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?
Describe two methods for measuring soil pH.
Explain how the following factors affect soil pH:
Parent material
Precipitation
Explain the concept of soil horizons and describe the characteristics of three main horizons.
Describe two methods for improving soil fertility in sustainable agriculture.
Figures 1(a) and 1(b) show the availability of renewable freshwater per capita in 2013 and its predicted availability in 2040.
Figure 1(a): Water stress by country in 2013
Figure 1(b): Predicted water stress by country in 2040
[Source: Maps adapted from www.wri.org. File licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)\]
Figure 2: Relationship between vegetation cover and evaporation
from different soil types
© International Baccalaureate Organization 2018
Using Figures 1(a) and 1(b):
State one country with no expected change in water stress between 2013 and the 2040 prediction.
State one difference in water scarcity between 2013 and the 2040 prediction.
Outline how climate change may affect the availability of freshwater resources.
Describe two water management strategies that can reduce water scarcity.
Describe the overall trend for sandy soil shown in Figure 2.
Calculate the change in evaporation from clay soil when the vegetation cover changes from 50% to 100%.
Outline two reasons why loam soils are the most productive for plant growth.
Explain how the following soil properties affect water movement and retention:
Soil texture
Soil structure
Describe three main types of agriculture and provide an example for each.
Describe two approaches to sustainable pest management in agriculture.
The following graph shows the wheat yield in developing countries from 1950 to 2004.
Calculate the percentage average annual growth in wheat yields from 1950 to 2000.
Describe the reasons for the increase in wheat yields from the 1950s to about 1999.
With reference to your answer for question (b), outline two environmental impacts of increasing wheat yields.
Explain why there is still hunger in some places when enough food is being produced to feed the entire world population.
