Efecto de la deforestación ribereña sobre la materia orgánica particulada gruesa en quebradas con influencia ganadera de la región Andina de Colombia / Effect of riparian deforestation on coarse particulate organic matter in streams with livestock influence in the Andean region of Colombia

Introducción: La materia orgánica particulada gruesa originada en la vegetación ribereña es la fuente principal de energía en muchas cuencas de cabecera. Sin embargo, la transferencia de dicha materia es alterada por la destrucción de los bosques. Objetivo: Evaluar diferencias en la materia orgánica en quebradas con bosques y con pastizales. Métodos: Comparar las entradas, el almacenamiento y la exportación de esta materia orgánica en el cauce de quebradas con bosques y con pastizales, en la región central de los Andes de Colombia. En cada quebrada, se midieron los aportes verticales y laterales de hojarasca con canastas; hojarasca del lecho de las quebradas con cuadrantes, y la exportación de material con redes de deriva, con un alcance de 100 m. Resultados: Las quebradas con bosques ribereños recibieron un promedio anual de 915 g m-2 de materia orgánica particulada gruesa, exportando un total de 334 g m-3 y almacenando 732 g m-2, valores que fueron significativamente más altos que en quebradas con pastizales, donde los valores correspondientes fueron: 125.4 g m-2; 128 g m-3 y 205.5 g m-2. Conclusiones: La remoción de cobertura boscosa de la zona ribereña reduce la materia orgánica en estas cuencas de cabecera en Colombia.

Introduction: Coarse particulate organic matter originated in riparian vegetation is the main source of energy in many headwater streams. However, the transfer of such material is altered by the destruction of forests. Objective: To assess flow differences of this organic matter in streams with forests and grasslands. Methods: We compared input, storage and export of this organic matter in the riparian belts of streams with forests, and streams with grasslands, in the central Andean region of Colombia. For each stream, we measured vertical and lateral litter with baskets; stream bed litter with a quadrant, and matter export with drift nets, in a 100 m reach. Results: The streams with riparian forest received an average of 915 g m-2 of coarse particulate organic matter annually, exported a total of 334 g m-3 and stored 732 g m-2, values that were significantly higher than in grassland streams, where the corresponding values were: 125.4 g m-2; 128 g m-3 and 205.5 g m-2. Conclusions: The removal of tree cover from the riparian zone reduced the organic matter in these headwater streams of Colombia.

Doses of sulfur at topdressing and organic compost supply at planting in the production, quality and content of macronutrients in lettuce seeds

The purpose of this study was to evaluate doses of sulfur applied at topdressing, with and without organic compost supply at planting, in the production, physiological quality and content of macronutrients in lettuce seeds. Ten treatments were evaluated in a 5x2 factorial scheme (five sulfur doses at topdressing x with and without application of organic compost at planting). The experimental design was a randomized block design, with four replicates. The sulfur doses applied at topdressing fertilization were 50, 100, 150 and 200 kg ha-1 of S, in addition to the control treatment (dose zero). Regarding the treatments with organic compost, the dose of 70 t ha-1 of compost (wet basis) was supplied at planting. The following characteristics were evaluated: seed production (mass and number of seeds per plant), seed quality (mass of one thousand seeds, first count of the standard germination test, germination percentage, and germination speed index) and content of macronutrients and mineral accumulation. The organic compost supply at planting increased seed production by 43% compared to the treatment without the application of organic compost, while the doses of sulfur did not affect the production of lettuce seeds. The supply of organic compost increased the accumulation of a great part of the macronutrients, except for the accumulation of calcium. The lettuce seeds quality was not affected by both the main treatments, the sulfur doses at topdressing and the organic compost supply at planting. The descending order of nutrients accumulated in the lettuce seeds was nitrogen> potassium> phosphorus> magnesium> calcium> sulfur.

Growth and productivity of ágata potato cultivar under different doses of organomineral fertilizer

Potato is a plant that has high nutrient demand during its cycle. Given the concern with the environment, due to the large amount of synthetic mineral fertilizer used in the crops, the objective of this work was to evaluate the efficiency of organomineral fertilizers in the cultivation of potato, cultivar Ágata, under cerrado conditions. The experimental design was in subdivided plots, consisted of four doses of organomineral fertilizer, corresponding to 40, 60, 80, 100 and 120% of the mineral fertilizer dose in the organomineral source (2800 kg ha-1 of formulated 3-32-6) and the subplots consisted of four collection seasons (61, 74, 89 and 110 days after planting) and four repetitions. Organomineral fertilizer with 40% of the recommended dose for potato cultivation provides higher yield of tubers in the Especial potato class and higher accumulation of total dry mass, in addition to providing satisfactory productivity for the tubers of higher commercial value. The use of organomineral fertilizers promotes the same behavior as mineral fertilizers, not interfering with potato development.

Ciclo de vida em laboratório de imaturos de Phylloicus elektoros e Phylloicus amazonas (Trichoptera: Calamoceratidae) de um igarapé da Amazônia Central / Immature life cycle of laboratory-reared Phylloicus elektoros and Phylloicus amazonas (Trichoptera: Calamoceratidae) from a central Amazonian stream

Nós criamos massas de ovos dos tricópteros Phylloicus amazonas (n = 2) e Phylloicus elektoros (n = 7) coletadas no campo até a fase adulta. A mediana do tempo de desenvolvimento do primeiro instar larval ao adulto foi de 229 dias para P. amazonas e 275 dias para P. elektoros, incluindo o tempo de desenvolvimento pupal (mediana de 13.5 e 16 dias, respectivamente). Fragmentadores têm sido frequentemente usados em estudos relacionados ao processamento de matéria orgânica em ecossistemas aquáticos. As informações biológicas fornecidas neste estudo podem ser úteis para o planejamento de estudos experimentais em campo ou em condições de laboratório.(AU)

Action of benzalkonium chloride in different pH

Ammonium quaternary compounds are widely used in poultry and swine production as disinfectants in the control of pathogens. They act on gram-positive bacteria, gram-negative bacteria, enveloped fungi and viruses. However, in some conditions of pH and presence of organic matter can be inactivated. This study evaluated the action of ammonium quaternary compounds at 1:1,000 and 1:2,000 dilutions against Salmonella enterica serovarTyphimurium and Salmonella enterica serovar Enteritidis in the presence of three different organic matter simulators, fetal bovine serum, skim milk and whole milk concentration of 1, 3, 5, and 7% and at pH 6 and 9, with 15 min of contact. It was possible to verify that the organic matter simulators adjusted in the same conditions of contact time and percentage, in the in vitro tests, presented different results and the fetal bovine serum did not inactivate the disinfectant. However, the best result against S. Typhimurium and S. Enteritidis was obtained at pH 6 at the dilution of 1:1,000 in all organic matter simulators.

Litter decomposition and nutrient release dynamics of leaves and roots of the babassu palm in eastern Amazonia

The ruderal babassu palm (Attalea speciosa) is expanding on large areas of degraded Amazon landscapes. Decomposition of leaves and roots is in the center of plant:soil interactions. We evaluated decomposition and nutrient concentrations of leaves and fine roots of babassu in comparison with two exotic reference species, Acacia mangium (slow degradability) and Leucaena leucocephala (fast degradability), in a 138-day litterbag assay carried out in secondary forest stands of different age and babassu abundance. We chose 4-mm over 2-mm mesh litterbags based on a pilot study. Babassu leaves degraded slower than leaves of A. mangium and L. leucocephala, and also had lower nitrogen, phosphorus and calcium concentrations in all stages of decomposition. By contrast, potassium concentrations in babassu leaves were higher than in both reference species at 0 and 50 days. Roots of all three species decomposed slower than leaves. Compared to the leaves, both biomass loss and nutrient concentrations differed less between babassu and reference-species roots, except for lower nitrogen concentration in babassu roots. Leaf-litter decomposition of all three species was significantly faster in old than in young secondary forest, suggesting an acceleration of decomposition along succession. Babassu leaves decomposed faster in old babassu-dominated than non-dominated secondary forest, pointing to the existence of specialized decomposer communities in babassu-dominated stands. (AU)

Eficácia do etidronato na remoção da smear layer dos canais radiculares: um estudo com microscopia eletrônica de varredura / Effectiveness of etidronate in root canal smear layer removal: A study with scanning electron microscopy

Avaliar, por microscopia eletrônica de varredura (MEV), o efeito do uso individual e combinado do etidronato 18% (HEBP) na remoção da smear layer do canal radicular. Métodos: Trinta dentes humanos unirradiculares foram utilizados. As raízes foram preparadas com instrumentos rotatórios do Sistema ProTaper Universal e divididas aleatoriamente em três grupos, de acordo com o protocolo de irrigação empregado: G1 = hipoclorito de sódio 2,5% (NaOCl) e ácido etilenodiaminotetracético 17% (EDTA); G2 = NaOCl 2,5% e HEBP 18%; e G3 = NaOCl 2,5% + HEBP 18%, misturados em partes iguais. As raízes foram seccionadas longitudinalmente e metalizadas, para análise em MEV. As fotomicrografias obtidas dos terços cervical, médio e apical foram avaliadas por três examinadores calibrados, que atribuíram escores de 1 a 5 às imagens. Os grupos experimentais foram comparados usando o teste de Kruskal-Wallis e o teste de Student-New- man-Keuls. Os terços radiculares foram comparados pelo teste de Friedman. O nível de significância foi estabelecido em 5%. Resultados: A capacidade de remoção da smear layer com NaOCl 2,5% e 18% HEBP (G2) foi semelhante à obtida com NaOCl 2,5% e EDTA 17% (G1) no terço médio e cervical da raiz; o nível de limpeza do terço apical foi semelhante, independentemente do protocolo de irrigação utilizado. Conclusão: HEBP é uma solução promissora para uso em tratamentos endodônticos (AU).

Introduction: We evaluated the effect of individual and combined use of 18% etidronate (HEBP) in root canal smear layer removal using scanning electron microscopy (SEM). Methods: Thirty human single-rooted teeth were used. The roots were prepared with ProTaper Universal System rotary files and randomly divided into three groups according to the irrigation protocol used. G1: 2.5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA); G2: 2.5% NaOCl and 18% HEBP; and G3: 2.5% NaOCl + HEBP 18%, mixed in equal parts. The roots were sectioned longitudinally and metallized for SEM analysis. The photomicrographs obtained from the cervical, middle, and apical thirds were evaluated by three calibrated examiners, who assigned scores from 1 to 5 to the images. The experimental groups were compared using the Kruskal-Wallis test and the Student-Newman-Keuls test. Root thirds were compared by the Friedman test. The level of significance was set at 5%. Results: The capacity for removal of the smear layer by 2.5% NaOCl and 18% HEBP (G2) was similar to that achieved with 2.5% NaOCl and 17% EDTA (G1) in the cervical and middle thirds of the root; the cleansing level of the apical third was similar, regardless of the irrigation protocol used. Conclusion: HEBP is a promising solution for use in endodontic treatments (AU).

Diagnóstico do tratamento de esgotos no Rio Grande do Sul e sua associação aos riscos com a saúde / Diagnosis of sewage treatment in Rio Grande do Sul and its association with health risks

O presente trabalho tem como objetivo estimar o volume de esgoto gerado no RS em Demanda Bioquímica de Oxigênio (DBO kg/dia), e o volume de esgoto (DBO kg/dia) que chega até as estações de tratamento de esgoto ETEs; diagnosticar a eficiência das estações de tratamento de esgotoem relação ao percentual de remoção de (DBO kg/dia); correlacionando com a presença de cianobactérias próximas aos pontos de captação de água superficial para consumo humano; analisar se há inativação ou remoção de protozoários no lançamento do efluente ao retornar ao manancial. Como resultado obteve-se o volume total de matéria orgânica lançada nos corpos hídricos por dia estimado no Rio Grande do Sul é 511.769,00 DBO kg/dia no RS. As Estações de Tratamento de Esgoto captam 390.285,45 DBO kg/dia apresentaram resultados de remoção de 145.500,50 DBO kg/dia e de 22.963,21 DBO kg/dia residual; O volume ocioso das ETEs fica em torno de 5.049,89 L/s. O processo de eliminar ou inativar grande quantidade de protozoários presentes no afluente se dá através de etapas terciárias avançadas nas ETEs. Não encontramos no RS no ano 2019 ETEs com esses tipos avançados de tratamento. Sugere-se então que haja um melhor aproveitamento destas estações de tratamento no que se refere à quantidade e qualidade de volume de esgoto tratado e que sejam ampliados estudos para viabilidade de projetos de execução de novas ETEs para os demais municípios que despejam seus esgotos in natura nos mananciais impactando-os.

This work aims to estimate the volume of sewage generated in RS in Biochemical Oxygen Demand (BOD kg/day), and the volume of sewage (BOD kg/day) that reaches the sewage treatment stations (STS)s; diagnose the efficiency of sewage treatment station in relation to the percentage of removal (BOD kg/day); correlating with the presence of cyanobacteria close to the surface water intake points for human consumption; analyze if there is inactivation or removal of protozoa in the discharge of the effluent when returning to the source. As a result, the total volume of organic matter released into water bodies per day estimated in Rio Grande do Sul is 511,769.00 BOD kg/day in RS. The Sewage Treatment Plants capture 390,285.45 BOD kg/day showed removal results of 145,500.50 BOD kg/day and 22,963.21 BOD kg/day residual; The idle volume of ETEs is around 5,049.89 L/s. The process of eliminating or inactivating a large amount of protozoa present in the tributary takes place through advanced tertiary stages in the STSs. We did not find in RS in the year 2019 STSs with these advanced types of treatment. It is therefore suggested that there is a better use of these treatment plants with regard to the quantity and quality of the volume of treated sewage and that studies for the feasibility of projects for the execution of new STSs be expanded to the other municipalities that dump their raw sewage in water sources impacting them.

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.

Influence of Landfill Leachate on Organic Matter Removal in Activated Sludge and Activated Sludge with Carrier Processes

Abstract This study assessed the performance of two pilot units, a conventional activated sludge (CAS) and an Integrated Fixed-Film Activated Sludge (IAS), in the treatment of leachate from sanitary landfill combined with domestic sewage, with the aim of removing organic substances. In order to assess the possible impacts on treatment, three experimental phases were designed using influent leachate contributions of 5%, 10%, and 20% of the total BOD load. Overall, the results showed that no significant changes in the behavior of biological processes. The IAS unit presented average BOD removal efficiencies of above 88%, 87% and 80% for the three leachate load contributions of 5%, 10% and 20% studied. The CAS unit presented lower average efficiency with a 5% leachate contribution (64%), but displayed a similar performance to the IAS unit in the other phases (82% and 80%); similar quantitative aspects were observed for both treatment processes with regards to biomass composition analysis. The kinetic coefficients related to heterotrophic metabolism did not indicate negative effects on treatment efficiency as a result of the increase in leachate addition, with values of 2.8; 2.8 and 2.7 d-1 obtained respectively for each phase with the CAS unit, and 2.0; 1.5 and 1.6 d-1 with the IAS unit, representing similar values to those found in the literature (1.5 a 5.0 d-1). The results reinforced the conclusion that the leachate load introduced did not cause inhibition or significant alterations to heterotrophic metabolism, and, therefore, to the removal of organic matter.

Organic matter and moringa leaf extract's effects on the physiology and fruit quality of red seedless watermelon (Citrullus lanatus) / Efeitos da matéria orgânica e do extrato da folha de moringa sobre a fisiologia e qualidade do fruto da melancia vermelha sem sementes ( Citrullus lanatus )

This study was designed to assess the effects of different types of organic matter on the quality and biochemical properties of red seedlesswatermelon.The research was a single factor experiment, which involved six (6) treatments and four (4) replications. Watermelon grown and harvested from five (5) different organic matter sources, namely; vermicompost (VC), poultry manure (PM), cow dung (CD), goatdung (GD), and moringa leaf extract (MLE), at the rates of 10 ton, 20 ton, 30 ton, 30 ton, and 3000 L ha-1, respectively, were used in this study. The results revealed that the treatment of vermicompost improved the chlorophyll content, chlorophyll fluorescence, stomatal conductance, internal carbon dioxide, net photosynthetic rate, fruit weight and mineral nutrient content of watermelon. The application of cow dung reduced the rind thickness and increased the TSS and antioxidant activity of the watermelon. The goat dung treatment significantly affected fruit size, juice content and the pH content of the watermelon's fruit juice. The poultry manure (PM) and moringa extract (MLE) treatments resulted in the highest anthocyanin content of all the watermelon. Although all the organic matter, in their unique ways, improved the quality of red seedless watermelon, the study shows that the vermicompost application had better growth, yield and improvement in the quality of watermelon.

Este estudo foi desenhado para avaliar os efeitos de diferentes tipos de matéria orgânica sobre a qualidade e propriedades bioquímicas da melancia vermelha sem sementes. A pesquisa foi um experimento de fator único, que envolveu seis (6) tratamentos e quatro (4) repetições. Melancia cultivada e colhida de cinco (5) diferentes fontes de matéria orgânica, nomeadamente; vermicomposto (VC), esterco de galinha (PM), estrume de vaca (CD), esterco de cabra (GD) e extrato de folhas de moringa (MLE), nas doses de 10 ton, 20 ton, 30 ton, 30 ton e 3000 L ha-1, respectivamente, foram utilizados neste estudo. Os resultados revelaram que o tratamento do vermicomposto melhorou o teor de clorofila, a fluorescência da clorofila, a condutância estomática, o dióxido de carbono interno, a taxa fotossintética líquida, o peso do fruto e o teor de nutrientes minerais da melancia. A aplicação de esterco bovino reduziu a espessura da casca e aumentou o TSS e a atividade antioxidante da melancia. O tratamento com esterco de cabra afetou significativamente o tamanho do fruto, o teor de suco e o teor de pH do suco de fruta da melancia. Os tratamentos com esterco de galinha (PM) e extrato de moringa (MLE) resultaram no maior teor de antocianina de todas as melancias. Apesar de toda a matéria orgânica, em seus meios únicos, melhorar a qualidade da melancia vermelha sem sementes, o estudo mostra que a aplicação do vermicomposto apresentou melhor crescimento, rendimento e melhora na qualidade da melancia.

Correlação entre métodos de monitoramento de limpeza e desinfecção de superfícies ambulatoriais / Correlación entre métodos de monitoreo de limpieza y desinfección de superficies en unidades ambulatorias / Correlation among monitoring methods of surface cleaning and disinfection in outpatient facilities

Resumo Objetivo Avaliar a correlação entre cultura microbiológica, teste de ATP por bioluminescência e inspeção visual na monitorização da eficiência da limpeza e da desinfecção de superfícies de uma unidade ambulatorial e determinar o valor de corte de ATP-bioluminescência capaz de indicar superfície limpa em relação à avaliação microbiológica. Métodos Estudo exploratório, longitudinal e correlacional. Foram realizadas 720 avaliações em cinco superfícies antes e após a limpeza e a desinfecção. Nos resultados, foram realizadas análises de duas proporções, a correlação de Spearman e a curva ROC. Resultados Ocorreram proporções semelhantes (p≥0,05) entre as taxas de reprovação apenas entre ATP-bioluminescência e contagem de colônias aeróbias (CCA) quando somadas as avaliações de todas as superfícies antes e depois da limpeza e da desinfecção. Houve correlação significativa entre os métodos de quantificação de ATP e a contagem microbiana para o balcão da recepção e a maca. A análise ROC indicou que a quantificação de ATP apresentou resultado significativo na comparação com a CCA (p=0,044). Conclusão Embora discreta, houve correlação significativa entre os métodos de quantificação de ATP e contagem microbiana para duas superfícies. Sugere-se que superfícies que apresentam valores ≤49 unidades relativas de luz estão limpas.

Resumen Objetivo Analizar la correlación entre cultivo microbiológico, prueba de ATP por bioluminiscencia e inspección visual en el monitoreo de la eficiencia de la limpieza y desinfección de superficies en una unidad ambulatoria y determinar el valor de referencia de ATP-bioluminiscencia que indique que la superficie está limpia con relación a la evaluación microbiológica. Métodos Estudio exploratorio, longitudinal y correlacional. Se realizaron 720 evaluaciones en cinco superficies antes y después de la limpieza y desinfección. En los resultados, se realizaron análisis de dos proporciones: la correlación de Spearman y la curva ROC. Resultados Hubo proporciones semejantes (p≥0,05) entre los índices de reprobación solo entre ATP-bioluminiscencia y recuento de colonias aerobias (RCA) cuando se sumaron las evaluaciones de todas las superficies antes y después de la limpieza y desinfección. Hubo una correlación significativa entre los métodos de cuantificación de ATP y el recuento microbiano en el mostrador de la recepción y la camilla. El análisis ROC indicó que la cuantificación de ATP presentó un resultado significativo en la comparación con el RCA (p=0,044). Conclusión Hubo una correlación significativa, aunque discreta, entre los métodos de cuantificación de ATP y recuento microbiano en dos superficies. Se sugiere que las superficies que presentan valores ≤49 unidades relativas de luz están limpias.

Abstract Objectives To evaluate the correlation among microbiological culture, ATP bioluminescence assay, and visual inspection in monitoring the effectiveness of surface cleaning and disinfection in an outpatient facility and determine the ATP bioluminescence cutoff capable of indicating a clean surface regarding microbiological evaluation. Methods Exploratory, cross-sectional, and correlation study consisting of 720 evaluations in five surfaces before and after cleaning and disinfection. The results were used to run two-proportions tests, calculate Spearman's correlation, and plot the receiver operating characteristic curve. Results Similar proportions (p≥0.05) occurred for non-approval rates between ATP-bioluminescence and aerobic colony count only when the evaluations of all the surfaces before and after cleaning and disinfection were put together. There was a significant correlation between the ATP quantification and microbial count methods for the reception desk and the stretcher. Receiver operating characteristic analysis indicated that ATP quantification showed a significant result in comparison with aerobic colony count (p=0.044). Conclusion There was a discrete correlation between the ATP quantification and microbial count methods for two surfaces. It is suggested that surfaces showing values ≤49 relative light units are clean.

Soil organic matter and production of ears of green corn after four years under tillage systems and previous crops in costal tablelands / Matéria orgânica do solo e a produção espigas de milho-verde após quatro anos sob sistemas de cultivo e culturas antecedentes nos tabuleiros costeiros

The current study aimed to evaluate the effects of different tillage systems on soil organic matter (SOM) contents and green corn yield (total ear weight) of an Argissolo Vermelho-Amarelo(Ultissol) in Coastal tablelands of northeast Brazil. The experiment was arranged as a strip plot design with three replications. Three tillage practices [conventional tillage (CT), minimum tillage (MT) and no-tillage (NT)] were laid out as a whole plot each (830 m²). Then, each plot was equally split into 12 experimental units (60 m²), distant 1 x 10 m from each other, where in four cover crops [pigeon pea (Cajanus cajan (L.) Millsp.), sunn hemp (Crotalaria juncea L.), beans (Phaseolus vulgaris) and peanut (Arachis hypogeae) were seedling previous to corn cultivation. Neither cover crops, nor tillage practices affected SOM contents at 0.20 m depth. An exception was observed on beans plots in which CT resulted on the lowest SOM content (8.5 dag kg-1) at 0-10 cm soil layer. Regarding green corn ears yield, CT adoption also resulted in lower weight (4.11 t ha-1) than those on NT (7.65 t ha-1), regardless of cover crop. On the other hand, the influence of cover crops on green corn yield relied upon tillage practices. Peanuts and sunn hemp performed best to improve corn yield in CT; peanuts and beans increased by 14 % the green corn ears yield in MT, while sunn hemp resulted in the highest total ear weight (9.42 t ha-1). Linear correlation of Pearson was significant for SOM and productivity green maize ears in minimum tillage beans (p <0.001; r = 0.996). After four years of absence or reduced soildisturbance, there was no increase in SOM levels. The plowing appears to be important for increasing the entry of C soil and chemical protection SOM of Argissols mainly in the surface layer of Coastal tablelands in brazilian northeast. Although the NT did not provide higher levels of SOM, the yield of green maize incommercial was significantly higher when adopting conservation systems.

O presente estudo teve como objetivo avaliar o efeito de diferentes sistemas de cultivo nos teores de matéria orgânica do solo (MOS) e na produtividade do milho verde (peso total das espigas) emArgissolo Vermelho-Amarelo (Ultissol) nos Tabuleiros costeiros da região nordeste do Brasil.. O experimento foi disposto em faixas experimentais com três repetições.Três práticas de cultivo [cultivo convencional (CC), cultivo mínimo (CM) e plantio direto (PD)] foram arranjadas em faixas (830 m²). Então, cada faixa foi dividida igualmente em doze unidades experimentais (60 m²), distante entre si a cada 1 x 10 m, onde quatro culturas antecessoras [guandu (Cajanus cajan (L.) Millsp.) crotalária (Crotalaria juncea), feijão (Phaseolus vulgaris) e amendoim (Arachis hypogeae)] foram semeadas previamente ao cultivo do milho. As culturas antecessoras e as práticas de cultivo não afetaram os teores de MOS da profundidade de 0.20 m. Uma exceção foi observada nas parcelas com feijão no qual o CC resultou no menor teor de MOS (8.5 dag kg-1) na camada 0-10 cm. Em relação a produtividade das espigas de milho verde, a adoção do CC também resultou em menor peso (4,11 t ha-1) que no PD (7,65 t ha-1), independente da cultura antecessora. Por outro lado, a influência da cultura de cobertura sob a produtividade do milho verde foi dependente da prática de cultivo. Amendoim e crotalária saíram-se melhor para aumentar a produtividade do milho no CC; amendoim e feijão aumentaram em 14 % a produtividade das espigas de milho verde no CM, enquanto crotalária resultou no mais alto peso total das espigas (9,42 t ha-1). A correlação linear de Pearson foi significativo para a MOS e produtividade de espigas de milho verde com crotalária sob o cultivo mínimo (p <0,001; r = 0,996). Após quatro anos da ausência ouredução do revolvimento do solo, não houve aumento nos níveis de MOS. A aração parece ser importante para aumentar a entrada de C no solo e a proteção química da MOS em Argissolos, principalmente na camada superficial. Embora o PD não tenha fornecido níveis mais elevados de MOS, o rendimento de espigas comerciais de milho verde foi significativamente maior ao se adotar sistemas conservacionistas.

Respuesta de Fragaria mexicana y comunidades microbianas rizosféricas al aumento de temperature / Response of Fragaria Mexicana and rhizophere microbial communitites to temperature increase

Resumen Para los próximos 100 años se pronostica un incremento en la temperatura del planeta de casi 4 °C, lo cual pondrá en riesgo las especies que no logren adaptarse. En esta investigación se determinaron las respuestas morfofisiológicas de F. mexicana y los cambios en la población de bacterias fijadoras de nitrógeno atmosférico (BFN) asociadas a sus raíces, debido a dos condiciones ambientales con diferencias medias de temperatura de 5.1 oC: invernadero (temperatura alta, TA) y campo abierto (temperatura baja, TB); y con cuatro tratamientos: sin inocular (T), inoculadas con la cepa ocho (CP8), cepa cuatro (CP4) y con ambas cepas (CP8 + 4). Las BFN fueron aisladas de la rizosfera de F. mexicana y transformadas genéticamente con reporteros, para cuantificar la población al final del experimento. Se midió el peso seco de la parte aérea y la raíz, la tasa de asimilación de CO2 (A), el inicio de la floración, el número de flores y frutos; y la persistencia de las bacterias fijadoras de N atmosférico (BFN). Además, se evaluó la concentración de NO3, NH4, P y materia orgánica (MO) en el sustrato, al inicio y final del experimento. Las plantas sometidas a alta temperatura presentaron mayor peso seco de la parte aérea y fotosíntesis; con una disminución en el peso seco de la raíz, y en el número de flores y frutos. La MO en el sustrato disminuyó, mientras que la disponibilidad de NO3, NH4 y P aumentó. El incremento de temperatura y la mayor presencia de N en el substrato provocaron reducción en la población de BFN. Estos resultados sugieren que temperaturas altas estimulan el crecimiento de F. mexicana y tienen un impacto negativo sobre su reproducción y en las BFN asociadas a sus raíces.(AU)

Abstract The earth could experience a warming of 4 °C in the next one hundred years. This would put at risk the plants that can´t adapt. Fragaria mexicana is an endemic plant of temperate forest of Mexico. The response of this wild strawberry to temperature increasing has not been studied and could play an important role for event of global warming. This study determinate the morphological and physiological responses of F. mexicana and changes in the N2-fixing bacteria (BFN) population on its roots, due to two environmental conditions with differences of temperature 5.1 °C: greenhouse (high temperature, TA) and open land (low temperature, TB); and with four free-living nitrogen-fixing bacteria (BFN) treatments: non-inoculated (T), inoculated with strain eight (CP8), strain four (CP4), and strains eight and four mixed (CP8 + 4). BFN were isolated from the rhizosphere of F. mexicana and were genetically transformed with reporters to quantify the population at the end of the experiment. NO3, NH4 and P and organic matter (MO) in the substrate were determined at beginning and finish of the experiment. Shoot and root dry weight, photosynthetic rate, flowering and fructification starting, flowers and fruits number, were measured. Shoot dry weight and photosynthetic rate were lower in TB than TA, decreasing 3.1 g and 0.94 µmol m-2 s-1, respectively. Root dry weight was 3.0 g less in TA compared with TB. Number flowers decrease in 40.89 % and number fruits in 38.11 % on TA than TB. F. mexicana plants start flowering 14 days previously in TB than TA. MO in the substrate decrease in TA, while the concentration of NO3, NH4 and P, increased. Population of BFN was lower in TA. Results obtained indicated that higher temperature promotes the growth of F. mexicana and reduce its reproduction and BNF population associated with its roots.(AU)

Micro spray and end caps performance operating with water containing different concentrations of organic matter / Desempenho de micro spray e válvula fim de linha operando com águas contendo diferentes concentrações de material orgânico

Recently a micro spray and an end cap with drain valve device were launched on the market. Their main advantage is the low cost. The micro spray provides a higher percentage of irrigated area relative to the drippers and an end cap with drain valve removes all air from the pipes and minimizes obstructions of the emitters. However, these components need to be tested operating with different water quantities and qualities. Therefore, this study aimed to evaluate the performance of this micro spray and end cap with drain valve operating with water containing different concentrations of total solids. The experiment was conducted in a split plot scheme, with two end caps in the plots (conventional and with drain valve) and five total solid concentrations in the subplots (7 mg L-1, 407 mg L-1, 1007 mg L-1, 2007 mg L-1 and 4007 mg L-1) in a completely randomized design, with three replications. Sixty evaluations of the irrigation system were performed and the emitters were evaluated every application of 60 L up to a volume of 3.6 m3. The water flow rate and application uniformity were evaluated through distribution uniformity (DU) and statistical uniformity (US) coefficients. The micro spray performance was not affected by water application containing total solid concentrations below 270 and 500 mg L-1 in irrigation systems equipped with conventional end caps or with drain valves, respectively. Irrigation systems equipped with end caps with drain valve provided a better performance of micro sprays when operating with water containing total solid concentrations greater than 407 mg L-1. These end caps did not provided difference in micro spray performance when operating with public water.

Recentemente foi lançado no mercado um micro spray e um dispositivo fim de linha autolimpante tendo como principais vantagens o baixo custo. O micro spray propicia maior porcentagem de área irrigada em relação aos gotejadores e o fim de linha autolimpante retiram todo o ar das tubulações e minimizam o entupimento dos emissores. Entretanto, esses componentes precisam ser testados operando com diferentes quantidades e qualidades de água. Diante disso, o presente trabalho teve como objetivo avaliar o desempenho do micro spray e da válvula autolimpante operando com águas contendo diferentes concentrações de sólidos totais. O experimento foi conduzido em esquema de parcelas subdivididas, tendo nas parcelas dois finais de linha (convencional e válvula autolimpante) e nas subparcelas cinco águas com concentrações de sólidos totais (7 mg L-1, 407 mg L-1, 1.007 mg L-1, 2.007 mg L-1 e 4.007 mg L-1) no delineamento inteiramente casualizado (DIC), com três repetições. Foram realizadas 60 avaliações do sistema de irrigação e os emissores eram avaliados a cada aplicação de 60 L, acumulando o volume de 3,6 m3. Os parâmetros avaliados foram a vazão e as uniformidades de aplicação de água por meio dos coeficientes de distribuição (CUD) e estatístico (CUE). O desempenho dos micros spray testados não foi afetado com aplicação de águas contendo concentrações de sólidos totais inferiores a 270 e 500 mg L-1 nos sistemas de irrigação equipados com finais de linha convencionais e autolimpantes, respectivamente. Sistemas de irrigação equipados com finais de linha autolimpantes proporcionam melhor desempenho dos micros spray quando operam com águas contendo concentrações de sólidos totais superiores a 407 mg L-1. Esses mesmos finais de linha não proporcionam diferença no desempenho dos micros spray quando operam com água de abastecimento.

Degradación de hojarasca y aporte de nutrientes del manglar en la Laguna Mecoacán, Golfo de México / Leaf litter degradation and nutrient supply in the mangroves of Mecoacán Lagoon, Gulf of Mexico

Resumen Los manglares son ecosistemas de importante productividad primaria, donde se establece un flujo de energía (nutrientes) con zonas adyacentes y su ambiente acuático, impulsado principalmente por los procesos de degradación. El objetivo del estudio fue estimar el coeficiente de degradación diario (k) de hoja de mangle por medio de bolsas de degradación, en relación con los factores físico químicos del suelo y el aporte de nutrientes (fósforo y nitrógeno) en sedimento del manglar de la Laguna Mecoacán, Golfo de México. El coeficiente de degradación se estimó por medio de bolsas de degradación de hojarasca en seis sitios de monitoreo mensual. Se identificó una rápida degradación durante el primer mes de hasta 51 % en Avicennia germinans (L.) Stearn asociado a procesos de lixiviación por condiciones de inundación. La degradación (k) de Rhizophora mangle L. (k= 0.0052 ± 0.0002) (F= 12.2 p<0.05 n= 216) y Laguncularia racemosa (L.) Gaertn (k= 0.005 ± 0.0003) (F= 3.7 p= 0.02 n= 108) difieren significativamente de A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.02 n= 216). En relación al T50 de R. mangle y L. racemosa presentaron mayor tiempo de degradación (133 y 138 días respectivamente) comparado con A. germinans (74 días). Se registró una correlación significativa entre la materia orgánica y la humedad del suelo con la constante de descomposición de A. germinans (r= 0.65 p< 0.05 y r= 0.55 p< 0.05 respectivamente). El más alto contenido de nitrógeno total se dio en Pajaral (2 683 mg.Kg) y presentó alta correlación con el contenido de materia orgánica (r= 0.9 p= 0.03); en relación al fósforo total, el nivel más alto se presentó en Boca (2 031 mg.Kg) correlacionado de forma negativa con el pH (r= -0.61 p< 0.05). En conclusión, las diferencias en la velocidad de degradación de las hojas de mangle dependen de la especie (composición foliar), tiempo de exposición o inmersión en agua (patrón de inundación) y heterogeneidad del sedimento (i.e., textura, pH, contenido de humedad y densidad aparente).

Abstract Mangroves are ecosystems with a high primary productivity that is mainly driven mainly by degradation processes. Energy (nutrients) flows from mangroves toward adjacent zones and the surrounding aquatic environment. The objective of the present study was to estimate the daily degradation coefficient (k) of mangrove leaves in relation to physical-chemical soil factors and in situ nutrient supply (phosphorus and nitrogen) in Mecoacán Lagoon, Gulf of Mexico. Leaf litter degradation bags were placed at six monthly monitoring sites to evaluate degradation and to calculate the corresponding degradation coefficients. A rapid degradation of up to 51 % was observed for Avicennia germinans (L.) Stearn during the first month in association with leaching resulting from flood conditions. The degradation of Rhizophora mangle (L.) (k= 0.0052±0.0002) (F= 12.2 p< 0.05 n= 216) and Laguncularia racemosa (L.) Gaertn (k= 0.005±0.0003) (F= 3.7 p= 0.2 n= 108), differed significantly from that of A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.2 n= 216) did not present significant differences. To reach T50 degradation, R. mangle and L. racemosa required more time (133 and 138 days, respectively) than A. germinans (74 days). Organic matter and soil humidity were significantly correlated with the decay constant of A. germinans (r= 0.65 p< 0.05 and r= 0.55 p< 0.05, respectively). Total nitrogen content was highest in the Pajaral site (2 683 mg.kg) and was also highly correlated with organic matter content (r= 0.9 p= 0.003). Total phosphorus content was highest in the Boca site (2 031 mg.kg) and was also negatively correlated with pH (r= -0.61 p= 0.004). In conclusion, differences in the rate of mangrove leaf degradation depend on the involved species (leaf composition), time of exposure or immersion in water (flooding patterns) and sediment heterogeneity (i.e., texture, pH, humidity content and bulk density). Rev. Biol. Trop. 66(2): 892-907. Epub 2018 June 01.

Contributions of organic matter and nutrients via leaf litter in an urban tropical dry forest fragment / Contribuciones de materia orgánica y nutrientes a través de la hojarasca en un fragmento de bosque seco tropical urbano

Abstract The litterfall and decomposition represent the main transfer of organic matter and nutrients from the vegetation to the soil surface and determine positive trajectories in the process of rehabilitating and restoring degraded ecosystems. The aim of this study was to evaluate the contributions of organic materials and nutrients through the characterization of fine litter in an urban dry forest fragment. Litter production was monitored for one year by collecting 29 traps (0.5 m2). To evaluate leaf nutrient resorption, green leaves were collected from 5-10 individuals that represented the dominant tree species. Litter-bags (20 x 20 cm, 2 mm pore) were used for six months to evaluate the decomposition of leaf litter. Annual fine litter production was found to be 8 574 kg ha-1, with the Cordia alba species contributing the most leaf litter (1 134 kg ha-1) and nutrients (N: 6.16; P: 0.21; Ca: 4.72; Mg: 0.47; K: 1.27 kg ha-1). Decomposition rates (k constant) followed the decreasing order: C. alba (k: 4.6) > Machaerium milleflorum (k: 3.5). M. milleflorum and Albizia niopoides presented a pattern of rapid N and P release in the first 30 days, with more than 80 % and 60 % released from M. milleflorum and C. alba, respectively, by the end of the experiment. The litterfall monitoring carried out in this urban dry forest fragment revealed some important aspects of the functioning of an ecosystem as seriously threatened as the tropical dry forest. Rev. Biol. Trop. 66(2): 571-585. Epub 2018 June 01.

Resumen La caída de hojarasca y su descomposición representan la principal transferencia de materia orgánica y nutrientes desde la vegetación a la superficie del suelo y determinan trayectorias positivas en el proceso de rehabilitación y restauración de ecosistemas degradados. El objetivo de este estudio fue evaluar los aportes de materiales orgánicos y nutrientes a través de la caracterización de la hojarasca fina en un fragmento de bosque seco urbano. La producción de hojarasca fina se monitoreó durante un año mediante 29 trampas (0.5 m2). Para evaluar la reabsorción de nutrientes foliares, se recogieron hojas verdes de 5-10 individuos que representaban las especies arbóreas dominantes. Bolsas de descomposición (20 x 20 cm, 2 mm de poro) fueron usadas durante seis meses para evaluar la descomposición de la hojarasca foliar. La producción de hojarasca fina anual fue de 8 574 kg ha-1. La especie Cordia alba presentó los mayores aportes de hojarasca foliar (1 134 kg ha-1) y nutrientes (N: 6.16; P: 0.21; Ca: 4.72; Mg: 0.47; K: 1.27 kg ha -1). Las tasas de descomposición (constante k) siguieron el orden decreciente: C. alba (k: 4.6)> Machaerium milleflorum (k: 3.5). M. milleflorum y Albizia niopoides presentaron un patrón de liberación rápido de N y P en los primeros 30 días, con más del 80 % y 60 % de M. milleflorum y C. alba, respectivamente, al final del experimento. El monitoreo de la caída de hojarasca llevado a acabo en este fragmento de bosque seco urbano reveló algunos aspectos importantes del funcionamiento de un ecosistema tan seriamente amenazado como es el bosque seco tropical.

Revamping soil quality and correlation studies for yield and yield attributes in sorghum-legumes intercropping systems / Melhoria da qualidade do solo e estudos de correlação para a produtividade e os atributos de produtividade em sistemas de plantio consorciado de sorgo e legumes

Restoration, preservation and sustainability of agricultural resources including soil demands biologically and economically viable farming practices. For boosting physico-chemical properties of soil from 2012 to 2015, three legumes including cowpea, cluster bean and soybean were intercropped with sorghum in 40-60, 75-25 and 100-100 seed blending ratios, while pure stand of sorghum was kept for comparison. Correlation studies were also conducted to determine linear or inverse relationship between physiological and agronomic attributes with green forage yield of sorghum. Results revealed that intercropping systems were not effective in significantly improving the physical properties of soil, however soybean and sorghum mixed seeded crop in 100-100 seed ratio resulted in the highest total and available nitrogen especially during last two years of the study and it was followed by mixed seeded crop of cluster bean and sorghum (100-100 seed ratio), while pure stand of sorghum appeared to be the most exhaustive farming system. Correlation analysis depicted a linear relationship between all agronomic attributes (seedling count, plant population at harvest, plant height, stem diameter, number of leaves and leaf area per plant, fresh and dry weights per plant) and physiological growth parameters (leaf area index and leaf area duration, crop growth rate and net assimilation rate) with forage yield of sorghum. Thus, legumes inclusion was found to be effective in restoring soil fertility, while long term legumes inclusion by following rotation may be suggested.

A restauração, a preservação e a sustentabilidade dos recursos agrícolas, incluindo o solo, exigem práticas agrícolas biologicamente e economicamente viáveis. Para aumentar as propriedades físico-químicas do solo de 2012 a 2015, três leguminosas, incluindo feijão-fradinho, guar e soja, foram consorciadas com sorgo nas proporções de mistura de 40-60, 75-25 e 100-100, enquanto que o sorgo puro foi mantido por comparação. Estudos de correlação também foram conduzidos para determinar a relação linear ou inversa entre atributos fisiológicos e agronômicos com a produtividade de forragem verde do sorgo. Os resultados revelaram que os sistemas consorciados não foram eficazes em afetar significativamente as propriedades físicas do solo, no entanto, soja e sorgo misturados na proporção de sementes 100-100 resultou no maior nitrogênio total e nitrogênio disponível, especialmente durante os últimos dois anos do estudo e foi seguido do plantio de sementes mistas de guar e sorgo (100-100 rácio de semente), enquanto a monocultura de sorgo parecia ser o sistema de agricultura mais exaustivo. A análise de regressão mostrou uma correlação linear entre todos os atributos agronômicos (contagem de plântulas, população de plantas na colheita, altura de planta, diâmetro de caule, número de folhas e área foliar por planta, peso fresco e seco por planta) e parâmetros de crescimento fisiológico (índice de área foliar e duração da área foliar, taxa de crescimento da cultura e taxa de assimilação líquida) com o rendimento de forragem do sorgo. Assim, a inclusão de leguminosas foi eficaz no aumento da fertilidade do solo, enquanto a inclusão de leguminosas a longo prazo por rotação de diferentes leguminosas é sugerida.

Degradation kinetics of organic matter in dairy industry wastewater by flotation/ozonation processes / Cinética de degradação da matéria orgânica nas águas residuárias da indústria de laticínios pelos processos de flotação/ozonização

This study evaluated the adjustment of four kinetic models and their respective parameters on data of dairy wastewater treatment by the physico-chemical process of flotation and ozonation. The experiment was implemented during the year 2014, with all the tests in triplicate. The treatments were carried out at different pH levels (3.6, 7.0 and 10.4), and flotation/ozonation was catalyzed by manganese (Mn2+) in neutral level (pH 7.0). Best removal efficiencies for chemical oxygen demand (COD) were obtained in acidic medium, with removals greater than 75% after 20 min of treatment. There was no significant difference with regards to addition of Mn2+ on COD removal by the physicochemical process. The kinetic models that best fit to the experimental data, for all treatments, were the asymptotic (residual) model and that of Chan and Chu. Treatment in acidic medium showed the highest values of the kinetic parameters for the adjusted model, obtaining a k coefficient equal to 0.2394 min-1 for the asymptotic model and kinetic coefficient 1/ of 0.4816 min-1 for the Chan and Chu model, both presenting a determination coefficient greater than 99%.

Neste estudo, avaliou-se o ajuste de quatro modelos cinéticos (modelo de escoamento pistonado, mistura completa, assintótico ou residual e de Chan e Chu e seus respectivos parâmetros, na degradação da matéria orgânica presente no efluente de laticínios pelo processo físico-químico de flotação e ozonização. O experimento foi implementado durante o ano de 2014, com todos os testes em triplicata, os s tratamentos foram realizados sob diferentes pHs (3,6; 7,0 e 10,4), além da flotação/ozonização catalisada pelo manganês (Mn2+) em meio neutro. Observando que em meio ácido ocorreram as melhores eficiências de remoção da demanda química de oxigênio (DQO), tendo sido obtida uma remoção superior a 75% em 20 min de tratamento. Não houve diferença significativa em relação à adição de Mn2+ ao processo físico-químico. Os modelos que mais se ajustaram aos dados experimentais, para todos os tratamentos realizados, foram o modelo assintótico e o de Chan e Chu. O tratamento em meio ácido foi o que apresentou os maiores valores dos parâmetros cinéticos para os modelos ajustados, obtendo-se para o modelo assintótico, coeficiente k igual a 0,2394 min-1, e para o modelo de Chan e Chu, coeficiente cinético 1/ de 0,4816 min-1, apresentando para ambos os modelos um coeficiente de determinação superior a 99%.

CARACTERIZACIÓN DE LA FERTILIDAD QUÍMICA DE LOS SUELOS EN SISTEMAS PRODUCTIVOS DE LA ALTILLANURA PLANA, META, COLOMBIA / CHEMICAL CHARACTERIZATION OF SOIL FERTILITY IN PRODUCTION SYSTEMS OF A FLAT HIGH PLATEAU, META, COLOMBIA

La Altillanura Plana de la Orinoquia de Colombia es por excelencia una despensa agropecuaria. Su fertilidad química dependerá principalmente de sistemas productivos que involucren un manejo de los suelos de manera apropiada y que incrementen los contenidos de la materia orgánica del suelo (MOS). Se aplicó un análisis de tipo multivariado con el objetivo de caracterizar la fertilidad química de los suelos en algunos sistemas productivos de la Altillanura Plana comparados con otros de Piedemonte del departamento del Meta, Oriente de Colombia. Fueron seleccionados cinco sistemas productivos en cada zona. Se encontró una alta variabilidad en las características químicas de los suelos, siendo la MOS y la acidez de los suelos las que tuvieron mayor capacidad discriminatoria entre los sistemas productivos. El análisis de clúster conformo tres grupos bien definidos: suelos de alta, mediana y baja fertilidad; y aunque no se encontró un patrón definido en cuanto a los sistemas productivos que los caracterice en cada uno de los grupos, cinco de los sistemas productivos de Piedemonte estuvieron ubicados en suelos de baja fertilidad. Las pasturas mejoradas y los sistemas silvopastoriles (SPSs) de la Altillanura Plana son una buena opción para aumentar la fertilidad química de los suelos.

The flat high plateau of the Colombian Orinoquia is, par excellence, an agricultural pantry. Its chemical soil fertility depends mainly of productive systems that involve appropriate soil management that increment soil organic matter (SOM). A multivariate analysis was applied in order to characterize the soil chemical fertility in some productive systems of the flat high plateau compared to other foothills of the Department of Meta in the western region of Colombia. Five production systems were selected for each zone. A high variability in the chemical characteristics of the soils was found, being SOM and the acidity of the soils the ones having greater discriminatory capacity among the productive systems. Cluster analysis consisted of three well-defined groups: high, medium and low fertility soils and, although a definite pattern of productive systems was not found in each of the groups, five productive foothill systems were located in low fertility soils. The improved pastures and the silvopastoral systems (SPSs) of flat high plateaus are a good option to increase the chemical fertility of the soils.