Avaliação dos atributos físicos dos horizontes com e sem caráter coeso de um Argissolo Amarelo

• Autor(a) principal: Ribeiro, Sharon Gomes
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/40009
• topic: Adensamento; Porosidade; Atributos físicos

Soils of Coastal Boards represent a significant portion in the Brazilian Northeast, with Latossolos Amarelos and Argissolos Amarelos most frequently found in this geoenvironmental unit, these soils commonly have a diagnostic attribute called cohesive in one or more subsurface horizons and have a very hard to extremely hard consistency when dried, and when moistened they exhibit friable or firm consistency. Based on the hypothesis that cohesive horizons present features that influence its densification, the present work aimed to perform the physical evaluation of a Bt horizon morphologically characterized as cohesive, making a comparison with a horizon without cohesive character. Samples were collected in duplicate of the A horizon that does not have a cohesive character and Bt horizon with a cohesive character of a Argissolo Amarelo Eutrocoeso típico, located in Campus do Pici of the Universidade Federal do Ceará for the evaluation of soil and particle density, total porosity, macro and microporosity, and preparation of the water retention characteristic curve in the soil using the Van Genuchten model for moisture adjustment, applying stresses of 0, 2, 4, 6, 8, 10, 33, 100, 700 and 1500 kPa, while for the granulometry, the samples were analyzed in triplicate. As far as the granulometry is concerned, the cohesive horizon presented a clay-sandy loam texture, while the non-cohesive horizon was classified as free sand, it was observed that, in the sand fraction, both horizons presented predominance of medium and fine sand, with a reduction of total sand and a clay accumulation in depth. The Bt horizon with cohesive character also presented a soil density of 1.52 g cm-3, being higher than that verified in horizon A, of 1.40 g cm-3, but presented a relatively lower density of particles. The total porosity was also reduced in depth, that is, the horizon A presented a higher total pore volume as well as macropore volume, while the Bt horizon with cohesive character showed a dominance of microporosity. The characteristic water retention curve showed that the cohesive horizon has the capacity to retain more moisture in relation to the A horizon even under high stress. With this, the analyzes carried out in this research confirmed the characterization of the Bt horizon with cohesive character regarding its physical aspect.