Soil and Food Production: Weathering, Conservation, and Sustainability

chemical weathering

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.

Choice of food production system

influenced by socio-economic, cultural, ecological, political and economic factors.

contour ploughing

following the contours of the land when ploughing to avoid soil washing downhill.

Fertile soils

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

food waste in LEDCs

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

food waste in MEDCs

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

Higher trophic levels

harvesting from these may be a cultural choice.

Human activities reducing soil fertility

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

Increased sustainability of food production - clean-up and restoration

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

Increased 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.

Increasing sustainability of food production - altering human activity

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

Inputs to soil system

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

leaching

minerals dissolved in water moving through soil (downward).

Lower trophic levels

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

no-plough cultivation

replanting through stubble of old crop.

outputs from soil system

uptake by plants, soil erosion.

parent material

the rock from which soil forms locally.

Per capita land for food production

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

physical weathering

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

properties of soil

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

reduced soil fertility results from

soil erosion, toxification, salination and desertification.

shelter belts

woodlands planted along the margins of fields.

soil conditioners

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

soil conservation measures

soil conditioners (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 profile

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

soil system storages

organic matter, organisms, nutrients, minerals, air and water.

soil texture triangle

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

strip cultivation

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

stubble

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

Sustainability of terrestrial food production

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.

terracing

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

transfers in soil

biological mixing, leaching.

transformations in soil

decomposition, weathering, nutrient cycling.

wind breaks

planting trees or using rock lines to reduce wind erosion.