Dendrogeomorfologia, erosão hídrica e uso do solo em uma área urbana do município de Goiânia, Goiás, Brasil
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2020-03-31
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Universidade Federal de Goiás
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soils, especially when it is inserted in urban environments. However, methods that have enough longevity to distinguish natural and accelerated erosion events are still poorly explored in the literature. In this context, dendrogeomorphology is an important methodology to date and estimate the magnitude of erosion and sedimentation processes, with high spatiotemporal precision. In this perspective, the objective of this work was to evaluate the intensity of the erosive processes in the Botanical Garden Amália Hermano Teixeira (JBAHT), using dendrogeomorphological indicators of the exposed roots wood and the rates of soil loss and annual sedimentation. The methodological procedures consisted of carrying out analyzes of the historical influence of use and occupation of the surrounding soils, the analysis of urban drainage and the texture and fertility of the soils. To determine the anthropic influence on the growth of individuals in the forest fragment of the Botanical Garden, two species were chosen, Anadenanthera macrocarpa and Schefflera morototoni. The analysis of the history of land occupation and use revealed intense changes in soil waterproofing from 1988 to 1992 and the analysis of the efficiency of the urban microgeneration system was characterized, predominantly as compromised, which allowed to infer association with the high rates of movement of land. soils in the forest fragment. The dendrochronological results indicated that the studied species showed high sensitivity to the external environment and formation of annual growth rings. Dendrogeomorphological analyzes revealed that the highest vertical rates of soil loss range from 7 to 500 millimeters per year, while horizontal losses are 110 to 665 millimeters. Sedimentation rates were 6.4 to 18.6 millimeters per year and the dates of root exposures are more frequent in the years 2006, 2008, 2010 and 2013. The chronological comparison of the probable years of occurrence of water erosion by the roots exposed with the intense and erosive rains determined that the dates of occurrence of the erosive processes occurred in the years 2006, 2008, 2010, 2012, 2013 and 2016. The individual erosive rains with more than 10 millimeters in interval of 15 minutes, correlated with the number of evidence of erosion, recorded by the exposed roots wood, showed a significant correlation with a 90% confidence level. Meanwhile, the erosive rainfall defined for tropical regions, greater than 25 mm.h-1, showed a relatively high correlation of 70%. Considering this, intense and erosive rains can have significant importance in carrying soil. As well as the texture of the soils that presented high sand content, above 50% in 65% of the samples. The analysis of soil fertility for the element Potassium (K +) showed values from 2 to 27 times above the normal level. These results indicate that the high levels of Potassium (K +) may be due to urbanization by transport through rainwater pipes or by disposal of chemical waste. It is concluded that, the anthropic waterproofing alterations, the high gradient of the relief associated with the frequent occurrence of intense rains may be affecting the appearance of the erosive processes. Soil water erosion affected the growth of the trees, such as, for example, the greater growth of the sampling groups of trees with exposed roots and buried in relation to the group of trees without changes in soil level.
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NICOLAU, R. F. Dendrogeomorfologia, erosão hídrica e uso do solo em uma área urbana do município de Goiânia, Goiás, Brasil. 2020. 180 f. Dissertação (Mestrado em Ciências Ambientais) - Universidade Federal de Goiás, Goiânia, 2020.