Functional traits and performance of woody species on oil-affected soils of the Ecuadorian Amazon / Rasgos funcionales y comportamiento de especies leñosas en suelos afectados por petróleo de la Amazonía ecuatoriana

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.

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.

The effect of aluminum treatment on metabolism in oil palm seedlings

Due to rainfall and high temperatures, the Amazonian soil undergoes changes in its source material and leaching of base cations. This results in deep, infertile, and acidic soil. Aluminum present in acidic soil impairs plant growth and development by inhibiting root formation, enzymatic reactions, absorption, transport, and nutrient utilization. This study aimed to evaluate the effects of aluminum dosage on the metabolism of the oil palm Elaeis guineensis Jacq. The study was conducted in a greenhouse at the Federal Rural University of Amazonia. The experimental design was randomized, with five replications, in which dosages of 0, 10, 20, 30, and 40 mg L-1 aluminum chloride (AlCl3.6H2O) were administered. Electrolyte leakage, nitrate, nitrate reductase, free ammonium, soluble amino acids, proline content, and soluble proteins were analyzed in the leaves and roots of the oil palm. The highest concentration of aluminum was found in the roots. AlCl3 treatment at 40 mg L-1 increased electrolyte leakage, nitrate, ammonium, and proline concentrations in the roots, and amino acid concentrations in both the leaves and roots. Furthermore, a decrease in nitrate reductase enzyme activity was observed in the roots. This study demonstrates that the oil palm has mechanisms of tolerance to aluminum toxicity.

Proposal of a system for measuring apparent electrical conductivity and moisture of soil for small farmers

In the last 30 years soils decreased 73 % of their productive capacity in the world. One of the main reasons for this decrease has been the politics implemented, as well as the absence of opportunity for the small producer to implement improvement strategies that can increase their productivity in the field. Therefore, in this research a soil measurement system is proposed for small farmers, based on the design of two sensors of low cost: (i) Apparent electrical conductivity (ECa) sensor and (ii) moisture sensor. These measurement variables have the particularity that their characteristics can be associated with the physical properties of the soil for decision-making. The sensors developed in this work employ two techniques: Wenner's method for ECa and electrical impedance measurement to identify the dielectric permittivity associated with the water content of the soil. The system is controlled by the Raspberry Pi 3 board through developed software that allows correlating data with its geolocation. The device was tested in controlled laboratory measurements with calibrated instruments, obtaining a coefficient of . Finally, on-site tests were made to validate their use for small farmers.

Durante los últimos 30 años, los suelos han disminuido un 73 % su capacidad productiva, a nivel mundial. Una de las principales razones para esta cifra a la baja son las políticas implementadas, así como la falta de oportunidad para que el pequeño productor adopte estrategias de mejora, con lo cual, pueda aumentar la productividad. Por lo anterior, en esta investigación, se propone un sistema de medición de suelo para pequeños productores, a partir del diseño de dos sensores de bajo costo: (i) sensor de conductividad eléctrica aparente (CEa) y (ii) sensor de humedad. Estas variables de medición tienen la particularidad que sus características se pueden asociar a las propiedades físicas del suelo, para tomar decisiones. Los sensores desarrollados en este trabajo usan dos técnicas: el método de Wenner, para la CEa y la medición de impedancia eléctrica, para identificar la permitividad dieléctrica asociada con el contenido de agua del suelo. El sistema es controlado mediante la tarjeta Raspberry Pi 3, a través de un software desarrollado, que permite correlacionar los datos con su geolocalización. El dispositivo, se probó en mediciones controladas en laboratorio, con instrumentos calibrados, obteniendo un coeficiente . Finalmente, se hicieron pruebas in situ, con el fin de validar su uso por pequeños agricultores.

Effects of nutrient (N, P, K) fertilization on the dynamics of fine roots in tropical rain forests with different soil texture in the Colombian Pacific region / Efectos de la fertilización con nutrientes (N, P, K) sobre la dinámica de raíces finas en bosques húmedos tropicales con diferente textura del suelo en la región del Pacífico colombiano

Abstract Introduction: Fine root dynamics include production, turnover and decomposition; they are crucial to forest health, affect the entire biogeochemical complex of the ecosystem, and consequently, they substantially affect carbon balance. However, the influence of environmental factors and soil nutrient limitation on fine roots presents considerable uncertainties and has not been studied in tropical forests with more than 7 000 mm annual rainfall. Objective: To measure the effect of fertilization on fine roots in the high precipitation Chocó forest. Methods: We worked in two sites of the Chocó region, Colombia (August 2014-May 2015), where rainfall exceeds 10 000 mm per year. We applied five fertilization treatments (N, P, K, NPK and Control) to two soil type plots. Soil cylinders were removed at pre-established intervals to measure roots. Results: Phosphorus applications increased fined roots; and more fine roots were produced in sandy than in loam soil. The effects of fertilization were related, but not clearly determined by edaphic conditions. Conclusions: In this Chocó forest, the production of fine roots was higher in sandy and nutrient-rich soils but belowground net primary productivity was limited by the content of edaphic Phosphorus.

Resumen Introducción: La dinámica de las raíces finas incluye producción, rotación y descomposición; son cruciales para la salud de los bosques, afectan todo el complejo biogeoquímico del ecosistema y, en consecuencia, afectan sustancialmente el balance de carbono. Sin embargo, la influencia de los factores ambientales y la limitación de nutrientes del suelo en las raíces finas presenta incertidumbres considerables y no se ha estudiado en bosques tropicales con más de 7 000 mm de precipitación anual. Objetivo: Medir el efecto de la fertilización en las raíces finas en el bosque chocoano de alta precipitación. Métodos: Se trabajó en dos sitios de la región del Chocó, Colombia (agosto 2014-mayo 2015), donde las precipitaciones superan los 10 000 mm anuales. Se aplicaron cinco tratamientos de fertilización (N, P, K, NPK y Control) a dos parcelas por tipo de suelo. Los cilindros de suelo se retiraron a intervalos preestablecidos para medir las raíces. Resultados: Las aplicaciones de fósforo aumentaron las raíces finas; y se produjeron más raíces finas en suelos arenosos que en francos. Los efectos de la fertilización estuvieron relacionados, pero no claramente determinados por las condiciones edáficas. Conclusiones: En este bosque chocoano, la producción de raíces finas fue mayor en suelos arenosos y ricos en nutrientes, pero la productividad primaria neta subterránea estuvo limitada por el contenido de fósforo edáfico.

Human and Environmental Reservoirs of Intestinal Parasites in the City of Yaoundé, Cameroon: An Update in the Context of COVID-19 Pandemic

Aims: Intestinal parasitic infections are persistent in Africa, and we questioned here whether prevention measures imposed by the occurrence of the COVID-19 pandemic in 2020 could alleviate this threat in lowlands of the city of Yaoundé, Cameroon. Study Design: We monitored the trend of intestinal parasites in human and environmental samples from the seven subdivisions of the city of Yaounde, before (November-December 2019) and during (July-August 2020, November-December 2020) the COVID-19 pandemic. Methodology: Parasitological analysis were performed to check for the presence of helminths and protozoans in stools from inhabitants as well as in water, soil and fresh vegetables, using standard Kato Katz and Formol Ether methods.The minimum effective sample size considered for the estimation of parasite richness, parasite infection and contamination indexeswas 30 for human and 30 for environmental samples (i.e. soils, water and vegetables) per location. Results: Of the 19 parasite species identified in human and the environments, twelve were helminths and seven protozoans. The overall parasite species richness reached 16 in 2019 (12 helminths and 4 protozoans) and 19 in 2020 (12 helminths and 7 protozoans), with about 62.5-68.4% of species shared by human and environments. The parasite frequencies in human (21.03%) and water/soils (32.3%) in 2019 did not differ statistically with those of 2020 (14.6-20.3% and 10.8-35.4%, respectively). The contamination rate of vegetables (i.e. carrots, lettuce, basil, celery, etc.) has increased from 2019 (6.1-9.1%) to 2020 (9.1-24.2%), and was frequently due to roundworms, hookworms, Entamoeba and Cryptosporidium cysts. The findings suggest persistent risk associated with intestinal parasite irrespective to measures imposed by COVID-19 in study locations. Conclusion: The current control approaches may therefore integrateecological epidemiology of the intestinal parasite infections as complementary strategy in African cities.

Efecto de los cultivos de cobertura invernales sobre el microbioma del suelo: revisión sistemática de la literatura / Effect of winter cover crops on the soil microbiome: a systematic literature review

Resumen La inclusión de cultivos de cobertura invernales (CCI) en un sistema de siembra directa (SD) en reemplazo del barbecho constituye una alternativa promisoria para mejorar la salud del suelo y contribuir a la sustentabilidad ambiental de los sistemas agrícolas. Esta revisión ofrece un panorama integral de los efectos sobre el microbioma del suelo que tiene la introducción de CCI en rotación con cultivos de verano en sistemas de SD vs. el barbecho desnudo. Se realizó una búsqueda sistemática de la literatura que reporta los efectos de los CCI sobre los parámetros de abundancia, actividad y diversidad microbiana del suelo. Combinando 7 criterios de búsqueda se seleccionaron y analizaron 22 trabajos. El conjunto de resultados de esos trabajos muestra que la actividad enzimática del suelo se ve favorecida con la inclusión de CCI en la rotación, principalmente si estos se componen de leguminosas y mezclas de especies. Más de la mitad de esos trabajos reportan una mayor biomasa microbiana con CCI que con barbecho. Además, se advierte que los efectos de los CCI sobre los parámetros microbianos son independientes de la duración de los ensayos. Sin embargo, aún se necesitan más investigaciones básicas que permitan reducir la heterogeneidad entre estudios y comprender las complejas interacciones que ocurren entre los CCI y el microbioma del suelo.

Abstract The inclusion of winter cover crops (WCC) in no-till (NT) systems in replacement of bare fallow is a promising alternative to improve soil health and consequently, contribute to environmental sustainability of agricultural systems. This review provides a comprehensive evaluation of the effects of the use of WCC in rotation with summer cash crops under NT systems on the soil microbiome versus bare fallows. A systematic literature search was conducted to evaluate the impact of WCC on microbial parameters indicative of abundance, activity and diversity. Twenty-two papers were selected based on seven combined criteria. The results of this review show that enzyme activities in soil are enhanced with the inclusion of WCC in the rotation, particularly those that include legumes and mix of species. ln general, more than half of the analyzed papers report higher microbial biomass in soils with WCC than in bare fallow. Interestingly, the effects of WCC on microbial parameters are independent of the duration of the experiments. However, more basic research is necessary to reduce the heterogeneity of the studies and to better understand the complexity of the interactions between WCC and the soil microbiome.

Seasonality, soil attributes and root biomass in cerrado, cerradão and forest environments, western Amazon

The Amazon rainforest region presents a phytophysiognomy that ranges from savannas to cerrados, all of them intimately associated to climate and soil characteristics. Evidence has been given that plant growth and development are affected by soil quality and seasonality, thus making it crucial to understand them and how they are related to each other in order to grasp the dynamics of the whole ecosystem. In this context, the goal of this research was to assess how seasonality, soil attributes, and root system biomass are related in natural cerrado, cerradão, and forest areas in southern Amazonas State, in Brazil. Soil samples were collected during dry (June/2018) and rainy (December/2018) seasons from three different layers 0.00­0.05m; 0.05­0.15m, and 0.15­0.30m deep. In each area ten sampling points were randomly chosen. Two kinds of soil samples were collected: the first using 4.0 cm height by 5.1cm internal-diameter soil sample rings; and the second were intact soil lumps. Physical and Chemical soil attributes assessed were macro-porosity (MaP), micro-porosity (MiP), total porosity (TP), soil density (SD), aggregates texture and stability (GMD and WAR), gravimetric humidity (HG), organic carbon (OC), exchangeable aluminum (Al3+), potential acidity (H+Al), sum of bases (SB), cation exchange capacity (CEC), and root biomass (RB). All data were analysed via Tukey t test and student T test to compare results between seasons and areas. Increasing vegetation density (cerrado < cerradão < forest) was followed by an increment in CEC and OC, showing the importance of these attributes to maintaining biodiversity in environments. In amazon cerrado, rainy season as well a sandier soil textures provided favourable conditions to the growth and development of plants' root system. Soil attributes were little affected by seasonality, that had greater effect on MiP, TP, SD, and OC, leading to lesser values for these variables during rainy season.

Optimization of soybean yield in ultisols through adaptive varieties screening and plant growth promoting Rhizobacter

This research was aimed at obtaining varieties of soybean adaptive to acid soils and to obtain Plant Growth-Promoting Rhizobacteria (PGPR) isolates that can improve the agronomic characteristics of soybean and increase the ultisols fertility. This research was conducted in two-stages research on Sampali Village, Percut Sei Tuan sub-District, Deli Serdang District, North Sumatra Province, Indonesia from August 2019 until March 2020. The first stage (adaptive varieties screening) using the non-factorial Randomized Block Design (RBD) with the varieties of Argomulyo, Wilis, Kaba, Dena-1, Devon-1, Dega-1, Demas-1, Burangrang, Detam-1, and Kipas Merah. The second stage (application of PGPR isolates singly and in combinations) using the factorial RBD, the first factor of applicative single and the combination of PGPR isolates, the second factor of adaptive varieties including Detam-1 and Wilis. Data were analyzed with ANOVA and followed by DMRT at P<0.05. The results showed that the Detam-1 and Wilis varieties had significantly higher yield per plant of 14.73 g and 14.54 g, respectively, than other varieties. The applications of a single and combination of PGPR isolates significantly increased the number of branches, stem diameter, plant height, yield per plant, soil pH, organic-C, available-P, and total-N and decreased the soil C/N. The Detam-1 variety had the higher in yield per plant compared to Wilis variety. The isolates combination of Rhizobium leguminosarum+Rhizobium sp2+Bacillus sp+Burkholderia sp for Detam-1 and Wilis varieties can be recommended to support the growth and yield of soybean on ultisols.

Efecto del pH sobre la concentración de nutrientes en cacao (Theobroma cacao L.) en la Amazonia Colombiana / Effect of pH on the nutrient concentration in cocoa (Theobroma cacao L.) in the Colombian Amazon

RESUMEN La acidez del suelo limita la disponibilidad, la absorción y la concentración de nutrientes y el rendimiento del cultivo de cacao. El objetivo fue evaluar el efecto del pH del suelo sobre la concentración de nutrientes en hoja, cáscara y grano, para cuatro clones de cacao autocompatibles (ICS-1, CCN-51) y autoincompatibles (ICS-39, TSH-565), en el departamento del Caquetá. El diseño experimental consistió en un arreglo factorial con cuatro clones (factor A), cuatro niveles de pH y fertilidad (factor B) y cuatro repeticiones. Los resultados indican diferencias en la concentración de nutrientes por efecto del clon y tratamiento, siendo la acumulación de N, P y Mg en grano>hoja>cáscara, K en cáscara>hoja>grano, Ca, Fe, Mn, Zn y B en hoja>cáscara>grano, S en cáscara>hoja>grano y Cu en grano>cáscara>hoja. La concentración de P, Mg y S fue mayor y, a su vez, menor Mn, cuando aumentó el pH. El orden de extracción nutrimental en grano fue N>K>P>Mg>S>Ca>Fe>Mn>Zn>Cu>B. Con relación a los clones, CCN-51 presentó habilidad para la toma de nutrientes y alcanzar mayores producciones, incluso, en suelos con pH ≥ 5,5, lo que sugiere efecto de las condiciones edafoclimáticas y, por lo tanto, la necesidad de evaluar los clones para cada zona de cultivo.

ABSTRACT The soil acidity limits availability, absorption and concentration of nutrients and yield of the cocoa crop. The objective was to evaluate the effect of soil pH on the concentration of macro and micronutrients in leaf, husk and grain for four cocoa clones, self-compatible (ICS-1, CCN-51) and self-incompatible (ICS-39, TSH-565) in the department of Caquetá. The experimental design consisted in a factorial arrangement with four clones (factor A), four pH and fertility levels (factor B) and four repetitions. The results indicate differences in the concentration of nutrients due to the effect of the clone and the treatment, being the accumulation of N, P and Mg in grain>leaf>husk, K in husk>leaf>grain, Ca, Fe, Mn, Zn y B in leaf>husk>grain, S in husk>leaf>grain and Cu in grain>husk>leaf. The concentration of P, Mg and S was higher, and in turn Mn lower, when the pH increased. The order of nutrient extraction in grain was N>K>P>Mg>S>Ca>Fe>Mn>Zn>Cu>B. Regarding clones, CCN-51 showed ability to take nutrients and reach higher productions, even in soils with pH ≥ 5.5, suggesting effect of edaphoclimatic conditions, and therefore, the need to evaluate the clones for each growing area.

Validación de una metodología para obtener la envolvente de ruptura al esfuerzo cortante en suelos no saturados compactados / Validation of a methodology to obtain the shear failure envelope of unsaturated compacted soils / Validação de uma metodologia para obter a envoltória de ruptura por cisalhamento em solos não saturados compactados

RESUMEN Obtener la envolvente de ruptura de suelos no saturados requiere de equipos especializados, de elevado costo y difícil acceso. Sin embargo, a través de ensayos de laboratorio simples combinados como corte directo, tracción indirecta y succión, es posible determinar la envolvente. La presente investigación busca, por tanto, validar dicha metodología, en un material limo de origen residual de la ciudad de Medellín-Antioquia, Colombia, compactado a la máxima densidad a través del ensayo Proctor normal. La validación se efectúa por medio de la repetitividad de una serie de ensayos de corte directo para diferentes valores de succión; comprobando que, es posible encontrar la envolvente de ruptura al corte de un suelo fino residual compactado, para distintas condiciones de succión, por medio de los ensayos de laboratorio de corte directo en condición consolidada y drenada, succión por el método del papel filtro y tracción indirecta, cuando no se cuenta con equipos de corte con succión controlada.

ABSTRACT Obtaining the failure envelope of unsaturated soils requires specialized equipment, which is expensive and difficult to access. Nevertheless, by combining simple laboratory tests like direct shear test on saturated samples, indirect tension test, and soil suction measurements by filter paper it is also possible to determine the envelope. This research aims to validate this latter methodology on a residual origin silt material from the city of Medellin, Colombia, which is compacted to the maximum dry density through the standard proctor test. The validation is carried out by repeating a series of direct shear tests for different suction values. It was verified that it is possible to find the shear failure envelope of a compacted fine-grained residual soil for different suction conditions, using the direct shear test under consolidated drained conditions, suction by the filter paper method, and the indirect tension test, when no suction controlled shear equipment is available.

RESUMO A obtenção da envoltória de ruptura de solos não saturados com controle de sucção requer equipamentos especiais, que são caros e de difícil acesso. No entanto, através de ensaios simples laboratoriais combinados, tais como os de cisalhamento direto, tração indireta e sucção, é possível determinar a envoltória de resistência. A presente investigação procura validar esta metodologia, usando um material siltoso de origem residual da cidade de Medellin-Antioquia, Colômbia, compactado na condição de densidade máxima obtida no ensaio de compactação Proctor normal. A validação é feita por meio da realização de uma série de ensaios de cisalhamento direto para diferentes valores de sucção; mostrando que é possível encontrar a envoltória de ruptura de um solo fino residual compactado, para diferentes condições de sucção, por meio de ensaios laboratoriais de cisalhamento direto consolidados drenados, sucção determinada pelo método do papel de filtro e ensaio de tração indireta, quando não se dispõe de equipamento de cisalhamento direto à sucção controlada.

Mapeamento da erodibilidade e erosão potencial do solo em uma bacia hidrográfica de encosta / Mapping of erodibility and potential soil erosion in a hillside watershed

RESUMO O objetivo deste estudo foi estimar o potencial de perda de solo por meio da equação universal de perda de solo e identificar os fatores que controlam o processo erosivo em uma bacia hidrográfica de encosta. O fator erosividade da chuva (R) foi calculado por meio de dados normais de precipitação, obtendo-se, assim, índices mensais de erosão. O fator erodibilidade do solo (K) foi obtido a partir de uma amostragem de solo realizada por meio de uma malha de 340 pontos, na qual os valores foram interpolados pelo método da krigagem ordinária. O fator topográfico (LS) foi gerado a partir do Modelo Digital de Elevação (MDE), já os fatores uso e manejo e práticas conservacionistas (CP) foram obtidos por meio de observações de campo e valores tabelados. As maiores taxas de perdas abrangem 27% da área e se concentram em locais de maiores declividades nos quais predominam solos rasos, como Neossolos Litólicos e Neossolos Regolíticos. O fator LS determinou a magnitude do processo erosivo e o fator CP apresentou a maior relação com o controle das perdas de solo. Os resultados encontrados mostram a importância do fator cobertura do solo, em que medidas de manutenção da vegetação e práticas conservacionistas devem ser adotadas e consideradas pelos gestores ambientais em regiões de encosta com predomínio de solos rasos associados a relevo declivoso.

ABSTRACT The objective of this study was to estimate the soil loss potential through the universal soil loss equation and to identify the factors that control the erosive process in a hillside watershed. Rainfall erosivity factor (R) was calculated through normal precipitation data, thus obtaining monthly erosion indexes. The soil erodibility factor (K) was obtained from a soil sampling in an irregular grid of 340 points, in which the values were interpolated by the ordinary kriging method. The topographic factor (LS) was generated from the Digital Elevation Model (MDE) and the use and management and conservationist practices factors (CP) through field observations and tabulated values. The highest loss rates cover around 27% of the area, and are concentrated in places with higher slopes where shallow soils such as Litolics Neosols and Regolithic Neosols predominate. The LS factor determined the magnitude of the erosive process and the CP factor showed the highest relation with the soil loss control. The results found show the importance of the cover-management factor, in which measures of vegetation maintenance and conservation practices should be adopted and considered by the environmental managers in hillside regions with predominance of shallow soils associated to slope relief.

Parasitic contamination in the soil of beaches from Mosqueiro Island, Pará State, Brazil / Contaminação parasitária no solo de praias da Ilha do Mosqueiro, Estado do Pará, Brasil

Objective: We aimed to evaluate the prevalence of intestinal parasitic in the soil of three beaches of Mosqueiro Island, located in the State of Pará, Brazil, as well as to compare the frequency of helminths and protozoa, pathogenic and non-pathogenic parasites according to the beaches analyzed. Methods: This is a cross-sectional analytical study conducted during August and September 2019, in which 155 soil samples were analyzed by Hoffman's method. Results: The results showed that 16.1% of samples were contaminated from 61.3% of collection points. Murubira beach and Farol beach presented the highest prevalence of parasites, however, there was no significant difference between beaches. Also, it was observed a predominance of protozoa (63%) and non-pathogenic parasites (55.6%) in analyzed samples, but there was no statistically significant difference according to the investigated location. Endolimax nana 25.9% (7/27) and hookworms 18.5% (5/27) were the most detected parasites on the beaches. Conclusion: Thus, this study showed parasitic contamination on the beaches from Mosqueiro Island, which may be associated with a lack of sanitation infrastructure and personal hygiene in these places. Therefore, these results reinforce the need to adopt educational and preventive measures to reduce parasitic agents.

Objetivo: Avaliar a prevalência de parasitos intestinais no solo de três praias da Ilha de Mosqueiro, localizada no estado do Pará, Brasil, além de comparar a frequência de helmintos e protozoários, parasitos patogênicos e não patogênicos de acordo com as praias analisadas. Metdodos: Este é um estudo transversal, analítico, realizado durante agosto e setembro de 2019, no qual 155 amostras do solo foram analisadas pelo método de Hoffman. Resultados: Os resultados revelaram que 16,1% das amostras estavam contaminadas em 61,3% dos pontos de coleta. As praias do Murubira e do Farol apresentaram a maior prevalência de parasitos, porém não houve diferença significativa entre os diferentes locais de coleta. Além disso, foi observada a predominância de protozoários (63%) e parasitas não patogênicos (55.6%) nas amostras analisadas, mas não houve diferença estatística significativa entre os locais investigados. Endolimax nana 25,9% (7/27) e Ancilostomídeos 18,5% (5/27) foram os parasitas mais detectados nas praias. Conclusao: Desse modo, este estudo mostrou contaminação parasitária nas praias da Ilha de Mosqueiro, o que pode estar associada à falta de infraestrutura de saneamento e higiene pessoal nesses locais. Além disso, esses resultados reforçam a necessidade de se adotar medidas educacionais e preventivas para a redução desses agentes parasitários.

Isolation of culturable mycota from Argentinean soils exposed or not-exposed to pesticides and determination of glyphosate tolerance of fungal species in media supplied with the herbicide / Aislamiento de la microbiota cultivable de suelos argentinos expuestos y no expuestos a plaguicidas y determinación de la tolerancia a glifosato de especies fúngicas en medios suplementados con el herbicida

Abstract The current agricultural system has led to the development of glyphosate (GP)-resistant weeds, causing an increase in GP doses and applications. Native mycota of pesticide-contaminated sites are the major source of pesticide-degrading microorganisms. The aims of the present study were to isolate the GP-tolerant culturable mycota in two soils with different pesticide exposure from Córdoba, Argentina, and to evaluate the growth parameters in native fungal isolates in the presence of GP and the effective dose that caused 50% growth reduction. The results showed that the genera Fusarium, Aspergillus, Mucor, Penicil-lium and Sterilia were the prevalent fungi isolated from soils both exposed and not-exposed to pesticides. The highest value (>100 mM) of effective concentration of herbicide that caused 50% growth inhibition (EC50), was found for Trichoderma isolates. Sterilia spp. had EC50 val-ues of 100mM, while Aspergillus spp. and Mucor had EC50 values between 50 and 100mM. The growth rate evaluation varied according to the isolates and GP concentrations. The data showed that all Aspergillus spp., Trichoderma spp., Mucor and three Sterilia spp. had the best growth performance in media supplied with GP after a variable acclimation period. This study provides valuable data for further studies that would allow to know the metabolic capacity of these fungal species that can be potential candidates for GP removal from contaminated environments.

Resumen El sistema agrícola actual condujo ai desarrollo de malezas resistentes a glifos-ato (GP), lo que deriva en el aumento de las dosis y el número de aplicaciones requeridas. La microbiota nativa de sitios contaminados con plaguicidas constituye la fuente principal de microorganismos capaces de degradar este herbicida. Los objetivos del presente estudio fueron aislar la microbiota cultivable tolerante a GP a partir de dos suelos agrícolas con diferente grado de exposición a plaguicidas, ambos de la provincia de Córdoba, Argentina, y evaluar en los hongos nativos aislados los parámetros de crecimiento en presencia de GP y la dosis efectiva que produce un 50% de reducción del crecimiento (EC50). Los géneros Fusarium, Aspergillus, Mucor, Penicillium y Sterilia fueron los de mayor prevalencia, tanto en suelos expuestos como no expuestos a plaguicidas. La mayor EC50 hallada (> 100 mM) correspondió a dos aislamientos de Trichoderma. En dos aislamientos de Sterilia, los valores de EC50 fueron de 100 mM, mientras que en los dos de Aspergillus y en uno de Mucor fueron de entre 50 y 100 mM. La velocidad de crecimiento varió según la concentración de GP empleada y el aislamiento considerado. Todos los aislamientos de Aspergillus, Trichoderma y Mucor, y tres aislamientos de Sterilia mostraron el mejor rendimiento en cuanto al crecimiento en los medios con GP después de un período de aclimatación variable. Este trabajo proporciona datos preliminares valiosos referidos a la capacidad metabólica de estos aislados y su potencial para remover GP en ambientes contaminados.

Ecotoxicity test as an aid in the determination of copper guideline values in soils / Ensaios de ecotoxicidade como auxílio na determinação de valores orientadores de cobre em solos

ABSTRACT: The process of identifying a contaminated area involves a preliminary assessment consisting of chemical analysis and comparison with guideline values. In Brazil, these values are included in the CONAMA Resolution no. 420/2009, based on chemical analysis and phytotoxicity. The objective of this research was to evaluate the ecotoxicity of copper in two natural soils in the state of Rio de Janeiro, a Haplic Planosol (sandy) and a Red-Yellow Argisol (medium texture), to verify if the values established by the legislation offer protection to the soil fauna. Lethality and reproduction tests were performed with Eisenia andrei worms and Folsomia candida springtails. Results indicated copper values in Planosol as LC50 435 mg kg 1 and EC50 29 mg kg 1 for E. Andrei and LC10 137 mg kg 1 and EC50 117 mg kg 1 for F. candida. In Argisol, these results were LC50 690 mg kg 1 and EC50 61 mg kg 1 for E. andrei, and LC10 42 mg kg 1 and EC50 138 mg kg 1 for F. candida. Values reported are lower than the research value (200 mg kg-1) established by the CONAMA resolution 420/09, indicating that concentrations lower than the limit values may affect these organisms, depending on the type of soil. Worms were more sensitive than springtails to copper contamination, and sandy soil was more susceptible to ecotoxicity due to copper contamination, probably due to the greater bioavailability of the metal. Results of such ecotoxicity tests should be considered in the development of soil guideline values.

RESUMO: O processo de identificação de uma área contaminada envolve uma avaliação preliminar que consiste em análise química e comparação com valores orientadores. No Brasil, esses valores constam na Resolução CONAMA no 420/2009, baseados em análises químicas e fitotoxicidade. O objetivo deste trabalho foi avaliar a ecotoxicidade do cobre em dois solos naturais do Estado do Rio de Janeiro, um Planossolo Háplico (arenoso) e um Argissolo Vermelho-Amarelo (textura média), para verificar se os valores estabelecidos pela legislação oferecem proteção à fauna do solo. Foram realizados ensaios de letalidade e de reprodução com minhocas da espécie Eisenia andrei e com colêmbolos da espécie Folsomia candida. Os resultados indicaram no Planossolo valores de cobre para E. andrei de CL50 435 mg kg-1 e CE50 29 mg kg-1 e para F. candida CL10 137 mg kg-1 e EC50 117 mg kg-1. No Argissolo esse resultado foi para E. andrei CL50 690 mg kg-1 e CE50 61 mg kg-1, e para F. candida CL10 42 mg kg-1 e CE50 138 mg kg-1. Os valores encontrados são menores que o valor de investigação (200 mg kg-1) estabelecidos pela resolução 420/09 do CONAMA, indicando que concentrações menores do que os valores-limite podem afetar esses organismos, a depender do tipo de solo. As minhocas mostraram-se mais sensíveis que os colêmbolos à contaminação por cobre, e o solo arenoso mostrou-se mais suscetível a apresentar ecotoxicidade diante de uma contaminação por cobre, devida, provavelmente, à maior biodisponibilidade do metal. Os ensaios de ecotoxicidade devem ser considerados no desenvolvimento de valores orientadores para solos.

Increasing the Productive Potential of an Ultisol using Cover Crops and Organic and Mineral Fertilization

Abstract The occupation of sandy soils in Brazil has occurred with poor adoption of management technology, which has caused its degradation. The recovery of organic matter, particularly when growing annual plants and cover crops, with mulch residue allows the maintenance of the productive potential of these soils. Thus, the shoot dry mass production (SDMP) of winter cover crops was evaluated in an Ultisol under no-tillage system and in rotation with soybean and maize using 0, 2, 4 and 8 t ha-1 year-1 of poultry litter, mineral fertilizer exclusively and 2 t ha-1 year-1 of poultry litter associated with a half-dose of mineral fertilizer. The experimental design included randomized blocks with four replicates. The use of poultry litter increased the SDMP of the cover crops; the production was relatively high when high doses of poultry litter were applied; on the other hand, the yield of SDMP and grain was limited by the exclusive use of mineral fertilizer. Organic matter and nutrient status improvement by cover crops were one of the reasons for the increase in soybean and maize grain yields.

Synthesis of enriched biochar as a vehicle for phosphorus in tropical soils

Phosphorus (P) is one of the nutrients that most limits agricultural productivity, especially in tropical soils. Enriched biochar has been proposed to increase the bioavailability of P and other nutrients in the soil. Thus, the objective of this study was to evaluate the availability of P in phosphate biochar (composed of biomass and soil) as a function of the triple superphosphate mixture before and after the pyrolysis process. We produced eight types of enriched biochar via pyrolysis by combining sandy or clayey soil with rice or coffee husk, and by adding triple superphosphate before or after pyrolysis. The heating of the phosphate fertilizer during the pyrolysis process resulted in a higher crystallinity of the phosphates, lower content of labile fractions of P and lower content of available P in phosphate biochars than when the superphosphate was added after pyrolysis. (AU)

Bacterial community structure in soils contaminated with electronic waste pollutants from Delhi NCR, India

Background: Microbial community analysis of electronic waste (e-waste)-polluted environments is of interest to understand the effect of toxic e-waste pollutants on the soil microbial community and to evaluate novel microorganisms resisting the toxic environment. The present study aims to investigate the bacterial community structure in soils contaminated with e-waste from various sites of Loni and Mandoli (National Capital Region (NCR), India) where e-waste dumping and recycling activities are being carried out for many years. Results: Interferences to soil metagenomic DNA extraction and PCR amplification were observed because of the presence of inhibiting components derived from circuit boards. Whole-metagenome sequencing on the Illumina MiSeq platform showed that the most abundant phyla were Proteobacteria and Firmicutes. Deltaproteobacteria and Betaproteobacteria were the most common classes under Proteobacteria. Denaturing gradient gel electrophoresis (DGGE) analysis of the bacterial 16S rRNA gene showed that e-waste contamination altered the soil bacterial composition and diversity. There was a decrease in the number of predominant bacterial groups like Proteobacteria and Firmicutes but emergence of Actinobacteria in the contaminated soil samples. Conclusions: This is the first report describing the bacterial community structure of composite soil samples of ewaste-contaminated sites of Loni and Mandoli, Delhi NCR, India. The findings indicate that novel bacteria with potential bioremediating properties may be present in the e-waste-contaminated sites and hence need to be evaluated further.

Physical and chemical properties of soils in different physiographic environments in the southern Amazonas region / Atributos físicos e químicos de solos em diferentes ambientes fisiográficos na região sul do Amazonas, Brasil

The Amazon region has a great diversity of landscapes such as forests galleries, natural fields ("Cerrados Amazônicos"), dense forest, these environments made possible the formation of a broad class of soils over time. The aim of this study was to evaluate the physical and chemical properties of soils in different physiographic environments in southern Amazonas, Brazil. Three areas of representative physiographies were selected, all of them in natural conditions: natural field / forest and floodplain / dry land transitions, and corrugated relief areas. Soil samples were collected in layers of 0.0 to 0.20 and 0.80-1.0 m. From the samples collected the following physical analyzes were performed: particle size, bulk density, particle density, total porosity and saturated hydraulic conductivity; and chemical: exchangeable calcium, magnesium, aluminum and potassium available, phosphorus, potential acidity, pH and organic carbon. Based on the results of chemical analysis were calculated the sum of bases and base saturation. The results were submitted to multivariate statistics analysis, at the discretion of the principal component analysis (PCA). From the results it is clear that different physiographic environments studied influence the formation of different soil classes, featuring the diversity of Amazonian soils. The PCA allowed the distinction and formation of differentsimilarity groups, thus enabling to relate the physical and chemical properties with the physiographic formation in which they are inserted.

A região amazônica possui uma grande diversidade de paisagens, como galerias de florestas, campos naturais (Cerrados Amazônicos), floresta densa, possibilitando a formação de uma ampla classe de solos ao longo do tempo. O objetivo deste estudo foi investigar as propriedades físicas e químicas de solos em diferentes ambientes fisiográficos no sul do Amazonas, Brasil. Três áreas de fisiografias representativas foram selecionadas, todas em condições naturais: campo natural / floresta e transições de várzea / terra firme e áreas de relevo corrugado. Amostras de solo foram coletadas em camadas de 0,0 a 0,20 e 0,80-1,0 m. Das amostras coletadas foram realizadas as seguintes análises físicas: tamanho de partícula, densidade do solo, densidade de partículas, porosidade total e condutividade hidráulica saturada; e químico: cálcio trocável, magnésio, alumínio e potássio disponíveis, fósforo, acidez potencial, pH e carbono orgânico. Com base nos resultados da análise química foram calculados a soma das bases e saturação por bases. Os resultados foram submetidos à análise estatística multivariada, a critério da análise de componentes principais (PCA). A partir dos resultados, percebe-se que diferentes ambientes fisiográficos estudados influenciam a formação de diferentes classes de solos, caracterizando a diversidade de solos amazônicos. O PCA permitiu a distinção e formação de diferentes grupos de similaridade, permitindo relacionar as propriedades físico-químicas com a formação fisiográfica em que estão inseridos.

Effects of phosphate, carbonate, and silicate anions on CO2 emission in a typical oxisol from cerrado region / Efeitos dos ânions fosfato, carbonato e silicato na emissão de CO 2 em um latossolo típico da região do cerrado

The effects of agricultural practices on greenhouse gases emissions (e.g. CO2) at the soil-atmosphere interface have been highlighted worldwide. The use of ground limestone has been considered as the main responsible for CO2 emission from soils. However, liming is need as conditioner of acidic soils and the CO2 emission can be compensated due to carbon sequestration by plants. This study simulated under laboratory conditions the effects of two common agricultural practices in Brazil (P-fertilization and liming) on soil CO2 emission. Columns made of PVC tubes containing 1 kg of a typical Dystrophic Red Latosol from Cerrado region were incubated with CaCO3 (simulating liming), CaSiO3 (simulating slag), and different doses of KH2PO4 (simulating P-fertilization). The soil columns were moistened to reach the field capacity (0.30 cm3cm-3) and, during 36 days, CO2 emissions at the soil surface were measured using a portable Licor LI-8100 analyzer coupled to a dynamic chamber. The results showed that CO2 emission was influenced by phosphate, carbonate, and silicate anions. When using CaSiO3, accumulated CO2 emission (36-day period) was 20% lower if compared to the use of CaCO3. The same amount of phosphate and liming (Ca-carbonate or Ca-silicate) added to the soil provided the same amount of CO2 emission. At the same P dose, as Si increased the CO2emission increased. The highest CO2 emission was observed when the soil was amended with the highest phosphate and silicate doses. Based on this experiment, we could oppose the claim that the use of limestone is a major villain for CO2 emission. Also, we have shown that other practices, such as fertilization using P + CaSiO3, contributed to a higher CO2 emission. Indeed, it is important to emphasize that the best practices of soil fertility management will undoubtedly contribute to the growth of crops and carbon sequestration.

Os efeitos das práticas agrícolas nas emissões de gases de efeito estufa (e.g., CO2) na interface solo-atmosfera têm sido destacados em todo o mundo. O uso de calcário tem sido considerado oprincipal responsável pela emissão de CO2 em solos. Entretanto, a calagem é necessária como condicionador de solos ácidos e a emissão de CO2 pode ser compensada devido ao sequestro de carbono pelas plantas. Este estudo simulou, em condições de laboratório, os efeitos de duas práticas agrícolas comuns no Brasil (adubação fosfatada e calagem) na emissão de CO2 do solo. Colunas de tubos de PVC, contendo 1 kg de amostra de um Latossolo Vermelho Distrófico típico da região de Cerrado, foram incubadas com CaCO3 (simulando calagem), CaSiO3 (simulando escória) e diferentes doses de KH2PO4 (simulando fertilização com P). As colunas de soloforam umedecidas para atingir a capacidade de campo (0,30 cm3 cm-3) e, durante 36 dias, as emissões de CO2na superfície do solo foram medidas usando um analisador portátil Licor LI-8100 acoplado a uma câmara dinâmica. Os resultados mostraram que a emissão de CO2 foi influenciada pelos ânions fosfato, carbonato esilicato. Ao usar CaSiO3, a emissão de CO2 acumulada (período de 36 dias) foi 20% menor se comparado ao uso de CaCO3. A mesma quantidade de fosfato e calcário (Ca-carbonato ou Ca-silicato) adicionado ao solo proporcionou a mesma quantidade de emissão de CO2. Na mesma dose de P, o Si aumentou a emissão de CO2. A maior emissão de CO2 foi observada quando o solo foi alterado com as maiores doses de fosfato e silicato. Com base neste experimento, nega-se que o uso de calcário em solos é um grande vilão para a emissão de CO2. Além disso, foi mostrado que outras práticas, como a fertilização usando P + CaSiO3, contribuíram para uma maior emissão de CO2. Assim, é importante enfatizar que práticas adequadas de manejo da fertilidade do solo, sem dúvida, contribuirão para o crescimento das culturas e o sequestro de carbono.

Bacterias halófilas con potencial para la recuperación de suelos salinizados en Sáchica-Boyacá, Colombia

Es posible usar bacterias halófilas aisladas de ambientes salinos como una posible alternativa de rehabilitación de suelos salinizados para la producción agrícola y agropecuaria. En este estudio se evaluaron seis bacterias halófilas para determinar su potencial en la disminución de la conductividad eléctrica (Ce) de suelo moderadamente salino del municipio de Sáchica- Boyacá (Colombia). Las bacterias se aislaron en agar nutritivo con diferentes concentraciones de NaCl, luego fueron inoculadas en el suelo (3 kg puesto en materas) para realizar un bioensayo en invernadero durante 2 meses. Se realizaron dos fases, la primera hasta conseguir un valor de 2 ds/m (Ce) con el fin de sembrar plantas de tomate en la segunda fase. Se realizaron mediciones semanales de la (Ce) durante todo el bioensayo y solo en la fase 2 se determinaron semanalmente variables cualitativas de crecimiento de tomate (altura, número de hojas, área foliar, marchitez y clorosis). Los resultados mostraron un efecto directo de las bacterias halófilas en la disminución de la (Ce) del suelo, pasando de 5.2 a 0.8 ds/m (T1), 0.7 ds/m (T2), 0.8 ds/m (T3), 0.6 ds/m (T4), 0.7 ds/m (T5), 0.7 ds/m (T6), 3.0 ds/m (testigo), valores que corresponden a salinidad muy ligera (< 2 ds/m). En relación con las variables agronómicas, se evidenciaron mejoras en las características evaluadas en comparación con el testigo absoluto, sobre todo en altura y número de hojas de las plantas. Para el testigo absoluto se perdieron 80 % de las unidades experimentales, mientras que en el suelo con los diferentes tratamientos solo en algunos casos se perdió el 20 %. De acuerdo con esto, se evidencia que las bacterias halófilas utilizadas en esta investigación tienen potencial para la rehabilitación de suelos salinizados.

It is possible to use halophilic bacteria isolated from saline environments as a possible alternative for the rehabilitation of salinated soils for agricultural and agricultural production. Six halophilic bacteria were evaluated to determine their potential in the reduction of the electrical conductivity (Ce) of moderately saline soil in the municipality of Sáchica-Boyacá (Colombia). The bacteria were isolated on nutritive agar with different concentrations of NaCl, then inoculated in the soil (3 kg placed in pots) to perform a bioassay in the greenhouse for 2 months. Two phases were carried out, the first until obtaining a value of 2 ds / m (Ce) in order to plant tomato plants in the second phase. Weekly measurements of the ( Ce ) were made throughout the bioassay and only in phase 2 were determined weekly qualitative variables of tomato growth (height, number of leaves, foliar area, wilting and chlorosis). The results showed a direct effect of the halophilic bacteria in the decrease of the (Ce) of the soil, going from 5.2 to 0.8 ds / m (T1), 0.7 ds / m (T2), 0.8 ds / m (T3), 0.6 ds / m (T4), 0.7 ds / m (T5), 0.7 ds / m (T6), 3.0 ds / m (Control), values that correspond to very light salinity (< 2 ds / m). Regarding the agronomic variables, improvements were observed in the characteristics evaluated in comparison with the absolute control, especially in height and number of leaves of the plants. For the absolute control 80 % of the experimental units were lost, while in the soil with the different treatments only in some cases 20 % was lost. Accordingly, it is evident that the halophilic bacteria used in this research have potential for the rehabilitation of salinated soils.