Atenuação de riscos em sistemas de terraceamento em Goiás
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Data
2009-06-05
Autores
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Universidade Federal de Goiás
Resumo
The design, implementation and maintenance of terracing does not always
follow technical standards, resulting in unnecessary costs or structures failure risks. This
study quantified by means of simulations, the increase in the recommended ridge height of
level terraces (Hr) promoted by the use of uniformity coefficients (Cd), relating them to the
ridge height promoted by change in return period (TR). These were conducted using the
software Terrace 3.0, which were determined Hr to 10 locations in the state of Goias,
Brazil. For this purpose was considered a standard condition, changing between systems of
conventional tillage and no till and varying the TR and Cd. Also been raised, through
interviews with agronomists, the aspects were that used in the design and implementation
of this soil conservation practice. We evaluated also the uniformity of level terraces in five
areas, in which readings were the height of ridge using an engineer level. In points of
highest and lowest reading of each terrace were raised sections of accumulation. The
simulations were obtained Hr average of 40.8 cm for conventional tillage and 47.7 cm for
no-tillage system. On average, an increase of 0.1 in Cd value, was equal to the change in 5
years or more in the TR. Major differences were generate with use of Cd. Hr generate by
Cd 1.7 was equivalent to a 113.39 years to TR value for conventional tillage and 112.12
years for no till. The average increase in Hr for each increment of 5 years in the TR or 0.1
on the Cd was, in all cases, less than two centimeters. According to the interviews, in
general, agronomists contract another professional to design and employ the project.
Interviewed professionals don t realize terracing projects and not consider technical criteria
for the design and deployment of the system. On field measurements don t was observed
uniformity in any of the terraces studied, and in some cases, the height read at one point
was below the bottom of the channel in another position in the same terrace. The
unevenness in the ridge section between the highest and lowest ranged from 18 cm to 60.5
cm. Real accumulation section ranged from 0.0 m2 to 1.4 m2. Based on the results, it is
concluded that: needs to be included in the design of terracing systems the use of Cd or
increased TR values. The system design doesn t consider technical criteria, resulting in
inefficiency and, the terraces deployed present deficiencies that compromise their
performance.
Descrição
Palavras-chave
erosão , conservação do solo , desuniformidade de terraços , irregularidade
em terraços , atuação profissional , erosion , soil conservation , terraces inequality , professional action , 1.Erosão - Goiás [Estado] 2.Conservação do solo 3.Desuniformidade de terraços 4.Irregularidade em terraços 5.Atuação profissional
Citação
OLIVEIRA, Janaina de Moura. Mitigation of risks to systems of terraces in Goiás. 2009. 75 f. Dissertação (Mestrado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2009.