How Can Plants Help to Stop Soil Erosion?

Method

Two seed trays were prepared. Both had sand to a depth of 3cm in them. One tray had cress seeds evenly scattered over the sand. The tray was well-watered and the seeds allowed to grow for 10 days.

After 10 days the seed trays were taken and arranged so that they sloped at an angle of approximately 30°. Plastic markers were arranged at equal distances along the centre line of each tray. Water was then poured into the trays at the top of the slope. The movement of sand and the markers was then observed.

Results

Demonstrating that plant cover reduces erosion.

It was observed that in the tray with no plant cover much of the sand was carried to the bottom end of the tray. Several plastic markers were moved, while the ones at the bottom of the tray became buried in sand. The tray with plant cover showed a little bit of sand moving but no markers were moved or buried.

Conclusion

Plant cover can considerably reduce the effect of flooding. It does this in several ways. Firstly, the roots of plants physically hold the soil together and stop it moving. Secondly, plants are constantly absorbing water through their roots and this then evaporates into the atmosphere (See our celery experiment!). This helps to reduce the amount of water that is actually in the soil. Plants also reduce the impact of raindrops on the soil as the drops hit plant leaves.


For more information about the problem of plant removal and soli erosion take a look at this Australian website — Erosion - Adelaide University


Navigation

  • Return to Science Week Index
  • Return to Science Index
  • Return to St John's Home