Soil Science

• Critical Zone: The portion of the planet extending from the top of the tallest vegetation to the bottom of groundwater, where various components interact to create life-essential resources for the planet
• Decomposition: The process by which once-living organisms break down, contributing organic compounds to water in contact with bedrock
• Infiltrate: The process where precipitation penetrates into the soil, either to be retained for plant root uptake or to percolate downward under gravity
• Percolation: The process by which water moves vertically through the soil under the influence of gravity, contributing to groundwater recharge and influencing the movement of water within the earth's subsurface
• Aeration: The presence of air or oxygen in the soil, facilitating the movement of oxygen through soils consumed by roots and heterotrophic microorganisms
• Anaerobic: Conditions where excessive soil wetness hinders gas exchange, leading to a lack of oxygen
• Geological Erosion: The process where rocks and minerals exposed to the near-surface environment become unstable and weather into unconsolidated material, contributing to soil formation
• Sediment: Material formed by the deposition of weathered rocks and minerals, which may eventually become buried and transform back into rock
• Evapotranspiration: The combined process of water evaporation from plant and soil surfaces, representing the total water loss from the soil-plant system to the atmosphere
• Surface Reflection: The bouncing back of solar radiation from the surface of the soil or other objects, contributing to the loss of heat energy
• Humus: A stable form of soil organic carbon resulting from the decomposition of organic matter, contributing to soil fertility and characterized by dark color
• Detritus: The remains of once-living organisms, such as plant material or organic matter, which undergo decomposition and contribute to the organic content of the soil
• Soil Food Web: A complex network of interactions among organisms in the soil, including primary producers, consumers, and decomposers, where energy and nutrients are transferred through various trophic levels
• Nutrient Losses: Processes through which nutrients are lost from ecosystems, including water runoff, deep leaching, soil erosion, and volatilization
• Volatilization: The process in soil science where gaseous forms of nutrients are converted from a solid or liquid state into a vapor or gas and released into the atmosphere
• Unconsolidated Porous Medium: A material, such as soil, composed of small, separate particles (mineral and organic) that are not compacted or cemented together, allowing the presence of spaces or pores between the particles
• Diurnal Cycles: Variations in temperature within a 24-hour period, reflecting changes in soil conditions during daylight hours and darkness
• pH Buffering: The ability of the soil to resist changes in pH, influencing nutrient retention and overall soil stability for living organisms
• Colloid Charges: The electric charge carried by soil particles, influencing pH buffering, nutrient retention, and overall soil stability for living organisms
• Ecosystem Services: The economic benefits provided by soil, including water availability, cleanliness, enhanced soil biological activity, and support for plant and animal biodiversity.
• Geophagia: The practice of eating earthy substances, often associated with certain cultural or nutritional practices.
• Geologist: A scientist who studies the Earth's structure, composition, and processes, including the formation and characteristics of rocks, minerals, and soils.
• Pedologist: A scientist specializing in the study of soils, including their formation, classification, and mapping.
• Soil Health: The overall well-being and functionality of soil, reflecting its ability to sustain plant and animal life, support biodiversity, and provide ecosystem services.
• Soil Horizon: Distinct layers in the soil, parallel to the land surface, exhibiting variations in composition and properties.
• Soil Orders: The highest category in the soil classification system, representing a broad level of soil classification based on characteristics such as soil composition, temperature, and moisture.
• Heterotrophic Microorganisms: Organisms that obtain their energy by consuming organic substances produced by other living organisms.
• Thermal Exchange: The transfer of heat energy between the soil and its surroundings, involving processes such as the flow of heat across the soil surface and influencing temperature variations.
• Dust Bowl: A severe environmental disaster in the 1930s, marked by extensive wind erosion and dust storms in the Great Plains of the United States, highlighting the consequences of poor soil management practices.
• Electrostatic Charge: The electric charge carried by the surfaces of soil colloids; these charges can be either positive or negative and are influenced by the nature of the colloids and soil pH.
• Classification Schemes: Systems or methods for categorizing and organizing objects or concepts based on their characteristics.
• Specific Surface Area: The surface area per unit mass of a particle collection, often measured in cm² per gram or m² per kilogram.
• Flocculation: The process of bringing together small particles to form larger aggregates, often facilitated by certain ions.
• Aggregation: The formation of groupings of soil particles that are bound to each other more strongly than to surrounding particles.
• Granular Structure: Soil structure characterized by the presence of well-formed, rounded aggregates, resembling clusters of cereal.
• Blocky Structure: Soil structure with block-like aggregates, often found in well-developed soil B-horizons.
• Prismatic Structure: Soil structure appearing as a collection of vertical columns, resembling French baguettes.
• Platy Structure: Soil structure with flattened, plate-like aggregates, often causing poor drainage and aeration.
• Massive Structure: Soil structure where virtually all particles are tightly cemented, lacking separating cracks or fissures.
• Single-Grained Structure: Soil structure in very sandy soils where each particle acts independently, not forming aggregates.