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What is a soil profile?
A vertical section through a soi divided into horizons. Although the layers have distinct physical and chemical characteristics, the boundaries may be blurred by earthworm activity.
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What are soil system storages?
Organic matter, organisms, nutrients, minerals, air and water.
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What vital ecological duties does soll perform?
- Medium for plant growth
- Important store of relatively accessible fresh water
- Filters water and maintains water quality
- Medium for nutrient recycling
- Serves as a habitat
- Provides raw materials such as clay, peat, sands, gravels and minerals
- Protection against adverse effects of temperature change and pH change
- Supply of oxygen for plants
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Is soil a renewable resource?
Soil is a non-renewable resource because it takes a geological time period for it to replenish itself.
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Describe soil systems.
Soils are open-system at steady state equilibrium.
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What are the principal soil forming processes?
Weathering, movement of organic material and water (leaching, drainage) between horizons, chemical transformations within the soil
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What are some inputs and outputs of soil systems?
- Inputs: leaf litter, inorganic material from parent material, precipitation, energy
- Outputs: Soil erosion, plant uptake
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What is the difference between translocation and leaching?
Translocation is the movement of water (mostly downwards). Leaching is the movement of soluble material.
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Explain evapotranspiration.
It is heavy in arid environments. Calcification refers to calcium and sodium being left behind when the water evaporates. This may be toxic to plant growth. However, in grasslands, this effect is beneficial for grass growth.
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What are some of the transformations that occur in soil?
Decomposition, weathering (can be physical, chemical or biological, like plants breaking rocks) and nutrient cycling
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What are some factors that may limit plant growth?
- Mechanical barriers
- Absence of cracks
- Dryness
- Extreme temperatures
- Lack of oxygen due to waterlogging
- High Al, low pH
- Low nutrient supply
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How to read soil texture triangles?
Clockwise
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What does the agricultural potential of soil depend on?
Permeability, porosity, surface area of soil peds, mineral and nutrient content, drainage, water retention, biota, air spaces, potential to hold organic matter
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Which type of soil has the highest water infiltration rate?
Sand (think pee in desert lmao)
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What does the sustainability of food production systems depend on?
Cale, industrialization, mechanisation, fossil fuel use, seed/crop/livestock choice, water use, fertilizer use, pesticide/herbicide use, antibiotics, legislation, subsistence/commercial farming
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How can sustainability be improved?
- Reduction of meat consuming
- Increase of the consumption of organic and locally sourced food
- Improving the accuracy of food labels
- Monitoring and control oft he standards and practices of food corporations
- Lanting of buffer zones around agricultural zones to absorb nutrient run-off
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Explain agribusiness
- Became more prominent with the rise of the concept of self-sufficiency after the second world war
- Common characteristics include:
- Large-scale monoculture, intensive use of fertilizers and herbicides, mechanized ploughing and harvesting, commercial food production rather than subsistence farming
- The common goal of agribusiness is to maximize profits, which is a cultural factor of capitalistic societies
- National policies support agribusiness as a way of generating GDP. However, agribusiness in LEDCs continue to suffer from lack of technology, lack of capital and high levels of labour
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What are some issues that rise from unsustainable water use?
- Reduction in water resource sizes
- Eutrophication
- Salinization
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Explain inequality in food production and distribution in MEDCs and LEDCs
- Import tariffs and subsidies for MEDCs can have knock-on effects on LEDCs
- Increased oil prices and food prices as a result of higher demand for biofuel and consequent reduction in the proportion of crops used for eating rather than fuel production has led to increased inequalities in food distribution in LEDCs
- LEDCs struggle to produce enough food and most of the agriculture is for cash crops rather than something that can be eaten to promote GDP generation. This further increases food prices and thus increases the struggle for food in LEDCs.
- Agriculture in MEDCs is more technocentric, preventing LEDCs from catching up to the yields which have now been maximized. Food production in LEDCs is more labour-centered.
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What are the causes of food waste?
- Poor agricultural practices (pests destroy food in LEDCs)
- Inadequate infrastructure for transporting food (LEDCs)
- Poor storage facilities
- Strict sell-by dates
- Aesthetic standards in Western countries
- Consumer practices, customer behaviour, (sales that promote excessive buying, consumerism)
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Shifting cultivation or slash and burn may be sustainable if it is for the reason of subsistence and the land that is burnt is allowed to replenish itself. The ash resulting from the burning serves as a nutrient boost for the land that is then used for agrilcutre. After use for a couple of seasons, the land is left to replenish itself.
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What are the effects if socio-cultural factors on terrestrial food production systems?
- Technological state goes hand in hand with socio-cultural factors, altering practices. Technology also develops based on socio-cultural demands.
- Consumer demand for more organic food has led to the promotion of more sustainable practices in MEDCs
- Practices such as land ownership, migration and attitudes towards the environment determine agricultural practices as well.
- Cultural choices may also influence the society harvesting food from higher or lower trophic levels, which has a significant effect on the sustainability of the agricultural practice.
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What are the inputs of agricultural production?
Fertilizers, water (irrigation, precipitation), pest control, labour, seed, breeding stock, livestock growth promoters (hormones, antibiotics)
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What are the outputs of agricultural production?
Food quality, food quantity, consumer quality, erosion, degradation, fertility, pollutants, yield
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What are intensive farms?
Small area of land with high input
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What are extensive farms?
Large scale farming with large amount of money and large amount of labour
- How to determine the sustainability of agricultural practices?
- The balance between inputs and outputs
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Which human activities may reduce soil fertility?
Urbanization, deforestation, intensive grazing, monoculture, irrigation
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What is a result of loss in soil fertility?
Erosion, toxification, salinization, desertification
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What are some soil conservation methods?
- Soil conditioners (organic materials and time)
- Wind reduction techniques (wind breaks, shelter belts)
- Cultivation techniques (terracing, contour ploughing, strip cultivation)
- Use of marginal lands
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What are some direct and indirect effects of biological activity on soil?
- Blocking precipitation, evapotranspiration, source of nutrient through decomposition or fecal matter, areation through activity of earthworms
- Liming, fertilizers, gardening, deforestation, agricultural practices, trampling
- Fertile soils contain a community of organisms that work to maintain the fertility of the soil. These communities are disturbed by human activity.
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Monoculture leads to soil exhaustion
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Terracing, cover crops, aforestation, crop rotation, flushing of salt in soil
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