Geoambientes na RPPN Capivari II e monitoramento térmico e hídrico em solos de canga ferrífera e quartzito, Quadrilátero Ferrífero Minas Gerais

• Ano de defesa: 2013
• Autor(a) principal: Ferrari, Lucas Teixeira
• Orientador(a): Schaefer, Carlos Ernesto Gonçalves Reynaud
• Banca de defesa: Mendonça, Bruno Araujo Furtado de , Fernandes Filho, Elpídio Inácio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: Canga; Gradientes de solo e vegetação; Dinâmica físico-hídrica
• Palavras-chave em Inglês: Canga; Gradients of soil and vegetation; Physical and water dynamic
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5514

The Iron Quadrangle (IQ) in Minas Gerais State is a mountainous region with rather peculiar ecosystems, conditioned by the heterogeneity of the landscape, composed of various geological substrates. The more resistant and prominent rocks in the landscape, such as quartzites and itabirites, support diverse rocky environments with high number of endemics. Despite the importance of ecosystems conservation, for many years the iron ore has been mined in IQ, removing the lateritic surface (canga) and the associated vegetation growing on it. However, the ecological studies of this peculiar vegetation are scarce and necessary to understand its environmental importance. The region posseses several IQ conservation units, such as the Private Natural Reserves (PNR), belonging to mining companies, requiring integrated environmental studies, needed for the appropriate management of these areas and promoting long-term ecological research. This project aimed to enhance the knowledge about the relationship between soil and vegetation in the IQ. For this purpose, two separate chapters were developed. In the first chapter, we made the geoenvironmental stratification of the PNR Capivari II, in which the geoenvironmental units were described, mapped and identified using high-resolution Ikonos image, geological map in ArcGIS 10 program and field campaings. In chapter 2, we characterized and compared the thermic and water dynamics of soils on canga and quartzite substrates, in IQ. For this purpose, we conducted for in situ monitoring of soil moisture, soil temperature and air temperature in four different environments for 14 months, namely: Rocky Field on Canga (CC), Forest on Canga (MC), Rocky Field on Quartzite (CQ) and Forest on Quartzite (MQ). The soil moisture monitoring method was based on the TDR (Time Domain Reflectometer), by means of calibration of sensors in laboratory, in which the propagation time of electromagnetic pulse detected by sensors installed in the soil were converted into gravimetric moisture values. Representative soil profiles at each environment sampled, both in the PNR as the monitoring sites were described and classified according to the Brazilian System of Soil Classification and soil samples were subjected to physical and chemical routine analysis at the Soil Science Department of UFV. The PNR Capivari II presented 10 different geoenvironmental units, mostly represented by shallow, rocky and nutrient-poor soils and grassy vegetation; geoenviroments with forest and shruby vegetation are restricted to areas with greater moisture, provided by soil depth and landscape position, or protected areas from the action of fire, due to the soil rockiness/stoniness. The mapping also revealed its environmental fragility, and showed how diverse is the landscape in IQ, even in areas of limited size. The thermic and hydric dynamic characterization showed the influence of temperature, soil moisture and depth on vegetation physiognomies in canga and quartzite. The data also revealed the magnitude of temperature and soil moisture variations, highlighting the extreme environmental conditions to which these plant comunities are subjected. Results allowed a deeper understanding of the pedoclimatic dynamics in these environments. The use of TDR equipment for the soil moisture determination presents some methodological challenges, like its correct installation on the field, as well as the soil density determination, required for sensors calibration. Finally, the studies illustrated the close relationship between soil and vegetation in IQ, a region with considerable environmental fragility, offering new challenges for further investigations on the adaptation mechanisms of plants that are naturally adapted to these environments.