Significant Ideas
Fertile soils require significant time to develop through the process of succession.
Human activities may reduce soil fertility and increase soil erosion.
Soil conservation strategies exist and may be used to preserve soil fertility and reduce soil erosion.
Knowledge & Understanding
Soil ecosystems change through succession. Fertile soil contains a community of organisms that work to maintain functioning nutrient cycles and that are resistant to soil erosion.
Human activities that can reduce soil fertility include deforestation, intensive grazing, urbanization and certain agricultural practices (such as irrigation and monoculture).
Commercial, industrialized food production systems generally tend to reduce soil fertility more than small-scale subsistence farming methods.
Reduced soil fertility may result in soil erosion, toxification, salination and desertification.
Soil conservation measures include soil conditioners (such as organic materials and lime), wind reduction techniques (wind breaks, shelter belts), cultivation techniques (terracing, contour ploughing, strip cultivation) and avoiding the use of marginal lands.
Applications & Skills
Explain the relationship between soil ecosystem succession and soil fertility.
Discuss the influences of human activities on soil fertility and soil erosion.
Evaluate the soil management strategies of a given commercial farming system and of a given subsistence farming system.
Guidance
Applying knowledge of specific food production systems to their associated soil degradation and consequent soil conservation management strategies is recommended.
Key Vocabulary
XYZ
Textbook Reading and/or Activities
Pages 265-273
ToK (p.269)
To think about (p.270)
Case Study (p.271)
Review (p.273)
Notes
i-Biology Notes (Not available)
A detailed set of notes, created by Stephen Taylor, examining U1 - U8 and A1 - A4.
i-Biology Study Questions (Not available)
A series of questions, created by Stephen Taylor, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
Bioknowledgy Notes (Not available)
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
Bioknowledgy Study Questions (Not available)
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
Learning Activities
Case Study - Protecting the Ozone Layer
This case study, prepared by the Australian Government (Sept.2015), will help you better understand the issues related to ozone depletion, how it can affect a country and what can be done to resolve the problem (K&U 1-8 as well as A&S 1).
Supplemental Reading
This video examines the externalized costs associated with our food production systems.
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