GEO Brasil - UNEP

soil conditions
Losses of 600 million tonnes were
broadcast in 1992 (Bahia et al, 1992)
the state of the environmet in Brazil
Box 1 - Economic Valuing of Losses
A erosão gera perdas anuais correspondentes a 15,2 milhões de t de Calcário Dolomítico (23
percent de CaO) valorados em R$563 milhões; 879 mil t de Superfosfato Triplo que valem R$483
milhões e 3 milhões de t de Cloreto de Potássio valorados em R$1,7 bilhões A reposição das
perdas de N e S, totalizam 5,3 milhões de t de Uréia ou R$2,77 bilhões e 995 mil t de Sulfato de
Amônio custando R$394 milhões Somando-se a esses valores R$2,06 bilhões que é o custo do
adubo orgânico necessário à reposição da matéria orgânica ao solo, estima-se que a erosão hídrica
gere um prejuízo total relativo às perdas de fertilizante, calcário e adubo orgânico, da ordem de R$
7,9 bilhões por ano
Pode-se ainda estimar com base em diferentes autores, o efeito da erosão na depreciação da terra
(Landers et al, 2001a), no custo do tratamento de água para consumo humano (Bassi, 1999), no
custo de manutenção de estradas (Bragagnolo et al, 1997) e na reposição de reservatórios,
decorrente da perda anual da capacidade de armazenamento hídrico (Carvalho et al, 2000)
Somando-se os impactos anteriores estima-se, de forma parcial (há uma extensa relação de
efeitos aqui não valorados), que a erosão promoveria R$13,3 bilhões de prejuízos por ano (Tabela
8)
Table 8 - Valuing of Soil Erosion Impacts in Brazil
Nowadays, due to the expansion of the
agricultural area and the intensive use
of the land, soil losses have increased
in some regions Considering the total
area taken by agricultural lands (annual
and perennial) and pastures (natural
and cultivated) reported in the
Agricultural and Cattle - Ranching
Census of 1995/1996, and admitting
average annual losses of 150 tonnes
ha -1 for agricultural land (Bragagnolo
& Pan, 2000) and 0,4 t ha -1 for pastures
(Bertoni & Lombardi Neto, 1990), total
soil losses added up to 8227 million
tonnes per year – 7516 million in
agricultural lands and 71,1 million
tonnes due to pastures (Table 31) In
the end, 247 million tonnes of
sediments (or 30 percent) out of that
amount may have been stored in rivers,
dams and roads, causing great socioeconomic
and environmental
drawbacks Even higher numbers were
obtained by Vergara Filho (1994), who
calculated that annual soil losses in
Brazil were around 1,054 billion tonnes
1 US$ = 2,5 R$
Fonte: Baseado em Landers et al - 2001a; Bassi - 1999; Bragagnolo et al - 1997 e Carvalho et al - 2000
three stages: disaggregation, transport
and deposal Its main manifestations
are laminar, sulcos and major erosion
tendencies (Bertoni & Lombardi Neto,
1990) In 1982, it was calculated that
125 million tonnes of sediments were
released every year into the reservoir of
the Itaipu hydroelectric power plant, 4,8
million tonnes coming from the State
of Paraná (Derpsch et al, 1991) In Sao
Paulo, for every 194 million tonnes of
fertile land eroded yearly, 485 million
have caused sand accumulation and
pollution in water springs This means
that, for every kilo of soy, 10 kilos of
soil eroded and for every kilo of cotton,
12 kilos of eroded soil (Bertolini et al,
1993) In the state of Rio Grande do
Sul, soil losses reported added up to
40 tonne ha- 1 year -1 (Schmidt 1989) In
1949, it was estimated that losses of
500 million tonnes of land would occur
in Brazil every year, caused by erosion
(Bertoni & Lombardi Neto, 1990)
Besides the suspended soil particles,
superficial drainage washes out
nutrients, organic matter seeds and
pesticides that pollute water resources
and hinders agriculture and cattle
raising activities According to Hernani
et al (1999) and the data previously
shown, calcium depletion may be
around 25 million tonnes Other
mineral depletions are: Mg, 186,000, P,
142,000, K, 1,45 million tonnes and 26
million tonnes of organic matter
Considering N and S depletions of
863,000 e 86,000 caused by erosion in
agricultural lands (Malavolta, 1992), and
50 percent lower depletion in pastures,
it was estimated that total depletion
would be about 24 million and 239,000
tonnes every year
According to De Maria (1999), water
depletion amounts to 2,519 m 3 ha -1 /
year -1 in cultivated agricultural lands
and one tenth of this number in
pastures Thus the estimated annual
water depletion adds up to 126,2 billion
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