topic 5 enviro

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)

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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