1-2 Introduction: Soil functions and definition

Soil functions

Raw material → ressource (gravel f.e.)

Support → constructions over the soil (buildings, roads, sewer system…)

Production → food but also wood…

Living space → microorganism and soil biota → lot’s of ecosystems in the soil

Regulation → between different sphere → atmosphere, biosphere, hydrosphere and lithosphere → the pedosphere is in the middle, really important → stores, buffers, filters and transports nutrients, pollutant and water

Archive → cultural archive but also for natural history (Löss Soil sequences in China)

Threats to soil functions

Land consumption → urbanisation, in CH 1m² per second

Sealing → because of urbanisation the precipitation are drainde by channels, there’s less infiltration in the soil → water not available for plants of groundwater reserve, higher flood risks

Soil compaction → heavy machinery and soil drought → less oxygen for organism, less infiltration and increasing risk of floods

Soil erosion → washing away of fertile arable soil → causes: inappropriate soil management, soil compaction → consequences: economic damage, water eutrophication, damage to infrastructure

Soil pollution

Four sources:

• atmospheric pollution

• ground/surface water pollution

• direct effects of land management (agriculture, industry, waste, mining)

• geogenic pollution (bedrock)

Three types of pollutant:

• Inorganic pollutant

• organic pollutant

• radioactive pollutant

Soil acidification → decrease of pH in soil due to sulfuric and nitric acid emissions/formation → strong laws to stop it

Impact of human activity on soil (image)

10 key points for soil protection

1. Knowledge (soil is not dirt)

2. Precautionary soil protection

3. Coordinated soil monitoring and surveillance (NaBo)

4. Sustainable, careful use

5. Remediate polluted soils to such an extent that there is no danger

6. Soil = common property. Whoever uses soil is responsible for its protection

7. Integrity of the soil is ensured by legal standards

8. Soil protection = corporate mandate > improve institutional conditions for soil protection + financial resources

9. Implement soil protection by all actors

10. Important partners in soil protection: spatial planning, agriculture and forestry

Legislation EU

New soil strategy and monitoring for 2030

60% of EU soils are unhealthy, big economic cost

Legislation CH

Strategy soil 2020

Six general objectives are to be achieved in order to preserve soil functions in the long term:

• reduction of soil consumption

• consideration of soil functions in spatial planning

• protection of the soil against persistent damage

• restoration of degraded soils

• awareness of the value and vulnerability of the soil

• strengthening international engagement

Important institution CH:

• Agroscope: Federal Competence Centre for Agricultural Research

• Swiss Federal Institute for Forest, Snow and Landscape Research (WSL): Forest soils

• Federal Office for Agriculture (BLW)

• Federal Office for the Environment (BAFU) → Department Soil & Biotechnology

KoBo

National centre of competence for soil science: KoBo. Started in 2020. Objectives: “improve the basis for the implementation of measures promoting the sustainable use and effective protection of soil resources.”

Tasks:

• Standardize and improve methods of surveying and analysing soil

• Define technical standards for soil mapping

• National information platform for the Confederation, the cantons and private organisations

• Provides methods for evaluating soil functions and threats

• Promotes interdisciplinary exchange between the different actors

Soil functions circle

Different soil definition

Soil is the living, breathing skin of our planet

Soil is any loose material on the surface of the Earth that is capable of supporting life

Definition: surface component of the Earth that developed from geological materials (lithosphere, bottom) and dead biomass (biosphere, top) by physical, chemical and biological processes

Other definition (sediment, regolith, coal and peat, pedosphere)

Sediment = Displaced soil without in situ soil formation → not a soil

Regolith = weathered rock without biological influence → not a soil

Coal and peat = biogenic sediments → not a soil

Pedosphere = uppermost part of the lithosphere

Pedosphere

Environmental condition around pedosphere

Extremes: Sharp temperature fluctuations, low to very high relative humidity, complete darkness to full light

Soils definition (horizon and group/type/unit)

Soils are made of horizons (total of horizons = solum, no OM layer or bedrock)

Soil group, soil type, soil unit (Bodenart): same horizon sequence, same characteristics of the horizons, not necessarily the same bedrock

Soil type can also refer to grain size (Bodentyp)

Horizons arise from the (geologic) substrate through soil-forming processes: Weathering, Mineral formation, Decomposition of litter and humus formation, Microstructure formation, Material transfer

Horizon is different from a layer which include OM and bedrock

Soil unit definitions

Elementary Soil unit: Pedon (1-10 m2 and 0.5 – 2 m deep)

Vertical pit: soil profile

Polypedon = company of pedons (few m²-1000 km²)

Soil composition

Fine pores < 0.2 µm uninhabited

Medium pores 0.2 - 10 µm bacteria, fungi, algae, root hairs, unicellular organisms

Coarse pores & secondary pores > 10 µm roots, nematodes, mites, collembola and other fauna

Grain size

Soil formation

Soil definitions → zonal, intrazonal and azonal

Zonal soils = climate & vegetation determine development

Intrazonal soils = differentiation within climate zones due to specific influences of relief, water balance, bedrock and age

Azonal soils = young soils without characteristic profile

Other definitions

Catena = Relief-controlled soil sequence (typically a slope)

Chronosequence = chronological sequence of soil development