| Date | November 2020 | Marks available | 3 | Reference code | 20N.1.SL.TZ0.4 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Outline | Question number | 4 | Adapted from | N/A |
Question
Figure 3(d): Landslide caused by heavy rains after a hurricane
[Source: Photo courtesy of Jodie Dangleben.]
Figure 3(d) shows a landslide caused by heavy precipitation on a steep slope. Outline one technique that could be used by farmers in Dominica to reduce soil erosion.
Markscheme
contour ploughing;
… slows down surface runoff;
… allows infiltration to occur;
… less sediment is washed into the rivers;
stone lines;
… slows down surface runoff;
… allows infiltration to occur;
… less sediment is washed into the rivers;
mulching;
… residue on the surface of the soil reduces rainfall impact;
... residue on the surface holds water, reducing runoff;
… less sediment is washed into the rivers;
terracing;
… flat steps on steep slopes slow down surface runoff;
… allows infiltration to occur;
… less sediment is washed into the rivers/ flat areas are more stable and the soil is less likely to slide down the slope;
planting trees/agroforestry/intercropping with trees;
...trees intercept precipitation/rainfall, reducing surface run-off / absorb water reducing run-off / increase infiltration due to root systems;
...roots stabilize/hold soil;
...reducing loss of nutrients/top soil;
Note: [1] for naming the technique and [2] for outlining how it reduces soil erosion.
Examiners report
Most candidates were able to identify a suitable technique to reduce soil erosion on a steep slope but few were able to outline how the technique worked in sufficient detail for the full 3 marks.
