Atenuação de riscos em sistemas de terraceamento em Goiás

• Autor(a) principal: OLIVEIRA, Janaina de Moura
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/2645
• topic: erosão; conservação do solo; desuniformidade de terraços; irregularidade em terraços; atuação profissional; 1.Erosão - Goiás [Estado] 2.Conservação do solo 3.Desuniformidade de terraços 4.Irregularidade em terraços 5.Atuação profissional; erosion; soil conservation; terraces inequality; professional action; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA

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.