(2) Zero Hunger Soil & Fertilisers ILOs

Vicky Cocker

Explain the main processes of soil formation and the factors that control them

consist of mineral particles, air, water, organic materials (5%), etc

dependent on:

• parent material

• climate

• vegetation

• topography

• time

Distinguish between physical and chemical weathering processes and describe how they form soils

physical:

• mechanical breakdown by frost, water wind

• different expansion and contraction due to rapid temperature changes

chemical:

• chemical reaction resulting in the breakdown of a primary material into secondary

• oxidation

  • bonding with oxygen for metallic elements

• carbonation

  • reaction with carbonic acid, typically limestones

• hydrolysis

  • water decomposition of minerals like olvine

• hydration

  • swelling due to water absortion in clays

Identify the major mineralogical components of soils, including the role of clay minerals

clay which is important for soil fertility due to high capacity of ion exchange known as Cation Exchange Capacity (CEC)

Describe soil classification systems

• colour

  • black → high in organic matterial

  • red → high in Fe oxides

• texture (determines water capacity)

  • sand

  • silt

  • clay (most water)

Describe soil horizons and distribution

O = loose organic material

A = top soil → most black and organically rich

E = clays and insoluble materials

B = insoluble minerals and Fe oxides

N = partially altered parent material

R = unaltered parent material

10% of Earth’s surface provides 97% crop output

Identify the key inorganic fertiliser nutrients and how N, P, K are sourced and processed

Nitrogen

• Haber-Bosch process: Nitrogen & Natural Gas in to produce ammonia

Potassium

• evaporite mineral potash

Phospate

• mineral exploitation

• marine and sedimentary

all sourcing and processing methods release pollution due to excessive heat and GHG emissions