World’s Soil Resources

Some examples of analysis of the data show the value of the national assessment:
1. The analysis of the socio-economic drivers of land degradation in the country showed that poverty and
population pressure are the main drivers, while governance and education are also significant. Land
tenure and conflict situations were reported to be of minor importance as drivers of land degradation
in Senegal.
2. It is population pressure and poverty which lead in a majority of cases to deforestation and overgrazing
and which, together with lack of access to extension services, lead to unsustainable soil and crop
management. Urbanisation and mining are minor pressures in the country.
3. Impacts of land degradation on ecosystem goods and services fell mainly on the productive services
(affecting 15 percent of the area), while impacts on ecological services, in particular on biodiversity,
were slightly less (13 percent). The influence on the socio-cultural provisioning services was the
smallest, affecting only 6 percent of the area.
4.
Further field and socio-economic studies were undertaken at the local level, both in areas that were
considered ‘hotspots’ for degradation and in ‘bright spots’ where degradation was less prevalent and
sustainable management was practiced.
The analysis of results in these local areas is illustrated in Figure 9.9 which gives the impact of degradation
on the various ecosystem services. There is a major impact on the net returns of the farmers in all areas, but
there are also important differences according to the different situations in each zone.
Figure 9.9 Impact of degradation on ecosystem
services in the local study areas in Senegal.
Source: Ndiaye and Dieng, 2013.
Responses have included measures implemented by the government, NGOs, the communities themselves
and local producers. The principal responses were: assisted natural regeneration, agro-forestry, application of
organic amendments, introduction or extension of fallow periods, composting, and using a millet/groundnut
rotation. Most of these responses have proved to be efficient, but their adoption by land users has been slow,
affected by lack of information and by economic and/or political constraints.
9.5.2 | South Africa
Of South Africa’s total area of 123.4 million ha, arable land accounts for only 11 -1 5 percent. Of this arable
land, only about a quarter is high potential. This high potential land is thus a critical resource which needs to
be protected. South Africa’s soils are diverse and complex as a result of varied soil formation and weathering
processes. The largest proportion (81 percent) are slightly weathered and calcareous soils. More than 30
percent of soils are sandy (e.g. less than 10 percent clay content) and almost 60 percent of soils have low
organic matter content (Scotney, Volschenk and Van Heerden, 1990). The most important soil limitations
are shallow depth, extremes of texture, rockiness, severe wetness and high erosion hazard. In terms of soil
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in Africa South of the Sahara