The soil system includes storages of inorganic nutrients.

Identify two inputs to these storages.

The soil system includes storages of inorganic nutrients.

Identify two outputs from these storages.

Solid domestic waste may contain non-biodegradable material and toxins that have the potential to reduce the fertility of soils.

Explain how strategies for the management of this waste may help to preserve soil fertility.

The provision of food resources and assimilation of wastes are two key factors of the environment that determine its carrying capacity for a given species.

To what extent does the human production of food and waste each influence the carrying capacity for human populations?

Inputs:

Candidates may present their answers in the form of a diagram, but it is not necessary for full credit.
Award [1] for each correct input identified, up to [2 max].
Do not credit flows that are transfers or transformations within the soil eg ammonification / nitrification / capillary movement, etc.
Do not accept “pesticides” (these do not provide inorganic nutrients).

Outputs:

Candidates may present their answers in the form of a diagram, but it is not necessary for full credit.
Award [1] for each correct output identified, up to [2 max].
Do not credit flows that are transfers or transformations within the soil eg ammonification / nitrification / capillary movement, etc.

recycling/re-use helps by preventing the release of non-biodegradable material/toxins into the soil;
reduction helps by reducing the quantity of non-biodegradable material/toxins produced/manufactured;
promoting selective consumerism to avoid toxic products prevents them being present in domestic waste;
education/laws/fines that promote disposal of hazardous domestic waste in appropriate collecting facility will reduce their impact on soil fertility;
incineration may be helpful in breaking down non-biodegradable substances/organic toxins;
…and the remaining mineral content can be used to enhance soil fertility;
landfills can limit the release of non-biodegradable material/toxins into soil with effective lining;
sorting of waste before entry to landfill can remove many toxic substances eg batteries/fluorescent lamps/tyres/spray cans reducing risk to soil fertility through leakage;
deep well injection of hazardous wastes will prevent soil toxification;
all strategies that prevent release of toxins will preserve the soil fauna that contribute to fertility;
composting (although it does not breakdown non-biodegradable material/toxins) can compensate to some extent by providing soil nutrients that improve soil fertility.

Award [1] for each correct explanation, up to [7 max].

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria given in each of the markbands (although “ESS terminology” has been conflated with “Understanding concepts”). This guide simply provides some possible inclusions and should not be seen as requisite or comprehensive. It outlines the kind of elements to look for when deciding on the appropriate markband and the specific mark within that band.

Answers may include:

• understanding concepts and terminology of carrying capacity, ecological footprint, waste assimilation, recycling/re-use/reduction strategies, BOD, toxicity, greenhouse gases, global warming/climate change, selective breeding/genetic engineering, commercial vs artisanal farming, mono-cropping, soil quality, desertification, Malthus/Boserup theories, etc
• breadth in addressing and linking a range of ways in which different sources of waste eg agricultural, domestic, industrial, transport etc and food production systems eg commercial, polyculture, artisanal, etc impact/deplete available resources thus influencing carrying capacity for humans, etc
• examples of how carrying capacity may be influenced through wastes eg toxicity to natural populations, increasing BOD in aquatic systems, greenhouse gases leading to global warming/climate change reducing (or possibly increasing?) productivity, and through food production eg use of pesticides reducing natural populations, reducing soil quality through overharvesting/compaction/irrigation, habitat destruction, etc and examples of how these influences may be reduced through waste management strategies eg recycling, etc, alternative energy, and alternative agricultural practices eg polyculture, crop rotation, more efficient crops/GMOs, etc
• balanced analysis of the net impact of waste and food production on the carrying capacity for humans etc
• a conclusion that is consistent with, and supported by, analysis and examples given eg “Although there are many mitigating strategies that can reduce the influence of waste and food production on carrying capacity, overall, an increasing per capita footprint of humans will inevitably result in a reduced carrying capacity.”

Refer to paper 2 markbands, available under the "your tests" tab > supplemental materials.

Question 6 was a quite popular choice. Part (a) very rarely scored full credit with a lot of responses going for non-mineral inputs and outputs (e.g. water, sun, CO₂ etc).

Question 6 was a quite popular choice. Part (a) very rarely scored full credit with a lot of responses going for non-mineral inputs and outputs (e.g. water, sun, CO2 etc).

Most candidates were able to name a few relevant strategies for managing solid domestic waste. However, credit was generally less than maximum because responses focused on evaluating the strategies (particularly their weaknesses), which was not required by the question. Responses would have scored more by identifying further modifications or other strategies.

A significant proportion of responses identified the fundamental relationship between food/waste production and carrying capacity …but then did not go far beyond this in exploring how these are influenced by agricultural techniques/management strategies/geographical and social factors and so on.