Introduction to Soil ScienceSC-111 3(2+1)

Prepared by ProfessorDr. B.K. Pany

Course DetailsModule-1 (15 classes)

• Soilscience and its scope• Pedological and edaphological concepts,• Origin of the earth,• Earth’s crust: Composition:• Rocks and minerals,• Weathering, soil formation factors and processes,• Components of soils,• Soil profile,• Soil physical properties, like• Soil texture, textural classes, particle size analysis,• Soil structure, classification, soil aggregates, significance, soil

consistency, soil crusting,• Dencities of soil:Bulk density and particle density of soils , porosity,

their significance and manipulation,• Soil compaction, soil colour,• Elementary knowledge of soil classification and soils of India;

Course Details...Module-1I (9 classes)

• Soil water,

• Retention and potentials of soil water,

• Soil moisture constants,

• Movement of soil water, Infiltration, Percolation,Permeability, Drainage,

• Methods of determination of soil moisture.

• Thermal properties of soil, soil temperature,

• Soil air, Gaseous exchange,

• Influence of soil temperature and air on plant growth;

• Soil colloids,

• Properties, nature, Types & significance;

• Layer silicate clays, their genesis and sources of charges,

Course Details...Module-1II (8 classes)

• Adsorption of ions,

• Ion exchange, CEC and AEC ,

• Factors influencing ion exchange and itssignificance.

• Soil organic matter, composition, decomposability,

• Humus, Fractionation of organic matter,

• Carbon cycle, C:N ratio,

• Soil biology, Biomass,

• Soil Organisms & their beneficial & harmful roles.

PracticalModule-1 (10 classes)

• Determination of Bulk density• Determination of Particle density,• Aggregate analysis,• Soil strength,• Soil moisture determination,• Soil moisture constants-Field capacity,• Infiltration rate,• Water holding capacity,• Soil Texture : Mechanical analysis-• Soil temperature,• Analytical chemistry-Basic concepts, Techniques & calculations-

Module-1I (6 classes)• Collection & processing of soil for analysis-• Organic carbon, • pH and EC, • Soluble cations and anions-• Study of a soil profile-• Identification of rocks and minerals.

L-1• Introduction to soil science,

• Fields of application in soil science

• Soil

• Function of Soil and

• Major environmental issues

• Scope of soil science,

• Pedological and edaphologicalconcepts,

Soil

•Man is dependent on soils and

• To certain extent good soilsare dependent upon manand the use he makes ofthem

Soil Science

Soil science

• Soil science is the study of soil as a naturalresource on the surface ofthe earth including soil formation,classification and mapping; physical,chemical, biological, and fertilityproperties of soils; and these properties inrelation to the use and management ofsoils for crop production.

Fields of application in soil science

1.Soil survey 2.Soil management

3.Standard methods

of analysis

4.Soil fertility

/ Nutrient management

5.Ecosystem studies 6.Climate change

7.Watershed and wetland

studies

8.Pedotransfer function

Soil

• Soil is a dynamic natural body developedas a result of pedogenic processes duringand after weathering of rocks, consistingof mineral and organic constituents,possessing definite chemical, physical,mineralogical and biological properties,having a variable depth over the surfaceof the earth and providing a medium forplant growth for land plants

SOIL...• Soils lie at the interface of Earth's ,

atmosphere, biosphere, hydrosphere and lithosphere and interact with the hydrosphere and atmosphere.

• To understand soil requires some knowledge of metrology, climatology, ecology, biology, Hydrology, geomorphology, geology and many other earth sciences and natural sciences

• Soils play a vital role in the quality of our environment.

• For example, soil impact the quality and quantity of our food, and serve as foundations of our structures,

SOIL...• Soil can be a source, a sink, or an interacting

medium for many nutrients, as well ascontaminants that impact humans, plants,wildlife, and other organisms.

• An understanding of soil properties andprocesses is therefore critical to evaluate soilmanagement processes.

• The word “Soil” is derived from Latin word‘Solum’ means ‘Floor’ or ‘Ground’ “With outlife, there is no soil and without soil, there is nolife on the earth planet”

Function of SoilSoils perform six key functions in the global ecosystem.

Soil serves as a• Medium for plant growth (provides nutrients), it store

and supply nutrients to plants.• As an anchor for plant roots enabling plants to stand

erect• Regulator of water supplies (water holding tank, it

absorb and store the moisture for later use),• Recycler of raw materials ( Decomposition)• Habitat for soil organisms• Landscaping and engineering medium (Soils are the base

material for roads, homes, buildings, and otherstructures) and ,

• It provide space for air which creates healthyenvironment)

Major environmental issuesMajor environmental issues addressed will be:

• Soil stability and erosion

• Soil hydrology

• Biodiversity of soils

• Plant nutrition

• Quality of agricultural crops

• Pollution by trace elements and nutrients in excess

• Climate change and global warming

• Water quality

• Role of micro and meso faune in soil

Scope of Soil Science• Soil Science has several well defined and developed

disciplines. Scope of soil Science is reflected throughthese disciplines.

1. Soil physics: Involves the study of physical propertiesof soils as well as the measurements and control ofphysical processes that takes place in and through thesoil

2. Soil chemistry: Chemical constituents, chemical properties and the chemical reactions

3. Soil biology: Soil biology deals with soil ecology -micro organisms, its population, classification, its rolein transformations

Scope of Soil Science….4. Soil mineralogy: Soil mineralogy deals with the

minerals (primary rock minerals and secondaryminerals present in soil and their contributionto the chemistry, physics, biology and fertilityof soil and their relation to genesis of soil

5.Soil fertility: Soil fertility deals with the nutrientstatus or ability of soil to supply nutrients forplant growth under favorable environmentalconditions such as light, temperature andphysical conditions of soil. (Nutrient supplyingproperties of soil)

Scope of Soil Science….

6. Soil genesis and classification (Pedology): Itdeals with weathering of rocks and minerals,factors and processes of soil formation, andclassification of soils in a recognized system

7. Soil survey: It is the systematic examination ofsoil in the field and laboratories, theirdescription and classification, the mapping ofkinds of an area, and also interpretation of soilsaccording to adaptability to various crops andtheir productivity under different managementsystems.

Scope of Soil Science….8. Soil Technology: It is an applied science

and deals with the principles and practicesof soil erosion and conservation, andmanagement of problem soils, viz. saline,sodic (alkali), acid, waterlogged and otherdegraded soils

9. Soil conservation: Dealing with protectionof soil against physical loss by erosion oragainst chemical deterioration i.e.excessive loss of nutrients either natural orartificial means.

Pedological and edaphological concepts

• Approaches of Soil Study: Two approaches (Concepts)

• There are two main branches/ divisions of soil science,

• Pedology

• Edaphology

(a) Pedology(a) Pedology (From Greek word pedon, means soil or

earth).

• Pedology is a branch of soil science that focusing soil as a natural body on the formation (pedogenesis-soil genesis), morphology, classification (or studies the soil profile or solum in its natural setting) and distribution patterns of soils worldwide that have developed along with broader landforms, biogeochemical environments, and habitats of living organisms of soils as bodies within the natural landscape.

• A soil: A soil (means- pedology) is studied as a naturalbody from the point of view of pedology (formation,chemistry, morphology and classification of soil), and asa part of the landscape

(a) Pedology...• Pedogenic (soil-forming) processes act to both

create and destroy order within soils; theseprocesses can proceed simultaneously.

• The resulting soil profile reflects the balance ofthese processes, present and past.Pedological Approach

• The origin of the soil, its classification and itsdescription are examined in Pedology.

• Pedology is the study of soil as a natural body anddoes not focus on the soil’s immediate practicaluse.

• A pedologist studies, examines and classifies soilas they occur in their natural environment.

(b) Edaphology(b) Edaphology(from Greek word edaphos, means soilor ground and logia means science or study)

• Edaphology is concerned with the influence of soils asa medium of growth for living things, particularlyplants, fungi, and other living things

• The term Edaphology is also applied to the study ofhow the soil influences human’s use of the land forgrowing plants and overall use of the land of the man.

• General subfields within edaphology are agriculturalsoil science and environmental soil science.

• Soil: ( Sudy of soil means edaphology) Soil is amaterial who’s chemical, physical, mineralogical andbiological characteristics are studied in relation toplant growth or to any other use (edaphology)

Edaphological Approach• Edaphology, studies the soil from the standpoint of crop

production of higher plants.• Edaphologists examin and consider the various

properties of soil in relation to plant production (food,fiber and timber crops)

• Edaphologists also studies the causes of the variation insoil productivity and find means of conserving andimproving this productivity.

• From the edaphological viewpoint, the soil has certainfunctions in relation to plant life and these are:– It serves as a medium in which seeds can germinate or

tubers and cuttings can start to take roots;– It provides support for vertically growing plants;– It serves as an absorber of moisture for the use of plants;

and– It furnishes most of the nutrients which sustain plant life.