SOIL CHEMISTRY
Page 1: Overview of Soil Chemistry
References:
Brown, et al. 2018. Chemistry for Engineering students. Cengage Learning
Petersen, et al. 2017. Physical Geography. Cengage Learning
Topics Covered:
Formation of Soil
Elements/Minerals in the Lithosphere
Methods of Solid Waste Disposal
Chemistry of the Environment
Page 2: Soil Horizons and Course Outcomes
Soil Horizons:
0" to 2" (A Horizon)
10" (B Horizon)
30" (C Horizon)
48" (D Horizon)
Course Outcome:
CO3: Discuss chemical processes occurring in the environment
Page 3: Importance of Soil
Critical Resource:
Soil is essential alongside air, water, and sunlight for life on Earth.
Challenges:
Threatened by erosion, pollution, construction, etc.
Functions:
Provides nutrients that support life forms.
Page 4: Characteristics of Soil
Dynamic Natural Body:
Supports vegetation and contains chemical solutions, gases, organic matter, flora, and fauna.
Processes Affecting Soil:
Influenced by climate, land configuration, vegetative cover, and animal activities.
Page 5: Integration in Earth’s Subsystems
Subsystem Integration:
Soil reflects atmospheric, hydrologic, lithologic, and biotic conditions.
Pedosphere:
Soils may be considered distinct systems due to their integration of subsystems.
Page 6: Soil and Living Organisms
Habitat for Organisms:
Soil is home to diverse organisms crucial for its development and characteristics.
Impact of Human Activities:
Population growth affects soil negatively through pollution and erosion.
Page 7: Soil Ecosystem Services
Ecosystem Services:
Provided by soils as outlined by Food and Agriculture Organization of the United Nations.
Page 8: Major Components of Soil
Four Components:
Inorganic materials
Soil water
Soil air
Organic matter
Page 9: Inorganic Materials in Soil
Content of Soil:
Contains insoluble rock fragments and soluble minerals for chemical exchange.
Importance of Elements:
Essential elements: carbon, hydrogen, nitrogen, and trace minerals.
Page 10: Chemical Constituents Sources
Sources:
Breakdown of rocks through weathering, deposits in sediments, soluble minerals from water.
Page 11: Organic Activities in Soil
Activities:
Disintegrate rocks, form compounds, and release gases.
Soil Fertilization:
Adding nutrients for supporting plant growth potential.
Page 12: Soil Water Introduction
Primary Source:
Soil water originates from precipitation.
Functions:
Acts as a catalyst in chemical reactions and nutrient provider for vegetation.
Page 13: Reinforcement of Soil Water
Soil Water:
Presence and dynamics continue from previous discussions on functions and roles in soil dynamics.
Page 14: Capillary Water
Definition:
Adheres to soil particles, serving as a stored water supply for plants.
Movement:
Can migrate laterally and upward to supply moisture during dry periods.
Page 15: Evaporation of Capillary Water
Effects:
Evaporation leads to mineral deposits in topsoil, which may be harmful to vegetation.
Formation of Caliche:
Caliche can form and hinder water percolation.
Page 16: Hygroscopic Water
Nature:
Bound to soil particles, it does not supply moisture to plants.
Page 17: Gravitational Water
Definition:
Percolates downward due to gravity, aiding nutrient distribution in deeper soil layers.
Page 18: Functions of Gravitational Water
Dissolves Minerals:
Nutrient leaching through percolation can deplete topsoil in high rain regions.
Page 19: Different Depositional Processes
Hydrological Distinctions:
Compare deposition differences between capillary and gravitational processes.
Page 20: Eluviation and Illuviation
Definitions:
Eluviation: Downward removal of soil components by water.
Illuviation: Deposition of these materials lower in the soil profile.
Page 21: Changes in Soil Texture
Texture Alterations:
Eluviation leads to coarser topsoil, reducing its ability to retain water.
Page 22: Stratification of Soil
Layering Changes:
Fine particles are deposited at lower levels, contributing to soil stratification.
Page 23: Soil Air Composition
Voids in Soil:
Air in soil is diverse in composition, having unique characteristics compared to atmosphere.
Page 24: Importance of Soil Air
Microbial Requirements:
Soil air is crucial for microorganisms and plant roots; saturated soils hinder air access.
Page 25: Organic Matter in Soil
Definition:
Humus is decomposed organic matter crucial for nutrient availability and soil health.
Page 26: Soil Biodiversity
Life in Soil:
Diverse organisms enhance soil condition, contribute to nutrient cycling and stability.
Page 27: Soil Variations and Ecosystem Relationships
Soil and Vegetation:
Soils vary in relation to local vegetation and climate patterns.
Page 28: Soil Properties Indicating Productivity
Key Properties to Assess:
Color, texture, structure, acidity, moisture capacity.
Page 29: Color as an Indicator
Color Variation:
Soils range in color based on composition, affecting identification and fertility assessment.
Page 30: Humus and Soil Color
Humus Impact:
Dark-colored soils often indicate high humus content, which correlates with fertility.
Page 31: Iron in Soil Color
Iron Indicators:
Dark, red, or yellow soils often point to iron's presence or depletion in wet or dry climates.
Page 32: Soil Characterization
Key Characteristics:
Color, texture, composition details for proper assessment and classification.
Page 33: Soil Texture Understanding
Definition:
Soil texture refers to particle sizes and impacts water retention and root growth.
Page 34: Classifying Soil Texture
Distribution:
Triangular graphs display the proportion of each particle size in soil classification.
Page 35: Loamy Soil Properties
Ideal Soil for Crops:
Loams contain a balanced mix of textures promoting fertility and efficient plant growth.
Page 36: Moisture Retention and Soil Texture
Retention Dynamics:
Soil texture influences water retention, thus impacting plant growth and agricultural success.
Page 37: Soil Peds and Structure
Definition of Soil Structure:
Soil is structured into peds affecting porosity and permeability vital for water and root interaction.
Page 38: Factors Influencing Soil Structure
External Influences:
Moisture and human factors like cultivation impact the development and maintenance of soil structure.
Page 39: Count of Soil Structures
Classification of Soil Structures:
Various types classified based