;

Soils = soilscape = geopedological setting

OUTLINE

• INTRODUCTION

• THEORETICAL BACKGROUND AND ILLUSTRATIVE EXAMPLES

• CONCLUSION

•INTRODUCTION: Soil definition

• “A natural body consisting of layers (or horizons) of mineral (and/or organic constituents) of variable thickness, which differ from the parent material in their morphological, physical, chemical, and mineralogical properties and their biological characteristics”

S = f (Cl, O, R, P, T,……M)

Definition :A soil = “pedon” is the smallest volume with a surface extent which varies from

about 1 to 10 m²”

Soil sample Pedons/ polypedons in ‘soilscape’

Definition:Pedon / polypedon

• For mapping purposes, similar pedons are pooled together, forming a polypedon, obviously associated with variability, depending on scale

Functions:

What does soil do? 1- Soil provides the required setting for water, nutrient, air, and heat exchange for living organisms.

2- Soil controls the water distribution;affects the movement of soluble materials.

3- Soil regulates biological activity and molecular exchanges among solid, liquid, and gaseous phases.

4- Soil acts as a filter to protect the quality of water, air, and other resources.

What does soil do? 5- Soil provides mechanical support for living organisms and their structures. People and wildlife depend on this function.

6- Soils act:- as an archive (=history book of the landscape), - as a guide, and - as a ‘predictor’

Soils speak out; an account of

the past, present, and future

• THEORETICAL BACKGROUND AND ILLUSTRATIVE EXAMPLES

An account of the past, present, and future

Past Paleoecology

Present Soil Management

Future Soil Degradation/ Conservation

Past:

Paleoecology

History book of the landscape (archive)

Examples of features revealing paleoecology:1. Pedogenic (horizons):

* Anthropic, * Plaggen, etc * Argillic, *Agric, etc2. Geomorphic (features):

* Glacis formation:Tunisia, Morocco

* Travertine (karstic): Iran

1. Pedogenic (horizons)

2. Geomorphic; glacis formation2.1 Tunisian example:

Pedimentation/ planation : in practice, erosional glacis – adjacent to the mountain front— is followed by an accumulation glacis. A fan distinguishes itself from the glacis by being associated with a distributary (dichotomic) drainage pattern .

2. Geomorphic; glacis formation 2.2 Moroccan example

Erosional glacis terraces Accumulation glacis

2. Geomorphic; glacis formation 2.3 Iranian example

Stereogram depicting glacis Pedostratigraphy (approving)

2. Geomorphic featuresKarstic springs; Travertine

Karst spring (dried out) Travertine in scattered patches

Microgram of travertine speciman

Iran:

• A wetter climate, karstic springs where travertine is spread out;

• Once upon a time (27000 yr BP-13000 yr BP) the study area was subject to cycles of erosion and sedimention, also approved by the occurrence of Argillic and Petrocalcic horizon ;

• Aridification has never been as degrading as it is today

Morocco: • Occurrence of Ultisols and Plinthite implies a wetter

and hotter climatic condition• Different vegetation cover

Present:Soil-

management

Present: Soil Management

Guiding features:

*Soil properties (Physico-chemical): particle size class, depth, pH,…… *Position in landscape (Site)

When well managed

Traditional wooden device for plowing; pulled by oxen

When mis-managed

Future:Prediction

”A soil survey describes the characteristics of the soils in a given area, classifies the soils according to a standard system of

classification, plots the boundaries of the soils on a map, and makes predictions

about the behavior of soils.”(SSM, 1993)

Future : Predictionregarding (possible) land degradation

Guiding features:

• Pedon (individual soil body)

• Diagnostic soil characteristics- Abrupt textural change

- COLE (coefficient of Linear Extensibility)

- (Para-) Lithic contact,……..

Change of erosion base-level: gully formation and landslide

Landslide

Bushes hold soils together

The gully

Gully running perpendicular

Landslide

It is clearly seen that the gullyin the bottom of the vale (fig c)is triggering; landslide has occurred once the slope hasbeen de-bushed (cleared)

Fig. c

Gullies formed

Bush land

Cereals

Ploughed for Vine tree plantation

Gully

Gully

Boundary between 2 soil series

Incision (gully) occurs in a joint, the weakest line between two pedons

If you want to conserve the environment

Listen to what soils say

Prevention is better than cure

• CONCLUSION:

Is check-dam solving the problem?!

Slump

Check-dam does not help

The first check dam

Second trial

Water goes like this; neglecting the dam

Rferences

Rosa M.Poch (editor- in- Chief) and Kovda, Irnia and Curtis Monger (Guest editors). 2013.1st volume of the proceedings of the 14th IWMSM.Departament de Medi Ambient i Ciències del Sòl Universitat de Lleida Av. Rovira Roure 191, 25198 Lleida (Catalonia)

Buol, S.W., Hole, F.D., and R.J. McCracken. 1973. Soil Genesis and Classification. The Iowa State University Press, Ames.

Farshad, A. 2006. Introduction to Applied Geomorphology for Soil Scientists (Geopedologists). Lecture-notes, Department of Earth System Analysis (ESA), ITC, Enschede, The Netherlands.

USDA, 1975. Soil Taxonomy, A Basic System of Soil Classification for Making Interpreting Soil Surveys. Soil Survey Staff. Agricultural Handbook No. 436.

Zinck, G.A. 1988/89. Physiography and soils; soil survey courses (Lecture-notes), ITC, Enschede, The Netherlands.