Land and Soil degradation Flashcards
What are ecosystem services?
The capacity of natural processes and components to provide goods and services that satisfy human needs, directly or indirectly.
What is soil degradation?
A change in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries.
What is land degradation?
A negative trend in land condition caused by direct or indirect human-induced processes including anthropogenic climate change. This is expressed as long-term reduction or loss of at least one of the following: biological productivity, ecological integrity, or value to humans.
What percentage of agricultural land is affected by human-induced degradation?
34% (1,660 million ha)
List some drivers of soil change.
- Population growth
- Food production
- Increased demand
- Land use change
- Clearing land
- Intensification
- Atmospheric deposition
- Climate change
What are the types of erosion?
- Wind erosion
- Water erosion
What factors influence erosion?
- Climate (wind, rainfall, temperature)
- Soil
- Topography
- Vegetation
- Land Management (Tillage, Conservation measures, Cover management)
What is the median net rate of soil formation?
0.004 mm/yr
What is salinisation?
The accumulation of salts in the soil.
List some anthropogenic causes of salinisation.
- Inappropriate irrigation practice (i.e. salty irrigation water)
- Poor drainage and rise of groundwater table
What is soil compaction?
An increase in density and decline in macro-porosity in the soil that results from pressure being applied at the soil surface.
What is soil contamination?
The addition of chemicals or materials to soils that have a significant adverse effect on any organism or soil functions.
What is soil acidification?
The lowering of soil pH due to the buildup of hydrogen and aluminium ions in the soil, and the associated loss of base cat-ions such as calcium, magnesium, potassium, and sodium from the soil due to leaching or product removal.
What are the impacts of excess nutrients in soil?
- Major contributor to water quality issues and GHG emissions.
- Agriculture accounts for >80% global anthropogenic N2O emissions.
What causes a loss of soil organic carbon (SOC)?
- Land use change
- Conversion to agriculture
- Agricultural practices (tillage, intensification, decreasing fallow, drainage of wetlands, biomass burning/removal, lower organic inputs)
What is soil sealing?
Permanent covering of an area of land and its soil by impermeable artificial material (e.g. asphalt and concrete).
What is desertification?
Degradation of land in arid, semi-arid, and dry sub-humid areas.
List some examples of the impacts of land degradation.
- Land degradation due to land use and land cover change costs $231 billion per year.
- Crop losses due to soil erosion in EU cost €1.25 billion per year.
- Soil carbon loss in England and Wales costs £570 million pa.
List some mitigation and remediation strategies for soil degradation.
- Erosion mitigation: Minimising land use changes, protecting the soil surface, minimising runoff, and sediment trapping.
- Carbon management: Enriching soil carbon with cover cropping, organic mulch, crop rotations, intercropping, tillage practices, nutrient management, limited soil disturbance, grazing management, and agroforestry.
- Minimising salinisation: Optimizing surface cover, efficient irrigation, adequate drainage, reclamation of salt-affected soils, planting salt-tolerant varieties, and chemical amelioration.
- Minimising sealing: Limiting, mitigating, and compensating for soil sealing.
- Preventing compaction: Avoiding inappropriate tillage, minimising vehicular traffic, adjusting machines to soil strength, cropping systems, adding organic matter, and sufficient cover in grazing systems.
What are the four key categories of measures for erosion mitigation?
- Minimising land use changes
- Reducing soil vulnerability to exposure
- Reducing SOC losses which enhance erosion
- Protecting soil surface
