Pedology, soil science

The lectures aim to present the basic concepts for describing, classifying, and characterizing soils: their different constituents (minerals, clays, organic matter, living organisms), their physical properties (grain size, texture, structure), chemical properties (clay-humic complex, CEC, oxidation-reduction), and biological (horizons and humus, root system, plant nutrition, role of bacteria, C/N ratio, soil fauna). We will study the factors involved in soil formation (climate, parent rock, living organisms, relief, time), the different processes of soil formation and evolution (weathering, humification, leaching, podzolization, pedoturbation, ferrallitization, etc.), the major soil classification systems, and the distribution of soils around the world. This scientific foundation will enable us to address current societal issues related to soils in tutorials: their degradation (erosion, pollution, artificialization, compaction, etc.) and their restoration (decontamination, phytoremediation, agroecology).

The field trip will provide an opportunity to put the concepts learned in class into practice.

Hourly volumes:

CM: 12 p.m.

Tutorial: 9 a.m.

Field: 6 hours

The objective of this module is to establish a foundation of knowledge in pedology and soil science in order to describe, classify, and characterize soils, their physical, chemical, and biological properties, as well as their formation and evolution in different environments.

General geology knowledge at L1 level: IGN mapping and geological mapping, external geodynamic cycle (weathering, erosion, transport, deposition).

• Continuous assessment
• Final exam

Brief description of the concepts covered in CM:

1. Introduction

• definitions of soil (colloquial, literary, scientific language)
• origin of soil, the three phases of formation: weathering, incorporation of organic matter, transfer of elements
• examples of soil diversity (thickness, color, etc.) on a global vs. local scale

2. The building blocks of the floor system

• mineral constituents (minerals in rock and soil minerals, mineralogy of clays)
• organic constituents (humus litter)
• living organisms (bacteria, fungi, fauna); molecular ecology cultivable/visible diversity

3. Soil properties

a) A physicist's vision

• 3 phases: solid, water, air
• grain size (sand, silt, clay)
• structure, porosity, and air
• soil and water (water reserves)

b) A chemist's vision

• clay-humus complex
• CEC, pH,
• oxidation-reduction

c) Vision of a naturalist

• Profile and outlook
• Type of humus (horizon O)
• Color and spots, texture, structure, roots, coarse elements, etc.

4. Soil and plant nutrition

• the root system
• plant nutrition: from deficiency to toxicity, total vs. available elements
• role of microbes: catalysis of decomposition, fate of organic matter, recycling, humification > C, N, P cycles
• soil symbioses (mycorrhizae, nitrogen fixers)
• role of soil fauna (earthworms, ants, termites, etc.): soil disturbance, upwelling of mineral elements, incorporation and transformation of organic matter
• In conclusion:
  -- functional feedback on types of humus

-- soil and vegetation distribution (azonality, zonality)

5. Formation, evolution, classification, and global distribution of soils

• Factors influencing soil formation: climate, parent material, living organisms, relief, time (age of soil)
• some processes involved in soil formation and evolution: weathering, humification, leaching, podzolization, pedoturbation, ferralitization, etc.
• soil classification: diagnostic horizons; major classification systems (CPCS, Soil Reference System, Soil Taxonomy, WRB)
• global soil distribution (climate), national (bedrock), local (relief)
• Mediterranean soils

6. Soil biodiversity and metal pollution. Phytoremediation. 

7. Soil biodiversity and hydrocarbon pollution (DNAPL and LNAPL). Phytoremediation

Brief description of tutorial sessions and number of hours associated with each session

Six 1.5-hour tutorials will address current issues in soil science and environmental science. Students will be required to study scientific articles using the concepts learned in class. The articles used will be drawn from the following topics:

Session 1: Description of soil (color, texture, macrofauna, etc.)

Session 2: Soils and the water cycle (runoff vs. infiltration, water storage, evapotranspiration)

Session 3: Soil degradation – 1: Erosion and flooding, artificialization, compaction, decline in organic matter content

Session 4: Soil degradation – 2: Pollution of agricultural soils (pesticides: chlordecone, copper, etc.) and industrial soils (mining sites, hydrocarbons, etc.)

Session 5: Remediation of contaminated soil (decontamination, phytoremediation)

Session 6: Restoring agricultural soils: alternatives to conventional agriculture (agroecology, agroforestry, permaculture, direct seeding, intercropping, legumes, terra preta)

Description of the topics/activities covered during your field trip(s) and details of the destinations/sites

• Description of a typical Mediterranean soil profile
• Study of the spatial variability of soils along a toposequence, depending on topography and bedrock.

Basic knowledge of pedology and soil science

Recognition, characterization, and specific functions of the most common soils