LandIB Environmental Systems and Societies SL: Topic test

20 questions, 54 marks

IB Environmental Systems and Societies SL

Land topic test

Total 54 marks

Name

Class

Date

1
In the Amazon rainforest the soil is often thin and low in nutrients, even though the vegetation above it is dense and productive. Warm, moist conditions mean that fallen leaves and dead wood are decomposed very quickly, so there is only a shallow layer of organic matter on the surface. Heavy rainfall washes dissolved minerals down through the soil and out of the system. Most of the nutrients in the ecosystem are held in the living plants rather than in the soil.
(a)
Which is an output from the soil system in the rainforest?
[1 mark]
AMinerals washed out of the soil by rainwater
BLeaves falling onto the soil surface
CMinerals released from weathering of rock
DWater entering the soil as rainfall
(b)
Why is the layer of organic matter on the rainforest soil so thin?
[1 mark]
AFew leaves fall from rainforest trees
BRainforest plants take up carbon from the soil
CDecomposition is rapid, so dead organic matter is broken down almost as fast as it arrives
DDecomposers cannot live in warm soils
(c)
Explain why clearing the rainforest can quickly reduce the fertility of the soil.
[2 marks]
Total for question 1: 4 marks
2
In parts of the Peruvian Amazon, families practise slash-and-burn agriculture. They cut and burn a small area of forest, grow crops such as cassava and plantain on the ash-enriched soil for two or three years, and then move on to clear a new plot. The old plot is left to regrow as forest for 15 to 20 years before it is cleared again. As the local population has grown and land has become scarcer, many families now return to plots after only five or six years.
(a)
Why has this traditional technique been able to sustain people in the past?
[1 mark]
AThe burned soil never loses its nutrients
BThe population density was low, so each plot had a long time to recover
CThe crops grown need no soil nutrients
DBurning increases the amount of organic matter in the soil permanently
(b)
What is the most likely effect of shortening the fallow period to five or six years?
[1 mark]
AYields rise because the soil is used more often
BThe forest regrows faster in each cycle
CMore nutrients are stored in the soil
DThe soil has less time to recover its fertility, so yields decline over time
(c)
Explain why slash-and-burn agriculture becomes less sustainable as the population increases.
[2 marks]
Total for question 2: 4 marks
3
A cereal-growing region has two types of farm of equal size, each covering 120 hectares. Farm P is intensive and applies synthetic nitrogen fertiliser every year to a single wheat crop; its mean yield is 7.5 tonnes per hectare. Farm Q is managed organically. It uses no synthetic fertiliser and instead rotates wheat with a legume crop, spreads animal manure and ploughs in crop residues; its mean wheat yield is 5.4 tonnes per hectare.
(a)
Calculate the total wheat production of Farm P and Farm Q, and the percentage by which the yield of Farm Q is lower than that of Farm P.
[3 marks]
(b)
Discuss the advantages and disadvantages of using synthetic fertiliser compared with the methods used on Farm Q to maintain soil fertility.
[4 marks]
Total for question 3: 7 marks
4
The highlands of Ethiopia have steep slopes, and heavy rain falls in a few months of the year. Farmers plough the slopes to grow cereals, and for generations the land has been cleared of trees and grazed heavily. The fertile topsoil has been washed away in many places, and yields have fallen. Since the 1980s many communities have built stone terraces across the slopes, planted trees and grasses on the steepest land and dug small trenches to hold rainwater.
(a)
Explain why the loss of topsoil reduces the ability of the land to support plants and other living things.
[6 marks]
(b)
Evaluate the soil conservation techniques used in the Ethiopian highlands.
[6 marks]
Total for question 4: 12 marks
5
A peat bog in northern Scotland has formed over thousands of years. The ground is waterlogged, so there is very little oxygen, and dead plant material from bog mosses and other plants is decomposed extremely slowly. As a result, metres of partly decayed plant matter have built up. The bog is home to specialised species such as sundews and breeding wading birds. In some places the bog has been drained so that trees can be planted or the peat can be cut for fuel.
(a)
Why has the peat bog acted as a carbon store?
[1 mark]
ADecomposers are very active in waterlogged soil
BPeat releases more carbon than it takes in
CInputs of dead organic matter have exceeded losses from decomposition for a long time
DCarbon dioxide cannot enter the bog
(b)
What is the most likely effect of draining the peat bog?
[1 mark]
AThe peat becomes a carbon source because air enters and decomposition speeds up
BThe peat stores more carbon because it is drier
CThe peat stops taking in dead organic matter
DThe rate of decomposition falls
(c)
Explain how soils such as peat contribute to biodiversity.
[2 marks]
Total for question 5: 4 marks
6
Researchers compared the land needed to produce the same amount of protein from different foods. They estimated that producing 100 g of protein from beef takes about 20 times as much land as producing 100 g of protein from lentils. Beef cattle are fed on crops or grazing land, so only a small fraction of the energy in the plants they eat ends up in the meat. Many countries are trying to improve food security while reducing the area of land used for agriculture.
(a)
Why is a diet lower in trophic levels more sustainable?
[1 mark]
APlants contain more energy than animals in total
BAnimals cannot be farmed sustainably
CPlants do not need soil or water
DLess energy is lost between trophic levels, so less land is needed per person fed
(b)
Which definition describes food security?
[1 mark]
AProducing more food than a country needs
BThe physical and economic availability of food so that everyone can get the balanced diet they need
CHaving no imported food
DThe ability to grow any crop in any climate
(c)
Explain one way that a country could reduce the demand for agricultural land.
[2 marks]
Total for question 6: 4 marks
7
Country Q has a population of 25 million people. Each person needs about 0.45 tonnes of food a year. Its farms produce 15 million tonnes of food a year. About 18% of this is lost during storage and transport. Households then waste 12% of the food that reaches them. Country Q wants to meet its needs without clearing more land for farming.
(a)
Calculate the total amount of food that Country Q needs each year, and the shortfall between this and the amount of food actually eaten.
[3 marks]
(b)
Suggest how Country Q could close this gap without increasing the area of farmland.
[4 marks]
Total for question 7: 7 marks
8
In Indonesia, large areas of tropical forest have been cleared for oil palm plantations, which now supply a large share of the world's palm oil. The plantations are often owned by large companies. Local communities and Indigenous peoples who have traditionally used the forest for hunting, collecting forest products and small-scale farming often have no formal land titles. Plantations provide jobs and export income, but the loss of forest has also reduced biodiversity and increased flooding and smoke from fires.
(a)
Explain why marginalised groups may be more vulnerable when land-use decisions are made, using the example of oil palm expansion.
[6 marks]
(b)
Evaluate the sustainability of intensive oil palm plantations compared with the traditional farming and forest use that they replaced.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).