Geoscience Reference
In-Depth Information
Figure 26.1. Reclaimed gully, middle Son Valley, north-central India.
vulnerable to accelerated soil erosion from wind and water and/or salt accumulation,
depending on the type of soil.
Fortunately, even quite simple measures can be used to minimise soil erosion. In
North Africa, the Romans built stone dams across the coastal stream channels to trap
sediment behind the dams, which in turn trapped water within the sediments, so wheat
could be grown and olive trees planted. Two thousand years later, the farmers in the
arid limestone country of Tunisia use the same technique, and flourishing groves of
date palms or olive trees may be seen in the valley bottoms. In the gullied lands
adjacent to the Son Valley in semi-arid north-central India, the local peasant farmers
build check dams of soil eroded from the gully walls and obtain two crops a year
from the small fields within the gullies upstream of each earth dam (
Figure 26.1
).
