Tamanho da amostra foliar para avaliação do estado nutricional e índice SPAD de capim-elefante irrigado para corte.

Resumo: compor a amostra promoverá a otimização da mão de obra, além de diminuir erros inerentes à recomendação e avaliação do estado nutricional. A coleta de folhas de forrageiras para a diagnose do estado nutricional é uma etapa importante para subsidiar a adubação, sendo o tamanho da amostra imprescindível para representar adequadamente a população de plantas a ser manejada. Assim, objetivou-se dimensionar o número de amostras de folhas para a diagnose do estado nutricional de capim-elefante irrigado para corte, bem como o índice de clorofila SPAD (Soil Plant Analysis Development). A avaliação foi realizada em capineira de capim-elefante, var. Cameroon, com irrigação fixa de baixa aspersão, em área localizada em Sobral-CE, em solo Neossolo fluvico. Coletaram-se 40 amostras simples, em zigue-zague, de maneira aleatória, escolhendo-se folhas recém-expandidas. As variáveis mensuradas foram os teores foliares de macro (N, P, K, Ca, Mg e S) e micronutrientes (B, Cu, Fe, Mn e Zn) e o índice indireto de clorofila, com auxílio de um clorofilômetro. Considerando aceitável um erro amostral de 10%, a coleta de amostras simples de 16 e 80 plantas, respectivamente, para macro e micronutrientes em capim-elefante seria adequada. Para a medida indireta da clorofila, 8 amostras são necessárias para obter um erro de 10%. [Leaf size sample to nutritional state and SPAD index evaluation in elephant grass irrigated under cuts management]. Abstract: The determination of the amount of sample units that will compose the sample express the optimization of the workforce, and reduce errors inherent in the report of recommendation and evaluation of nutritional status. The leaf collection for diagnosis of nutritional status is an important step, and the sample size necessary to adequately represent the population to be assessed. Thus, the objective was evaluation to the number simple design of leaf samples for the diagnosis of nutritional status of elephant grass irrigated for cutting and SPAD (Soil Plant Analysis Development) index. The study was conducted in elephant grass, with a low fixed sprinkler irrigation, in an area located in Sobral-CE in alluvial soil. It was collected 40 samples simple, randomly, choosing newly expanded leaves. The variables measured were foliar concentrations of macro (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) and the indirect index of chlorophyll, using a chlorophyll meter. Considering an acceptable error of 10%, the collection of single samples of 16 and 80 plants, respectively, for macronutrients and micronutrients in elephant grass would be appropriate. For the indirect measurement of chlorophyll (SPAD index) 8 plants would be required to obtain a 10% error

Relações biométricas e índice SPAD do milho submetido a fontes e doses de nitrogênio na regiao Semiárida do Brasil.

Resumo: O correto manejo da adubação nitrogenada e o emprego de tecnologias agregadas visam o melhor aproveitamento do N pelas culturas, em especial a cultura do milho. Objetivou-se avaliar as variáveis biométricas e os teores de clorofila, através de medidas indiretas em folhas de milho, em função da aplicação de fertilizantes nitrogenados em diferentes doses. O estudo foi conduzido no campo experimental da Empresa Brasileira de Pesquisa Agropecuária (Embrapa/CNPC) em Sobral-CE. Os tratamentos consistiram de cinco fontes de nitrogênio: uréia; uréia + NBPT; uréia + polímero; uréia + inibidor enzimático; e uréia + capeamento com enxofre elementar, em três níveis de adubação nitrogenada em cobertura: 100%, 75% e 50% da dose recomendada para a cultura, aplicados em cobertura 30 dias após o plantio. Quando as plantas apresentavam-se 50% pendoadas, foram avaliadas quanto às características biométricas (altura; diâmetro do caule; número de folhas) e medidas indiretas de clorofila com o auxílio de um medidor portátil. A variedade estudada foi o milho Catingueiro, adaptado às condições Semiáridas. Pode-se constatar que as plantas apresentaram diferentes comportamentos para o índice SPAD, em função das doses e dos adubos utilizados. Houve diferença significativa para número de folhas, quando comparadas fontes e doses de adubos, em relação à testemunha sem adubação, evidenciando a importância da adubação nitrogenada para a cultura do milho

Spinning Loop Black Holes

In this paper we construct four Kerr-like spacetimes starting from the loop black hole Schwarzschild solutions (LBH) and applying the Newman-Janis transformation. In previous papers the Schwarzschild LBH was obtained replacing the Ashtekar connection with holonomies on a particular graph in a minisuperspace approximation which describes the black hole interior. Starting from this solution, we use a Newman-Janis transformation and we specialize to two different and natural complexifications inspired from the complexifications of the Schwarzschild and Reissner-Nordstrom metrics. We show explicitly that the space-times obtained in this way are singularity free and thus there are no naked singularities. We show that the transformation move, if any, the causality violating regions of the Kerr metric far from r=0. We study the space-time structure with particular attention to the horizons shape. We conclude the paper with a discussion on a regular Reissner-Nordstrom black hole derived from the Schwarzschild LBH and then applying again the Newmann-Janis transformation.Comment: 18 pages, 18 figure

Palatability of the Asian clam Corbicula fluminea (Müller 1774) in an invaded system

Biotic interactions such as predation may influence the success of invasive alien species (IAS). Although the Asian clam Corbicula fluminea is recognized as one of the most problematic aquatic IAS, few studies have investigated its use as a food resource. In this study, we aimed to investigate (i) the palatability of C. fluminea under natural (Minho River) and laboratory conditions and (ii) if C. fluminea submitted to different conditions (individuals from Lima and Minho Rivers) vary in palatability. Soft tissues from different Corbicula populations, plus soft tissues from a native clam, tuna and Corbicula shell powder were offered to consumers. Field assays were performed seasonally and laboratory assays only in summer; both assays also tested possible differences during distinct periods of the day. Overall, in natural conditions, the treatments containing C. fluminea had a low palatability. In laboratory assays, higher consumption (almost two times) was observed for Cyprinus carpio and Anguilla anguilla. Also, C. fluminea palatability was different between populations, with the treatment Corbicula Lima being more consumed than Corbicula Minho. Despite the low values of consumption in the field, laboratory results suggest that C. fluminea soft tissues can be a food resource to some species.This study was conducted as part of the project FRESCHO: Multiple implications of invasive species on Freshwater Mussel coextinction processes, supported by FCT (contract: PTDC/AGRFOR/1627/2014). MI is supported by a Post-doc grant (SFRH/BPD/90088/2012) from the Portuguese Foundation for Science and Technology—FCT through POPH/FSE funds. RS also acknowledge the support of the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER007569) funded by national funds through the FCT I.P and by the ERDF through the COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)

Potential impacts of the invasive species Corbicula fluminea on the survival of glochidia

Freshwater mussels (Bivalvia, Unionida) are one of the most imperilled faunal groups globally, being the introduction of invasive species a possible major mechanism of threat. The Asian clam Corbicula fluminea is a problematic invasive species in aquatic ecosystems and can impair the survival of parasitic larvae (glochidia) of native freshwater mussels. However, this possible mechanism of threat remains speculative and to date very few studies addressed quantitatively this issue. In order to cover this gap, we have performed a series of manipulative laboratory studies to assess how distinct densities of C. fluminea can affect the survival of glochidia after 6, 12, 24 and 48 h of exposure, using larvae of the native freshwater mussel Anodonta anatina. Our results suggest an increase in mortality of A. anatina glochidia with an increase in density of C. fluminea. Two main mechanisms may possibly explain our results: 1) the high filtration capacity of C. fluminea that can contribute to the mortality of glochidia due to the mechanical damage of their fragile shells when passing by siphons and/or digestive tract of C. fluminea and 2) the high excretion capacity of C. fluminea that can lead to mortality of glochidia due to increase in ammonia concentration. Mortality of glochidia was also time dependent with higher values registered after 48 h. This work is one of the first showing the influence of C. fluminea density on the survival of glochidia, being filtration (and consequent passage in the digestive tract) and biodeposition the main potential mechanisms explaining overall mortality. These results also suggest that sites with high densities of C. fluminea may be highly detrimental for the conservation of freshwater mussels, potentially impairing the survival of glochidia and negatively affecting the recruitment of juveniles.VM, MLL and PC were supported by doctoral grants (SFRH/BD/108298/2015), (SFRH/BD/115728/2016) and (SFRH/BD/131814/2017) from the Portuguese Foundation for Science and Technology - FCT through POPH/FSE funds. This study was conducted within the project FRESHCO - Multiple implications of invasive species on Freshwater Mussel coextinction processes, supported by FCT and COMPETE funds (contract: PTDC/AGRFOR/1627/2014). This study was also supported by the FCT project UID/Multi/04423/2019. We thank Allan Souza, Francisco Arenas, Jacinto Cunha and Lucia Guilhermino for their help in the design of the experiment. We also thank the editor and three anonymous referees for valuable suggestions

Uso fertilizante do subproduto da agroindústria processadora de goiabas em pomar comercial de goiabeiras.

Resumo: A utilização de resíduos orgânicos, urbanos ou industriais, em áreas agrícolas pode ser justificada pela necessidade de um destino apropriado para esses materiais visando a sua reciclagem, visto que a quantidade desses materiais tem aumentado rapidamente com o tempo. Assim, objetivou-se avaliar a fertilidade do solo, após a aplicação do resíduo da indústria processadora de goiabas, em pomar comercial da própria fruta. Foram aplicadas doses do subproduto da indústria processadora de goiabas (zero; 9; 18; 27; 36 t ha-1) em Argissolo. As aplicações foram realizadas superficialmente, em pomar de goiabeiras adultas, a partir de 2006. Antecedendo a aplicação de 2011, foram mensurados os atributos químicos do solo na camada de 0 - 0,20 m. O subproduto da indústria processadora de goiabas promoveu alterações na fertilidade do solo, com diminuição do pH e aumentos nas concentrações de fósforo e de nitrogênio, sendo este último até da dose de 19 t ha-1. [Fertilizer use of guava processing industry waste in orchard of guava trees]. Abstract: The use of organic waste, urban or industrial, in agricultural areas can be justified by the need for an appropriate target for such materials in order to recycle, since the amount of such wastes is increasing rapidly with time. The objective was to evaluate soil fertility, after applying the processing industry waste of guavas, commercial orchard in the fruit itself. Doses were applied by product processing industry guavas (zero, 9, 18, 27, 36 t ha-1) in Ultisol. The applications were made superficially in adult guava orchard from 2006. Prior to implementation of 2011, were measured soil chemical properties in the 0 - 0.20 m. The byproduct of the processing industry guavas promoted changes in soil fertility, decreased pH and increases in the concentrations of phosphorus and nitrogen, the latter to the dose of 19 t ha-1

Atributos químicos de um argissolo após a aplicação do resíduo agroindustrial do processamento de goiabas.

Resumo: O Brasil é um grande produtor de goiabas. A fruta pode ser consumida in natura ou industrializada e, neste último caso, gera resíduos. Esse subproduto pode ser empregado na agricultura como adubo orgânico, pois, é rico em nutrientes. Entretanto, são necessárias pesquisas para empregar com critério técnico. Assim, objetivou-se avaliar a fertilidade do solo, após a aplicação do resíduo da indústria processadora de goiabas, em pomar comercial da própria fruta. Foram aplicadas as seguintes doses: zero; 9; 18; 27; 36 t ha-1 em um Argissolo. As aplicações foram superficiais, em pomar de goiabeiras adultas, anualmente a partir de 2006. No final de 2010, foram mensurados os atributos químicos do solo na camada de 0 - 0,20 m. O subproduto da indústria processadora de goiabas promoveu alterações na fertilidade do solo, com diminuição do pH e aumentos nas concentrações de fósforo e de nitrogênio inorgânico, sendo este último até a dose de 19 t ha-1

Atributos químicos do solo tratado com composto orgânico de carcaça e despojo de abate de caprinos e ovinos.

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