The demand for biodegradable composite has grown worldwide in recent years, mainly in order to reduce environmental contamination by structural materials produced from the oil industry. The objective of this study was to evaluate the growth of isolates from the edible mushroom “Shiitake” (Lentinula edodes) in substrate coconut powder-based supplemented with wheat bran, as well as to analyze the influence of fungi growing period and drying time of the colonized substrate on the mechanical properties of the composite, in order to produce a biodegradable composite. The mycelial density is not influenced by the type of hyphae of L. edodes. Drying of the composite does not influence the residual odor, depending on the isolate. The compressive strength and foam type of the fungal composite may be influenced by the culture period and type of hyphae, depending on the fungal isolate. The composites colonized by the L. edodes isolates presented higher mechanical resistance at 30 days of complete colonization. The coconut powder supplemented with wheat bran colonized by isolated fungi LED 96/18 is an ecological alternative in the packaging production considering its mechanical properties.

Os taludes marginais no baixo curso do Rio São Francisco, dominados por solos de baixa coesão sofrem com o avanço da erosão que causa recuo da margem e assoreamento do canal. A proposta deste trabalho foi estudar a aplicação da bioengenharia de solos visando ao controle da erosão por meio da estabilização dos taludes marginais, para posterior recuperação da vegetação ciliar. A área experimental foi dividida em dois tratamentos com 3 repetições, sendo o tratamento sem uso de bioengenharia (testemunha) implantado à montante do fluxo da água e o tratamento com uso de bioengenharia, à jusante. A técnica de bioengenharia de solos foi caracterizada pela associação do geotêxtil Fibrax® 400 BF com gramínea Brachiaria decumbens, e retentores de sedimentos (Bermalongas®) ao longo da linha d'água. Para avaliação do comportamento do talude realizou-se levantamento topográfico planialtimétrico aos 30, 180, 360 e 540 dias de implantação do experimento. No tratamento sem proteção de bioengenharia (testemunha) ocorreram variações significativas no perfil topográfico, enquanto no talude protegido com bioengenharia ocorreram movimentos de massa pouco expressivos.

Changes in the hydrological regime of the Lower São Francisco River, located in Northeastern Brazil have brought negative environmental impacts, jeopardizing the flora and fauna of a global biodiversity hotspot, due to implementation of hydroelectric power dams and surface water withdrawal for irrigation in public and private perimeters. Remnants of the riparian stratum associated to the riverbank destabilization in six fragments were studied by surveying trees, shrubs, herbs, and aquatic species. The calculation of the Factor of Safety (FS) was performed in order to understand the riverbank's stability related to soil texture and vegetation cover. An overall number of 51 botanic families distributed in 71 genera and 79 species were recorded, predominantly from the families Mimosaceae, Myrtaceae, and Fabaceae. The fragmented riparian vegetation is mostly covered by secondary species under a strong anthropogenic impact such as deforestation, mining and irrigation, with an advanced erosion process in the river margins. Strong species that withstand the waves present in the river flow are needed to reduce the constant landslides that are mainly responsible for the river sedimentation and loss of productive lands. A lack of preservation attitude among the local landholders was identified, and constitutes a continuing threat to the riparian ecosystem biodiversity.

A Bacia Hidrográfica do rio São Francisco, vem sendo submetida a fortes impactos ambientais por meio de alterações do regime hidrológico e sedimentológico, além de avançada destruição da sua mata ciliar. A vegetação ciliar possui importante função na proteção das margens dos rios promovida pela cobertura vegetal e seu sistema radicular, melhorando a agregação de um solo pouco coeso, diminuindo o arraste de partículas e, consequentemente resultando em menor taxa de erosão e assoreamento do curso d'água. Este trabalho teve como objetivo avaliar o crescimento inicial de espécies florestais em talude marginal submetido à técnica de bioengenharia de solos no rio São Francisco. A bioengenharia de solos foi composta pela cobertura longitudinal do talude com o biotêxtil (Tela Fibrax® 400BF), e em razão das variações diárias de cota do rio foram também utilizados retentores de sedimentos (Bemalonga® D40) para redução ao impacto da água na base do talude, evitando o solapamento promovido pelo fluxo e refluxo das ondas. Antes da fixação do biotêxtil, foram semeadas a lanço sementes da espécie Brachiaria decumbens para promoção de uma rápida cobertura vegetal. Em seguida foram plantadas mudas de seis espécies florestais nativas da região: aroeira vermelha (Schinus terebinthifolius Raddi.), pau-pombo (Tapirira guianensis Aubl.), mulungu (Erythrina velutina Willd.), tamboril (Enterolobium contortisiliquum (Vellozo) Morong), canafístula (Cassia grandis L.f.) e pau-ferro (Caesalpinia leiostachya (Bentham) Ducke). O desenvolvimento das mudas foi analisado por meio da Taxa de Crescimento Relativo de Altura da parte aérea e Diâmetro do colo. Após 360 dias, ao final das avaliações, observou-se que o maior número de indivíduos vivos foi identificado no tratamento com bioengenharia de solos. A grande densidade e agressivo crescimento da espécie Brachiaria decumbens na área com biotêxtil, trouxe danos para o desenvolvimento inicial das mudas arbóreas.

The control of soil erosion along the banks of the São Francisco River requires the use of efficient and economically viable strategies. Soil bioengineering techniques may be an alternative to the conventional methods as they provide good soil stabilization by mechanical reinforcement promoted by the roots. The objective of this study was to evaluate the contribution of the root cohesion of vetiver grass (Chrysopogon zizanioides (L.) Roberty) on slope stabilization in erosion control along the right margin of the São Francisco river. Seedlings of vetiver grass were planted in the riverbank of the Lower São Francisco located in Sergipe State, northeast Brazil, and plants were sampled after two years of growth to evaluate the effect of grass on the shear strength of the soil. The monolith and cylinder method was used to collect roots for the evaluation of Root Density (RL), Root Length Density (RLD), Root Area Ratio (RAR), Root Tensile Strength (TR), and Root Cohesion (CR). Data were submitted to analysis of variance (p < 0.05), with polynomial regression analysis. The results show that for RL, RLD, and RAR, the layers of soil at depths of 0-0.10 m had the highest values of 4.84 kg m-3, 12.45 km m-3, 1.66%, respectively. The mean TR was 83 MPa and CR was 528 kPa. Vetiver increases shear strength of the soil and slope stabilization.

Geotextiles made from plant fibers creates a suitable environment for plant growth as part of soil bioengineering techniques. The faster decomposition of plant fiber geotextiles compared to synthetic ones demands the use of composites that enhance their waterproofing and extend their durability in the environment. The objective of this work was to evaluate the resistance of a geotextile made with Thypha domingensis to degradation caused by climatic variables. Tensile strength tests were conducted in the laboratory in order to evaluate the degradation of geotextiles treated with single and double layers of waterproofing resin. Based on Scanning Electron Microscopy (SEM) images, it was verified that applying double layer of waterproofing resin delays the fibers degradation up to 120 days of exposure to the effects of climatic variables other than temperature. The maximum resistance losses due to the geotextile's exposure to degradation were statistically significant for all three treatments: control-without waterproofing resin, with one layer resin, and with two layers resin. Therefore, waterproofing resin, provides a long-term protective solution for geotextiles made from cattail fibers.