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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

SPINY AMARANTH CONTROL AND AMINOPYRALID PERSISTENCE IN KENTUCKY PASTURES

Edwards, Meghan Elizabeth 01 January 2010 (has links)
Spiny amaranth is a problematic weed of heavily grazed pastures in Kentucky and surrounding states. The first objective was to evaluate spiny amaranth control when herbicides are applied before and after emergence. Spiny amaranth seed collected in 2008 were seeded in rows in the fall (November) and the following spring (March) in fields located near Lexington and Princeton, KY. Treatments consisted of five application dates and five herbicides plus an untreated control arranged in a split-split plot design. The following parameters were measured: fresh weight, plant height and percent visual control. At both locations pendimethalin applied in November, March and April before spiny amaranth emergence gave the greatest control and significantly reduced fresh weight biomass compared to other treatments. June applications of 2,4-D reduced plant height and provided 80 control. Fresh weight biomass and height were also reduced with dicamba, aminopyralid and aminocyclopyrachlor applied in June compared to pendimethalin and the untreated control. A soybean bioassay was conducted to measure soil dissipation of aminopyralid, a common pasture herbicide active ingredient. Soil samples were collected from two sites in Lexington and Princeton. During a season of above average rainfall aminopyralid had dissipated from the soil within 16 weeks at Lexington and by 4 weeks at Princeton.
2

Alimentação de peixes na plataforma continental externa e talude superior na região sudeste-sul do Brasil

Nascimento, Marcela Conceição do [UNESP] 02 October 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-02Bitstream added on 2014-06-13T21:00:41Z : No. of bitstreams: 1 nascimento_mc_me_rcla.pdf: 399072 bytes, checksum: 962f83889fd11e96ee20dff26744646c (MD5) / Universidade Estadual Paulista (UNESP) / Este trabalho tem como propósito indicar a atividade alimentar diária de Antigonia capros, Synagrops spinosus e Urophycis mystacea (Teleostei). Essas espécies apresentam hábitos demersais e são muito freqüentes na plataforma continental externa e talude superior das regiões Sudeste e Sul do Brasil. Para a identificação de padrões de atividade alimentar diária, foram analisados resultados de coletas realizadas em diferentes horários ao longo do dia, agrupados em cinco períodos: amanhecer, manhã, tarde, entardecer e anoitecer. Em cada período foram identificados estômagos em diferentes graus de repleção e de digestão. Após essa análise, foi observado que cada espécie apresentou características específicas na captura de alimento. Nas três espécies foi verificado que houve aumento na atividade alimentar nos períodos do dia com menor intensidade luminosa. Nestes períodos ocorreu maior consumo de animais bentônicos. Constatou-se também que nos horários de maior e menor atividade, houve variação entre o consumo de organismos bentônicos e pelágicos. / The aim of this study was to investigate the daily feeding activity of Antigonia capros, Synagrops spinosus and Urophycis mystacea (Teleostei). These species present demersal behavior and are very frequent in Brazilian South and Southeast outer continental shelf and the continental slope. We carried out collections in different times of the day clustered in five periods: dawn, morning, afternoon, nightfall and night, in order to identify the patterns of daily feeding activity. In each period the different levels of digestion and repletion of the material in the stomachs were identified. Through this analysis we oberved that each species presented specific food capturing characteristics. An increase in the feeding activity was observed in the less lightened periods. In these periods there was higher consumption of benthonic animals. We have also found out a relation between the periods of higher and lower activity and the consumption of benthonic and pelagic organisms.
3

Revision of the Genus Paramacrobiotus Guidetti et al., 2009 With the Description of a New Species, Re-Descriptions and a Key

Kaczmarek, Łukasz, Gawlak, Magdalena, Bartels, Paul J., Nelson, Diane R., Roszkowska, Milena 01 December 2017 (has links)
Based on the original species descriptions, a review of the genus Paramacrobiotus was conducted. We divided the genus into two subgenera, Microplacoidus subgen. nov. and Paramacrobiotus subgen. nov., based on the presence or absence of a microplacoid, characterized species within the genus based on seven different types of eggs. In a moss sample collected in Ecuador, Paramacrobiotus (Paramacrobiotus) spinosus sp. nov., was found. The new species differs from all species of the subgenus Parama crobiotus by the presence of richtersi type eggs and from other species by morphometric characters. Additionally, in the Ecuadorian material we found P. (Microplacoidus) magdalenae comb. nov., which is the first record of this species in Ecuador, we provide the full set of measurements for this species, not included in the original description. An additional new record is P. (M.) alekseevi comb. nov. found in Vietnam for the first time. After examining microscope slides from the Iharos' collection deposited in the Hungarian Natural History Museum, we prepared re-descriptions of P. (P.) csotiensis comb nov., P. (M.) submorulatus comb. nov. and P. (M.) wauensis comb. nov. Based on the morphological and morphometric characters of adults and eggs, we developed a diagnostic key to the genus Paramacrobiotus.
4

Ac?mulo e parti??o de mat?ria seca e nutrientes de cultivares de milho, feij?o e mandioca em competi??o com plantas daninhas. / Accumulation and partitioning of dry matter and corn, beans and cassava nutrients in competition with weed.

Cury, Jo?o Pedro 28 February 2011 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T13:30:34Z No. of bitstreams: 5 37.pdf: 3780972 bytes, checksum: 25735fd7c2f94a2a52a7a996adefcb6b (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-27T18:41:07Z (GMT) No. of bitstreams: 5 37.pdf: 3780972 bytes, checksum: 25735fd7c2f94a2a52a7a996adefcb6b (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Made available in DSpace on 2015-02-27T18:41:07Z (GMT). No. of bitstreams: 5 37.pdf: 3780972 bytes, checksum: 25735fd7c2f94a2a52a7a996adefcb6b (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Avaliaram-se neste trabalho os efeitos da competi??o entre cultivares de milho, feij?o e mandioca e seis esp?cies de plantas daninhas no ac?mulo e na aloca??o de mat?ria seca e nutrientes pelas plantas; o potencial de algumas dessas esp?cies em reciclar nutrientes e a efici?ncia nutricional do feijoeiro. Para isso foi realizado um experimento para cada cultura com tr?s gen?tipos de milho, tr?s de feij?o e dois de mandioca, cultivados em competi??o com seis esp?cies de plantas daninhas, al?m dos tratamentos adicionais, correspondentes ?s cultivares de milho, feij?o e mandioca e ?s esp?cies daninhas ausentes de competi??o. O per?odo de conviv?ncia entre as cultivares de milho, feij?o e mandioca e as plantas daninhas foi de 60, 45 e 75 dias ap?s emerg?ncia das culturas, respectivamente. Para a cultura do milho e do feij?o foi avaliada a aloca??o de mat?ria seca e de nutrientes, inclusive entre os diferentes ?rg?os. Ainda para o feij?o foram estimados os coeficientes para efici?ncia de absor??o, transporte e utiliza??o dos nutrientes. Para a cultura da mandioca, foram determinadas, al?m da aloca??o de mat?ria seca, caracter?sticas morfofisiol?gicas ligadas ? ?rea foliar. A folha e o caule do milho foram os principais ?rg?os afetados negativamente pela competi??o, enquanto as ra?zes das esp?cies competidoras foram os ?rg?os mais prejudicados. Em competi??o com o feijoeiro, as folhas e o caule das esp?cies daninhas foram os ?rg?os mais prejudicados. Com mandioca, os componentes vegetativos das plantas daninhas sofreram reduzidas modifica??es, sem preju?zos quanto ? produ??o de mat?ria seca. As ra?zes do feijoeiro e de mandioca foram os principais ?rg?os afetados negativamente pela competi??o. Os gen?tipos AL 25 (milho) e IPR Colibri (feij?o) foram os que menos toleraram a competi??o. De forma contr?ria, as cultivares P?rola (feij?o) e Periquita (mandioca) demonstraram possuir as maiores habilidades competitivas. O milho mostrou-se sens?vel ? competi??o com B. brizantha e C. benghalensis e competitivo com B. plantaginea. Esta esp?cie, entretanto, mostrou-se altamente competitiva com feij?o e mandioca. Al?m disso, A. spinosus, em competi??o com o feijoeiro, demonstrou possuir a maior habilidade competitiva. A capacidade competitiva entre esp?cies vegetais, quando se trata do ac?mulo de mat?ria seca e relativo de nutrientes, n?o representou vantagem para as esp?cies de plantas daninhas, quando elas foram mantidas em conviv?ncia com o milho. O feijoeiro apresentou baixa capacidade de competi??o por nutrientes, particularmente N e P. A ?rea foliar espec?fica e a raz?o de ?rea foliar da mandioca n?o foram afetadas pela competi??o. B. brizantha e C. echinatus, livre da conviv?ncia com o milho, apresentaram elevado potencial em reciclar nutrientes. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT There were evaluated in this study the effects of competition between maize, beans and cassava, and six weed species in the accumulation and allocation of dry matter and nutrients by plants, the potential of some of these species in recycling nutrients and nutritional efficiency of bean. For this end an experiment was performed to each culture with three genotypes of maize, beans and two of three cassava grown in competition with six weeds species, apart from additional treatment corresponding to the maize, beans and cassava cultivars and weed species absent from the competition. The period of coexistence among maize, beans and cassava cultivars and the weeds was 60, 45 and 75 days after crop emergence, respectively. For the corn and beans there were evaluated allocation of dry matter and nutrients, including between different organs. Even for the beans there were estimated coefficients for uptake, transport and utilization of nutrients. For cassava plants there were determined, besides the allocation of dry matter, morphological and physiological characteristics related to leaf area. The leaf and stalk of corn were the main adversely affected organs by competition, while the roots of competing species were the most affected organs. In competition with the beans, leaves and stems of weeds were the most affected organs. With cassava, the weeds vegetative components suffered reduced modifications without losses in the production of dry matter. The roots of bean and cassava were the main adversely affected organs by competition. Genotypes AL 25 (maize) and IPR Colibri (beans) were the less tolerant in the competition. Conversely, the P?rola (beans) and Periquita (cassava) have showed the greatest competitive abilities. The corn was sensitive to competition with B. brizantha and C. benghalensis and competitive with B. plantaginea. This species, however, proved to be highly competitive with beans and cassava. Furthermore, A. spinosus, in competition with the bean, has demonstrated the greatest competitive ability. The competitive ability of plant species when it comes to the accumulation of dry matter and related nutrients did not represent the advantage to the weeds, where they were kept in close contact with the corn. The bean had low capacity to compete for nutrients, particularly N and P. The specific leaf area and leaf area ratio of cassava were not affected by competition. B. brizantha and C. echinatus, free of coexistence with the corn, had high potential to recycle nutrients.

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