108 research outputs found

    Uso de fertilizantes organominerais fosfatados no cultivo da alface e de milho em sucessão / Use of phosphate organomineral fertilizers in the cultivation of lettuce and corn in succession

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    A alface (Lactuca sativa L.) é uma das hortaliças folhosas mais consumidas no Brasil e no mundo. Apresenta um crescimento rápido sendo muito exigente em nutrientes, o que requer um manejo da nutrição adequado. Novas tecnologias surgiram, com objetivo de aumentar a produtividade e a eficiência das adubações nas culturas. Os fertilizantes organominerais fornecem os nutrientes de maneira gradual, diminuindo os custos e evitando perdas para o ambiente. Desta forma, objetivou-se com este trabalho avaliar o uso dos fertilizantes fosfatados organominerais na produção, qualidade e crescimento pós-colheita da alface, e seu efeito residual na cultura do milho plantado em sucessão. O experimento foi realizado sob cultivo protegido, em canteiros, na UFVJM/Diamantina-MG. Utilizou-se do delineamento experimental de blocos ao acaso, com cinco tratamentos e quatro repetições. O solo foi classificado como um Neossolo quartzarênico e os tratamentos foram compostos por fertilizantes organomineral peletizado, organomineral farelado, MAP protegido por polímero, superfosfato simples e a testemunha (sem adubação). Foi utilizada a cultivar Veneranda (Feltrin, ®) e cada parcela foi composta por doze plantas com espaçamento de 30 cm x 30 cm. Aos 60 dias após o transplantio da alface avaliou-se: variáveis de crescimento, fisiológicas e o teor de P foliar. Após o cultivo da alface realizou-se a semeadura de um híbrido de milho com 5 sementes por metro linear, formando uma fileira por parcela. Após 120 dias à semeadura foi analisado a produção do milho. Os fertilizantes organominerais peletizado e farelado promoveram o maior crescimento e acúmulo de matéria fresca e seca de parte aérea e raiz nas plantas de alface, bem como maior teor de clorofila A. Não foram observadas diferenças significativas para o teor de fósforo nas folhas, clorofila B, perda de massa fresca e perda de água das plantas de alface. Para a avaliação da produção na cultura do milho plantado em sucessão, os tratamentos com fertilizantes organomineral peletizado e farelado apresentaram as maiores médias para as variáveis do peso das espigas, peso dos grãos e produtividade. Não foi observada diferença significativa para a massa de 100 grãos.  Pode-se concluir que os fertilizantes organominerais proporcionaram efeitos positivos para a produção das plantas de alface e para o milho plantado em sucessão, se mostrando como uma boa alternativa ao uso dos fertilizantes minerais devido ao seu efeito residual no solo

    Maize crop response to different levels of mineral and or-ganomineral fertilization associated with plant growth promoting bacteria (PGPBs): Resposta da cultura do milho a diferentes níveis de adubação mineral e organomineral associada à bactérias promotoras do crescimento de plantas (BPCPs)

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    Corn has a high nutritional requirement, especially with regard to NPK fertilization. However, the low efficiency of conventional fertilizers combined with the high cost of the input has limited the reach of high yields. The use of fertilizers with increased efficiency seeks to mitigate these limitations, reducing potential losses due to the gradual release of nutrients. The objective of this work was to compare the nutrition, growth and production of maize plants subjected to different doses and special NPK fertilizers fully applied at planting, as well as their residual effect on the soil. A randomized block design was used, in a 3 x 4 factorial scheme, with four replications. The first factor consisted of conventional mineral, polymer coated and organomineral fertilizers inoculated with PGPBs. The second factor was doses of 0, 60, 90 and 120 kg ha-¹ of NPK. Vegetative growth, foliar nutrition (N, P and K), yield growth components, productivity, profitability and P and K nutrient content remaining in the soil after cultivation were evaluated. The conventional mineral fertilizer presented higher production of dry biomass of the aerial part and profitability in relation to the special fertilizers. However, the special fertilizers presented better results in the vegetative and productive growth, in general, still showing a potential reduction of the applied doses, without compromising the grain yield, especially in the organomineral fertilization + PGPBs. The same showed greater residual effect of K in the soil, proving to be relevant longterm studies for better elucidation of these effects in the soil and subsequent culture

    Características fisiológicas do feijoeiro cultivado em solos após fitorremediação do picloram

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    Plant remediation has been reported as a promising technique for decontaminating soil herbicide residues. For hormonal herbicides there is difficulty in determining waste by bioassay technique due to the variation in growth in response presented by the indicator plant. The objective of this study was to evaluate the effect of doses of picloram through physiological characteristics of the bean in phytoremdiation soils with braquiaria. The experiment was arranged in greenhouse in the design of randomized blocks. Applied increasing doses of picloram (0; 2; 4; 8; 16 e 32 g ha-1), subsequently cultivated with Brachiaria for 120 days. In this date the brachiaria was harvested and sowed beans as bioindicator, 30 days after the emergence of the culture was evaluated the physiological characteristics and bean biomass accumulation. Even after remediation by plants Brachiaria, the doses of picloram affected the physiological characteristics of the bean, especially the water use efficiency, these variables are the most appropriate to evaluate the herbicide residues in the soil. The reduction of these variables promoted less accumulation of total biomass of bean plants in soils that was made remediation. The second higher dose of the herbicide also caused reduction of Fv / Fm ratio below 0.75, indicating some kind of stress photosynthetic apparatus of bean leaves.A fitorremediação tem sido relatada como técnica promissora para a descontaminação de solos com resíduos de herbicidas. Para herbicidas hormonais, há dificuldade na determinação de resíduos pela técnica do bioensaio em função da variação na resposta em crescimento apresentada pela indicadora. Objetivou-se com esse trabalho avaliar o efeito de subdoses do picloram, em solos fitorremediados com braquiária, nas características fisiológicas do feijoeiro. O ensaio foi realizado em ambiente protegido no delineamento de blocos ao acaso. Aplicou-se diferentes doses do picloram (0; 2; 4; 8; 16 e 32 g ha-1), sendo posteriormente cultivado com braquiária por 120 dias. Nesta data retirou-se a braquiária dos vasos e semeou o feijão como planta bioindicadora, sendo depois de 30 dias avaliada as características fisiológicas e a matéria seca do feijoeiro. Mesmo após a remediação por plantas de braquiária, as subdoses do picloram afetaram as características fisiológicas do feijoeiro, principalmente a taxa fotossintética e a eficiência no uso da água, sendo essas variáveis as mais indicadas para se avaliar o resíduo do herbicida no solo. A redução dessas variáveis promoveu menor acúmulo de biomassa total das plantas de feijão nos solos fitorremediados. A segunda maior dose do herbicida provocou também redução da relação Fv/Fm abaixo de 0,75, indicando algum tipo de estresse do aparato fotossintético das folhas do feijoeiro

    Sensibility of coffee plants micorrized to herbicides

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    Objetivou-se com esse trabalho avaliar o efeito de herbicidas aplicados em pós-emergência em plantas de café arábica inoculadas com fungos micorrízicos arbusculares. O experimento foi conduzido em esquema fatorial 2 x 6, sendo mudas de café arábica cultivar Catuaí IAC 99 inoculadas e não inoculadas com fungos micorrízicos arbusculares, e cinco herbicidas (chlorimuron-ethyl, oxyfluorfen, fluazifop-p-butil, fomesafen, [fluazifop-p-butil+fomesafen]) e uma testemunha, com quatro repetições. As mudas inoculadas com fungos micorrízicos arbusculares (Rhizophagus clarus e Gigaspora margarita) e produzidas em sacolas plásticas contendo solo e esterco (3:1) foram transplantadas para vasos de 20 dm3 de solo, no estádio de cinco pares de folhas. No estádio de sete pares de folhas foram submetidas a aplicação dos herbicidas. Após a aplicação do herbicida foram mensuradas: porcentagem de intoxicação, altura, área foliar, volume radicular, matéria seca das folhas e raízes, teor nutricional da folha e colonização radicular. Observou-se que a aplicação de chlorimuron-ethyl, oxyfluorfen e [fluazifop-p-butil+fomesafen] resultaram em menor incremento das variáveis e maior intoxicação. O fluazifop-p-butil apresentou maior seletividade para as plantas de café. As plantas inoculadas obtiveram maior colonização radicular de fungos micorrízicos que as não inoculadas. Apenas o fluazifop-p-butil não causou interferência na colonização, sendo que as plantas inoculadas mostraram menor intoxicação que as não inoculadas. Considerando todos os parâmetros avaliados conclui-se que as plantas de café arábica cultivar Catuaí Vermelho IAC 99 inoculadas com fungos micorrízicos arbusculares apresentaram maior tolerância ao fluazifop-p-butil. Da mesma forma, conclui-se também que plantas de café quando inoculadas com FMAs apresentaram-se mais tolerantes aos efeitos negativos dos herbicidas chlorimuron-ethyl, fomesafen, oxyfluorfen e [fluazifop-p-butil+fomesafen].  The objective of this work was to evaluate the effects of herbicides applied in post-emergence of Arabic coffee plants inoculated and non-inoculated with arbuscular mycorrhizal fungi. The experiment was conducted in a factorial arrangement 2 x 6, being seedlings of Arabic coffee (Catuaí IAC 99 cv) inoculated and non-inoculated with mycorrhizal fungi (Factor 1), and five herbicides (chlorimuron-ethyl, oxyfluorfen, fluazifop-p-butil, fomesafen, [fluazifop-p-butil + fomesafen]) and a control treatment (Factor 2), with four replications. The seedlings inoculated with mycorrhizal fungi (Rhizophagus clarus and Gigaspora margarita) were produced in polyethylene bags and transplanted to 20 dm3 pots when it was in five pairs leaves stage. In seven pairs leaves stage the plants were submitted to the herbicide applications. After 45 days were measured: percentage of intoxication, height, leaf area, root volume, leaves and roots dry matter, leaf nutrient content and root colonization. Noted that chlorimuron-ethyl, oxyfluorfen and [fluazifop-p-butil+fomesafen] resulting in less increment of variables and higher phytotoxicity. The fluazifop-p-butil showed greater selectivity to coffee plants. The inoculated plants obtained higher root colonization than non-inoculated. Considering all parameters, it is concluded that the Arabica coffee cultivar Catuaí Vermelho IAC 99 inoculated with mycorrhizal fungi showed higher tolerance to fluazifop-p-butil. Similarly, also concludes that coffee plants inoculated with FMAs had become more tolerant to the adverse effects of chlorimuron-ethyl, fomesafen, oxyfluorfen and [fluazifop-p-butil + fomesafen]

    Acidez do solo cultivado por cana-de-açúcar fertilizada com organomineral de lodo de esgoto e bioestimulante após terceira safra / Soil acidity cultivated by fertilized sugarcane with sewage sludge organomineral and bioestimulant after third crop

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    O objetivo do trabalho foi avaliar a acidez do solo cultivado com cana-de-açúcar adubada com fertilizante organomineral de lodo de esgoto e bioestimulante. O trabalho foi implantado em julho de 2015 no Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Morrinhos. As amostras de solo foram realizadas após terceira colheita em agosto de 2018. O delineamento experimental foi em blocos casualizados em esquema fatorial 2x5+1, sendo 5 tratamentos, com e sem bioestimulante e um tratamento adicional (adubação mineral) com 4 repetições. Foi avaliado acidez ativa do solo nas profundidades de 0 a 20 e 20 a 40 cm. As percentagens de fertilizante organomineral de lodo de esgoto no plantio e cobertura da cana-de-açúcar não alterou a acidez ativa do solo (pH em H2O). O bioestimulante não estimulou a planta a promover alterações químicas no solo quanto a acidificação. O fertilizante organomineral de lodo de esgoto e fertilizante mineral apresentam a mesma capacidade de acidificar o solo. 

    Ácido cítrico e fósforo no desenvolvimento e estado nutricional de mudas de café

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    In weathered soils, there is an increased retention of anions such as phosphate. Organic acids of low molecular mass have been shown an effective way to provide nutrients before it showed unavailable in the soil, such as phosphorus. The objective was to evaluate the quality and growth content of seedlings of ‘Catuaí Vermelho’ coffee (IAC-99), submitted the application of citric acid and phosphorus concentrations in the substrate. Was used the factorial scheme (4x4), being the first factor concerning the application of citric acid anidre to the substrate (0,0; 0,5; 1,0 e 2,0 mg dm-3), and the second concerning the doses of phosphorus (0, 450, 900 e 1800 mg P2O5 dm-3), in substrate. The experimental design was a randomized complete block with five replicates. The seeds were germinated in bags with standard substrate for coffee seedlings, adjusted according to the treatment with applications of phosphorus. Citric acid was applied when the seedlings had the cotyledons. The evaluation has been held at 180 days after sowing when the seedlings had four to five leaf pairs expands. Were measured the foliar levels, and fhytotechnical atributes and from these determined Dickson quality index. Doses of 1404.0 mg P2O5 dm-3 and 1.0 mg dm-3 of citric acid in the substrate positively influenced the maximum quality of the seedlings. Was not effective dose of 2.0 mg dm-3of citric acid for the development of the same quality to the point of planting, while increasing the concentration of Ca, N, P, S, Cu, Fe and Zn in the leaves.Em solos intemperizados existe um aumento da retenção de ânions como o fosfato. Ácidos orgânicos de baixa massa molecular têm sido eficazes para disponibilizar nutrientes considerados “indisponíveis no solo”, como o fósforo. Objetivou-se avaliar o desenvolvimento, a qualidade e o estado nutricional de mudas de café cultivar Catuaí Vermelho (IAC 99), submetidas à aplicação de diferentes concentrações de ácido cítrico e fósforo no substrato. Utilizou-se esquema fatorial (4x4), sendo o primeiro fator referente à aplicação de ácido cítrico anidro (0,0; 0,5; 1,0 e 2,0 mg dm-3) e, o segundo referente às doses de fósforo (0, 450, 900 e 1800 mg P2O5 dm-3), aplicadas no substrato. O delineamento experimental utilizado foi o de blocos casualizados, com cinco repetições. As sementes foram germinadas em saquinhos com substrato padrão para mudas de café, ajustado conforme os tratamentos. O ácido cítrico foi aplicado quando as mudas apresentavam as folhas cotiledonares. As avaliações foram realizadas aos 180 dias após a semeadura, quando as mudas apresentavam-se com quatro a cinco pares de folhas expandidas, sendo avaliados os teores foliares e atributos fitotécnicos e, a partir destes, determinado o índice de qualidade de Dickson. As doses de 1.404,0 mg P2O5 dm-3 e 1,0 mg dm-3 de ácido cítrico no substrato influenciam, positivamente, na qualidade máxima das mudas. Não foi efetiva a dose de 2,0 mg dm-3 de ácido cítrico para o desenvolvimento com qualidade das mesmas até o ponto de plantio, embora tenham aumentado os teores de Ca, N, P, S, Cu, Fe e Zn, nas folhas

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

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    We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe
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