1. soil a complex ecosystem made up of minerals, organic material, gases and liquids
which forms the habitat for many species of plant and animal
2. soil storages the energy and matter within soil - organic matter, organisms, nutrients, minerals,
air and water
3. soil transfers biological mixing, translocation, leaching
4. translocation movement of soil particles in suspension (liquid)
5. leaching minerals dissolved in water moving through the soil
6. soil inputs organic matter from leaf litter and dead or decaying organisms - inorganic matter
from parent material (rock), precipitation and energy
7. soil outputs uptake by plants (minerals and water)
soil erosion
8. soil transforma-
tion
decomposition or organic material taking place
weathering causes large particles (rocks) to become smaller
nutrient cycling within soil
9. minerals metal atoms and compounds which make up rocks - dissolved in water to become
an inorganic storage in soils
10. humus plant and animal material in the process of decomposition - generally the top layer
of soil
11. soil horizons the layers of soil in a cross-section which is modified over time as organic material
leaches downwards and mineral material moves upwards
12. O (soil horizon) leaf litter - newly added organic material
13. A (soil horizon) mineral horizon at the surface showing organic matter enrichment - where humus
forms
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3. soil transfers biological mixing, translocation, leaching
4. translocation movement of soil particles in suspension (liquid)
1 / 714. 15. 16. 17. 18. 19. 20. IB ESS Topic 5
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B (soil horizon) C (soil horizon) sandy soils clay soils loam soils porosity permeability 21. infiltration subsoil horizon showing enrichment of clay material, iron aluminum, or organic
compounds - where soluble minerals and organic matter tends to be deposited
from the layer above
horizons of loosened or unconsolidated material - mainly weathered rock from
which soil forms
gritty and fall apart easily - good drainage and air supply to the roots, however,
leaching is rapid
good nutrient retention, however, heavy soils which are relatively impermeable and
have poor drainage
roughly 40 - 40 - 20 sand, silt, clay
ideal for agriculture due to sand's drainage and porosity, clay's nutrient retention
and silt keeping the other two together
e.g. high in sand soils, low in clay
the amount of space between particles in soil
e.g. high in sand soil, low in clay
the ease at which gases and liquids can pass through the soil
the penetration of water into the soil
22. Nitrogen-Phos-
phorus-K(Potassi-
um)
the most important soil nutrients for plant growth - often leach out or may be
removed when plants are harvested
often found in soil fertilisers containing nitrogen, phosphates and potassium
(potash)
of the Earth - meaning "land" in ecology
23. terrestrial 24. LEDC
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less economically developed country - a country with low to moderate industriali-
sation and low to moderate average GNP per capita
MEDC agribusiness more economically developed country - a highly industrialised country with high
average GNP per capita
the business of agriculture production including farming, seed supply, breeding,
chemicals for agriculture, machinery, food harvesting, distribution, processing and
storage
large scale production of crops and livestock for sale
27. commercial agri-
culture/farming
28. subsistence agri-
culture/farming
farming for self-sufficiency to grow enough for a family
29. cash cropping growing crops for the market
30. extensive farm-
farming using more land with a lower density of stocking or planting and lower
ing
inputs = lower outputs
31. intensive farming farming using land more intensively with high levels of input and output per area
32. pastoral (pas-
ture) farming
raising animals, usually on grass and on land that is not suitable for crops
33. arable farming 34. mixed farming 35. 36. growing crops on good land to be eaten directly, or to be fed to animals
farming of both crops and animals - animal waste may be used as fertiliser and to
improve soil quality, and some crops are used to feed animals
malnutrition"bad nutrition" - a diet which is unbalanced (may be too much or not enough of
a particular nutrient(s)
provide half the human population's calories (energy)
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grain/corn pro-
duction
37. irrigation 38. cultural and reli-
gious (food choic-
es)
39. political (food
choices)
the supply of water for crops other than natural process such as rain or water tables
some people only eat certain foods/avoid certain foods due to their beliefs or
traditions
40. animal domesti-
cation
41. livestock governments may subsidise or tax some foods to encourage or discourage their
production
e.g. the EU manipulates food production in this way
the use and keeping of animals for human purposes - occured a long time before
humans started cereal farming
first dogs, then sheep, cattle, pigs
animals in pastoral farming - useful in converting plants which humans cannot
digest (grass) into valuable protein
a single species of plant grown on a farm, usually in high density
42. monoculture
farming
43. harvesting 44. crop rotation 45. palm oil the removal of biomass from the field, soil and ecosystem - results in a loss of
quality of the soil as nutrient which would have been recycled back into the soil
are removed (and must be replaced)
a way to reduce the loss of soil fertility - leguminous crops (soya beans, peas and
other beans) are grown every fourth year as they are able to fix their own nitrogen,
and so add it back into the soil
a tropical palm tree from West Africa and Central America, imported to South East
Asia
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46. shifting cultiva-
tion (comparison
of farming sys-
tems)
47. cereal growing
(comparison of
farming systems)
48. farming's energy
budget
49. genetically modi-
fied (GMO) crops
demand for palm oil in many food, cosmetic, lubricant and biofuel products is the
most significant cause of rainforest loss in Indonesia and Malaysia
e.g. Amazon rainforest
extensive subsistence farming
low inputs - manual labour and hand tools
high efficiency
low environmental impact (only if enough land to move to - forest is given time to
regrow)
e.g. Canadian Prairies
extensive commercial farming
inputs - high use of technology and fertilisers
low outputs per area (hectare) but high per farmer/farm
medium efficiency
high environmental impact - loss of natural ecosystems, soil erosion, loss of
biodiveristy
the energy of a farming system
may be measured as:
- energy contained in the crop of product per unit area
- efficiency of the system (the energy inputs compared to the outputs) = a more
scientific and honest look at energy usage in a farming system
may have DNA inserted from another species to provide a benefit from the other
species
PROS
may increase disease resistance
can be enhanced to contain extra nutrients
may increase yield
5 / 750. 51. 52. 53. 54. 55. 56. IB ESS Topic 5
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CONS
generally surrounded by concerns on safety, ethics and environmental concerns
soil degradation possibly one of the most pressing environmental and social problems facing
society today
generally caused by soil erosion and/or reduction in soil's suitability for use
soil erosion the process of soil being taken away
overgrazing too many animals graze (eat grass/plants) in the same area - results in bare
patches of soil where roots no longer hold the soil together leaving it open to soil
erosion from wind and rain
overcropping too many crops being used in an area of land without a break or crop rotation -
results in reduction of soil fertility as no nutrients are being returned to the soil
deforestation the removal of trees which often results in soil being left exposed, leading to soil
erosion
urbanisation the creation of cities - land is paved and built upon causing increased run-off and
probably increasing soil erosion elsewhere
soil conservation improving the soil - reducing erosion and conserving nutrients
57. addition of soil
conditioners (soil
conservation)
e.g. lime and organic material - used to increase soil pH and counteract acidifica-
tion (from acid deposition and soil processes)
58. wind reduction
(soil conserva-
tion)
planting trees or bushes between fields (shelter belts) or by alternating low and
high crops in adjacent fields - reducing wind action on soils = reduced wind ersion
59.
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cover crops (soil
use of fast growing crops between harvesting of main crops to ensure bare soil is
conservation)
not exposed for too long
60. terracing (soil
conservation)
terraces reduce the steepness of slopes by replacing the slopes with a series of
horizontal terraces separated by walls - common in Asian wet rice fields = reduces
run-off
61. reduced plowing
(soil conserva-
tion)
62. improved irriga-
tion (soil conser-
vation)
63. salinization (soil
degradation)
64. What is soil made
from?
65. Desertification traditionally the top layer of soil is broken up in Autumn - this damages soil as it
breaks up the soil structure and disrupts microbial activity
alternatives are no tillage and direct seed drilling
careful planning and construction of irrigation systems can reduce evaporation and
therefore salinisation
e.g. drip irrigation (trickle irrigation) - uses a series of pipes throughout a field to
add water slowly = less evaporation
the increase in salt levels of soil due to water evaporation leaving salts and
chemicals behind
mineral particles, organic remains, water, and air
the process by which fertile land becomes desert, typically as a result of drought,
deforestation, or inappropriate agriculture.
5.1 Introduction to Soil Systems
What is soil made from?
• Soil is composed of mineral particles (sand, silt, clay), nutrients (N, K, P), organic material, water, air, and living organisms.
Draw a soil profile, explaining the composition of the different horizons:
• Horizon O: Organic matter; layer of relatively undecomposed plant residues.
• Horizon A: Layer of mineral soil with greater accumulation of organic matter and soil life. This layer leaches Fe, clay, Ca, organic compounds, and other soluble components.
• Horizon B: This layer accumulates Fe, clay, Al, and organic compounds.
• Horizon C: Layer of large unbroken rocks. This layer can accumulate the most soluble compounds.
• Horizon R: This layer denotes the partially weathered parent rock at the base of the soil profile.
Identify the ecosystem services provided by the soil:
• Medium for plant growth
• Storage of freshwater
• Filtration of materials to maintain water quality
• Nutrient recycling through decomposition
• Habitat for microorganisms and larger animals
• Source of raw materials (peat, clay, sand, gravel, minerals)
Define:
• Eluviation: The process of leaching of minerals and nutrients from the upper layers of soil to lower layers.
• Illuviation: The accumulation of leached materials (such as clay, iron, or organic matter) in lower soil horizons.
Explain how soil can be described as an ecosystem:
• Soil is a dynamic ecosystem with inputs (e.g., organic matter, precipitation), outputs (e.g., erosion, leaching), storages (e.g., nutrients, water), and flows (e.g., water movement, nutrient cycling). It supports plant growth, hosts diverse organisms, and interacts with the atmosphere, hydrosphere, and lithosphere.
Key Words:
• Soil Profile
• Soil Horizon
• Leaching
• Eluviation
• Salinisation
Assessment:
• Draw and label a soil profile.
• Explain the processes of eluviation and illuviation.
• Describe the ecosystem services provided by soil.
5.2 Terrestrial Food Production Systems
Describe the following types of farming. Give an example of each:
• Subsistence: Small-scale farming for local consumption. Example: Slash and burn farming in Peru.
• Commercial: Large-scale farming for profit. Example: Intensive beef production in Argentina.
• Intensive: High input and output per unit area. Example: Greenhouse vegetable farming.
• Extensive: Low input and output per unit area. Example: Extensive cattle farming in East Africa.
• Pastoral: Farming focused on raising livestock. Example: Sheep farming in Australia.
• Arable: Farming focused on growing crops. Example: Rice farming in the Ganges Valley.
What is ‘agribusiness’?
• Agribusiness refers to the large-scale, industrialized, and commercialized farming operations that integrate various stages of production, processing, and distribution.
What is a ‘monoculture’?
• Monoculture is the agricultural practice of growing a single crop species over a large area for consecutive years.
State the factors that can influence the sustainability of terrestrial food production systems:
• Climate
• Soil quality
• Water availability
• Pest and disease control
• Socio-economic factors
• Political policies
• Technological advancements
Key Words:
• Subsistence
• Commercial
• Extensive
• Intensive
• Agribusiness
• Sustainability
• Monoculture
Assessment:
• Compare and contrast subsistence and commercial farming.
• Discuss the factors influencing the sustainability of food production systems.
5.3 Soil Degradation & Conservation
Outline how soil forms through succession:
• Soil formation begins with the weathering of parent rock, followed by the accumulation of organic matter from decomposing plants and animals. Over time, soil horizons develop, and the soil becomes more fertile and capable of supporting diverse plant and animal life.
Explain how the following human activities lead to soil degradation:
• Overgrazing: Trampling and overfeeding by livestock damage plant cover, leading to soil compaction and erosion.
• Overcropping: Continuous cropping depletes soil nutrients, reducing soil fertility and increasing vulnerability to erosion.
• Deforestation: Removal of trees reduces root support, leading to increased erosion and loss of soil structure.
• Unsustainable Agricultural Techniques:
• Pesticides: Toxic chemicals can kill beneficial soil organisms and contaminate soil and water.
• Irrigation: Excessive irrigation can lead to salinization, where salts accumulate in the soil, reducing fertility.
• Monocultures: Growing the same crop repeatedly depletes specific nutrients, reducing soil fertility.
• Total removal: Harvesting all plant material leaves soil bare and vulnerable to erosion.
• Plowing: Disturbs soil structure, increasing erosion and loss of organic matter.
• Urbanization: Paving and construction reduce soil permeability and increase runoff, leading to erosion and loss of fertile land.
Describe the relationship between soil succession and soil fertility:
• As soil undergoes succession, it accumulates organic matter and nutrients, increasing its fertility. Mature soils with well-developed horizons support diverse plant and animal life, contributing to a stable and productive ecosystem.
Explain the importance of organisms that live in the soil:
• Soil organisms, such as bacteria, fungi, earthworms, and insects, play crucial roles in decomposing organic matter, recycling nutrients, improving soil structure, and enhancing soil fertility.
Outline the 3 main processes of soil erosion:
• Water Erosion: Removal of soil by rainfall and surface runoff.
• Wind Erosion: Removal of soil particles by wind, common in dry and bare areas.
• Mass Movement: Downhill movement of soil and rock due to gravity, often triggered by heavy rainfall or human activities.
Explain how the following can conserve soil:
• Soil Conditioners: Add organic matter or lime to improve soil structure and fertility.
• Wind Reduction: Planting trees or using windbreaks to reduce wind speed and prevent soil erosion.
• Improved Irrigation: Using efficient irrigation methods, such as drip irrigation, to reduce water use and prevent salinization.
• Cultivation Techniques:
• Cover Crops: Planting crops to cover the soil and prevent erosion.
• Terracing: Creating terraces on slopes to reduce water runoff and erosion.
• Plowing: Plowing along contours to reduce erosion.
• Contour Farming: Planting crops along the natural contours of the land to reduce erosion.
• Crop Rotation: Rotating different crops to maintain soil fertility and reduce pest buildup.
Key Words:
• Succession
• Soil Fertility
• Soil Erosion
• Urbanization
• Deforestation
• Overgrazing
• Overcropping
• Soil Conditioners
• Irrigation
• Wind Reduction
• Cover Crops
• Contour Farming
• Terracing
• Crop Rotation
Assessment:
• Explain the processes of soil erosion and their impacts.
• Evaluate soil conservation strategies in different farming systems.
Diagrams
Soil Profile Diagram:
Soil Profile
Soil Texture Triangle:
Soil Texture Triangle
Systems Diagram for Soil as an Open System:
Soil System Diagram
Systems Diagram for Intensive Beef Production:
Intensive Beef Production System Diagram
Systems Diagram for Slash and Burn Farming:
Slash and Burn Farming System Diagram