Category: Introduction to Soil Science Notes

Introduction to Soil Science Notes

Soil – Pedological and Edaphological concepts
Origin of the Earth
Age of the Earth
Interior and Exterior of Earth
Rocks and minerals
Sedimentary rocks
Metamorphic rocks
Igneous rocks
Minerals
Physical properties of minerals
Formation of secondary minerals, Clay minerals & Amorphous minerals
Weathering – Soil Formation Factors and Processes – Physical Weathering
Weathering – Soil Formation Factors and Processes – Chemical Weathering – Biological Weathering
Factors Affecting Soil Formation
Soil Forming Processes
Soil Profile
Soil Physical Properties
Particle Size Distribution-Determination
Soil structure – Classification
Factors Affecting Soil Structure
Soil Aggregates-Significance-Soil Consistency-Soil Crusting
Bulk density and particle density of soils & porosity
Soil Compaction
Soil Water
Retention of Water by Soil
Soil Moisture Constants
Movement of Soil Water- Infiltration, Percolation, Permeability
Drainage – Methods of determination of soil moisture
Thermal properties of soils – Soil temperature – Soil air – Gaseous exchange – Influence of soil temperature and air on plant growth
Soil colloids – Properties, nature, types and significance
Types of Soil Colloids
Layer silicate clays – Genesis and classification
Ion exchange reactions – Cation exchange, anion exchange and base saturation – significance
Factors Influencing CEC
Soil Organic Matter – Composition, Decomposition, Mineralization and Immobilization
Humus – Fractionation of Organic Matter
Carbon cycle – CN ratio
Soil Biology

Weathering – Soil Formation Factors and Processes – Physical Weathering

Weathering – Soil formation factors and processes Weathering A process of disintegration and decomposition of rocks and minerals which are brought about by physical agents and chemical processes, leading to the formation of Regolith (unconsolidated residues of the weathering rock on the earth’s surface or above the solid rocks). (OR) The process by which the […]

Weathering – Soil Formation Factors and Processes – Chemical Weathering – Biological Weathering

Chemical Weathering Decomposition of rocks and minerals by various chemical processes is called chemical weathering. It is the most important process for soil formation. Chemical weathering takes place mainly at the surface of rocks and minerals with disappearance of certain minerals and the formation of secondary products (new materials). This is called chemical transformation. 1. […]

Thermal properties of soils – Soil temperature – Soil air – Gaseous exchange – Influence of soil temperature and air on plant growth

Thermal properties of soils – Soil temperature – Soil air – Gaseous exchange – Influence of soil temperature and air on plant growth a Soil temperature – Soil air – Gaseous exchange Soil Temperature Soil temperature is an important plant growth factor like air, water and nutrients. Soil temperature affects plant growth directly and also […]

Soil Water

Soil Water Plants absorb some water through leaf stomata (openings), but most of the water used by plants is absorbed by the roots from the soil. For optimum water used, it is vital to know how water moves into and through the soil, how the soil stores water, how the plant absorbs it, how nutrients […]

Soil structure – Classification

Soil structure – Classification Soil conditions and characteristics such as water movement, heat transfer, aeration, and porosity are much influenced by structure. In fact, the important physical changes imposed by the farmer in ploughing, cultivating, draining, liming, and manuring his land are structural rather than textural. Soil particles may be present either as single individual […]

Soil Profile

Soil profile The Soil Survey Staff (1960) defined the soil individual or polypedon (Pedon, Ground) as a natural unit of soil that differs from its adjoining unit on the landscape in one or more properties. The term pedon has been proposed for small basic soil entities that are part of the continuum mantling the land. […]

Soil Physical Properties

Soil physical properties Physical properties (mechanical behaviour) of a soil greatly influence its use and behaviour towards plant growth. The plant support, root penetration, drainage, aeration, retention of moisture, and plant nutrients are linked with the physical condition of the soil. Physical properties also influence the chemical and biological behaviour of soil. The physical properties […]

Soil Organic Matter – Composition, Decomposition, Mineralization and Immobilization

Soil organic matter – composition, decomposition, mineralization and immobilization SOIL ORGANIC MATTER Substances containing carbon are organic matter. Soil organic matter consists of decomposing plant and animal residues. It also includes substances of organic origin either leaving or dead. Soil organic matter plays an important role in deciding / maintaining soil physical conditions. It also […]

Soil Moisture Constants

Soil Moisture Constants Earlier classification divided soil water into gravitational, capillary and hygroscopic water. The hygroscopic and capillary waters are in equilibrium with the soil under given condition. The hygroscopic coefficient and the maximum capillary capacity are the two equilibrium points when the soil contains the maximum amount of hygroscopic and capillary waters, respectively. The […]