Soil erosion
Soil erosion is the mechanical removal of soil by rainwater, which washes away the surface layers.
Soil erosion involves two soil degradation processes :
- capping, which reduces water infiltration
- erodibility, which reflects a soil's susceptibility to the removal and transport of particles by rain and run-off.
In the long term, erosion can lead to irreversible soil degradation. It is often reinforced by human action.
It poses a real problem for farmers : as well as causing gullies to form and the land to subside, it also leads to the loss of fertile elements contained in the soil, a deterioration in water quality and the displacement of sediments that form mudflows.
File:Soil erosion.png
Soil erosion risk in small agricultural areas
What can be done to limit soil erosion?
Agronomic measures
- Planting crops perpendicular to the direction of the slope will reduce the intensity of runoff. Crop rows act as a physical barrier to water run-off.
- Avoid soil compaction, which will limit water infiltration and increase run-off. To do this, you need to work the soil or use suitable equipment.
- Once the soil has been worked, it should not be smooth, but lumpy and rough, to limit run-off.
- Avoid ploughing, which leaves the soil bare to the mechanical action of rain.
- Cover the soil with a mulch to provide a physical barrier to the action of the rain and avoid the "splash effect". This mulch can be natural (plant residues on the surface of the previous crop) or artificial (straw).
- Plant intercrops. This will avoid having bare soil between two crops. They can play a beneficial role for the soil, such as trapping nitrates, having a structuring effect on the soil but also a fertilising effect and limiting weed pressure.
- A well thought-out crop rotation will have an impact on the soil's resistance to run-off.
Creating barriers to run-off
- Ponds and hillside reservoirs retain water and sediment. They form a water reserve that can be used at a later date.
- Embankments slow down run-off and encourage infiltration.
- Hedges, with their roots, encourage infiltration and water absorption.
- Break up run-off paths with roads across the slope.
- Install grassed strips at least 30 cm wide along the slope.
- Ditches or drains will channel the water away from the plot.
Articles dans cette thématique
Is there a topic missing to add to this section? Feel free to suggest it in the forum!
Sources
- https://agrisur.fr/guides/limiter-lerosion-des-sols
- https://www.gissol.fr/thematiques/erosion-des-sols-48
