1,720,962 research outputs found
Caracterização química e estoque de carbono no solo sob agroecossistemas e mata nativa
Get PDFReplacement of vegetation cover and inadequate soil management alter soil incoming and outflow of nutrients. In this sense, two experiments were conducted; in the first one, the fertility components at different depths were evaluated under agroecosystems in comparison with secondary vegetation area in the municipality of Remígio-PB; in the second, in the same areas, depths and agroecosystems the carbon stock was qualified. The work was carried out in the localities of Caiana and Mata Redonda, belonging to the municipality of Remígio - PB, located in the mesoregion of the Paraíba agreste, Curimataú Microregion. Four areas were selected, characterized according to the cultivation system: conventional system, pasture, agroforestry system (SAF) and an area with secondary vegetation. Soil samples were collected from July to August / 2017 for chemical evaluation at the Soil Laboratory of the Federal University of Paraíba (UFPB), Campus III, Bananeiras, PB, at the Center for Human, Social and Agricultural Sciences (CCHSA). The studied variables were analyzed using the statistical model, in a completely randomized design, in a factorial arrangement [(3x3)+1], being the factors: cultivation system (conventional, pasture and agroforestry system), depth (0-20; 20-40 and 40-60 cm) and an additional treatment corresponding to secondary vegetation. The variables, in the first experiment, were studied for the active acidity by pH in H2O (1: 2,5) organic carbon (CO), available phosphorus (P), exchangeable contents of (Ca2+, Mg2+ and K+), exchangeable aluminum (Al3+) and potential acidity (H+ + Al3+). The sum of bases (SB), cation exchange capacity (CTC), base saturation (V%) and aluminum saturation (m%) were obtained. In the second experiment, besides those variables described above, the soil carbon stock (ECS) was obtained. In the first, the area with secondary vegetation had higher levels of organic matter, regardless of the depth in comparison to the agroecosystems in cultivation; (0-20 cm) presented in all areas the highest levels of organic matter and nutrient, with a decrease in depth. The aluminum contents increased with soil depth. In the second experiment, the cropping systems caused alterations in the chemical characteristics of the soil when compared to the preserved conditions of secondary vegetation and the soil carbon stock was higher in the superficial layer (0-20 cm) and in the environments where the characteristics are closer those of balance, describing in depth.NenhumaA substituição da cobertura vegetal e o manejo inadequado do solo alteram o fluxo de entrada e saída dos nutrientes do solo. Nesse sentido foram conduzidos dois experimentos, no primeiro, avaliou-se os componentes da fertilidade em diferentes profundidades sob agroecossistemas em comparação com área de vegetação secundária no município de Remígio-PB; no segundo, nas mesmas áreas, profundidades e agroecossistemas foi quantificado o estoque de carbono. O trabalho foi desenvolvido nas localidades Caiana e Mata Redonda, pertencentes ao município de Remígio- PB, localizado na Mesorregião do Agreste Paraibano, Microrregião do Curimataú. Foram selecionadas quatro áreas, caracterizadas de acordo com o sistema de cultivo: sistema convencional, pastagem, sistema agroflorestal (SAF) e uma área com vegetação secundária. As amostras de solo foram coletas no período de julho a agosto/2017 para avaliação química no Laboratório de Solos do Centro de Ciências Humanas, Sociais e Agrárias (CCHSA) da Universidade Federal da Paraíba (UFPB), Campus III, Bananeiras, PB. As variáveis estudadas foram analisadas utilizando-se o modelo estatístico, em delineamento inteiramente casualizado, em arranjo fatorial [(3x3)+1], sendo os fatores: sistema de cultivo (convencional, pastagem e sistema agroflorestal), profundidade (0-20; 20-40 e 40-60 cm) e um tratamento adicional correspondente a vegetação secundária. As variáveis, no primeiro experimento, foram estudadas quanto à acidez ativa pelo pH em H2O (1:2,5), carbono orgânico (CO), fósforo (P) disponível , teores trocáveis de (Ca2+, Mg2+ e K+) e sódio (Na+), alumínio trocável (Al3+) e a acidez potencial (H++ Al3+). Foram obtidas a soma de bases (SB), a capacidade de troca de cátions (CTC), saturação por bases (V%), saturação por alumínio (m%). No segundo experimento além dessas variáveis acima descritas obteve-se o estoque de carbono no solo (ECS). No primeiro experimento a área com vegetação secundária apresentou maiores teores de matéria orgânica, independentemente da profundidade em comparação aos agroecossistemas em cultivo; acamada superficial (0-20 cm) apresentou em todas as áreas os maiores teores de matéria orgânica e nutriente, ocorrendo decréscimo em profundidade. Os teores de alumínio aumentaram com a profundidade do solo. No segundo experimento, os sistemas de cultivo provocam alterações nas características químicas do solo quando comparadas às condições preservadas de vegetação secundária e o estoque de carbono do solo foi superior na camada superficial (0-20 cm) e nos ambientes onde as características estão mais próximas as de equilíbrio, decrescendo em profundidade
Frequência de irrigação e hidrogel no consumo hídrico e crescimento do maracujazeiro amarelo em lisímetro
Get PDFYellow passion fruit (Passiflora edulis Sims) is cultivated in climate countries tropical
and subtropical, with Brazil being the largest producer in the world, with the Northeast
region contributing 62.30%. water consumption of yellow passion fruit without and with
water-retaining polymer in a lysimeter. The treatments were distributed in randomized
blocks, with four replications of two plants per plot, using the 2 x 3 factorial, referring to
the soil without and with water-retaining polymer and three irrigation frequencies. The
variables evaluated were plant height (AP), stem diameter (DC), number of productive
branches (NRP), electrical conductivity of leached water (EC), daily water consumption
(Chd), humidity in field capacity (Ucc), initial time (TiD) and final drain time (TfD).
There was no interaction of the polymer and the frequencies the number of productive
branches, on the other hand, the hydroabsorbent polymer influenced (p≤0.05) the NRP at
110, 140 and 180 days after transplanting. Thus, it is clear that these treatments with
hydrogel® contributed to a release of water for the plants over time. The use of hydrogel
becomes viable with the use of irrigation frequencies to the growth of yellow passion fruit
(P. edulis), even with a decrease 63 days after transplanting in the diameter of the stem.
The polymer is efficient in retaining and releasing water for the plants, keeping the lowest
daily consumption in yellow passion fruit plants. The hydrogel becomes an indispensable
product for agriculture, so further research is needed to make the cost-effectiveness of
this input viable.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESO maracujazeiro amarelo (Passiflora edulis Sims) é cultivado em países de clima tropical
e subtropical, sendo o Brasil o maior produtor mundial, com a região Nordeste
contribuindo com 62,30%. Objetivou-se avaliar o efeito da frequência de irrigação no
consumo hídrico do maracujazeiro amarelo sem e com polímero hidroretentor em
lisímetro. Os tratamentos foram distribuídos em blocos casualizados, com quatro
repetições de duas plantas por parcela, usando o fatorial 2 x 3, referente ao solo sem e
com polímero hidroretentore três frequências de irrigação. As variáveis avaliadas, altura
de plantas (AP), diâmentro de caule (DC), número de ramos produtivos (NRP),
condutividade elétrica da água lixiviada (CE), consumo hídrico diário (Chd), umidade na
capacidade de campo (Ucc), tempo inicial (TiD) e tempo final de drenagem (TfD). Não
houve interação do polímero e as frequências o número de ramos produtivos, por outro
lado, o polímero hidroabsorvente influenciou (p≤0,05) o NRP aos 110, 140 e 180 dias
após transplantio.Assim, percebe-se que esses tratamentos com hidrogel® contribuíram
para uma liberação de água para as plantas ao longo do tempo.O uso do hidrogel torna-se
viável com o uso das frequências de irrigação ao crescimento do maracujazeiro amarelo
(P. edulis), mesmo apresentando diminuição aos 63 dias após o transplantio no diâmentro
do caule.O polímero é eficiente na retenção e liberação de água para as plantas, mantendo
os menores consumo diários nas plantas de maracujá amarelo.Ohidrogel torna-se um
produto indispensável para a agricultura, portanto é necessário outras pesquisas que
viabilize o custo-benefício desse insumo
Biofortificação agronômica do GERGELIM (Sesamum indicum L.) a partir da adubação com zinco
Get PDFSesame (Sesamum indicum L.), belonging to the Pedaliaceae family, is one of the oldest and most widely used oilseed plants by humanity. This study aimed to evaluate zinc accumulation and physiological parameters in sesame plants subjected to agronomic biofortification through zinc fertilization management. The experiment was conducted in a randomized block design with five treatments consisting of different zinc levels (1.03, 2.06, 3.09, 4.12, and 5.15 mg dm⁻³) and four replications. The analyzed variables included zinc concentration in plant organs, chlorophyll content, CO₂ concentration, stomatal conductance, transpiration rates, and net CO₂
assimilation. The application of increasing zinc doses directly benefits the production of photosynthetic pigments, particularly chlorophyll "a". Adequate zinc doses enhance photosynthetic efficiency, stomatal opening, and carbon assimilation. Among the studied sesame plant organs, the roots were identified as the main zinc accumulation site, while the grains directly benefit from its redistribution. The results confirm the effectiveness of agronomic biofortification of sesame, particularly in increasing zinc accumulation in grains to improve their nutritional qualityO gergelim (Sesamum indicum L.), pertencente à família Pedaliácea, é uma das mais antigas e amplamente utilizadas plantas oleaginosas pela humanidade. Este estudo teve como objetivo avaliar o acúmulo de zinco e os parâmetros fisiológicos em plantas de gergelim submetidas à biofortificação agronômica por meio do manejo da adubação com zinco. O experimento foi realizado em delineamento de blocos casualizados, com cinco tratamentos consistindo em diferentes níveis de zinco (1,03; 2,06; 3,09; 4,12 e 5,15 mg dm-³) e quatro repetições. As variáveis analisadas incluíram a concentração de zinco nos órgãos das plantas, teores de clorofila, concentração de CO₂, condutância estomática, taxas de transpiração e assimilação líquida de CO₂. A aplicação de doses crescentes de zinco promove benefícios diretos na produção de pigmentos
fotossintéticos, com destaque para a clorofila "a". Doses adequadas de zinco aumentam a eficiência
fotossintética, a abertura estomática e a assimilação de carbono. Dentre os órgãos das plantas de gergelim estudadas, as raízes mostraram ser o principal órgão de acumulação do zinco, enquanto os grãos se beneficiam diretamente dessa redistribuição. Com os resultados confirma-se a eficácia da biofortificação agronômica do gergelim, especialmente do acúmulo de zinco nos grãos para melhoria de sua qualidade nutricional
PLANTAS DE GERGELIM CRESCENDO EM SUBSTRATO COM ÁGUA SALINA E BIOFERTILIZANTE BOVINO
Get PDFSesame seed (Sesamun indicum) is a plant that adapts to high temperatures, low altitudes and
expressive lighting, whose cultivation area can be found in Asia, Africa, Central America,
South America and Europe. In the present work, the objective was to evaluate the initial growth
of sesame plants cultivated in substrate containing saline water and bio-fertilizer. The
experiment was carried out in the Department of Phytotechnology and Environmental Sciences
of the Federal University of Paraíba (DFCA / CCA / UFPB), in the city of Areia - PB. The
experimental design was a randomized block with factorial (5X2), consisting of five saline
concentrations (0.5-1.5-3.0-4.5-6.0) and two types of application to the soil (natural fertility Of
the soil and organic fertilization) with four replicates, the variables being analyzed stem
diameter, plant height, Dickson quality index and total chlorophyll. All the analyzed variables
obtained good results with the bovine biofertilizer, however, when they did not use the values
decreased. Due to high concentrations of saline water, causing effect on the physical and
chemical structures of the soil, affecting the development and metabolism of plants.O gergelim (Sesamun indicum) é uma planta que se adapta a altas temperaturas, altitudes
baixas e iluminação expressiva, cuja área de cultivo pode ser encontrada na Ásia, África,
América Central, América do Sul e Europa. No presente trabalho o objetivo foi avaliar o
crescimento inicial de plantas de gergelim cultivadas em substrato contendo água salina e
biofetilizante. O experimento foi realizado no Departamento de Fitotecnia e Ciências
Ambientais da Universidade Federal da Paraíba (DFCA/CCA/UFPB), na cidade de Areia – PB.
O delineamento experimental utilizado foi de blocos casualizados com fatorial (5X2),
constando de cinco concentrações salinas (0,5-1,5-3,0-4,5-6,0) e dois tipos de aplicação ao solo
(fertilidade natural do solo e adubação orgânica) com quatro repetições, sendo as variáveis
analisadas o diâmetro do caule, altura de planta, índice de qualidade Dickson e clorofila total.
Todas as variáveis analisadas obtiveram bons resultados com o biofertilizante bovino, no
entanto, quando não o utilizou os valores decresceram. Devido as concentrações elevadas de
água salina, causando efeito nas estruturas físicas e químicas do solo, afetando o
desenvolvimento e metabolismo das plantas
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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