5.2 Agriculture and foodIB Environmental Systems and Societies SL: Subtopic test

1. 1
   In the 1960s farmers in Punjab, India, began growing new wheat and rice varieties with irrigation, synthetic fertiliser and pesticides. Wheat yields rose dramatically and India stopped depending on food imports. Decades later, groundwater levels in parts of Punjab have fallen, soils have become less fertile and many small farmers carry heavy debts for inputs.

   (a)

   Which combination of features best describes the Green Revolution?

   [1 mark]

   • ATraditional crop varieties grown with no external inputs
   • BHigh-yielding crop varieties, improved irrigation, synthetic fertiliser and pesticides
   • CShifting cultivation with long fallow periods
   • DMixed farming with livestock and crop rotation only

   (b)

   Which is a criticism of the Green Revolution shown in the passage?

   [1 mark]

   • AIt reduced food production
   • BIt relied on traditional, low-input methods
   • CIt increased dependence on costly inputs, which harms small farmers and the environment
   • DIt had no effect on yields

   (c)

   Outline two consequences of the Green Revolution in Punjab, each from a different category (environmental, economic or sociocultural).

   [2 marks]

   Total for question 1: 4 marks

2. 2
   The Maasai of Kenya and Tanzania have traditionally practised nomadic pastoralism, moving their cattle, sheep and goats between areas of grazing as the seasons change. In parts of the Amazon basin, small communities practise slash-and-burn agriculture: a patch of forest is cut and burned, crops are grown for a few years and then the plot is left to regrow while a new patch is cleared.

   (a)

   Slash-and-burn agriculture is most likely to be sustainable when:

   [1 mark]

   • APopulation density is low and cleared plots are left fallow for long enough to recover
   • BPlots are cleared repeatedly without a fallow period
   • CIt is used to feed a large and growing urban population
   • DSynthetic fertiliser is applied to every plot

   (b)

   Why is nomadic pastoralism able to be sustainable in dry grasslands?

   [1 mark]

   • AAnimals are kept permanently in one field
   • BLarge numbers of animals are fed on imported grain
   • CCrops are irrigated from deep wells
   • DAnimals move between grazing areas, so no area is overgrazed for long

   (c)

   Explain why these traditional techniques have sustained low-density populations but would be unlikely to feed a large and growing population.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A farmer has one hectare of land. Growing wheat on it produces 20 000 000 kJ of edible energy per year. If the same hectare is used to grow grass for beef cattle, only about 2 000 000 kJ of edible energy is produced per year as meat, because about 90% of the energy is lost between trophic levels. An average adult needs about 10 000 kJ of food energy per day.

   (a)

   Calculate how many adults could be fed for one year from one hectare of wheat and from one hectare of beef production. Show your working.

   [3 marks]

   (b)

   Explain why diets lower in trophic levels are considered more sustainable, and outline one global strategy for achieving a sustainable food supply.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   The Loess Plateau in northern China is a large area of easily eroded soil that was heavily overgrazed and cultivated. From the 1990s a major restoration programme built terraces, planted trees and grasses and restricted free grazing. Erosion fell and many farm incomes rose. Worldwide, agriculture produces enough food for about eight billion people, but food is unequally distributed and a large proportion is lost or wasted.

   (a)

   Explain how soil conservation techniques can bring environmental, economic and sociocultural benefits, using the Loess Plateau or another named example.

   [6 marks]

   (b)

   Evaluate the strategies of reducing food waste, reducing demand for resource-intensive foods, and increasing productivity without using more land as ways of achieving a sustainable food supply.

   [6 marks]

   Total for question 4: 12 marks

End of questions