• No results found

Soils - What are they?

N/A
N/A
Protected

Academic year: 2023

Share "Soils - What are they?"

Copied!
14
0
0

Loading.... (view fulltext now)

Full text

(1)

SOIL

ENGG POINT OF VIEW

(2)

Soils - What are they?

Particulate materials

- Sedimentary origins (usually) - Residual

Wide range of particle sizes

- larger particles: quartz, feldspar - very small particles: clay minerals

Voids between particles

(3)

Definitions

Geologic definition: Loose surface of the earth as distinguished from solid bedrock;

support of plant life not required.

Traditional definition: Material which nourishes and supports growing plants;

includes rocks, water, snow, air.

Component definition: Mixture of mineral matter, organic matter, water, and air.

(4)

Soil Taxonomy definition: Collection of

natural bodies of the earth’s surface, in places modified or even made by man or earthy

materials, containing living matter and

supporting or capable of supporting plants out of doors.

Its upper limit is air or shallow water and its lower limit is the depth to which soil

weathering has been effective.

(5)

SOIL

• As a portion of the landscape: Collection of natural bodies occupying portions of the earth’s surface that support plants and that have properties due to the integrated effect of climate and living matter, acting upon parent material, as conditioned by relief, over periods of time.

(6)

Air 25%

Mineral Matter 45%

Water 25%

Organic Matter 5%

SOIL SOIL

Component definition: Mixture of mineral Component definition: Mixture of mineral matter, organic matter, water, and air.

matter, organic matter, water, and air.

Example:Example:

(7)

Soil Forming Processes

• Translocations

• Transformations

• Additions

• Losses

(8)
(9)

• Mineral matter

• Organic matter

• Air

• Water

Major Components

(10)

Three Fractions of Mineral Matter

• Sand

• Silt

• Clay

(11)

Granular

Platy

Blocky

(Angular) (Subangular)

Wedge

Columnar Prismatic

Examples of Soil Structure

Examples of Soil Structure

(12)

Aspects of Soil Structure

• The arrangement into aggregates of desirable shape and size

• The stability of the aggregate

• The configuration of the pores

(13)

Factors that Affect Aggregate Stability

• Kind of clay

• Chemical elements associated with the clay

• Nature of the products of decomposition or organic matter

• Nature of the microbial population

(14)

Factors that Affect Soil Structure

• Amount of organic matter

• Freezing and thawing

• Wetting and drying

• Action of burrowing organisms

• Growth of root systems of plants

References

Related documents

SaLt MaRSheS The latest data indicates salt marshes may be unable to keep pace with sea-level rise and drown, transforming the coastal landscape and depriv- ing us of a

These gains in crop production are unprecedented which is why 5 million small farmers in India in 2008 elected to plant 7.6 million hectares of Bt cotton which

INDEPENDENT MONITORING BOARD | RECOMMENDED ACTION.. Rationale: Repeatedly, in field surveys, from front-line polio workers, and in meeting after meeting, it has become clear that

3 Collective bargaining is defined in the ILO’s Collective Bargaining Convention, 1981 (No. 154), as “all negotiations which take place between an employer, a group of employers

To break the impasse, the World Bank’s Energy Sector Management Assistance Program (ESMAP), in collaboration with Loughborough University and in consultation with multiple

Angola Benin Burkina Faso Burundi Central African Republic Chad Comoros Democratic Republic of the Congo Djibouti Eritrea Ethiopia Gambia Guinea Guinea-Bissau Haiti Lesotho

3.6., which is a Smith Predictor based NCS (SPNCS). The plant model is considered in the minor feedback loop with a virtual time delay to compensate for networked induced

1 For the Jurisdiction of Commissioner of Central Excise and Service Tax, Ahmedabad South.. Commissioner of Central Excise and Service Tax, Ahmedabad South Commissioner of