DETERMINAÇÃO DE GLIFOSATO E ÁCIDO AMINOMETILFOSFÔNICO EM ÁGUAS SUPERFICIAIS DO ARROIO PASSO DO PILÃO

Para investigar a presença do herbicida Glifosato na microbacia hidrográfica arroio Passo do Pilão foram coletadas amostras de água em 15 distintos pontos no arroio Passo do Pilão, nos períodos de 30 e 60 dias após a aplicação do herbicida (DAAH), as quais foram analisadas por cromatografia a líquido de alta eficiência (CLAE). As análises revelaram a presença do herbicida nas águas superficiais dessa microbacia, tanto nas amostras após 30 dias de aplicação do Glifosato como nas de 60 DAAH. Concentrações elevadas (acima de 100 ppb) foram detectadas, principalmente em pontos próximos às áreas de intenso cultivo. As concentrações detectadas foram menores que 500 e 700 ppb, limites de concentrações máximas permitidas para o Glifosato pela legislação brasileira e pela Agência de Proteção Ambiental dos Estados Unidos, respectivamente. DETERMINATION OF GLYPHOSATE AND AMINOMETHYLPHOSPHONIC ACID IN SUPERFICIAL WATERS OF ARROIO PASSO DO PILÃO Abstract To investigation the presence of Glyphosate herbicide in Arroio Passo do Pilão watershed, samples of water were collected in 15 distinct points in Arroio Passo do Pilão, in period of 30 and 60 days after herbicide application (DAHA), which were analysed by high performance liquid chromatography (HPLC). The analysis revealed the presence of the herbicide in superficial areas of this watershed, even in the samples after 30 days of Glyphosate applicatication as in 60 DAHA. High concentrations (above 100 ppb) were detected, mainly in points near to intense cultivation areas. The concentrations detected were smaller than 500 and 700 ppb, limits of the maximum concentrations allowed for Glyphosate by the brazilian legislation and by the Environmental Protection Agency of United States, respectivelly

Identification and antibiotic control of endophytic bacteria contaminants in micropropagated potato explants

Este trabalho teve por objetivos isolar, caracterizar e identificar bactérias endofíticas contaminantes encontradas em tecidos de batata durante a micropropagação e selecionar antibióticos para o controle in vitro desses microrganismos por meio da determinação da concentração bactericida mínima inibitória. Brotações de batata apresentando contaminação bacteriana durante a etapa de multiplicação in vitro, foram superficialmente esterilizadas e os internódios transferidos para placas de Petri com ágar nutriente, onde permaneceram incubadas a 28°C por até cinco dias. Após purificação, as bactérias foram caracterizadas e identificadas por testes taxonômicos. Um total de oito estirpes bacterianas foram isoladas e identificadas como pertencentes às famílias Acetobacteriaceae (1) e Enterobacteriaceae (2) e aos gêneros Corynebacterium (3), Pseudomonas (1) e Xanthomonas (1). Os melhores resultados para a inibição do crescimento bacteriano foram obtidos com os antibióticos ampicilina, cloranfenicol, estreptomicina e tetraciclina em concentrações que variaram de 32 a 256 mg L-1.This work aimed to isolate, characterize and identify contaminant endophytic bacteria found in potato tissues during the micropropagation and to select antibiotics for in vitro control of these microorganisms by determining the inhibitory minimal bactericidal concentration. Potato shoots presenting bacterial contamination during the in vitro multiplication were superficially sterilized and the internodes transferred to Petri dishes with nutrient agar medium for up to five days at 28°C. After subcultures the grown bacteria were purified and identified through taxonomic tests. A total of eight bacterial endophytic strains were isolated and identified as belonging to Acetobacteriaceae (1) and Enterobacteriaceae (2) families and Corynebacterium (3), Pseudomonas (1) and Xanthomonas (1) genera. The best results for bacterial growth inhibition were obtained with ampicilin, chloramphenicol, streptomycin and tetracycline antibiotics in concentrations ranging from 32 to 256 mg L-1

Identification of pesticide-degrading Pseudomonas strains as poly-β-hydroxybutyrate producers

Polyhydroxybutyrate (PHB) is an ecological promising substitute for polypropylene because it is biocompatible, biodegradable and can be produced by renewable sources. This study investigated PHB accumulation on pesticide-degrading Pseudomonas. 14 strains of pesticide-degrading Pseudomonas isolated from subtropical lowland soil in southern Brazil were analyzed using optical microscopy. Lipid inclusions were identified in four strains, and three of them, which degraded the pesticide carbofuran, had extensive granules accumulation which was detected by transmission electron microscopy. These strains were cultivated in a shaker at 28°C and the polymer was characterized by Fourier transform infrared (FTIR) spectroscopy. Strain CMM43 had the best accumulation after 48 h. The biopolymer was identified as poly-β-hydroxybutyrate.Key words: Polyhydroxybutyrate (PHB), pesticide-degrading Pseudomonas sp., microscopy, subtropical lowland soil

Teor residual de fipronil no solo para o controle de Oryzophagus oryzae em cultivos subsequentes de arroz irrigado

The objective of this work was to evaluate the potential of fipronil (a.i.) residual content in the soil of flooded rice fields, for the control of Oryzophagus oryzae (Coleoptera: Curculionidae) in subsequent rice cultivations. In 2010/2011, plots (25x55 m) were installed with three treatments: 30 g fipronil (a.i.) 100 kg-1 seed; mixture of 1/3 treated seed (30 g fipronil 100 kg-1 seed) with 2/3 untreated seed equivalent to 10 g fipronil (a.i.) 100 kg-1 seed; and a control without insecticide application. The plots were regrown in 2011/2012, 2012/2013, and 2013/2014 without any insecticide application. The following variables were evaluated: number of larvae and adults from standard samples of soil and roots, and grain yield. In 2011/2012 and 2012/2013, the concentrations of fipronil and of its residues in the soil of plots were evaluated by liquid chromatography and mass spectrometry, and the metabolite fipronil-sulfide (≤ 1.1 µg kg-1) was detected. In the three seasons, after the use of seeds treated with 10 and 30 g fipronil, the average larval infestation of O. oryzae was 65.2 and 96.1% lower, and the average of rice grain yield was 16.9 and 25.5% higher than in the control plot, respectively. The residual fipronil content in the soil, mainly of the highest dose, effectively controls the insect.O objetivo deste trabalho foi avaliar o potencial do teor residual de fipronil (i.a.), em solo de arroz irrigado por inundação, para o controle de Oryzophagus oryzae (Coleoptera: Curculionidae), em cultivos subsequentes. Em 2010/2011, instalaram-se talhões (25x55 m) com três tratamentos: 30 g de fipronil (i.a.) 100 kg-1 de sementes; mistura de 1/3 de sementes tratadas (30 g de fipronil 100 kg-1 de sementes) com 2/3 de sementes não tratadas equivalentes a 10 g de fipronil (i.a.) 100 kg-1 de sementes; e testemunha sem inseticida. Os talhões foram replantados em 2011/2012, 2012/2013 e 2013/2014 sem qualquer aplicação de inseticida. Avaliaram-se as seguintes variáveis: número de larvas e adultos, emergentes de amostras-padrão de solo e raízes, e produção de grãos. Em 2011/2012 e 2012/2013, avaliaram-se as concentrações de fipronil e de seus resíduos no solo dos talhões, por meio de cromatografia líquida e espectrofotometria de massa, tendo-se detectado o metabólito fipronil-sulfeto (≤ 1,1 µg kg-1). Nas três safras, após o uso de sementes tratadas com 10 e 30 g de fipronil, a infestação larval média de O. oryzae foi 65,2 e 96,1% menor, e a produtividade média do arroz 16,9 e 25,5% maior do que no talhão testemunha, respectivamente. O teor residual de fipronil no solo principalmente o da maior dose, controla eficazmente o inseto

Economic evaluation of biological nitrogen fixation in flooded rice cultivation in subtropical lowlands

This study aimed to assess the economic viability of biological nitrogen fixation in flood rice cultivation in subtropical lowlands. A field experiment of seven treatments was carried out during the cropping seasons 2015/16, 2017/18, 2018/19 and 2019/20 at the Lowland Experimental Station of Embrapa, in Pelotas, RS, Brazil. The evaluated treatments were: (1) negative control (without N and inoculant); (2) positive control with recommended N-fertilization (120 kg N ha-1, without inoculant) (standard recommendation); (3) inoculant 1 (accessions CMM 174 + CMM 175 + CMM 179); (4) inoculant 2 (accessions CMM 176 + CMM 197 + CMM 205); (5) combination of reduced N-fertilizer doses (90 kg N ha-1) + inoculant 1; (6) combination of reduced N-fertilizer doses (90 kg N ha-1) + inoculant 2; and (7) commercial inoculant [Azospirillum brasilense (strains Ab-V5 and Ab-V6)]. A partial budget was used to compare evaluated treatments with the standard recommendation regarding nitrogen fertilisation. Inoculant 2 composed of bacterial accessions CMM 176 (Rhizobium sp.), CMM 197 (Bacillus sp.) and CMM 205 (Aeromicrobium sp.) combined with reduced mineral nitrogen fertilisation [90 kg N ha-1 (applied in top dressing)] demonstrates the best agroeconomic efficiency in the production of irrigated rice in subtropical lowlands with the cultivar BRS Pampa

Yield of peach trees, cv. Diamante, under different levels of N applied to the soil

Com o objetivo de avaliar o efeito do N na produção e tamanho dos frutos de pessegueiro (Prunus persica Batsch.) cv. Diamante, realizou-se este experimento. Foram estudadas diferentes doses de adubação nitrogenada. O pomar consistiu de plantas com sete anos de idade, plantadas a espaços de 4 m nas linhas de 6 m nas entrelinhas. O delineamento experimental foi inteiramente casualizado, com cinco repetições. Os tratamentos foram 0, 135, 270, 405, 540 e 675 g de N por planta, na formulação do adubo como uréia. Com o uso de N constataram-se maiores produções totais e de frutos de maior tamanho, enquanto que a produção de frutos de segunda a terceira classe não depende da adubação nitrogenada, apesar de dependentes da intensidade e época de raleio.An experiment with increasing levels of N was carried out to evaluate their effect on yield and size of peach tree fruits (Prunus persica Batsch.). The orchard consisted of 7-years old peach trees of cultivar Diamante, spaced 4 m on the row and 6 m between the rows. The experimental design was completely randomized, with five replications. The treatments were 0, 135, 270, 405, 540 and 675 g of N per plant, in the formula as urea of fertilizer. Nitrogen increased fruit yield and size. Second and third type peach yields did not depend on N fertilization, but did depend on intensity and thinning time

Growth and foliar contents of N, P, K, Ca and Mg in peach cv. Diamante under different levels of N applied to the soil

Com o objetivo de determinar o teor de N nas folhas que se relacionem com melhor crescimento vegetativo das plantas, e, também avaliar o comportamento dos teores foliares de P, K, Ca e Mg por meio da análise foliar, realizou-se experimento com doses cres­centes de N. O pomar foi constituído de plantas de pessegueiros (Prunus persica Batsch.) da cultivar Diamante, com sete anos de idade, com espaços, entre si, de 4 m nas linhas e 6 m nas entrelinhas. O delineamento experimental foi o inteiramente casualizado, com cinco repeti­ções. Os tratamentos aplicados foram 0, 135, 270, 405, 540 e 675 g de N por planta, na for­mulação de adubo como uréia. Os resultados obtidos ao longo dos anos de 1984-1986 permi­tiram extrair as seguintes conclusões: o vigor das plantas foi alterado de forma linear positiva com a aplicação de N ao solo, em dois ciclos vegetativos; houve uma correlação quadrática positiva entre o N aplicado no solo e o encontrado nas folhas. Os teores foliares de P, K, Ca e Mg diminuíram com o aumento da dose de N.An experiment with increasing levels of N was realized with the objective of determining the N content of the peach leaf related to better vegetative growth of the plants. The experiment had also the aim to evaluate N influence on foliar contents of P, K, Ca and Mg, using foliar analysis. The orchard consisted of 7 - years old peach trees of cultivar Diamante, spaced 4 m on the row and 6 m between the rows. The experimental design was completely randomized, with five replications. The treatments were 0, 135, 270, 405, 540 and 675 grams of N per plant, in the form of urea. Results obtained in 1985 through 1986 lead to the following conclusions: there was a linear positive correlation between plant vigor and N levels, in both vegetative cycles; there was also a positive quadratic correlation between N applied to the soil and N found in the leaves. Crescent levels of N decreased foliar contents of P, K, Ca e Mg

Biodegradação do herbicida glifosato por microorganismos isolados de solos cultivados com arroz irrigado

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