IB ESS SL 5.2.9 Soil conservation techniques Question Bank

a. Add windbreaks/trees/shelterbeds to reduce wind erosion;
b. Plant cover crops/mulch to reduce wind erosion / intercepts raindrops (reducing water erosion);
c. Terrace slopes/use contour ploughing to reduce water erosion / reduce water flow;
d. Reduce tillage/use conservation tillage to protect the soil surface and allows water to infiltrate/reduces water erosion / reduces physical disturbance of soil (e.g. by tillage machinery) / improves water holding/infiltration capacity of soil;
e. Rotational grazing/managing stocking density reduces soil compaction (by preventing overgrazing);
f. Drip irrigation to reduce water erosion;

Note to examiners: Do not credit techniques that are not clearly linked to soil erosion (e.g. crop rotation). As an "outline" there needs to be a little more than simply stating a technique.

Explain how overgrazing could impact soil quality.
a. Overgrazing removes plants from the system/reduces plant cover;
b. Reduced plant cover/fewer roots can lead to wind/water erosion;
c. Fewer plants mean less organic matter returned to the soil reducing nutrient availability/ water retention;
d. Overgrazing can lead to soil compaction;
e. Soil compaction could reduce porosity/water infiltration/soil holding capacity / increase run-off/water erosion;
f. Soil compaction could increase water logging could reduce available nitrogen/ nitrification/nitrogen fixation/increase denitrification;
g. Erosion/compaction of topsoil could greatly reduce microorganisms responsible for nutrient cycling;
h. Erosion can reduce the mineral and nutrient availability to soil;
i. Feces from animals can add nutrients/fertilizer to soil / can affect soil pH;