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| Registros recuperados: 414 | |
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| Bartz,Marie Luise Carolina; Brown,George Gardner; Pasini,Amarildo; Fernandes,Juliana de Oliveira; Curmi,Pierre; Dorioz,Julie; Ralisch,Ricardo. |
| The objective of this work was to evaluate the effect of organic and conventional coffee crops on biomass, population density and diversity of earthworms, in Lerroville, district of Londrina County, Paraná state, Brazil. Earthworm communities were sampled in three areas with organic coffee cultivation (CO1, CO2 and CO3), two with conventional coffee (CC1 and CC2), and a native forest fragment (MT). The soil of the areas CO1, CC1, and MT was classified as Nitossolo Vermelho (Rhodic Kandiudox), while CO2, CO3, and CC2 were on Latossolo Vermelho (Rhodic Hapludox). Eight samples were taken in each area on two occasions, winter and summer, using the Tropical Soil Biology and Fertility (TSBF) method in the 0-20 cm soil layer. The earthworms were handsorted and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biomass; Conventional cultivation; Diversity; Oligochaeta; Organic cultivation; Population density. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009000800019 |
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| Cividanes,Francisco Jorge; Barbosa,José Carlos; Ide,Sérgio; Perioto,Nelson Wanderlei; Lara,Rogéria Inês Rosa. |
| The objective of this study was to determined species composition and community structure of Carabidae and Staphylinidae in five areas of forest fragment and soybean/corn crops or orange orchard, from December 2004 to May 2007. Beetles were captured in pitfall traps distributed along two parallel transects of 200 m in length, placed across crop land/forest boundary fragment, with 100 m each. The Shannon-Wiener diversity and evenness indexes and Morisita similarity index were calculated. The carabids Abaris basistriatus Chaudoir, Calosoma granulatum Perty, Megacephala brasiliensis Kirby, Odontochila nodicornis (Dejean) and Selenophorus seriatoporus Putzeys. are dominant and are widely distributed in northeastern São Paulo state, Brazil. Point-scale species... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citrus sinensis; Glycine max; Zea mays; Diversity; No-tillage; Similarity. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009000800023 |
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| Camillo,Julcéia; Braga,Valentine Carpes; Mattos,Jean Kleber de Abreu; Lopes,Ricardo; Cunha,Raimundo Nonato Vieira da; Padilha,Joseane; Scherwinski-Pereira,Jonny Everson. |
| The objective of this work was to evaluate the morphological diversity of oil palm seeds and to cluster the accessions according to their morphological characteristics. Forty-one accessions from the oil palm germplasm bank of Embrapa Amazônia Ocidental were evaluated - 18 of Elaeis oleifera and 23 of E. guineensis. The groups were formed based on morphological characteristics, by principal component analysis. In E. oleifera, four groups were formed, tied to their region of origin, but with significant morphological differences between accessions from the same population. For tenera-type E. guineensis seeds, three widely divergent groups were formed, especially as to external parameters, which differentiated them from the other ones. The parameter endocarp... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Elaeis guineenses; Elaeis oleífera; American oil palm; Diversity; Dura; Tenera. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2014000800604 |
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| Concenço,G.; Tomazi,M.; Correia,I.V.T.; Santos,S.A.; Galon,L.. |
| In simple terms, a phytosociological survey is a group of ecological evaluation methods whose aim is to provide a comprehensive overview of both the composition and distribution of plant species in a given plant community. To understand the applicability of phytosociological surveys for weed science, as well as their validity, their ecological basis should be understood and the most suitable ones need to be chosen, because cultivated fields present a relatively distinct group of selecting factors when compared to natural plant communities. For weed science, the following sequence of steps is proposed as the most suitable: (1) overall infestation; (2) phytosociological tables/graphs; (3) intra-characterization by diversity; (4) inter-characterization and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Weed community; Density; Frequency; Dominance; Diversity; Similarity. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582013000200025 |
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| CARDOSO,I.S.; SOARES,M.P.; ARAÚJO,V.T.; CABRAL,P.H.R.; JAKELAITIS,A.; MADALÃO,J.C.. |
| ABSTRACT The seed bank is the reserve of viable seeds found in the soil and is related to diversity and abundance of species that make up the weed populations. This study aimed to determine the seed bank in four distinct environments (grazing area, area of vegetables, annual crop area and perennial crop area) in two seasons (rainy and dry season). To determine the seed bank, each environment was divided into four sub-areas of 0.2 hectares, considering that each area was a repetition, totaling 16 experimental units. Samples of 0.8 kg were taken from each area, and each sample was distributed on a plastic tray and allowed to germinate in a greenhouse. The density of the individuals was determined by observing the number of emerging seedlings in the trays,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rainy season; Dry season; Shannon index; Relative importance; Diversity. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582016000300443 |
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| MELO,T.S.; MAKINO,P.A.; CECCON,G.. |
| ABSTRACT: Composition and level of weed infestation interfere with crop yield and increase production costs. This study aimed to identify weed composition and infestation in corn grown with different plant populations, single, and intercropped with palisade grass. The phytosociological method was used to evaluate density, frequency, dominance, and infestation level of weeds in single and intercropped corn, a with conventional (0.90 m) and reduced (0.45 m) spacing, and low and high plant population in Dourados, MS, Brazil. Commelina benghalensis, Echinochloaspp., and Euphorbia heterophylla were the species most found in the treatments. Single corn with higher plant population decreased weed occurrence. Treatments with palisade grass under a reduced spacing... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Urochloa; Plant population; Phytosociology; Diversity. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582019000100199 |
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| CABRERA,D.C.; CHAILA,S.; SOBRERO,M.T.; VARELA,A.E.. |
| ABSTRACT: Weeds constitute the main constraint on the productivity of sugarcane agroecosystems in Argentina. This work aimed to analyze the floristic and phytosociological composition of sugarcane weed communities in different agroecological areas in Tucumán. Fifteen plots from each area were sampled 60 to 90 days after crop shooting, by throwing a 0.5 m x 0.5 m quadrat metallic frame six times in random directions in each of the plots. Species found within the frame were identified. Later, fresh and dry biomass weight were calculated per quadrat sample and species. Frequency, density, dominance, importance value index, Shannon-Wiener and Simpson species diversity index and Jaccard similarity index were calculated. The unweighted pair group method with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sacharum officinarum L.; Importance value index; Diversity; Similarity. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582019000100226 |
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| Ferreira, Almecina Balbino; Oliveira, Tadario Kamel; Sa, Claudenor Pinho De. |
| O objetivo deste trabalho foi analisar a diversificação de atividades agrícolas na produção familiar do Projeto de Assentamento Colibri (P.A), no Acre. A primeira fase foi levantamento de campo, por meio da aplicação de questionário geral semi – estruturado, quando foram entrevistados aleatoriamente 44 (quarenta e quatro famílias) das 66 que residem no P.A, para a caracterização dos sistemas de produção agrícola. A segunda fase foi aplicação de questionário para avaliação da porcentagem de renda bruta anual por produto em cada propriedade. Para tanto foram selecionados, aleatoriamente, 20 estabelecimentos. Em 10 estabelecimentos foi registrada a porcentagem de renda obtida por meio do consumo familiar, além do comercializado. A partir da porcentagem de... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Diversidade; Produção agrícola; Tipologia; Renda e agricultura familiar; Diversity; Agricultural Production; Tipologia; Income and familiar Agriculture; Farm Management. |
| Ano: 2008 |
URL: http://purl.umn.edu/108826 |
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| Joshi, Ganesh R.; Bauer, Siegfried. |
| Crop genetic resources are the building block of sustainable agricultural development as these can be used to develop crop varieties adaptable to heterogeneous environmental conditions. Nepal is considered the center of origin and diversity for Asian rice, which still has many landraces. However, there has been continuous loss of genetic diversity and concern over it has grown in recent years. The main objective of this paper is to identify the determinants of variety diversity on-farm in the rainfed ecosystem of Nepal by using two-limit Tobit procedure. The diversity on farm appeared to be quite high evaluated based on the number of named varieties grown by the farmers. Majority of the farmers cultivated both modern varieties and landraces simultaneously... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Diversity; Market; Nepal; Rice; Variety; Crop Production/Industries. |
| Ano: 2006 |
URL: http://purl.umn.edu/25422 |
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| Ranis, Gustav. |
| This paper reviews the literature on the impact of ethnic diversity on economic development. Ethnically polarized societies are less likely to agree on the provision of public goods and more likely to engage in rent seeking activities providing lower levels of social capital. Initial conditions are important determinants of adverse development outcomes. The role of decentralization, democracy and markets as potential remedies are discussed. The paper then presents a number of preliminary hypotheses on the relationship between diversity and instability in order to stimulate future research. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Africa; Diversity; Economic Growth; Instability; International Development; O11; O40; O43; O55. |
| Ano: 2009 |
URL: http://purl.umn.edu/54531 |
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| DISLICH,RICARDO; CERSÓSIMO,LUCIANA; MANTOVANI,WALDIR. |
| Neste trabalho é descrita a variação encontrada na estrutura de fragmentos florestais no Planalto Paulistano, sob diversos aspectos e em diferentes escalas de tamanho. Um censo do componente arbóreo dominante (PAP > ou = 50 cm) em duas áreas (0,5 ha e 0,2 ha) no interior de um fragmento florestal, a Reserva da Cidade Universitária "Armando de Salles Oliveira" (CUASO), Butantã, São Paulo, SP (aproximadamente 23°34'S, 46°43'W) incluiu 227 indivíduos de 50 espécies. Foi encontrada dominância absoluta total (Do) de 20,1 m².ha-1, índice de Shannon (H´) de 3,04 nats.ind-1 e equabilidade de Pielou (J´) de 77,79%. Em cada área, foram encontradas regiões de concentração de espécies pioneiras, secundárias e climácicas. As duas áreas apresentaram diferenças na... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ombrophilous dense forest; Fragments; Structure; Diversity. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042001000300011 |
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| MÜLLER,SANDRA CRISTINA; WAECHTER,JORGE LUIZ. |
| As sinúsias herbáceas e arbustivas são componentes de comunidades florestais pouco pesquisados nas regiões tropicais e subtropicais. Neste trabalho foram estudadas a composição florística e a estrutura fitossociológica destas sinúsias em uma floresta arenosa (restinga) da Planície Costeira do Rio Grande do Sul, Brasil. Os dados fitossociológicos foram obtidos em 30 parcelas de 2 x 2 m. Em cada parcela anotou-se a presença e a altura máxima das espécies herbáceas e arbutivas, e a cobertura foi estimada pela escala de Causton. A composição florística total da área compreende 61 espécies, 52 gêneros e 33 famílias. As famílias que apresentaram mais de duas espécies foram: Poaceae, Commelinaceae, Orchidaceae, Piperaceae, Rubiaceae e Asteraceae. As formas de... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbs; Shrubs; Restinga; Diversity; Life-forms. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042001000400005 |
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| Schoenlein-Crusius,Iracema Helena; Milanez,Adauto Ivo. |
| (Fungos microscópicos da Mata Atlântica de Paranapiacaba, São Paulo, Brasil). Na Mata Atlântica de Paranapiacaba, no estado de São Paulo, 1770 ocorrências de diferentes táxons de fungos foram registradas de julho de 1988 a maio de 1990. Para a água do riacho foram reportadas 319 ocorrências, 405 para o solo, 565 em folhas submersas de Alchornea triplinervia (Spreng.) M. Arg. e 481 em folhas dispostas sobre o solo. Mastigomycotina representou 316 ocorrências com 20 espécies, Zygomycotina 266 ocorrências com 13 espécies, Deuteromycotina 1107 ocorrências com 82 táxons e Ascomycotina 81 ocorrências com oito espécies. Os fungos foram isolados pelos métodos da lavagem de discos de folhas, placa de solo e iscagem utilizando substratos quitínicos, queratínicos e... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fungi; Atlantic rainforest; Diversity. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84041998000100007 |
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| Chia,Mathias Ahii; Bako,Sunday Paul; Alonge,Samson O; Adamu,Abu Kasim. |
| Green algal species and their association with physicochemical parameters in some manmade ponds in Zaria, Nigeria were studied from November 2005 to August 2006. Phytoplankton and water samples were collected, preserved and analyzed using standard methods. A total of 27 green algal species divided into 16 families were recorded. Shannon diversity indices ranged from 1.75 to 2.39 in all ponds, dominance index from 0.14 to 0.23 and species evenness 0.56 to 0.64. Closterium sp. and Rhizoclonium hookeri Kuetz. were positively associated with the concentration of Fe, however they were negatively correlated (sensitive) to alkalinity, total dissolved solids and electrical conductivity. Stichococcus bacillaris Naegeli, Staurastrum rotula Nordst. and Sphaeroplea... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chlorophyta; Diversity; Ecology; Lenthic water bodies; Trace metals. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042011000300004 |
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| Registros recuperados: 414 | |
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