Geoscience Reference
In-Depth Information
Fig. 16.5 Erosion damages
crops and makes areas of land
less productive. Gullying in a
cropped field can expose of
bare rocks
4.3
Soil Fertility Decline
Soil fertility decline is caused by soil erosion and poor cropping practices and nearly
1.6 Mha. of agricultural land in Sri Lanka is affected. Decline in crop yields have
been reported during the last two decades due to soil fertility loss and other forms of
degradation such as structural decline. The loss of 1 cm of top soil cover of tea and
rubber lands is associated with a decline in yield of 44 and 174 kg/ha/yr respectively.
The susceptibility to erosion (erosion hazard) has been assessed and map
prepared (Fig. 16.6 ) as a guide to land use planning agencies and those agencies
in charge of erosion control.
5
Control of Land Degradation
A major role for government is to create an enabling environment so that efforts to
control land degradation can proceed in an efficient and effective way. Typically,
government enact legislation and devise administrative regulations that are aimed at
providing constraints to developments that endanger the land and water resources
its biodiversity.
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