Sustainable Agriculture and Food: Four volume set (Earthscan Reference Collections)

28 The Global Food System

More terracing and more erosion

Despite decades of effort, soil and water conservation programmes have had sur-
prisingly little success in preventing erosion. The quantitative achievements of
some programmes can appear impressive. In Lesotho, all the uplands were said to
be protected by buffer stripping by 1960; in Malawi (then Nyasaland), 118,000km
of bunds were constructed on 416,000ha between 1945–1960; and in Zambia
(then North Rhodesia), half the native land in eastern province was said to be
protected by contour strips by 1950 (Stocking, 1985). In Ethiopia, during the late
1970s and 1980s, some 200,000km of terracing were constructed and 45 million
trees planted (Mitchell, 1987).
Ironically, though, many programmes have actually increased the amount of
soil eroding from farms. This is because these impressive achievements have mostly
been short lived. Because of a lack of consultation and participation, local people,
whose land is being rehabilitated, find themselves participating for no other reason
than to receive food or cash. Seldom are the structures maintained, so conservation

Table 1.4 Selection of the on- and off-site costs of soil erosion

On-site costs

Mali (1988) US$4.6–18.7 million per year

Equivalent to 3–13 per cent of agricultural GDP and

1.7 per cent total GDP

Malawi (1980s) US$25 million per year

Equivalent to 14.6 per cent of agricultural GDP and 4.8 per

cent total GDP

Java, Indonesia (1980s) US$320 million per year

Equivalent to 3 per cent of agricultural GDP

Off-site costs

US (1990) US$10,150 million of damage to freshwater and marine

recreation, to water storage, navigation, flooding, fishing,

water treatment, irrigation channels, roadside ditches and

steam cooling

Cape Verde (1984) US$2.6 million from a single storm

Java (1980s) US$25–90 million per year for sedimentation

Thailand (1980s) US$18 million per year for sedimentation

UK (1982–87):

Mile Oak, Sussex £105,000 of damage to housing, plus £150,000 on flood

alleviation works

Rottingdean, Sussex £400,000 of damage to 40 houses, gardens and roads

Breaky Bottom, Sussex £81,000 of damage to vineyard

Sources: Ribaudo, 1989; Boardman and Evans, 1991; Bishop, 1990; Bishop and Allen, 1989;
Attaviroj, 1991; Haagsma, 1990; Magrath and Arens, 1989; Faeth et al, 1991; Robinson and
Blackman, 1990