ABSTRACT Inadequate management of pasture soils in the Amazon has resulted in a predominance of degraded pastures. Considering the natural characteristics of this region can favor more appropriate strategies for sustainability, the objective of this study was to evaluate the differences in the chemical and physical attributes of pasture and forest soils in the Southern Amazon and to identify the most sensitive attributes of their fertility. Additionally, this study suggests appropriate management practices for sustainable pastures. Soil samples from the 0 to 0.20 m layer were analyzed to determine pH, exchangeable bases (calcium, magnesium, and potassium), exchangeable aluminum, potential acidity, phosphorus, organic carbon, bulk density, and texture. Pasture soils had a higher pH, calcium content, and bulk density than forest soils. However, the pasture soils had lower phosphorus and organic matter content. The soil organic carbon stocks were also lower in pasture soils, with levels 0.8 to 12 Mg ha-1 lower than in forest soils. The fertility attributes most sensitive to soil management in these pastures were phosphorus, pH, organic carbon, and bulk density. The lack of nutrients and soil and water conservation practices have contributed to the degradation of these pastures. Therefore, the recommended management for these pastures should aim to improve the organic matter content, reduce compaction, and replenish and cycle nutrients.

RESUMO O manejo inadequado de solos de pastagens na Amazônia resulta em predomínio de pastagens degradadas. Considerando as características naturais dessa região pode favorecer estratégias mais adequadas para sua sustentabilidade, o objetivo desse estudo foi avaliar as diferenças de atributos químicos e físicos de solos de pastagens e florestas no sul da Amazônia e identificar os atributos mais sensíveis de sua fertilidade. Além disso, sugerir práticas de manejo mais adequadas para essas pastagens em direção à sustentabilidade. Amostras de solo da camada de 0 a 0,20 m foram analisadas para determinação de pH, bases trocáveis (cálcio, magnésio e potássio), alumínio trocável, acidez potencial, fósforo, carbono orgânico, densidade aparente e textura. Os solos de pastagem tiveram maior pH, cálcio e densidade aparente do que os solos de floresta. No entanto, os solos de pastagem apresentaram menores teores de fósforo e matéria orgânica. Os estoques de carbono orgânico do solo também foram menores nas pastagens, com teores de 0,8 a 12 Mg ha-1 inferiores aos solos da floresta. Os atributos de fertilidade mais sensíveis ao manejo do solo nessas pastagens foram fósforo, pH, carbono orgânico e densidade aparente. A carência de nutrientes e de práticas de conservação do solo e da água têm contribuído para o estado de degradação dessas pastagens. Portanto, o manejo recomendado para essas pastagens deve visar a melhoria da matéria orgânica, redução da compactação, além da reposição e ciclagem de nutrientes.

Summary: Amphipterigyum adstringens “cuachalalate” is growing on degraded soils of the low deciduous forest of the coast of Oaxaca. Two objectives were carried out: 1. On cuachalalate: to define the vertical and horizontal population structure, to identify the dispersal pattern of the individuals, and observe the period of the phenological phases. 2. On the soil: to determinate the physical and chemical characteristics of the degraded Lithosol of San Pedro Mixtepec, Oaxaca, where cuachalalate is growing. In sites of 1000 m2 all cuachalalate individuals were registered. These were classified by growing stage (saplings, juveniles and trees). To analyze the size hierarchy, the horizontal and vertical structure of the cuachalalate populations was analyzed. The spatial dispersion of populations was estimated with the Morisita Index. Phenological events were recorded in the trees: foliation, female and male flowering, fruiting and defoliation, during one year (2017 rainy season to 2018 dry season). The cuachalalate presented lower (2.0 to 9.5 m) and upper (10.0 to 16.0 m) vertical structure; the horizontal structure showed that saplings and juveniles have diameters < 2.5 cm, and trees of 5 to 10 cm. The spatial distribution of the populations is aggregated. Flowering occurred during the rainy season, fruiting during rainy to dry season of next year, foliation from dry to rainy season of the same year and defoliation from rainy season to dry season of next year. Degraded lithosols tend to be eroded by runoff, are impermeable and hydrophobic. The piedmont soils have physical and chemical characteristics that highlight incipient accumulation processes, which anticipate a transition to an eutrophic regosol, a favorable soil for the persistence of the low deciduous forest.

Resumen: Amphypterigium adstringens “cuachalalate” crece en los suelos degradados de la selva baja de la costa de Oaxaca. Dos objetivos fueron llevados a cabo: 1. En cuachalalate: obtener la estructura poblacional vertical y horizontal, identificar el patrón de dispersión de los individuos y observar el periodo de las fases fenológicas. 2. En el suelo: determinar las características físicas y químicas del litosol degradado de San Pedro Mixtepec, Oaxaca, donde crece el cuachalalate. En sitios de 1000 m2 fueron registrados todos los individuos de cuachalalate. Éstos fueron clasificados por etapas de crecimiento (brinzal, latizal, fustal). Para analizar la jerarquía de tamaños de las poblaciones de cuachalalate se analizó la estructura horizontal y vertical. La dispersión espacial de las poblaciones fue estimada con el índice de Morisita. En los fustales se registraron los eventos fenológicos: foliación, floración femenina y masculina, fructificación y defoliación, durante un año (época lluviosa de 2017 a época seca de 2018). La estructura vertical de las poblaciones de cuachalalate presentó dos estratos: inferior (2.0 a 9.5 m) y superior (10.0 a 16.0 m); la estructura horizontal mostró que brinzales y latizales tienen diámetros < 2.5 cm y fustales de 5 a 10 cm. La distribución espacial de las poblaciones es agregada. La floración ocurrió durante la época lluviosa, la fructificación durante la época lluviosa a la seca del siguiente año, la foliación de la época seca a la lluviosa del mismo año, la defoliación de la época lluviosa a la seca del siguiente año. Los litosol degradados tienden a ser erosionados por escurrimiento, son impermeables e hidrófobos. Los suelos de piedemonte poseen características físicas y químicas que destacan procesos incipientes de acumulación, lo que anticipa transición hacia regosol éutrico, suelo favorable para la persistencia de la selva baja caducifolia.

Resumen Introducción: Los rasgos funcionales de las plantas han sido ampliamente utilizados para predecir la productividad (en términos de crecimiento en diámetro, crecimiento en altura, sobrevivencia e índice de respuesta integral) de las comunidades vegetales. Sin embargo, rara vez han sido utilizados para predecir el desempeño de las especies leñosas plantadas en suelos degradados. Objetivo: Evaluar la relación entre el desempeño y los rasgos funcionales de 25 especies leñosas plantadas en suelos afectados por actividades de extracción de petróleo en la Amazonía ecuatoriana. Métodos: Se establecieron 18 parcelas permanentes de muestreo y en cada parcela se sembraron aleatoriamente cinco plántulas de 6 meses de las 25 especies (125 individuos por parcela), a una distancia de 4×4 m. Se determinaron ocho rasgos funcionales (área foliar, área foliar específica, concentración de nitrógeno foliar, concentración de fósforo foliar, unidad mínima foliar, contenido foliar de materia seca, densidad específica del fuste y fuerza tensil foliar) de cada especie. Resultados: Las especies leñosas con alto desempeño presentaron mayor área foliar, área foliar específica y densidad específica del fuste que las especies de bajo desempeño. La concentración de nitrógeno foliar y la densidad específica del fuste mostraron una relación directa. El área foliar, la concentración de fósforo foliar, el contenido de materia seca foliar y la fuerza tensil foliar presentaron una relación inversa con el Índice de Respuesta Integral. Conclusión: Se demostró que el desempeño de las especies leñosas plantadas en suelos alterados puede predecirse satisfactoriamente por rasgos funcionales de hoja y de tallo, debido posiblemente a que los rasgos influyen en el crecimiento y supervivencia de las especies, y reflejan la mayoría de las condiciones ambientales.

Abstract Introduction: Plant functional traits are widely used to predict community productivity. However, they are rarely used to predict the performance (in terms of growth diameter, growth height, survival, and integral response index) of woody species planted in degraded soils. Objective: To evaluate the relationship between the functional traits and the performance of 25 woody species planted in disturbed soils affected by oil extraction activities in Ecuadorian Amazon. Methods: Eighteen permanent sampling plots were established and five 6-month-old seedlings of each 25 species were randomly planted in each plot (125 individuals per plot), at a distance of 4×4 m. Eight quantitative functional traits (leaf size, specific leaf area, leaf nitrogen concentration, leaf phosphorus concentration, leaf minimum unit, leaf dry matter content, stem specific density and leaf tensile strength) were determined for each species. Results: The woody species with high performance shows greater leaf size, specific leaf area and Stem Specific Density than those showing low performance. Leaf nitrogen concentration and stem specific density had a direct relationship with the integral response index. The leaf size, leaf phosphorus concentration, leaf dry matter content and leaf tensile strength showed a negative relationship with the integral response index. Conclusions: Our study demonstrated that the performance of woody species o disturbed soils can be predicted satisfyingly by leaf and stem functional traits, presumably because these traits capture most of environmental and neighborhood conditions.

Abstract Background: Percentage and speed of germination are crucial factors that can restrict processes involved in plant succession during ecological restoration. Pre-germination treatments and the effect of storage time on germination percentage and mean germination time were investigated in nine native herbaceous plants of the La Primavera Flora and Fauna Protection Area. Question: Do the seeds of the studied species go dormant, and can storage time affect germination percentage and mean germination time? Species studied: Aeschynomene villosa var. longifolia (Micheli) Rudd, Crotalaria pumila Ort., Dalea leporina (Ait.) Bullock, D. foliolosa (Ait.) Barneby, Desmodium aparines (Link) DC., D. distortum (Aubl.) JF Macbr., D. tortuosum (Sw.) DC., Paspalum notatum Flüggé, and Zornia reticulata I. E. Smith. Place and dates of study: Area of Protection of Flora and Fauna La Primavera. From 2019 to 2020 Methods: Under greenhouse conditions, four treatments were applied prior to germination: scarification with a tweezer pliers, immersion in water at 40 ᵒC for 24 and 48 h, and control. Results: Seven species had highly viable (≥ 90 %) seeds after 12 months of storage. Five species with seed dormancy reached germination above 80 % after 24 months of storage and scarification with a tweezer pliers. Mean germination time for most species decreased with the scarification treatment. Conclusion: Our findings provide basic information on the germination of native species that could help restore degraded sites in the La Primavera Flora and Fauna Protection Area.

Resumen Antecedentes: La germinación de semillas y la velocidad de germinación podrían ser factores que restringen los procesos de sucesión de plantas en la restauración ecológica. Se investigó el efecto de tratamientos de germinación y tiempo de almacenamiento en el porcentaje de germinación y el tiempo medio de germinación de nueve herbáceas nativas del Área de Protección de Flora y Fauna La Primavera. Pregunta: ¿Las semillas de las especies estudiadas tienen latencia y puede el tiempo de almacenamiento afectar el porcentaje de germinación y el tiempo medio de germinación? Especies estudiadas: Aeschynomene villosa var. Longifolia (Micheli) Rudd, Crotalaria pumila Ort., Dalea leporina (Ait.) Bullock, D. foliolosa (Ait.) Barneby, Desmodium aparines (Link) DC., D. distortum (Aubl.) JF Macbr., D. tortuosum (Sw.) DC., Paspalum notatum Flüggé y Zornia reticulata I. E, Smith. Lugar y fechas de estudio: Área de Protección de Flora y Fauna La Primavera. De 2019 a 2020 Métodos: En invernadero, con cuatro tratamientos: escarificación con pinzas alicata, inmersión en agua a 40 ᵒC/24 horas y por 48 horas, así como el control. Resultados: Siete especies tuvieron altos porcentajes de viabilidad (≥ 90 %) en semillas con 12 meses de almacenamiento. Cinco especies alcanzaron germinación superior al 80 % con 24 meses de almacenamiento y escarificadas con alicata. El tiempo medio de germinación para la mayoría de las especies disminuyó con el tratamiento de escarificación con alicata. Conclusión: Nuestros hallazgos brindan información básica sobre la germinación de especies nativas que podrían ayudar a restaurar sitios degradados en el APFFLP.

ABSTRACT Phosphorus (P) is an essential nutrient for growth and yield of sweet potatoes; in sandy soils, sweet potato yield and quality may be limited by application of low P doses, mainly in degraded areas. The objective of this work was to evaluate the effect of P doses on yield and quality of sweet potato root tubers grown in tropical sandy soils with different initial P availabilities: 23.2 mg dm-3 (high P - crop rotation) and 3.7 mg dm-3 (low P - post degraded pasture). Two experiments were carried out in a randomized block design, with four replicates. The treatments consisted of P doses (0, 22, 44, 88, and 176 kg ha-1) applied to the planting bed. Tuber yield, number and mean weight of tubers, P concentration in leaves and tubers, exported P, as well as the percentage of starch, reducing sugars, total sugars, and sucrose in the tubers were evaluated. P concentration in the soil was evaluated at the end of the experiment. In the area with high P availability (> 20 mg dm-3 - resin), increasing P doses did not increase root tuber yield and decreased root starch concentrations. In the area with low P availability (< 3.7 mg dm-3 - resin), root tuber yield and starch concentration peaked when applying 68 and 33 kg ha-1 of P, respectively. In areas after degraded pasture, with low initial soil P concentration, P fertilization for sweet potato crops should be carried out with a P dose of 68 kg ha-1. In areas with crop rotation and adequate soil P concentration, P fertilization should be carried out to replace the amount of P exported by the harvested root tubers to avoid decreases in soil fertility.

RESUMO O fósforo (P) é um nutriente essencial para o crescimento e produtividade da batata-doce, e em solos arenosos, a produtividade e a qualidade da batata-doce podem ser limitadas pela baixa dose de P aplicada, principalmente em áreas degradadas. O objetivo deste trabalho foi avaliar o efeito de doses de fósforo na produtividade e qualidade das raízes tuberosas de batata-doce cultivadas em solos arenosos tropicais com diferentes disponibilidades iniciais de P; 23,2 mg dm-3 (P alto - rotação de culturas) e 3,7 mg dm-3 (P baixo - pós pastagem degradada). Dois experimentos foram conduzidos em blocos casualizados, com quatro repetições. Os tratamentos consistiram de doses de P (0, 22, 44, 88 e 176 kg ha-1) aplicadas no sulco de plantio. Foram avaliadas a produtividade, número e peso médio de tubérculos, teor de P nas folhas e nos tubérculos, exportação de P, além da porcentagem de amido, açúcar redutor, açúcar total e sacarose nos tubérculos. No final do estudo foi avaliado o teor de P no solo. Em área com alta disponibilidade de P (> 20 mg dm-3 - resina), o aumento das doses de P não aumenta a produtividade de tubérculos e diminui as concentrações de amido nas raízes. Em área com baixa disponibilidade de P (< 3,7 mg dm-3 - resina), a produtividade de tubérculos e a concentração de amido atingiram o máximo ao aplicar 68 e 33 kg ha-1 de P, respectivamente. Cultivo de batata-doce em área após pastagem degradada com baixo teor inicial de P no solo, a adubação fosfatada deve ser realizada na dose de 68 kg ha-1 de P. Em área com rotação de culturas e teor adequado de P no solo, a adubação fosfatada deve ser realizada para repor a quantidade de P exportada pelas raízes tuberosas colhidas para evitar a perda da fertilidade do solo.

RESUMEN En Patagonia árida, la forma de uso de la tierra más extendida es el pastoreo por ganado doméstico. Si bien se conoce que el pastoreo puede afectar las características hidrológicas de los suelos, existen muy pocos estudios sobre la generación de los flujos de escorrentía en áreas con este tipo de uso. En el presente estudio evaluamos la relación entre el estado del pastizal y las características de la superficie de una ladera que influyen en la respuesta hidrológica del suelo a las precipitaciones. Comparamos las características del paisaje, índices de funcionalidad y propiedades del suelo de los interparches (descubiertos), en distintas posiciones de la pendiente con dos estados de degradación, y monitoreamos el contenido de humedad en los interparches durante una temporada de lluvias. El estado de degradación más avanzado reunió características en favor de un mayor escurrimiento superficial, sugiriendo la posibilidad del transporte de recursos pendiente abajo. Por ejemplo, la ladera alta del estado más degradado resultó el sitio con menor profundidad del perfil, mayor resistencia a la penetración e infiltración más lenta, y la ladera baja del mismo estado registró el segundo grado de saturación más elevado luego de los eventos de precipitación. Estas diferencias en propiedades hidrológicas habrían dejado también su impronta en el comportamiento de la vegetación, evaluados a través del NDVI. Los resultados apoyan la idea de que la respuesta hidrológica en pendientes de zonas áridas depende de la funcionalidad del suelo de los interparches y de la humedad antecedente.

ABSTRACT In arid Patagonia grazing by livestock is the most widespread form of land use. Although grazing is known to affect soils hydrological characteristics, few studies have addressed runoff flows generation as influenced by cattle grazing in these areas. In this study, we evaluated the relationship between grass-land condition and hillside surface characteristics that influence the response to rainfall. We compared landscape characteristics, landscape function indices and soil properties of bare soil (uncovered) inter-patches at different slope positions with two degradation conditions and monitored interpatch moisture content during a rainy season. Severe degradation was associated with greater surface runoff, suggesting downslope resource transport. In the most severely degraded soils the upper slope showed a the lowest profile depth, greatest resistance to penetration and slowest infiltration rate, and the lower slope registered the second highest degree of saturation after rainfall events. These differences in hydrological properties would have also modified vegetation behavior as indicated by the NDVI. These results support the premise that the hydrologic response on arid zones slopes depends on the functionality of bare soil interpatches and on the previous moisture content.

ABSTRACT Ecosystems with dry soils are particularly sensitive to climate changes and anthropogenic actions, which represents a threat to the survival of many cactus species. Ex situ seed conservation strategies should be adopted to support in situ conservation. This study evaluated the effect of conservation conditions on germination and vigor of seeds of Pilosocereus pachycladus subsp. pernambucoensis and Tacinga inamoena. The seeds were packaged in paper bags and glass containers and stored under controlled (8 ± 1 °C; 56 ± 2% relative humidity) and non-controlled (24 ± 2 °C; 75 ± 5% relative humidity) environmental conditions for 0 (control), 12, 16, and 20 months. The experiment was conducted in a completely randomized design, in a 2 × 2 × 4 factorial arrangement (conservation environment × packaging × storage period) for each species. The variables evaluated were: water content (%), germination (%), germination speed index (GSI), and mean germination time (MGT). The physiological quality of seeds of both species were preserved when seeds were maintained under controlled environment, regardless of the packaging. However, when stored under non-controlled environment, the packaging in paper bags was more efficient for the conservation of seeds of P. pachycladus subsp. pernambucoensis, and the glass container was more efficient for T. inamoena. This information may be needed for ex situ conservation of these species and to support the recovery of degraded areas susceptible to desertification in the Caatinga biome.

RESUMO Os ecossistemas de terra seca são particularmente sensíveis às mudanças climáticas e às ações antrópicas, que representam uma ameaça à sobrevivência de muitas espécies de cactos. Estratégias de conservação de sementes ex situ devem ser adotadas para apoiar a conservação in situ. Este estudo avaliou a influência da condição de conservação sobre a germinação e o vigor de sementes de Pilosocereus pachycladus subsp. pernambucoensis e Tacinga inamoena. As sementes foram acondicionadas em embalagem de papel e vidro e armazenadas em condições ambientais controladas (8 ± 1 °C; 56 ± 2% de UR) e não controladas (24 ± 2 °C; 75 ± 5% UR) por um período de 0 (controle), 12, 16 e 20 meses. O experimento foi conduzido em delineamento inteiramente casualizado, em esquema fatorial 2 × 2 × 4 (ambiente de conservação × embalagem × período de armazenamento), para cada espécie. As variáveis avaliadas foram: teor de água (%), germinação (%), índice de velocidade de germinação (IVG) e tempo médio de germinação (TMG). As sementes de ambas as espécies têm sua qualidade fisiológica preservada quando conservadas em ambiente controlado, independente da forma que foram embaladas. Entretanto, quando armazenadas em condições não controladas, a embalagem de papel foi mais eficiente para a conservação das sementes de P. pachycladus subsp. pernambucoensis e a embalagem de vidro para T. inamoena. Esses conhecimentos podem ser necessários na conservação ex situ dessas espécies e apoiar a recuperação de áreas degradadas suscetíveis à desertificação na Caatinga.

ABSTRACT Anthropic activities in their various aspects have promoted soil degradation in the Brazilian semi-arid region (SAB). As a result, significant losses in productivity and in the ability of soils to fulfill their ecological functions have been reported. The present study investigated the effects of degradation on soil attributes and properties under dense (CAD) and sparse (CAE) shrubby Caatinga in Campina Grande, PB, Brazil. Samples from the 0-20 cm layer of soil were investigated via physical (particle size distribution and soil density), chemical (acidity, electrical conductivity, macronutrients, soil organic matter) and microbiological attributes (microbial biomass carbon (C-BMS), basal respiration of the soil (RBS) and metabolic quotient (qCO2) Data were submitted to the Mann-Whitney Test and Principal Component Analysis (PCA). Anthropic actions on the CAE promoted the exposure of the saprolitic layer on the surface. This layer has imperfect drainage, low levels of nutrients and organic matter and high sodicity, which contributes to the slow regeneration of vegetation. Carbon stock and microbial activity are significantly lower in CAE compared to CAD. Degradation resulted in losses of supporting ecosystem services (nutrient cycling and primary production) and regulation (erosion control and climate regulation). The results can be used to understand the dynamics of landscapes of low complexity (high degradation) in the SAB and serve as a framework to find strategies to restore the productive capacity of extensive degraded and/or desertified areas in the SAB.

RESUMO As atividades antrópicas em seus diversos aspectos têm promovido a degradação dos solos no Semiárido brasileiro (SAB). Como consequência, têm sido reportadas perdas significativas de produtividade e da capacidade dos solos em cumprir suas funções ecológicas. O objetivo desta pesquisa foi avaliar os efeitos da degradação nos atributos e propriedades de solos sob Caatinga arbustiva densa (CAD) e esparsa (CAE) em Campina Grande, PB, Brasil. Amostras da camada de 0-20 cm do solo foram analisadas quanto aos atributos físicos (granulometria e densidade do solo), químicos (acidez, condutividade elétrica, macronutrientes, matéria orgânica) e microbiológicos (carbono da biomassa microbiana (C-BMS), respiração basal do solo (RBS) e quociente metabólico (qCO2). Os dados foram submetidos ao Teste de Mann-Whittney e à Análise de Componentes Principais (ACP). As ações antrópicas na CAE promoveram a exposição da camada saprolítica em superfície. Esta camada possui drenagem imperfeita, baixos teores de nutrientes e de matéria orgânica e elevada sodicidade, o que contribui para a lenta regeneração da vegetação. O estoque de carbono e a atividade microbiana são significativamente mais baixos na CAE em relação à CAD. A degradação acarretou em perdas de serviços ecossistêmicos de suporte (ciclagem de nutrientes e produção primária) e de regulação (controle da erosão e regulação do clima). Os resultados podem ser utilizados para compreensão da dinâmica de paisagens de baixa complexidade (elevada degradação) no SAB, bem como para adoção de estratégias de restabelecimento da capacidade produtiva de extensas áreas degradadas e/ou desertificadas no SAB.

Sugarcane is considered one of the greatest alternatives for the biofuels sector due to the high potential in the production of ethanol and its respective by-products. Processes of converting degraded pastures into sugarcane crops have been increasingly common in Brazil, as well as the use of pesticides to control plant diseases and pests in several crops. The objective of this work was to evaluate the occurrence of 2,4-D, ametryn, tebuthiuron, fipronil and its degradation products (fipronil sulfide and fipronil sulfone) in clay and sandy soils when applied to pasture and sugarcane management. Solid-liquid extraction and liquid chromatography coupled to mass spectrometry were used to quantify the compounds. The optimized method was validated with the following parameters: linear range from 0.5 to 300 µg L-1; linearity (r) > 0.99; precision with CV from 1.0 to 15.0%; accuracy of 60 to 117%, instrumental limit of detection (LOD) from 0.1 to 1.0 µg L-1 and instrumental limit of quantification (LOQ) of 0.5 µg L-1 for all pesticides, except 2,4-D (5.0 µg L-1). Pesticides concentrations of the experimental farms ranged from 0.1 to 266 µg kg-1, with the highest concentrations found in the months of pesticide’s application. The results showed the persistence of some pesticides in the soils even after months of use.

ABSTRACT The naturally fragile sandy soils of the Pampa Biome (PB) may be degraded with the introduction of poorly managed agricultural crops. Anthropic use can markedly decrease vegetation cover on sandy soils, leaving them more exposed to erosive agents. Decreases in organic matter content, biodiversity, and nutrient availability, increased soil compaction, and decreased water availability are also some of the impacts caused on PB soils by implementing poorly managed agricultural crops. In Rio Grande do Sul, in areas with sandier soils, the intense replacement of PB with commercial crops that has occurred in recent years (2000-2020) may be starting a disastrous cycle of degradation of these soils. However, it is not yet known how much these soils are degraded by recent anthropic use. There are no local scientific publications dedicated to the diagnosis of the degradation of these soils by anthropic use. Therefore, the need for this study was based on the objective of evaluating the physical and hydraulic properties of sandy PB soils with the insertion of agricultural crops. The study was conducted on three different soils, where soil samples were collected under three systems of use (extensive cattle raising on native grassland, eucalyptus afforestation, and soybean crop). Our results show that it can take more than nine years for soybean and ten years for eucalyptus land-use change to indicate some level of degradation in soil physical and hydraulic properties after replacing PB with these cultivated crops.

Abstract Areas of high concentration of seal carcasses have been observed in localized areas of James Ross Island, Antarctica. Such carcasses show an unusual vegetation development, in a semi-arid area with bare soils under intense winds, high salinity and sandy texture. We investigated carcasses of seals around a lake in James Ross Island, with four different stages of decomposition, with three replicates: Seal (S01), with recently mummified carcasses; S02, with partially degraded carcasses; S03, with broken carcasses with partially degraded exposed bones, and S04, with completely broken, scattered skeletons. The vegetation showed a maximum degree of development in carcasses at stages S02 and S03, with the environment between the skin and the skeleton as the preferred place for vegetation establishment. The chemical alteration was greater with increasing carcass decomposition but reduced with the spreading and final decomposition of the bones, with anomalous values observed only in the vicinity of the carcasses. It is concluded that the presence of carcasses of seals, concentrated in wet places, even in a semi-desert climate, represent important oases of nutrients, with a combination of physical and chemical effects throughout the decomposition process that favor plant establishment and succession.

Resumo O Montado é um ecossistema mediterrânico florestal com particular resiliência, rico em biodiversidade e de grande relevância para a conservação da natureza. No entanto, está exposto a ameaças por pressões ambientais agravadas pelas mudanças climáticas e pela pressão do Homem, o que está a levar ao seu declínio. Os microrganismos do solo são cruciais na manutenção de várias das funções do solo onde se inclui a regulação de azoto no solo disponível para as plantas. As bactérias dos nódulos radiculares das leguminosas (conhecidas por rizóbios) podem melhorar o rendimento destes ecossistemas agroflorestais devido ao processo de fixação biológica de azoto que é levado a cabo pela simbiose que se estabelece entre estas bactérias e as leguminosas. Em Portugal, a mortalidade generalizada registada em sobreiros e azinheiras nas últimas décadas deve-se, entre outros fatores, a infeções por Phytophthora spp. nas raízes destas árvores. É, por isso, importante desenvolverem-se meios de biocontrolo para esta doença. O presente trabalho tem por base a avaliação da dimensão e eficácia da população rizobiana existente em solos de Montado. Foram também avaliadas outras importantes atividades in vitro, das bactérias isoladas dos nódulos radiculares dos trevos, como o antagonismo à Phytophthora, a solubilização de fosfato e a capacidade de degradarem a celulose.

Abstract The Montado is a particularly resilient Mediterranean forest ecosystems, rich in biodiversity and of great importance for nature conservation, However, it is exposed to threats from environmental pressures aggravated by global climate change and human pressure, which is leading to its decline. Soil microorganisms are crucial in the maintenance of several soil functions including the regulation of soil nitrogen available to plants. The bacteria in the root nodules of legumes (known as rhizobia) can improve the performance of these agroforestry ecosystems due to the process of biological nitrogen fixation that is carried out by the symbiosis established between these bacteria and legumes. In Portugal, the widespread mortality recorded in cork and holm oaks in recent decades is due, among other factors, to infections by Phytophthora spp. in the roots of these trees. It is therefore important to develop means of biocontrol for this disease. The present work is based on the evaluation of the size and effectiveness of the rhizobial population existing in Montado soils. It was also evaluated, the in vitro antagonist activity to Phytophthora, of the bacteria isolated from root nodules, phosphate solubilization and the ability to degrade cellulose, an essential component of Phytophthora cell wall.

Resumo Na remediação de solos potencialmente contaminados por atividades mineiras, é importante considerar tecnologias ambientalmente sustentáveis, aplicáveis a áreas extensas. A estratégia de remediação in situ, que recorre à adição de corretivos orgânicos, ou inorgânicos, permite a reabilitação destes solos, melhorando as suas características e imobilizando os contaminantes, colocando-os em formas menos biodisponíveis. Os corretivos adicionados ao solo podem ser, preferencialmente, resíduos, cuja valorização vai ao encontro das metas Europeias estabelecidas relativamente à deposição de resíduos em aterros. De facto, é fundamental a diminuição dessas quantidades, valorizando os resíduos, e promovendo a sua integração no sistema produtivo. Este estudo teve como objetivo avaliar o uso sustentável de materiais provenientes da indústria da pasta de papel e do papel (cinzas de biomassa e lamas biológicas) na melhoria da qualidade de solos contaminados por atividades mineiras na Faixa Piritosa Ibérica (FPI): Minas de Aljustrel, Lousal e São Domingos), em dois tempos distintos: 1 e 25 meses após a aplicação dos materiais. Foram utilizados parâmetros físico-químicos e ecotoxicológicos. Os resultados sugerem que os aditivos testados permitiram uma clara melhoria nas propriedades físico-químicas dos solos, essenciais para a recuperação das suas características e funções, e diminuição nas respostas tóxicas para vários organismos-teste, Pseudokirchneriella subcapitata, Thamnocephalus platyurus e Daphnia magna, quando expostos a extratos dos solos corrigidos.

Abstract In the remediation of soils potentially contaminated by mining activities, it is important to consider environmentally sustainable technologies, applicable to large areas. The in situ remediation strategy that consists in the addition of organic, or inorganic, amendments, allows the rehabilitation of these soils, improving soil characteristics and immobilizing contaminants, turning them into less bioavailable forms. The recovery of this type of materials meets the European goals established for the disposal of waste in landfills, considering that it is essential to reduce the quantities deposited in landfills and increase their recovery, promoting their integration into the production system. This study aimed to evaluate the sustainable use of materials from the pulp and paper industry (biomass ashes and biological sludge) in improving the quality of soils contaminated by mining activities in the Iberian Pyrite Belt (IPB: Aljustrel, Lousal and São Domingos Mines), at two different times: 1 and 25 months after application of the materials. Physicochemical and ecotoxicological parameters were used in that evaluation. The results suggested that the tested amendments allowed a clear improvement in the physicochemical properties of the soils, essential for the recovery of their characteristics and functions, and a reduction of the toxic response of several test organisms, Pseudokirchneriella subcapitata, Thamnocephalus platyurus and Daphnia magna, when exposed to the soil-water extracts of amended soils.

Resumen El objetivo de este trabajo fue comprobar la capacidad biorremediadora de tres bioestimulantes (BS) producidos a partir de lodos de depuradora en un suelo contaminado por aceite de motor de gasolina. Dos de los bioestimulantes (BS1 y BS2) se obtuvieron por fermentación con Bacillus. licheniformis y el tercero (BS3) por hidrólisis enzimática. El aceite de motor tiene un elevado contenido en hidrocarburos aromáticos poilcíclicos (PAH) y produjo una fuerte inhibición de la actividad microbiana del suelo. La degradación de estos hidrocarburos dependió del número de anillos aromáticos y en los suelos sin enmendar fue nula para los de 5 y 6 anillos. La aplicación de los tres BS conllevó al incremento de la actividad deshidrogenasa respecto al suelo contaminado sin enmendar, así como a un aumento de la degradación de los PAHs. El efecto de estas enmiendas sobre la degradación de los PAHs no solo dependió de su naturaleza, sino también del tipo de BS aplicado, siendo el hidrolizado enzimáticos el que arrojó los mejores resultados.

Abstract The aim of this work was to evaluate the bioremediation capacity of three biostimulants (BS) produced from sewage sludge in a motor oil contaminated soil. Two of the BS (BS1 and BS2) were obtained by a fermentation process with Bacillus licheniformis and the third (BS3) by enzymatic hydrolysis. Motor oil has a high content of polycyclic aromatic hydrocarbons (PAHs) and caused a strong inhibition of the soil microbial activity. The degradation of these PAHs depended on the number of aromatic rings, being observed that hydrocarbons with 5 and 6 aromatic rings were not degraded in non-organically amended soils. The soil dehydrogenase activity as well as the degradation of PAHs increased respect to the non-amended soil when the three BS were used. The effect of these amendments not only depended on the structure of PAHs but also on the chemical composition of BS, being the better results those of the soils amended with the enzymatic hydrolysate.

Resumen: Las tecnologías “ómicas” son herramientas novedosas que facilitan el estudio de las comunidades microbianas de distintos ecosistemas, particularmente de la costra biológica del suelo, también llamada biocostra. Entre estas tecnologías se encuentran la genómica, transcriptómica, proteómica, metabolómica y metagenómica, que son utilizadas para analizar la diversidad y las funciones que llevan a cabo los microorganismos a través del estudio de sus biomoléculas y vías metabólicas. Entre los microorganismos que habitan la biocostra destacan las cianobacterias, las cuales son un grupo de bacterias fototróficas encargadas de realizar procesos importantes en el suelo, tal como la fijación de nitrógeno atmosférico, carbono orgánico, síntesis de clorofila y ficobilinas, así como la producción de exopolisacáridos para mejorar la estabilidad y fertilidad del suelo. Por lo tanto, el objetivo de la presente revisión es el de explorar la diversidad y la función que desempeñan estas comunidades microbianas en la biocostra, particularmente las cianobacterias, destacando los estudios realizados mediante el uso de las tecnologías ómicas. El conocimiento generado en los últimos años a través de las tecnologías ómicas ha demostrado la limitada cobertura que presentan las técnicas moleculares tradicionales, resultando en una subestimación de la diversidad real de las comunidades microbianas. Además, se ha mejorado la comprensión de los procesos ecológicos desarrollados por los microorganismos en beneficio de la biocostra, así como las capacidades funcionales individuales y colectivas, las cuales servirán como línea base para proponer estrategias importantes que solucionen la problemática de la degradación de los suelos.

Summary: The "omics" technologies are novel tools that facilitate the study of microbial communities in different ecosystems, particularly the biological soil crust, also called biocrust. These technologies include genomics, transcriptomics, proteomics, metabolomics, and metagenomics, which are used to analyze the diversity and functions carried out by microorganisms through the study of their biomolecules and metabolic pathways. Among the microorganisms that inhabit the biocrust are the cyanobacteria, which are a group of phototrophic bacteria responsible for important processes in the soil, such as the fixation of atmospheric nitrogen, organic carbon, chlorophyll and phycobilin synthesis, as well as the production of exopolysaccharides to improve soil stability and fertility. Therefore, the objective of this review is to explore the diversity and role that these microbial communities play in the biocrust, particularly cyanobacteria, highlighting studies conducted using omics technologies. The knowledge generated in recent years through omics technologies has demonstrated the limited coverage of traditional molecular techniques, resulting in an underestimation of the real diversity of microbial communities. In addition, there has been an improvement in the understanding of the ecological processes developed by the microorganisms for the benefit of the biocrust, as well as the individual and collective functional capacities, which will serve as a baseline to propose important strategies to solve the problem of soil degradation.