ESS Topic 5 Soil systems and terrestrial food production systems and societies

Soil profile

the layers (horizons) seen in a vertical cut through soil.

consists of

1. O - organic matter (undecayed)

2. A - surface/topsoil (includes decayed organic matter, good)

3. B - subsoil (minerals)

4. C - substratum (weathered rocks from parent material)

5. R - bedrock

soil system storages

organic matter, organisms, nutrients, minerals, air and water in soils

transfers in soil

biological mixing, leaching

leaching

____ of minerals dissolved in water moving through soil (down)

Inputs to soil system

leaf litter, inorganic matter from parent material, precipitation, energy

parent material

the rock from which soil forms locally

outputs from soil system

uptake by plants, soil erosion

transformations in soil

decomposition of organic matter, weathering, nutrient cycling

properties of soil

mineral and nutrient content, drainage, water holding capacity, air spaces, biota, potential to hold organic matter, primary productivity

soil texture triangle

diagram to compare the composition of soil with sand, clay and loam percentages identified

physical weathering

involves the mechanical breakdown of pieces of rock into smaller pieces e.g. frost, salt, insolation and biological weathering,

chemical weathering

weathering that breaks down chemical bonds, chemically modifies the rock minerals, and produces new compounds; the most common types are oxidation, carbonation and hydrolysis. Lichens can chemically weather rock.

Sustainability of terrestrial food production

is influenced by factors such as scale, industrialisation, mechanisation, fossil fuel use, seed, crop and livestock changes, water use, fertilisers, pest control, pollinators, antibiotics, legislation, and levels of commercial versus subsistence food production

food waste causes in LEDCs

lack of: refrigeration, transport infrastructure, knowledge of markets, communication and information availability

food waste causes in MEDCs

regulatory standards which require food to be discarded by expiry dates; over purchasing and overselling (multi-packs)

Choice of food production system

Influenced by socio-economic, cultural, ecological, political and economic factors

Per capita land for food production

area falls due to urbanisation, degradation of soil resources and growing populations

Lower trophic levels

_____ _____ _____ provide greater yield per unit area, are greater in quantity, lower in cost and may require fewer resources

Higher trophic levels

harvesting from ___ ___ ___ may be a cultural choice - it may cost more and require more energy to harvest per mass of food

Increasing sustainability food production - altering human activity

reduce meat consumption, increase consumption of organically grown and locally produced terrestrial foods, improving the accuracy of food labels to assist in consumer choice

Increasing sustainability of food production - controlling release

monitoring and control of standards and practices of multi-national and national food corporations by governmental and intergovernmental bodies

Increased sustainability of food production - clean-up and restoration

planting of buffer zones around land suitable for food production to absorb nutrient runoff, pollution

Fertile soils

require a significant time to develop through succession. they are considered a non-renewable resource.

Human activities reducing soil fertility

deforestation, intensive grazing, urbanisation, certain agricultural practices such as irrigation and monocultures

causes of reduced soil fertility

soil erosion, toxification, salination and desertification

soil conservation measures

soil conditioners (such as organic materials and lime), wind reduction techniques (wind breaks and shelter belts), cultivation techniques (terracing, contour ploughing, strip cultivation), avoiding use of marginal lands

soil conditioners

organic materials like manure, mulches and lime (calcium carbonate) to increase the pH or introduce nutrients

wind breaks

planting trees, using rock lines

shelter belts

woodlands planted along the margins of fields

terracing

creating terraces (shelves) that step down/up the land with walls to support the soil from slipping

contour ploughing

following the contours of the land when ploughing to avoid soil washing down hill

strip cultivation

planting alternating crops in a field to reduce nutrient depletion and the chance of pests

no-plough cultivation

replanting through stubble of old crop instead of removing it

stubble

the dead lower stem and roots of a harvested crop that remain in the land, holding the soil in place