Farming and conservationAQA A-Level Biology: Subtopic test

1. 1
   A farmer removes the hedgerows that divide several small fields, creating one large field. The whole field is sown with wheat every year, and the farmer sprays it with a herbicide and an insecticide.

   (a)

   Growing the same crop over the whole field year after year is an example of which of the following?

   [1 mark]

   • ACrop rotation
   • BPolyculture
   • CMonoculture
   • DIntercropping

   (b)

   Which is the main reason that removing the hedgerows reduces biodiversity?

   [1 mark]

   • AIt increases the light reaching the crop, so more wild plants grow
   • BIt removes habitats, food sources and nesting sites for wildlife
   • CIt increases the soil's nitrate content
   • DIt reduces the rainfall reaching the field

   (c)

   Explain how spraying the field with a herbicide and an insecticide would reduce the biodiversity of the farmland.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A hill farmer increased the number of sheep on a grassland from 2 to 12 per hectare. The farmer also began applying inorganic nitrate fertiliser every spring to increase grass growth.

   (a)

   What is the most likely direct effect of the heavy grazing on the plant community?

   [1 mark]

   • APlant diversity is unaffected because grass grows back
   • BPlant species that need shade become more common
   • CMore plant species become established because sheep disperse seeds from many places
   • DSpecies that cannot tolerate grazing or trampling decline, so plant diversity falls

   (b)

   How is the nitrate fertiliser most likely to affect the plant community?

   [1 mark]

   • AFast-growing grasses outcompete other plants, so species richness falls
   • BAll species grow better, so species richness rises
   • CIt kills the animals that feed on the grass
   • DIt affects only the soil bacteria, not the plants

   (c)

   Suggest why a fall in the number of plant species on the hill could lead to a fall in the number of insect species.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A farm manager joins a government scheme that pays farmers to leave uncultivated margins around the edges of their fields, to replant hedgerows and to stop spraying insecticide near the hedges. The margins will take up 5% of the farm's cropland.

   (a)

   Explain how the measures in the scheme would increase biodiversity on the farm.

   [3 marks]

   (b)

   Discuss how the scheme helps to balance conservation with the need to produce food.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Over fifty years, farmland in a lowland county has been reorganised. Hedgerows were removed to merge small fields into large ones, ponds were filled in and wet areas were drained. The same cereal crop was grown over large areas treated with herbicides, insecticides and inorganic fertiliser. Yields rose steeply, but numbers of farmland birds, bees and wild flowers fell. The county council now wants to encourage wildlife-friendly farming without causing food prices to rise.

   (a)

   Explain how the changes in farming described have reduced the biodiversity of the county.

   [6 marks]

   (b)

   Discuss how the council could balance conservation with the need for farmers to produce food profitably.

   [6 marks]

   Total for question 4: 12 marks

End of questions