2OUTLINE INTRODUCTION THEORETICAL BACKGROUND AND ILLUSTRATIVE EXAMPLES CONCLUSION
3INTRODUCTION: 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)
4Definition : A soil = “pedon” is the smallest volume with a surface extent which varies from about 1 to 10 m²”Soil samplePedons/ polypedons in ‘soilscape’
5Definition: Pedon / polypedon For mapping purposes, similar pedons are pooled together, forming a polypedon, obviously associated with variability, depending on scale
6Functions: 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.
7What 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’
8Soils speak out; an account of THEORETICAL BACKGROUND AND ILLUSTRATIVE EXAMPLESSoils speak out; an account ofthe past, present, and future
9An account of the past, present, and future Past PaleoecologyPresent Soil ManagementFuture Soil Degradation/ Conservation
132. Geomorphic; glacis formation 2.1 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 .
18Iran:A wetter climate, karstic springs where travertine is spread out;Once upon a time (27000 yr BP 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 todayMorocco:Occurrence of Ultisols and Plinthite implies a wetter and hotter climatic conditionDifferent vegetation cover
23Future: 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)
24Future : Prediction regarding (possible) land degradation Guiding features:Pedon (individual soil body)Diagnostic soil characteristics - Abrupt textural change- COLE (coefficient of Linear Extensibility) - (Para-) Lithic contact,……..
26Change of erosion base-level: gully formation and landslide Bushes hold soils togetherLandslideGully running perpendicularLandslideIt is clearly seen that the gullyin the bottom of the vale (fig c)is triggering; landslide hasoccurred once the slope hasbeen de-bushed (cleared)The gullyFig. c
27Gullies formed Bush land Cereals Boundary between 2 soil series Gully Ploughed for Vine tree plantation
28Incision (gully) occurs in a joint, the weakest line between two pedons
29If you want to conserve the environment CONCLUSION:If you want to conserve the environmentListen to what soils sayPrevention is better than cure
30Is check-dam solving the problem?! Water goes like this; neglecting the damCheck-dam does not helpSlumpSecond trialThe first check dam
33Buol, S. W. , Hole, F. D. , and R. J. McCracken. 1973 Buol, S.W., Hole, F.D., and R.J. McCracken Soil Genesis and Classification. The Iowa State University Press, Ames.Farshad, A Introduction to Applied Geomorphology for Soil Scientists (Geopedologists). Lecture-notes, Department of Earth System Analysis (ESA), ITC, Enschede, The Netherlands.RferencesRosa M.Poch (editor- in- Chief) and Kovda, Irnia and Curtis Monger (Guest editors) st volume of the proceedings of the 14th IWMSM.Departament de Medi Ambient i Ciències del Sòl Universitat de Lleida Av. Rovira Roure 191, Lleida (Catalonia)USDA, Soil Taxonomy, A Basic System of Soil Classification forMaking Interpreting Soil Surveys. Soil Survey Staff. AgriculturalHandbook No. 436.Zinck, G.A. 1988/89. Physiography and soils; soil survey courses (Lecture-notes), ITC, Enschede, The Netherlands.