GEO Brasil - UNEP

environmental availability (shallow, rocky or saline soils in
arid climates), which have currently been used for extensive
cattle raising, subsistence farming and cotton plantations,
in narrow land belts
34 Decharacterisation of humid areas
Humid areas in Brazil add up to 447 million ha or 5 percent
of the territory Also known as meadow soils solos de
várzeas, the are mostly constituted by Organossolos,
Gleissolos e Neossolos Despite the small extension they
represent in the total Earth surface, they are extremely
relevant to certain economies due to their agricultural
potential Generally, these soils are especially used in an
intensive manner for the production of rice, sugar cane,
olerícolas and livestock When drained and/or cultivated,
they are subject to considerable changes in their attributes
The UN Convention to Combat Desertification (United
Nations, 2001) has defined desertification as “land
degradation in arid, semi-arid and dry sub-humid areas
brought about by factors such as climatic variation and
human activity” This refers to degradation of soil, fauna,
flora and water resources Arid and semi-arid areas in the
Northeast are the most vulnerable to desertification
for instance) causes expressive quantity and quality
alterations in its organic matter owing to oxidation,
affecting physical, chemical and morphological properties,
besides hampering productivity Spontaneous burning in
Organossolos, as seen during drought periods at the
Golden Lion Tamarin Reserve in Silva Jardim, state of Rio
Superphosphate costing around R$483 million e 3 million
tonnes of Potassium Chloride at R$1,7 billion In order to
make up for N and S depletions, around 5,3 million tonnes
of Urea or R$2,77 billion and 995,000 tonnes of Amonium
Sulphate at R$394 million are necessary As organic fertilisers
are necessary to replace organic matters, almost R$2,06 billion
must be added to the costs above In conclusion, it is
estimated that water erosion should generate a total loss of
around R$ 79 billion every year, spent on Lime, chemical and
organic fertilisers
The effect of erosion on land depreciation may also be
evaluated in light of other studies (Landers et al, 2001a) about
cost of water treatment for human consumption (Bassi, 1999),
road conservation costs (Bragagnolo et al, 1997) and reservoir
restocking, as a consequence of the annual loss of water
storage capacity (Carvalho et al, 2000) If all the impact costs
are added, a partial estimate –as there is an extensive list of
unmentioned effects – would be R$ 133 billion(Table 08)
de Janeiro is an example of inadequate soil management
and/or excessive draining
the state of environment in Brazil
Exploitation consisting of small and medium land
shares together with the average population density of
15-20 inhabitants/km 2 exert a lot of population pressure
on soil and vegetation Thus, the amount of vulnerable
areas to desertification must be larger than previously
estimated
As a result, some of these areas have been degraded by
desertification Four degradation zones, where extremely
severe degradation is concentrated on small portions of
land (about 15,000 Km 2 ), have been recently divided:
Gilbués in the State of Piaui, Irauçuba in the State of Ceará,
Seridó between Rio Grande do Norte and Paraiba, and
Cabrobó in Pernambuco
Intensive and inadequate use of land (excessive draining,
Although official data is not available, it is estimated that
soil decharacterisation occurs in all parts of Brazil, due to
draining for agricultural purposes and sedimentation
resulting from erosion in highlands A typical example of
the latter is may be observed on the Pantanal Plain in the
State of Mato Grosso In addition, macro-draining and
river straightening actions for sanitation purposes, as seen
during the 1960s and 1970s, totally decharacterised soils
originally classified as Organossolos and Gleissolos in the
States of Rio de Janeiro, Espírito Santo and others These
works also caused an increase in salinisation an/or extreme
acidification of acidic sulfate soils, in several States, with
negative impacts on water resources and the ichthyofauna
even nowadays
35 Sandification
Sandification is here defined as the process of re-projection
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