut in soil; Pedon: 3D unit capturing soil variability.

Soil Morphology Types

• Profile Morphology: Macroscopic methods for horizon characterization.

• Micromorphology: Microscopic analysis of soil thin sections.

Subordinate Features of Horizons

• Various lowercase letters designate specific master horizon layers (e.g., organic material, gleying, etc.).

Classification of Minerals

• Primary Minerals: Formed at high temperatures and pressures without chemical alteration.

• Secondary Minerals: Formed through weathering of primary minerals at Earth's surface conditions.

Rock Definition and Types

• Rock: natural substance with solid crystals of different minerals.

• Igneous Rock: Formed from molten rock cooling.

  • Intrusive: Crystallizes below surface (e.g., granite).

  • Extrusive: Erupts to surface (e.g., basalt).

• Sedimentary Rock: Formed by deposition and cementation at Earth’s surface, can include organic, clastic, and chemical types.

• Metamorphic Rock: Formed under heat and pressure, can be foliated (e.g., gneiss) or non-foliated (e.g., marble).

Rock Cycle

• Understanding the continuous transformation among igneous, sedimentary, and metamorphic rock forms.