Essential idea: Soil cycles are subject to disruption.
Intensive agriculture relies heavily on the use of artificial fertilisers to maintain high crop yields. The manufacture and the application of fertilisers is a major disruption to nutrient cycles. One consequences of this is the unbalancing of natural ecosystems around agricultural areas.
Understandings, Applications and Skills
| C.6.U1 | Nitrogen-fixing bacteria convert atmospheric nitrogen to ammonia. |
| C.6.U2 | Rhizobium associates with roots in a mutualistic relationship. |
| C.6.U3 | In the absence of oxygen denitrifying bacteria reduce nitrate in the soil. |
| C.6.U4 | Phosphorus can be added to the phosphorus cycle by application of fertilizer or removed by the harvesting of agricultural crops. |
| C.6.U5 | The rate of turnover in the phosphorus cycle is much lower than the nitrogen cycle. |
| C.6.U6 | Availability of phosphate may become limiting to agriculture in the future. |
| C.6.U7 | Leaching of mineral nutrients from agricultural land into rivers causes eutrophication and leads to increased biochemical oxygen demand. |
| C.6.A1 | The impact of waterlogging on the nitrogen cycle. |
| C.6.A2 | Insectivorous plants as an adaptation for low nitrogen availability in waterlogged soils. |
| C.6.S1 | Drawing and labelling a diagram of the nitrogen cycle. |
| C.6.S2 | Assess the nutrient content of a soil sample. |
[Text in square brackets indicates guidance notes]
Starters
|
Hank from Crash Course introduces the Nitrogen and Phosphorous cycles
|
Mohamed Hijri in his TED.com talk offers a simple solution to the coming phosphorus crisis.
|
Presentation and Notes
The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
|
|
Weblinks
|
_Nitrogen Cycle
Root nodule formation by McGraw and Hill What is the Nitrogen cycle? by Braingenie Phosphorous Cycle The Phosphorous Cycle by Sunamas Inc. |
Eutrophication
Eutrophication by Absorb Learning Eutrophication by Rutgers University Cool Classroom design team |
Nature of science
Assessing risks and benefits of scientific research—agricultural practices can disrupt the phosphorus cycle. (4.8)
