ABSTRACT
Soil water repellency (SWR) has been detected worldwide in various biomes and climates. However, this phenomenon has not been shown yet in the Brazilian neotropical savanna. The present study addressed the following questions: (a) Does SWR occur in the Brazilian neotropical savanna? If so, (b) does it exhibit seasonality? (c) Does it influence infiltration? To do that, we selected two similar study areas covered by similar soils (oxisol) and vegetation (netropical savanna). We performed water repellency and infiltration tests in both areas during the transition from dry to wet season. Our results indicate that SWR occurs in soils of the Brazilian neotropical savanna only during the dry season and influence water infiltration in the dry season. The likely cause of SWR might be related to the chemical composition of soil organic matter since neotropical savanna plants produce hydrophobic substances as a survival strategy, especially during the dry season.
Subject(s)
Environmental Monitoring , Grassland , Brazil , Seasons , Soil , WaterABSTRACT
Plant composition, diversity and structure of riparian forests of Central Brazil are well known. However, little is known about soil physical properties under these forests. This knowledge is important as a baseline for biodiversity restoration and ecosystem services that occur in riparian zones. In order to bridge this gap, here we assessed the infiltration capacity and soil penetration resistance in a plinthic soil under gallery forest in Planaltina, Distrito Federal, Brazil. We measured infiltration capacity (Mini-Disk infiltrometer) and soil penetration resistance (Stof penetrometer) following linear transects. The plinthic soil had high infiltration capacity and low penetration resistance. Our infiltration estimate is in the middle range when compared to other permeability studies in tropical forests. Like their counterparts, high biological activity along with the lack of disturbance are the likely explanations for such high topsoil permeability to water.
As florestas de galeria são bem descritas em termos de composição, diversidade e estrutura da vegetação. No entanto, pouco se sabe sobre as propriedades físicas do solo sob essas florestas que são importantes para a restauração de zonas ripárias. A fim de preencher essa lacuna, no presente trabalho, avaliou-se a capacidade de infiltração e a resistência do solo à penetração em um solo plíntico sob floresta ripária em Planaltina, Distrito Federal, Brasil. Mediu-se a capacidade de infiltração (infiltrômetro de Mini-Disk) e a resistência à penetração no solo (penetrômetro de Stolf) seguindo transectos lineares. O solo plíntico apresentou alta capacidade de infiltração e baixa resistência à penetração. Nossa estimativa de infiltração está na faixa intermediária em comparação com outros estudos de permeabilidade em florestas tropicais. Mesmo assim, a mediana da capacidade de infiltração foi superior à intensidade de chuva de alto período de retorno o que descarta a possibilidade de escoamento superficial Hortoniano. Como em outras florestas tropicais, a alta atividade biológica junto com a ausência de perturbação do solo são as razões prováveis para essa alta permeabilidade do solo à água.
