SCSC 301 Chapter 5
Structure of water: Refers to the arrangement of hydrogen and oxygen atoms in a water molecule, leading to its unique properties.
How this results in water properties: The angular arrangement and polarity of the water molecule confer characteristics like high heat capacity, solvent abilities, and cohesion.
Capillary movement: The movement of water through narrow spaces in soil driven by adhesion and cohesion.
Cohesion & adhesion: Cohesion allows water molecules to stick together, while adhesion refers to the attraction between water molecules and soil particles.
Forces on water: Various forces play crucial roles in regulating water movement.
Gravitational force: The force that pulls water downwards, impacting drainage and movement.
Matric force: Attraction of water to soil particles, influencing how water is retained or released in soil.
Osmotic force: The effect of solute concentrations that attracts water towards areas with higher solute levels.
Soil Water Potential: Represents the potential energy of water in soil, influencing its movement due to gravitational, matric, and osmotic forces.
Soil Water Content (θ): The amount of water present in soil, expressed in volumetric or mass terms.
Types of water flow: Different mechanisms of how water moves through soil.
Saturated flow: Occurs when soil pores are completely filled with water, primarily influenced by gravity.
Unsaturated flow: Involves the movement of water through partially filled soil pores, governed by capillary forces.
Preferential flow: Rapid movement of water through larger pores and channels, bypassing the soil matrix.
Hydraulic Conductivity: The ease with which water can flow through soil pores, influenced by texture and structure.
Infiltration: The process of water entering the soil surface and moving into the soil profile, affected by soil texture and structure.
Percolation: Movement of water downward through soil layers after infiltration.
Textural discontinuities: Changes in soil texture that can affect water movement and retention capabilities.
Soil Wetness Descriptors: Classifications that describe the moisture status of soil, crucial for understanding water availability.
Saturated: Soil condition where all pores are filled with water.
Field Capacity: The maximum amount of water that soil can hold after gravitational drainage.
Permanent Wilting: The point at which plants can no longer extract water from the soil.
Plant Available Water: The water that can be absorbed by plants between field capacity and permanent wilting point.
How plants acquire water: Mechanisms by which plants draw moisture from the soil, mainly through capillary movement and root growth dynamics.
Cheat Sheet
Structure of water: Arrangement of hydrogen and oxygen atoms influencing water's unique properties.
How this results in water properties: Polarity and angular arrangement result in high heat capacity, solvent abilities, and cohesion.
Capillary movement: Movement of water through narrow soil spaces driven by adhesion and cohesion.
Cohesion & adhesion: Cohesion refers to water molecules sticking together; adhesion is the attraction between water and soil particles.
Forces on water: Key forces influencing water movement:
Gravitational force: Pulls water downwards, affecting drainage.
Matric force: Attraction of water to soil particles, influencing retention.
Osmotic force: Draws water towards areas of higher solute concentration.
Soil Water Potential: Potential energy of water in soil influencing movement due to gravitational, matric, and osmotic forces.
Soil Water Content (θ): Amount of water in soil, expressed volumetrically or as mass.
Types of water flow:
Saturated flow: Occurs when soil pores are full of water, influenced by gravity.
Unsaturated flow: Involves water movement through partially filled soil pores, governed by capillary forces.
Preferential flow: Rapid movement through larger pores, bypassing the soil matrix.
Hydraulic Conductivity: Ease of water flow through soil pores, affected by texture and structure.
Infiltration: Water entering and moving into the soil profile, influenced by soil texture and structure.
Percolation: Downward movement of water through soil layers post-infiltration.
Textural discontinuities: Changes in soil texture affecting water movement and retention.
Soil Wetness Descriptors: Classifications regarding moisture status in soil:
Saturated: All pores filled with water.
Field Capacity: Maximum water soil can hold after drainage.
Permanent Wilting: Point where plants cannot extract water.
Plant Available Water: Water between field capacity and permanent wilting.
How plants acquire water: Mechanisms of drawing moisture, mainly through capillary movement and root dynamics.