Managing Arid Areas and Sand Dunes in Sri Lanka - Combating Desertification in Asia, Africa and the Middle East - page 321

• Farmers who do not see the short term benefits of implementing soil conservation

and who have no concern for soil conservation

• Inadequate attention on soil conservation particularly in annual cropping

• Inadequate legislation or non-implementation of available legislation towards

proper use of lands

• Land fragmentation, ownership and unfavorable tenancy condition (land tenure

issues)

• Lack of proper land use policies

• Ad hoc planning of infrastructure development or lack of holistic approach

• Lack of efficiency in plan implementation

• Decision makers/Politicians still use land allocation among poor unemployed

citizens as a means of employment generation

• Lack of incentives for proper land use

• Lack of collaboration in related institutes, departments etc.

In Sri Lanka, the major contributors to land degradation are (i) soil erosion
and (ii) soil fertility degradation. Over exploitation of ground water, salinization,
water logging and water pollution are also becoming important contribution to land
degradation. According to the Global Assessment of soil degradation (GLASOD
1990 ), about 50 % of land is degraded. The area affected by soil fertility decline is
61 % of the total agricultural land.

4.2 Soil Erosion

It has been estimated that nearly one-third of the land in the country is prone to
soil erosion; the proportion eroded ranging from less than 10 % in some districts to
over 50 % in others. Much of the erosion has been taking place in the hill country,
the problem being given over to the cultivation of highly erosive temporary crops
such as vegetables, potatoes, tobacco and seedling tea. The highest figures of soil
loss in mid country wet zone and intermediate zone are 40 tons/ha/year for old seed
tea plantation and 70 tons/ha/year for tobacco cultivation with no soil conservation
measures adopted (Fig. 16.5 ).
A clear pattern of soil erosion has been observed in the Hill Country, mid country
and the low country. Comparative studies of erosion by zones have shown that mid
country to be the most vulnerable to erosion. Soil loss by erosion varies between
regions and ranges from 140 tonnes per ha each year (t/ha/yr) in the low country to
over 1,020 t/ha/yr in the mid country. High country losses are 412 t/ha/yr. According
to the National Report on Desertification/Land Degradation in Sri Lanka (2000),
the on-site and offsite costs of soil erosion have been estimated in recent studies.
Some of the estimates are: (A) Onsite cost - (1) Value of loss of productivity -
Rs. 3,529 ha/yr; (2) Value of loss of nutrients - Rs. 5,068 ha/yr; (3) Estimated cost
due to nutrient loss in Upper Mahaweli watershed - Rs. 953.0 million (B) Offsite
cost - (1) Based on value of loss of productivity - Rs. 3,952 ha/yr; (2) Based
on value of loss of nutrient - Rs. 5,481 ha/yr; (3) Estimated loss in hydro-power
production and irrigation from the Upper Mahaweli Watershed - Rs. 15.0 million
per annum.