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Dissertations / Theses on the topic 'Weeds Cultural control'

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Published: 4 June 2021
Last updated: 19 February 2022

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1

Tripp, Timothy A. "Cultural control of broadleaf weeds in turfgrass swards." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ27549.pdf.

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2

Mkhonta, Vusumuzi Meshack. "The biology and cultural control of grass-weeds in smallholder maize cropping systems." Thesis, University of Reading, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430913.

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3

Gaongalelwe, Motlhasedi Olebile. "Effect of delayed sowing and increased crop density on weed emergence and competition with wheat." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09AFM/09afmg2118.pdf.

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4

Lacroix, Mireille 1958. "Cropping to suppress yellow nutsedge (Cyperus esculentus L.)." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65450.

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5

Neeser, Christophe. "Rhizome bud production and growth characteristics of clonal colonies in two biotypes of quackgrass (Elytrigia repens (L.) Nevski)." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56676.

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This study examined the effect of density on rhizome bud production in quackgrass (Elytrigia repens (L.) Nevski). The treatments consisted of two biotypes (L8 and L9), and nine density levels ranging from 1 to 22 plants m$ sp{-2}$. The results showed that bud production per plant diminished with increasing density in both biotypes. However, biotype L8 was less productive at low densities, but almost equal to L9 at higher densities. A second experiment was undertaken to measure the expansion of clonal colonies and the distribution of shoots within these colonies. For both biotypes the growth rate was highest in late summer and early fall, but colonies of L9 grew more rapidly. Biotype L9 had 59% of its total biomass located within 40 cm of the centre as compared with 81% in L8. Overall, Biotype L9 produced more rhizome buds, responded more strongly to intraspecific interference, and grew more rapidly as a colony.
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6

Bradley, Kevin Wayne. "Characterization of the Mechanism of Resistance of a Johnsongrass (Sorghum halepense) Biotype to Selected Graminicides in Virginia and Response of Mugwort (Artemisia vulgaris) to Specific Herbicidal and Cultural Control Strategies." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27343.

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Johnsongrass [Sorghum halepense (L.) Pers.] and mugwort (Artemisia vulgaris L.) are both rhizomatous perennial weeds that are capable of rapidly colonizing a variety of different environments. Separate experiments were conducted throughout Virginia from 1996 to 1999 to determine more effective methods for reducing infestations of these perennial weeds in the future. Field and greenhouse experiments conducted on a resistant johnsongrass population discovered in New Kent County, Virginia revealed that this biotype exhibits low levels of resistance to the aryloxyphenoxypropionate (APP) herbicides quizalofop-P and fluazifop-P and the cyclohexanedione (CHD) herbicide sethoxydim. Additional laboratory experiments revealed that resistance is not due to differential absorption, translocation, or metabolism of the APP and CHD herbicides in the resistant vs. the susceptible biotype. However, acetyl-coenzyme A carboxylase (ACCase) assays revealed that resistance to the APP and CHD herbicides is conferred by an overproduction of the ACCase enzyme in the resistant compared to the susceptible johnsongrass biotype. In field experiments conducted on mugwort infestations discovered in several counties throughout Virginia, 100% mugwort control was achieved with standard application rates of picloram at 4 months after treatment (MAT), and also greater than 70% mugwort control was achieved with the higher application rates of clopyralid, glyphosate, and dicamba at 4 MAT. However, all other herbicides evaluated in these experiments provided less than 65% mugwort control at 4 MAT, even at exceptionally high use rates. Additionally, the results from these trials revealed that sequential herbicide applications and sequential mowings prior to herbicide application are both effective mugwort control strategies.
Ph. D.
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7

Oliveira, Odiluza Maria Saldanha de. "Capacidade competitiva de cultivares de feijão-caupi (Vigna unguiculata (L.) Walp) combinada com espaçamento na supressão de plantas daninhas." Universidade Federal do Amazonas, 2014. http://tede.ufam.edu.br/handle/tede/4360.

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FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas
The weed interferencein in crop areas of cowpea reduces their yield of cowpea at 90%, varying in intensity that depends on factors related to weeds community Among the options for weed management, is the cultural method in which the use of cultivars with high competitive ability coupled with narrow row spacing provides conditions for the culture to be established effectively on the soil surface. However, in order not to compromise the yield of cowpea proper use of plant density, which depends on the intrinsic characteristics of the cultivar as size, growth habit, plant architecture and management system used is required. Analysis of the correlation coefficient is a complementary tool to assess the contribution of each factor in the productivity of cowpea under this stress situation. The objective of this experiment was to evaluate the competitiveness of cowpea cultivars at different spacings in upland soil in the state of Amazonas. The experimental design was a randomized complete block with three replications, arranged in sub-subplots. In the plots was used the row spacings of 0,50 m (recommended); 0,40 m and 0,30 m; in the subplots two system of control of weeds, and in sub-subplots cultivars of cowpea caupi BR8 Caldeirão, IPEAN V69, BRS Guariba e BR 17 Gurguéia. Were evaluated: leaf area, dry weight of leaves and of the aerial part, size of pods, number of pods per plant, number of pods, number of seeds per pod, harvest index, one hundred seed weight and yield, leaf area ratio, specific leaf area and leaf area index. Weed evaluation was carried at intervals of 7 days with the use of a square of 0.25 m2 that was carried out with in the useful area subplot for identification, counting and collecting weeds bounded by the square to verify the dry weight of shoots. The phytosociological parameters of frequencies, densities and abundances relative and absolute indices and importance value of species were calculated. It was used the path analysis to decompose the different correlations and their direct and indirect effects. The cv. BR8 Caldeirão had the highest values for measured characteristics followed in order of decreasing values for BRS Guariba, BR 17 Gurguéia IPEAN V69 viii respectively. The yield of cvs. showed a similar trend to the other variables analyzed. The spacing between rows of plants was not significant for productivity, but the cultivars differed from each other between different linear arrangements. The weeds highest IVI in row spacing of 0,5 e 0,4 m were Croton glandulosus and Mimosa pudica for 0,3 m. The most important species for the quantity cvs. were Paspalum multicaule for BR8 Caldeirão, Elephantopus mollis to BRS Guariba and Cleome affinis to IPEAN V69 and BR 17 Gurguéia. IPEAN V69 was the most susceptible to weed competition for dry matter production.The number of pods per plant and leaf area were the features most correlated with productivity. These features showed to be efficient for indirect selection to obtain genetic gains on the productivity of grains. Moreover, these features are also important on the indirect effects of the number of seeds per pod, plant height and dry weight of the aerial parts.
Plantas daninhas em área de cultivo de feijão-caupi causam interferência que pode reduzir a obtenção de grãos em até 90%, o que dependerá de fatores ligados à comunidade infestante. Dentre as opções de manejo das plantas daninhas, encontra-se o método cultural em que o uso de cultivares com elevada capacidade competitiva aliado à redução do espaçamento entrelinhas fornece condições para que a cultura se estabeleça eficazmente na superfície do solo. Entretanto, para não comprometer a produtividade da cultura de feijão-caupi é necessária a utilização adequada da densidade das plantas, o que depende das características intrínsecas da cultivar como porte, hábito de crescimento, arquitetura de planta e do sistema de manejo utilizado. Para quantificar a contribuição de cada fator na produtividade do feijão-caupi nesta situação de estresse competitivo é realizada complementarmente a análise de coeficiente de correlação. O objetivo deste experimento foi avaliar a capacidade competitiva de cultivares de feijão-caupi em diferentes espaçamentos em solo de terra firme no estado do Amazonas. O experimento foi delineado em parcelas sub-subdivididas em blocos casualizados com três repetições. Na parcela foram usados os espaçamentos de 0,50 m (recomendado); 0,40 m e 0,30 m; nas subparcelas os dois sistemas de manejo das plantas daninhas com e sem capina e nas sub-subparcelas as cultivares de feijão-caupi IPEAN V69, BR8 Caldeirão; BRS Guariba; BR 17 Gurguéia. Foram determinadas a área foliar, massa seca das folhas e da parte aérea, tamanho das vagens, número de vagens por planta, número total de vagens, número de sementes por vagem, índice de colheita, peso de cem sementes e produtividade, razão da área foliar, área foliar especifica e índice de área foliar. A avaliação da infestação de plantas daninhas foi realizada em intervalos de 7 dias com a utilização de um quadrado de 0,25 m2, lançado aleatoriamente na área útil da sub-subparcela não-capinada para identificação, contagem e coleta das plantas daninhas delimitadas pelo quadrado para verificar a massa seca da parte aérea. Foram calculados os parâmetros fitossociológicos das espécies. Estimou-se as vi correlações genotípicas entre pares de caracteres e seus efeitos diretos e indiretos considerando os componentes de produção. A cv. BR8 Caldeirão apresentou os maiores valores para as características avaliadas, seguida respectivamente em ordem decrescente de valores por BRS Guariba, BR 17 Gurguéia e IPEAN V69. A produtividade das cvs. seguiu tendência similar às demais variáveis analisadas. Os espaçamentos entre linhas não foram significativos para a produtividade, mas as cultivares diferiram entre si dentro de cada espaçamento. As plantas daninhas com maior IVI foram Croton glandulosus nos espaçamentos de 0,5 e 0,4 m, Mimosa pudica para 0,3m e Paspalum multicaule para BR8 Caldeirão, Elephantopus mollis para BRS Guariba e Cleome affinis para IPEAN V69 e BR 17 Gurguéia. A cultivar IPEAN V69 foi a mais susceptível aos problemas de competição com a flora infestante quanto à produção de matéria seca. O número de vagens.planta-1 e a área foliar foram os caracteres mais correlacionados com a produtividade e se mostram eficientes em praticar-se seleção indireta, com o intuito de obter ganhos genéticos sobre o rendimento de grãos. A cultivar BR8 Caldeirão foi a que demonstrou maior habilidade competitiva com base nos parâmetros avaliados.
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8

Brak, Bastiaan. "Modelling weed population dynamics : impact of cultural control and climate change." Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/2743/.

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Over the last three decades, concern about food safety and the management of natural resources has increased. Instigated by the previous EU pesticide review, (EU 91/414) carrot growers in particular have been hit by the revocation of several post-emergence herbicides. There is real concern among growers that this may impair profits. To identify alternative weed control strategies, a modelling framework capable of simulating the impact of alternative weed management strategies on long-term weed population dynamics, was proposed. Scentless mayweed (Tripleurospermum inodorum) was chosen as model weed species. The system represented in ECOSEDYN (Effects of Cultural control and climate On SEedbank DYN For each component model in ECOSEDYN the literature was reviewed to identify the best mathematical representation and then the model was parameterised. To improve accuracy of model projections and address gaps in knowledge, field experiments were conducted in two areas: soil cultivation, and plant growth and reproduction. The results of the cultivation experiments revealed that key assumptions in models for weed seed re-distribution are incorrect. The experiments focusing on plant growth and reproduction resulted in a novel approach to the modeling of biomass increase, flowering and seed shedding where the different processes were quantitatively and temporally linked using Beta functions. amics), comprises a six-year crop rotation: one year of carrot and five years winter wheat and repeated four times. The weed management strategies consist of combinations of cultural control measures (sowing time and crop maturity time). In addition, the interaction of climate with the cultural control measures was assessed by implementing two future climate scenarios, (‘No change’ vs ‘Heating up’) based on weather data over the last 18 years. The results of the ECOSEDYN simulations showed that, regardless of the prevailing climate, choosing a fast maturing carrot cultivar is by far the most important factor in maintaining the weed seedbank low. In addition, the risk for higher seedbank levels in the long-term under ‘Heating up’ climate is largest if carrot is continuously sown late.
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9

Kolo, Musa G. Matthew. "A comparative study of the biology of Cirsium arvense (L.) Scop. and Equisetum arvense L. in relation to their cultural control." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262613.

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10

Adoryan, Marcio Luiz. "Efeitos de densidades de Aeschynomene rudis Benth e seu controle com o herbicida Ethoxysulfuron em duas épocas de aplicação na cultura do arroz (Oryza sativa L.) irrigado." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-14012005-082507/.

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Com o objetivo de avaliar os efeitos de densidades de Aeschynomene rudis Benth. na cultura do arroz irrigado e a eficiência do herbicida ethoxysulfuron aplicado em duas épocas como pós-emergente, foi instalado um experimento no município de Taubaté, região do Vale do Paraíba-SP, no ano agrícola de 2001/2002. O cultivar de arroz Epagri 109 e a planta daninha A. rudis foram semeados em 30/10/2001 em solo drenado. Os tratamentos foram constituídos de quatro densidades de A. rudis (3, 6, 12 e 24 plantas por metro quadrado) e duas épocas de aplicação do herbicida ethoxysulfuron dentro de cada densidade (estádio de 4 e 6 folhas do A. rudis), e cinco parcelas testemunhas com densidades de 0, 3, 6, 12 e 24 plantas de A. rudis por metro quadrado sem a aplicação do produto, constituindo 13 tratamentos com 4 repetições, delineados em blocos ao acaso. O herbicida foi aplicado na dose de 80 g.ha-1, sendo adicionado à calda o adjuvante lauril éter sulfato de sódio na dose de 0,3 % base volume, e as pulverizações efetuadas nos dias 27/11/2001 e 04/12/2001. Os parâmetros avaliados foram: número de plantas, colmos e panículas por metro, altura das plantas de arroz, comprimento de panículas, número de espiguetas por panícula, número de grãos formados por panículas, rendimento de grãos, eficiência do herbicida no controle de A. rudis e fitointoxicação à cultura. Considerando-se os resultados obtidos pode-se concluir que: a) densidades de 3, 6, 12 e 24 plantas de A. rudis por metro quadrado, influenciam negativamente de forma linear, o número de colmos e de panículas por metro, o comprimento das panículas, o número de espiguetas e de grãos formados por panícula, o rendimento de grãos e o índice para colheita mecânica e não afetam o número de plantas por metro e a altura das plantas de arroz. b) o herbicida ethoxysulfuron é eficiente no controle de A. rudis nos estádios de 4 e de 6 folhas, nas densidades de 3, 6, 12 e 24 plantas por metro quadrado. c) ethoxysulfuron na dose de 80 g.ha-1, quando aplicado em pós-emergência precoce e mediana em densidades de 3, 6, 12 e 24 plantas de A. rudis por metro quadrado é seletivo para o cultivar de arroz Epagri 109, não interferindo nos parâmetros avaliados.
During the season 2001/2002, an experiment was conducted in Taubaté city, area of the Paraíba-SP valley, to evaluate the effect of Aeschynomene rudis Benth. densities on paddy rice, and the efficacy of the herbicide ethoxysulfuron applied in early and mid post emergence. The rice variety Epagri 109 and A. rudis were planted October 30, 2001 in dry soil. The treatments were four A. rudis densities (3, 6, 12 and 24 plants per square meter) and two application timings of the herbicide ethoxysulfuron in each density. The two application timings were at the 4 and 6 leaf stage of A. rudis. There were also untreated densities of 0, 3, 6, 12 and 24 plants of A. rudis per square meter without the herbicide application, resulting in 13 treatments with 4 replications delineated in randomized blocks. The herbicide was applied at 80 g.ha-1, with the adjuvant laurel ether sulfate of sodium at .3% v/v. The applications were made on November 27 and December 4, 2001. The assessed crop parameters were: number of plants, stems and panicles per meter, height of the plants, panicle length, number of spikelets by panicle, number of grains formed by panicles, income of grains, A. rudis control and crop damage. We can conclude from the results that A. rudis densities of 3, 6, 12 and 24 plants per square meter influence the crop negatively, in a linear way, the number of stems and panicles per meter, the length of the panicles, the number of spikelets and grains formed by panicles, the mechanical harvest index, and rice yield. There were no effects on the number of rice plants per meter or the height of the rice. Also, ethoxysulfuron was effective in controlling A. rudis at both the 4 and 6 leaf stage, in densities of 3, 6, 12 and 24 plants per square meter. Ethoxysulfuron at 80 g.ha-1, when applied early post or mid post emergence in densities of 3, 6, 12 and 24 plants per square meter was selective to the rice variety Epagri 109, not affecting the assessed parameters.
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11

Dias, Ana Carolina Ribeiro. "Germinação, competitividade com a cultura da soja e resposta biológica a aplicações de glyphosate para plantas de trapoeraba (Commelina benghalensis L.)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-09022009-160509/.

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Em áreas onde o herbicida glyphosate é utilizado freqüentemente, populações da planta daninha trapoeraba (Commelina benghalensis L.) têm sido selecionadas, devido à tolerância da espécie à ação deste herbicida. Neste sentido, há necessidade de utilização de alternativas de manejo, as quais, por sua vez, são dependentes de conhecimentos profundos sobre a biologia da espécie; e também do controle químico eficiente em condições de pós-emergência, cuja eficácia depende, sobretudo, do estádio de desenvolvimento da planta daninha no momento da aplicação. Desta forma, este trabalho foi desenvolvido com o objetivo de avaliar: a germinação e a emergência das plântulas de sementes aéreas pequenas de trapoeraba (Commelina benghalensis L.) quando submetidas a diferentes temperaturas, condições de luz, superação de dormência e profundidade de semeadura; a competitividade com a cultura da soja; e avaliar a resposta biológica da C. benghalensis e da B. plantaginea a aplicações de diferentes doses do herbicida glyphosate em seis estádios fenológicos, ajustando-as aos modelos tradicionais e a funções de duas variáveis. Com relação à germinação, avaliouse o efeito da luz, temperatura, escarificação química e profundidade de semeadura no substrato. A temperatura ótima para germinação da trapoeraba foi de 25°C. Não houve efeito da luz na germinação das sementes. Não houve interferência positiva na germinação por conseqüência do tratamento das sementes com ácido sulfúrico, em diferentes períodos de exposição, indicando que o lote de sementes de trapoeraba testado não possuía impermeabilidade do tegumento à água. A emergência das plântulas de trapoeraba é influenciada negativamente e de forma linear, pela profundidade de semeadura dos propágulos no substrato. Não houve emergência das plântulas quando as sementes foram depositadas a 80 mm de profundidade. O substrato areia favorece a emergência das plântulas. Com relação à competitividade, a habilidade competitiva da trapoeraba foi semelhante à das plantas de soja, com evidências que a competição intraespecífica teve maior importância para as espécies que a competição interespecífica. Com relação ao controle químico com glyphosate, observou-se que o desenvolvimento das plantas de trapoeraba comprometeu o controle, ou seja, melhores controles foram obtidos com a aplicação de glyphosate sobre plantas jovens. Quando em análise conjunta, a trapoeraba foi mais tolerante ao herbicida que o capim-marmelada. Houve ajuste dos dados a modelos tridimensionais, correlacionando estádio fenológico, dose e controle, contudo novas estimativas devem ser realizadas, sobretudo com a inclusão de doses mais elevadas de glyphosate
In areas where the herbicide glyphosate is used frequently, populations of the weed Bengal dayflower (Commelina benghalensis) have been selected, due to the species tolerance to the action of that herbicide. This way, the use of alternative management is necessary, which are dependent upon deep knowledge on species biology; as well as, the efficient chemical control in post emergence conditions, which efficacy depends on the growth development stage of the weed at the moment of herbicide application. Therefore, this work was carried out with the objective of evaluating: the germination and emergency of small aerial seeds of Bengal dayflower (Commelina benghalensis L.) when exposed to different temperatures, light conditions, dormancy overcoming and seeding depth; the competitive ability with the soybean crop; to evaluate the biological rates of the C. benghalensis and the B. plantaginea the applications of different rates of the herbicide glyphosate in six phenologic stages, adjusting them the traditional models and the functions of two variable. Related to germination, light, temperature, chemical scarification and depth of seeding effects were evaluated. The optimal temperature for Bengal dayflower germination was 25°C. Light effects were not observed on seed germination. Positive consequences of seed treatment with sulfuric acid were not identified, considering different periods of exposition; that indicates that the portion of Bengal dayflower seeds tested did not have tegument water impermeability. Seedling emergence is negative and linearly influenced by seeding depth in the substrate. Seedling emergence was not figured out when seeds were 80 mm depth placed. Sand substrate favored seedling emergence. Related to competitiveness, Bengal dayflower competitive ability revealed similar to soybean plants, with evidences that intraspecific competition was more important for species than interespecific competition. Studying chemical control with glyphosate, it was observed that the development of Bengal dayflower plants compromised the control, i.e., better results were obtained with glyphosate applications on young plants. When in joint analysis, Bengal dayflower was more tolerant than alexandergrass to the herbicide. Data were adjusted to tridimensional models, correlating phenologic stage, rate and control, although new estimative must be achieved, mainly including higher doses of glyphosate.
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Campos, Caio Ferraz de [UNESP]. "Períodos de interferência de uma comunidade infestante na cultura do milho em primeira e segunda safras." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/86446.

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A interferência de plantas daninhas com a cultura do milho pode refletir em perdas relevantes na produtividade de grãos. Em ecossistemas agrícolas, a cultura e as plantas daninhas possuem suas demandas por água, luz, nutrientes e, na maioria das vezes, um ou mais desses fatores de crescimento estão disponíveis em quantidade insuficiente até mesmo para o próprio desenvolvimento da cultura, o que estabelece, assim, a Interferência. O objetivo desse trabalho foi determinar o Período Anterior à Interferência (PAI), o Período Crítico de Prevenção à Interferência (PCPI) e o Período Total de Prevenção à interferência (PTPI) de plantas de capim-colchão (Digitaria nuda) na cultura do milho no município de Botucatu/SP, em dois períodos de semeadura, safra e safrinha. Os tratamentos foram divididos em duas modalidades: períodos de convivência da cultura com as plantas infestantes e períodos em que a cultura permaneceu livre da presença da comunidade infestante, sendo estes de 7, 14, 21, 28, 35, 42, 49 e 56 dias, além de uma testemunha com controle de plantas daninhas até o fim do ciclo da cultura e outra com convivência das plantas daninhas até a colheita. A origem das plantas de capim-colchão foi do banco de sementes, garantido pelo conhecimento do histórico da área experimental. Para determinação dos períodos de interferência quanto ao rendimento de grãos, foi realizada a análise de regressão não linear. Determinou-se também a altura de plantas, altura da inserção da espiga, comprimento das espigas, número de grãos por fileiras, número de fileiras e peso de 100 sementes. Os dados obtidos foram submetidos à análise de variância pelo teste F, sendo as médias dos tratamentos comparadas pelo teste Tukey...
The interference between weeds and corn can reflect significant losses in grain yield. In agricultural ecosystems, crop and weeds have their demands for water, light and nutrients and, in most cases, one or more of these growth factors are not available in sufficient quantity even for the crop development, thereby establishing competition. The aim of this study was to determine the Period Before Interference (PBI), the Critical Period of Interference Prevention (CPIP) and Total Period of Interference Prevention (TPIP) of the crabgrass plant (Digitaria nuda) into corn in Botucatu/SP, in two periods of sowing, in season and out of season. The treatments were set up into two categories: coexistence periods between crop and weeds, and weed free periods. The periods consisted of 7, 14, 21, 28, 35, 42, 49 and 56 days, a weed control and a no weed control treatment during whole crop cycle. The source of the crabgrass was from soil seed bank as confirmed by the area’s known history. To determine the periods of interference on the yield, a nonlinear regression analysis was performed. Plant height, ear insertion height, ear length, number of grains per row, row number and 100 seeds weight ware also analyzed. The data were subjected to variance analysis by the F test, and treatment averages were compared by the Tukey test at 5% probability. For the crop studied 5% yield loss was considered acceptable, in first season conditions the period before interference was 22 days after emergence (DAE) and the total period of interference prevention was 54 DAE, the Critical Period of Interference Prevention was 29 days. For second season the period before interference and the total period of interference prevention were 23 and 26 DAE, respectively and the Critical Period of Interference Prevention was 29 days was 2 days.
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13

Campos, Caio Ferraz de 1984. "Períodos de interferência de uma comunidade infestante na cultura do milho em primeira e segunda safras /." Botucatu, 2013. http://hdl.handle.net/11449/86446.

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Orientador: Dagoberto Martins
Banca: Pedro Luis da Costa Aguiar Alves
Banca: Sílvio José Bicudo
Resumo: A interferência de plantas daninhas com a cultura do milho pode refletir em perdas relevantes na produtividade de grãos. Em ecossistemas agrícolas, a cultura e as plantas daninhas possuem suas demandas por água, luz, nutrientes e, na maioria das vezes, um ou mais desses fatores de crescimento estão disponíveis em quantidade insuficiente até mesmo para o próprio desenvolvimento da cultura, o que estabelece, assim, a Interferência. O objetivo desse trabalho foi determinar o Período Anterior à Interferência (PAI), o Período Crítico de Prevenção à Interferência (PCPI) e o Período Total de Prevenção à interferência (PTPI) de plantas de capim-colchão (Digitaria nuda) na cultura do milho no município de Botucatu/SP, em dois períodos de semeadura, safra e safrinha. Os tratamentos foram divididos em duas modalidades: períodos de convivência da cultura com as plantas infestantes e períodos em que a cultura permaneceu livre da presença da comunidade infestante, sendo estes de 7, 14, 21, 28, 35, 42, 49 e 56 dias, além de uma testemunha com controle de plantas daninhas até o fim do ciclo da cultura e outra com convivência das plantas daninhas até a colheita. A origem das plantas de capim-colchão foi do banco de sementes, garantido pelo conhecimento do histórico da área experimental. Para determinação dos períodos de interferência quanto ao rendimento de grãos, foi realizada a análise de regressão não linear. Determinou-se também a altura de plantas, altura da inserção da espiga, comprimento das espigas, número de grãos por fileiras, número de fileiras e peso de 100 sementes. Os dados obtidos foram submetidos à análise de variância pelo teste F, sendo as médias dos tratamentos comparadas pelo teste Tukey... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The interference between weeds and corn can reflect significant losses in grain yield. In agricultural ecosystems, crop and weeds have their demands for water, light and nutrients and, in most cases, one or more of these growth factors are not available in sufficient quantity even for the crop development, thereby establishing competition. The aim of this study was to determine the Period Before Interference (PBI), the Critical Period of Interference Prevention (CPIP) and Total Period of Interference Prevention (TPIP) of the crabgrass plant (Digitaria nuda) into corn in Botucatu/SP, in two periods of sowing, in season and out of season. The treatments were set up into two categories: coexistence periods between crop and weeds, and weed free periods. The periods consisted of 7, 14, 21, 28, 35, 42, 49 and 56 days, a weed control and a no weed control treatment during whole crop cycle. The source of the crabgrass was from soil seed bank as confirmed by the area's known history. To determine the periods of interference on the yield, a nonlinear regression analysis was performed. Plant height, ear insertion height, ear length, number of grains per row, row number and 100 seeds weight ware also analyzed. The data were subjected to variance analysis by the F test, and treatment averages were compared by the Tukey test at 5% probability. For the crop studied 5% yield loss was considered acceptable, in first season conditions the period before interference was 22 days after emergence (DAE) and the total period of interference prevention was 54 DAE, the Critical Period of Interference Prevention was 29 days. For second season the period before interference and the total period of interference prevention were 23 and 26 DAE, respectively and the Critical Period of Interference Prevention was 29 days was 2 days.
Mestre
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14

Carbonari, Caio Antonio [UNESP]. "Eficácia do herbicida amicarbazone em aplicação conjunta com a colheita de cana-de-açúcar no controle das principais plantas daninhas da cultura." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/97188.

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Os herbicidas aplicados em pré-emergência em cana-crua tem como principais limitações a retenção parcial dos produtos na palha (mesmo após chuvas) e a dependência de chuvas após a aplicação para que o herbicida atinja o solo. Para minimizar estas limitações, foi desenvolvido um sistema de aplicação de herbicidas adaptado à colhedora de modo que as operações de colheita e aplicação do herbicida fossem feitas simultaneamente. A aplicação ocorre entre o sistema de coleta e o lançador de palha da colhedora, atingindo o solo e sendo coberto pela palhada. O objetivo deste trabalho foi avaliar a eficácia do herbicida amicarbazone, aplicado em operação conjunta com a colheita mecanizada da cana-de-açúcar, no controle das principais plantas daninhas da cultura em diferentes épocas de aplicação. Os experimentos foram conduzidos em áreas de cana-crua das Usina Ferrari, nos municípios de Porto Ferreira/SP e Santa Cruz das Palmeiras/SP e Usina Dedini, no município de Tambau/SP. Foram conduzidos cinco experimentos, em diferentes épocas, sendo realizadas aplicações nos dias 27 de junho, 31 de agosto, 03 de outubro, 20 de outubro e 23 de novembro, no ano de 2005. As parcelas experimentais foram constituídas de cinco linhas de cana-de-açúcar espaçadas em 1,5 m, com 8,0 e 11,0 m de comprimento (para a primeira e as demais épocas de aplicação, respectivamente), com 1 m de corredor frontal e 3 m de corredores laterais, com quatro repetições. As espécies Ipomoea grandifolia (Dammer) O Donell, Ipomoea quamoclit L., Ipomoea nil (L.) Roth., Merremia cissoides (Lam.) Hall.f., Euphorbia heterophylla L., Bidens pilosa L., Brachiaria decumbens Stapf, Panicum maximum Jacq e Digitaria spp foram semeadas nas parcelas para garantir as infestações e testar o desempenho do herbicida. Os tratamentos testados foram...
The application of pre-emergence herbicides in sugarcane harvested without burning the leaves is limited by the retention of the compounds by the mulch set up after the harvest and having 5 to 20 t of dry matter ha-1. To avoid this limitation, it was developed an application system set up with a magnetic speed sensor, a tank of 200L in capacity, an eletric pump coupled to a flow regulator and a boom, with two nozzles, wide enough to treat one row of the crop. This equipment mounted on the harvester allowed applying the herbicide over the soil surface before the sugarcane residues were deposited on the soil surface by the backside of the harvester. The objective of this study was to evaluate the efficacy of the amicarbazone applied by a sprayer mounted on a sugarcane harvester to control weeds. The herbicide was also conventionally sprayed over the soil (without mulch) and over the mulch (after the harvest) in five application timings (June 27, august 31, october 03 and 20 and november 23) and locations of São Paulo State - Brazil. Two treatments without the application of the herbicide (with or without the mulch) were also set up to referee the efficacy evaluations. Each plot corresponded to 5 lines of the crop lengthening 8-11 m. The experiments were set up with four replications. Ipomoea grandifolia, Ipomoea nil, Ipomoea quamoclit, Merremia cissoides, Euphorbia heterophylla, Bidens pilosa, Brachiaria decumbens, Panicum maximum and Digitaria spp were seeded in the plots to improve the precision of the efficacy evaluations. The herbicide amicarbazone was applied at the rate of 1050 g. ha-1. For P. maximum and Digitaria spp. when applied in the dry season (June 27 and august 31) highest efficacy levels were observed on the plots applied by the equipment set up in the harvester. The application of amicarbazone over... (Complete abstract, click electronic access below)
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15

Inácio, José Miguel Mira Lopes. "Controlo de infestantes em pós-emergência na cultura do grão-de-bico (Cicer Arietinum L.)." Master's thesis, Universidade de Évora, 2021. http://hdl.handle.net/10174/29690.

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O presente trabalho foi levado a cabo na Herdade do Passinho (Elvas), pertença do INIAV (Instituto Nacional de Investigação Agrária e Veterinária) no ano agrícola de 2018/2019 e consistiu no estudo do efeito de dois herbicidas comerciais, no caso o Agil® e o Lentagran®, cujas substâncias ativas são o propaquizafope e o piridato, respetivamente. A primeira destas duas substâncias ativas, está indicada para controlar infestantes de folha estreita (monocotiledóneas) e a segunda, para controlar infestantes de folha larga (dicotiledóneas) em pós-emergência, na cultura do grão-de-bico (Cicer arietinum L.). Foi objetivo deste trabalho, estudar a eficácia do propaquizafope no controlo do Lolium rigidum Gaudin (erva-febra) e do piridato, no controlo das infestantes de folha larga presentes no ensaio, bem como o seu efeito na produtividade da cultura. Para isso, aplicaram-se três doses diferentes de propaquizafope em mistura com uma dose de piridato, em duas épocas diferentes, correspondendo cada uma delas a dois estádios de desenvolvimento também diferentes, das infestantes e da própria cultura. Constatou-se, que a eficácia do propaquizafope no controlo do Lolium rigidum foi elevada para as duas doses mais altas, em ambas as épocas de aplicação e significativamente menor para a dose mais baixa, também em ambas as épocas. O piridato, mostrou uma muito baixa eficácia no controlo das infestantes dicotiledóneas, em ambas as épocas de aplicação. Esta baixa eficácia, conduziu a uma diferença não significativa na produtividade da cultura entre todos os tratamentos, onde se aplicaram os herbicidas. Não foram observados, quaisquer sintomas de fitotoxidade dos herbicidas na cultura; Post-emergence weed control in chickpea crop (Cicer Arietinum L.) ABSTRACT: The present work was carried out in the Farm of Passinho (Elvas), belonging to INIAV (National Institute of Agrarian and Veterinary Research) in the year of 2018/2019 and consisted in the study of the effect of two commercial herbicides, in this case Agil® and Lentagran®, whose active ingredients are propaquizafop and pyridate, respectively. The first of these two active ingredients is indicated to control grass weeds and the second, to control broadleaved weeds in post-emergence, in the chickpea crop (Cicer arietinum L.). The aim of this work was to study the efficacy of propaquizafop in the control of Lolium rigidum Gaudin (erva-febra) and pyridate, in the control of broadleaved weeds present in the experiment, as well as its effect on crop yield. For this, three different doses of propaquizafop were applied in mixture with a dose of pyridate, in two different timings, each corresponding also, to two different weed and crop development stages. The obtained results showed that the efficacy of propaquizafop in the control of Lolium rigidum was high for the two highest doses, in both application timings and significantly lower for the lowest dose, also in both timings. Pyridate showed a very low efficacy in the control of broadleaved weeds in both application timings. This low efficacy led to a non-significant difference in crop yield among all treatments, where herbicides were applied. No symptoms of herbicide phytotoxicity were observed in the crop.
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16

VanLieshout, Lawrence Anthony. "Weed control in no-till corn as affected by cultivation, herbicide banding, and cover crop suppression." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12172008-063419/.

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17

Carbonari, Caio Antonio 1982. "Eficácia do herbicida amicarbazone em aplicação conjunta com a colheita de cana-de-açúcar no controle das principais plantas daninhas da cultura /." Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/97188.

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Resumo: Os herbicidas aplicados em pré-emergência em cana-crua tem como principais limitações a retenção parcial dos produtos na palha (mesmo após chuvas) e a dependência de chuvas após a aplicação para que o herbicida atinja o solo. Para minimizar estas limitações, foi desenvolvido um sistema de aplicação de herbicidas adaptado à colhedora de modo que as operações de colheita e aplicação do herbicida fossem feitas simultaneamente. A aplicação ocorre entre o sistema de coleta e o lançador de palha da colhedora, atingindo o solo e sendo coberto pela palhada. O objetivo deste trabalho foi avaliar a eficácia do herbicida amicarbazone, aplicado em operação conjunta com a colheita mecanizada da cana-de-açúcar, no controle das principais plantas daninhas da cultura em diferentes épocas de aplicação. Os experimentos foram conduzidos em áreas de cana-crua das Usina Ferrari, nos municípios de Porto Ferreira/SP e Santa Cruz das Palmeiras/SP e Usina Dedini, no município de Tambau/SP. Foram conduzidos cinco experimentos, em diferentes épocas, sendo realizadas aplicações nos dias 27 de junho, 31 de agosto, 03 de outubro, 20 de outubro e 23 de novembro, no ano de 2005. As parcelas experimentais foram constituídas de cinco linhas de cana-de-açúcar espaçadas em 1,5 m, com 8,0 e 11,0 m de comprimento (para a primeira e as demais épocas de aplicação, respectivamente), com 1 m de corredor frontal e 3 m de corredores laterais, com quatro repetições. As espécies Ipomoea grandifolia (Dammer) O’Donell, Ipomoea quamoclit L., Ipomoea nil (L.) Roth., Merremia cissoides (Lam.) Hall.f., Euphorbia heterophylla L., Bidens pilosa L., Brachiaria decumbens Stapf, Panicum maximum Jacq e Digitaria spp foram semeadas nas parcelas para garantir as infestações e testar o desempenho do herbicida. Os tratamentos testados foram... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The application of pre-emergence herbicides in sugarcane harvested without burning the leaves is limited by the retention of the compounds by the mulch set up after the harvest and having 5 to 20 t of dry matter ha-1. To avoid this limitation, it was developed an application system set up with a magnetic speed sensor, a tank of 200L in capacity, an eletric pump coupled to a flow regulator and a boom, with two nozzles, wide enough to treat one row of the crop. This equipment mounted on the harvester allowed applying the herbicide over the soil surface before the sugarcane residues were deposited on the soil surface by the backside of the harvester. The objective of this study was to evaluate the efficacy of the amicarbazone applied by a sprayer mounted on a sugarcane harvester to control weeds. The herbicide was also conventionally sprayed over the soil (without mulch) and over the mulch (after the harvest) in five application timings (June 27, august 31, october 03 and 20 and november 23) and locations of São Paulo State - Brazil. Two treatments without the application of the herbicide (with or without the mulch) were also set up to referee the efficacy evaluations. Each plot corresponded to 5 lines of the crop lengthening 8-11 m. The experiments were set up with four replications. Ipomoea grandifolia, Ipomoea nil, Ipomoea quamoclit, Merremia cissoides, Euphorbia heterophylla, Bidens pilosa, Brachiaria decumbens, Panicum maximum and Digitaria spp were seeded in the plots to improve the precision of the efficacy evaluations. The herbicide amicarbazone was applied at the rate of 1050 g. ha-1. For P. maximum and Digitaria spp. when applied in the dry season (June 27 and august 31) highest efficacy levels were observed on the plots applied by the equipment set up in the harvester. The application of amicarbazone over... (Complete abstract, click electronic access below)
Orientador: Edivaldo Domingues Velini
Coorientador: Roberto Estêvão Bragion de Toledo
Banca: Ricardo Victoria Filho
Banca: Julio Cezar Durigan
Mestre
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18

Michelon, Micheli Fochesato. "Controle químico de azevém e buva na cultura da macieira." Universidade do Estado de Santa Catarina, 2017. http://tede.udesc.br/handle/handle/2430.

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Apple crop has a great economical importance worldwide. Weed control is fundamental to avoid yiels losses. There are few herbicides registered for use in apple culture, although many apple producers use herbicides without knowing the setbacks for the plant such as crop injury, fruit residue or alterations in fruit size and shape. Thus, the objective of this experiment was to evaluate ryegrass and horseweed control and fruit injury caused by herbicides on ´Maxi Gala´ apple trees at the municipality of Vacaria-RS, in the seasons of 2015/2016 and 2016/2017. Seven experiments were carried out in a stable producing orchard. The first experiment consisted of three sequential herbicide applications, where the first was the association of clethodim + gluphosinate, the second was clethodim + paraquat and the third of clethodim associated to saflufenacil or diquat or carfentrazon or bentazon or flumioxazin. The experiments II, III, IV and V were prepared aiming to test the efficiency of clethodim, sethoxidim, clodinafop and fenoxaprop associated to glyphosate or paraquat or diquat or gluphosinate or saflufenacil or carfentrazone or bentazon or flumioxazin, where the difference among experiments was the graminicide. The experiment VI was conducted to test the efficiency of saflufenacil and flumioxazin sprayed alone or associated to glyphosate. The experiment VII was prepared to evaluate crop injury simptons caused by the herbicides on leaves and fruits. For this, it was used 5% of the commercial rate of the herbicides 2,4-D, flumioxazin, gluphosinate, glyphosate, paraquat and saflufenacil in a single spray to ´Fuji´ and different spraying times for ´Gala´apple trees. It was evaluated in the experiments from I to VI the variables: weed control at 7, 14, 21 and 28 days after treatmens (DAT). On the apple trees, it was evaluated leaf injury, number of fruits, crop yield, fruit diameter and weight, flesh firmness (lbs), seed number and soluble solids level (ºBrix). Under the conditions in which this work was developed for the application of registered herbicides to the crop, it was concluded that ryegrass and horseweed plants were efficiently controlled by clethodim + paraquat dichloride, clethodim + saflufenacil and saflufenacil + glyphosate; for application of herbicides without registration to the crop, the ryegrass and horseweed plants were efficiently controlled by the clethodim + carfentrazone-ethyl, clethodim + diquat, sethoxydim + diquat, sethoxydim + ammonium glufosinate, sethoxydim + glyphosate, sethoxydim + paraquat dichloride, sethoxydim + saflufenacil, clodinafop-propargyl + ammonium glufosinate, fenoxaprop-p-ethyl + paraquat dichloride and flumioxazin + glyphosate; in general, herbicide spray to ryegrass and horseweed control did not affect characteristics qualitative and quantitative of apple fruits and productivity of ‘Maxi Gala’ apple trees. The 2,4-D, flumioxazin, ammonium glufosinate, glyphosate, paraquat dichloride and saflufenacil drift caused phytotoxicity symptoms on leaves and fruit of apple. Herbicides drift changed fruit quality and productivity of Fuji Standart e Gala Standart apple trees
A cultura da macieira é de grande importância para a economia mundial. O controle de plantas daninhas é de fundamental importância para que não ocorram perdas significativas na sua produtividade. Poucos são os herbicidas registrados para a cultura e muitos são os utilizados pelos produtores, sem conhecer ao certo os danos que podem causar à cultura, como fitotoxidez à planta, residual nos frutos, bem como alteração no peso e tamanho dos mesmos. Assim, o presente trabalho tem como objetivo avaliar o controle de plantas de azevém e buva e as injúrias causadas por herbicidas em maçãs do clone ‘Maxi Gala’, no município de Vacaria-RS, nas safras 2015/16 e 2016/17. Foram realizados sete experimentos a campo. O experimento I constou de três aplicações sequenciais de herbicidas, sendo a primeira com a associação de clethodim + amônio glufosinate, a segunda clethodim + dicloreto de paraquat e a terceira clethodim associado a saflufenacil ou diquat ou carfentrazone-ethyl ou bentazon ou flumioxazin. Os experimentos II, III, IV e V, foram realizados com o objetivo de testar a eficiência de clethodim, sethoxydim, clodinafop-propargyl e fenoxaprop-p-ethyl, associados a glyphosate ou dicloreto de paraquat ou diquat ou amônio glufosinate ou saflufenacil ou carfentrazone-ethyl ou bentazon ou flumioxazin, onde a diferença dos experimentos se deu pelo uso do graminicida. O experimento VI foi conduzido para testar a eficiência de saflufenacil e flumioxazin aplicados isolados ou em associação com glyphosate. O experimento VII foi realizado para avaliar o aparecimento de sintomas causados pelos herbicidas nas folhas e frutos da macieira. Para isso, foi utilizado 5% da dose comercial dos herbicidas 2,4-D, flumioxazin, amônio glufosinate, glyphosate, dicloreto de paraquat e saflufenacil, em uma única época de aplicação para a cutlivar Fuji Standart e diferentes épocas de aplicação para a cultivar Gala Standart. Nos experimentos de I a VI, as variáveis analisadas foram percentual de controle de plantas daninhas aos 7, 14, 21 e 28 dias após a aplicação dos tratamentos (DAT). Nas plantas de macieira foi avaliada fitotoxidez nas folhas, número de frutos por planta, produtividade média, diâmetro e peso dos frutos, firmeza de polpa (lbs), número de sementes e sólidos solúveis (°Brix). Nas condições em que este trabalho foi desenvolvido, para a aplicação de herbicidas registrados para a cultura, conclui-se que plantas de azevém e buva foram eficientemente controladas pelas associações de clethodim + dicloreto de paraquat, clethodim + saflufenacil e saflufenacil + glyphosate; para a aplicação de herbicidas sem registro para a cultura, as plantas de azevém e buva foram eficientemente controladas pelas associações de clethodim + carfentrazone-ethyl, clethodim + diquat, sethoxydim + diquat, sethoxydim + amônio glufosinate, sethoxydim + glyphosate, sethoxydim + dicloreto de paraquat, sethoxydim + saflufenacil, clodinafop-propargyl + amônio glufosinate, fenoxaprop-p-ethyl + dicloreto de paraquat e flumioxazin + glyphosate; de forma geral, o uso de herbicidas para o controle de azevém e buva não afetou as características físico-químicas dos frutos e a produtividade de macieiras cv. Maxi Gala; a deriva de 2,4-D, flumioxazin, amônio glufosinate, glyphosate, dicloreto de paraquat e saflufenacil provocou sintomas de fitotoxidez nas folhas e frutos de macieira e alterou as características físico-químicas e a produtividade de macieiras cv. Fuji Standart e Gala Standart
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19

Zeeshan, Kashif. "Optimization of the production of Plectosporium alismatis, a potential mycoherbicide against Alismataceous weeds in rice." Brest, 2010. http://www.theses.fr/2010BRES2002.

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L’objectif de cette thèse était le développement d’un mycoherbicide efficace contenant les propagules stables de Plectosporium alismatis, un mycoherbicide potentiel de riz. Le champignon produit des conidies (109 L-1) et des chlamydospores (108 L-1) dans les erlens. Le nitrate est essentiel pour la production de chlamydospores qui ont une survie élevée (6. 6% germination après 4 mois) comparée aux conidies. Des agrégats hétérogènes (contenant les clilamydospores) ont été aussi observés en milieu liquide contenant du nitrate. Ces agrégats pouffaient augmenter la résistance de P. Aljymatis contre les stresses environnementaux. La production d’agrégats homogènes sphériques (les pellets) est nécessaire pour améliorer la reproductibilité. Un milieu « Aggregate Production Medium (APM) » a été développé dans lequel des pellets (~2. 8 x 105 L-1), des conidies (~6. 5 x 109 L-1) et des chlamydospores (~9. 6 x 108 L-1) ont été produits. Après la dessiccation et l’exposition aux UV, le nombre maximal de propagules libres (~104 conidies et ~2 x 102 chlamydospores) n’a pas infecté la feuille alors qu’un seul pellet était suffisant pour causer la nécrose. Nous avons donc conclu que ces pellets étaient plus pathogènes car probablement plus résistants aux UV et à la dessiccation que les conidies. Les études de survie ont montré que la formulation diatomite contenant des conidies libres, des chlamydospores libres et des pellets, stockée à 4°C, survivait après 9 mois de conservation (12% de germination) et restait pathogène. En conclusion, P. Alismatis peut produire des pellets en milieu APM, et la formulation diatomite contenant ces pellets pourrait répondre aux qualités exigées d’un mycoherbicide efficace
The objective of this thesis was to develop an efficient mycoherbicide based on the stable propagules produced by Plectosporium alismatis, a potential mycoherbicide in rice crops. The fungus produced conidia (109 L-1) and chlamydospores (108 L-1) in shake-flasks. Nitrate was required for production of chlamydospores which had a ligher shelf-life (6. 6% germination after 4 months) compared to conidia. The presence of aggregates (containing chlamydospores) ws also observed in nitrate-based medium. These aggregates may increase P. Alismatis resistance against environmental constraints. To overcome the lack of culture reproducibility due to aggregates’ heterogeneous nature, an alternative, the production of homogeneous spherical aggregates (i. E. , pellets) was developed. In a new medium “Aggregate Production Medium (APM)” in which up to 2. 8 x l05 pellets L-1, 6. 5 x l09 conidia L-1 and 9. 6 x 108 chlamydospores L-1 were produced. When maximal number of free propagules (~104 conidia and ~2 x 102 chlamydospores) was not able to infect leaf when dried and exposed to U, only a single pellet was required to induce disease in the same conditions. We conclude that pellets were far more pathogenic and tolerant to desiccation and UV compared to conidia. In shelf-life experiments, diatomite formulation containing free conidia, free chlamydospores and pellets, stored at 4°C survived for a long period (12% germination after 9 months) and remained pathogenic. In conclusion, P. Alismatis can produce pellets in APM, and diatomite formulations based on these pellet-containing cultures could satisfy the requirements for an efficient mycoherbicide
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20

Fonseca, Luciano Ferreira da. "Seletividade de herbicidas na cultura da batata." Universidade Federal de Uberlândia, 2016. https://repositorio.ufu.br/handle/123456789/12242.

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Weed competition occurs during potato planting and development, demanding for the application of specific herbicides, especially pre-emergent ones. There are few herbicides registered for this crop and the cultivars present different selectivity levels to them. Thus, the study of selectivity and weed management are fundamental for obtaining high yields. This study evaluated the selectivity and weed control with the use of pre-emergent herbicides on potatoes. Two experiments were done in Perdizes-MG, using the cultivar Innovator. The first one was installed on August 2014 to evaluate pre-emergent herbicide selectivity to potatoes. Treatments consisted of a control, a hoed control, metribuzin (240 g ha-1), metribuzin (480 g ha-1), linuron (450 g ha-1), linuron (990 g ha-1), diclosulan (25.2 g ha-1), imazetapir (700 g ha-1), prometrine (1000 g ha-1), clomazone (360 g ha-1), clomazone + carfentrazone (300 + 7.5 g ha-1), clomazone + carfentrazone (600 + 15 g ha-1) and sulfentrazone (125 g ha-1). The second experiment was installed on March 2015 using pre-emergent herbicides to evaluate the control of weeds. Treatments consisted of a control, a hoed control, clomazone (360 g ha-1), metribuzin (480 g ha-1), linuron (990 g ha-1), clomazone + metribuzin (360 + 480 g ha-1), and clomazone + linuron (360 + 990 g ha-1). Both experiments were done as randomized blocks with four replications. Plant vegetative development, phytotoxicity and weed control were evaluated 10 and 30 days after shoot emergence (DAE), while total soluble solids, yield and classification were evaluated after harvest. Averages were compared by the Tukey test at 5% significance. The herbicides evaluated for selectivity, in the first trial, did not affect plant development. The herbicides metribuzin, diclosulan and imazetapir presented high phytotoxicity, lowe soluble solids contents and lower yield, and were considered as less selective. In contrast, the herbicides linuron and clomazone were not phytotoxic, did not affect soluble solids contents and did not cause crop yield reduction, and were considered more selective to this potato cultivar. The herbicides evaluated for weed control, in the second experiment, alone or in association, provided 100% control for the species Eleusine indica and Digitaria horizontalis. The best control of Commelina benghalensis, was obtained with clomazone alone or in association with metribuzin or linuron. Plots treated with clomazone presented phytotoxicity at 10 DAE; however, plants recovered from it at the 30 DAE evaluation. . The greatest yields were observed in treatments with clomazone and metribuzin applied by themselves. However, metribuzin reduced total solids contents, which affects potato industrial yield. Therefore, for this potato cultivar, the herbicides conserved more selective were clomazone and linuron, applied alone or in association.
Durante a implantação e o desenvolvimento da cultura da batata ocorre competição por plantas infestantes, exigindo aplicações de herbicidas específicos, principalmente pré-emergentes. Existem poucos herbicidas registrados para esta cultura e as cultivares apresentam diferentes níveis de seletividade a esses herbicidas. Por tanto, o estudo da seletividade e o manejo das plantas infestantes são fundamentais para obtenção de elevadas produtividades. O objetivo deste trabalho foi avaliar a seletividade e o controle de plantas infestantes com a utilização de herbicidas pré-emergentes na cultura da batata. Para isto, foram instalados dois experimentos em Perdizes-MG utilizando a cultivar Innovator. O primeiro foi instalado em agosto de 2014 com o objetivo de avaliar a seletividade dos herbicidas pré-emergentes na cultura da batata. Os tratamentos consistiram em testemunha, testemunha capinada, metribuzin (240 g ha-1), metribuzin (480 g ha-1), linuron (450 g ha-1), linuron (990 g ha-1), diclosulan (25,2 g ha-1), imazetapir (700 g ha-1), prometrina (1000 g ha-1), clomazone (360 g ha-1), clomazone + carfentrazone (300 + 7,5 g ha-1), clomazone + carfentrazone (600 + 15 g ha-1) e sulfentrazone (125 g ha-1). O segundo experimento foi instalado em março de 2015 utilizando os herbicidas pré-emergentes com objetivo de avaliar o controle de plantas infestantes. Os tratamentos consistiram em testemunha, testemunha capinada, clomazone (360 g ha-1), metribuzin (480 g ha-1), linuron (990 g ha-1), clomazone + metribuzin (360 + 480 g ha-1), clomazone + linuron (360 + 990 g ha-1). Os dois experimentos foram realizados em delineamento de blocos casualizados com quatro repetições. Foram realizadas avaliações de desenvolvimento vegetativo, fitotoxicidade e controle de plantas infestantes aos 10 e 30 dias após emergência das hastes (DAE), teor de sólidos solúveis, produtividade e classificação após a colheita. As médias foram comparadas pelo teste de Tukey a 5% de significância. Com relação à seletividade avaliada no primeiro ensaio, os herbicidas não afetaram desenvolvimento das plantas. Os herbicidas metribuzin, diclosulan e imazetapir apresentaram elevada fitotoxicidade, menor teor de sólidos solúveis e menor produtividade, sendo assim considerados menos seletivos. Ao passo que linuron e clomazone, não proporcionaram fitotoxicidade, não afetaram o teor de sólidos solúveis e não proporcionaram redução de produtividade, sendo dessa forma considerados mais seletivos para esta cultivar. Já no segundo ensaio, no qual objetivou-se avaliar o manejo de plantas infestantes, os herbicidas tanto isolados como em associação apresentaram controle de 100% para as espécies Eleusine indica e Digitaria horizontalis. Para o controle de Commelina benghalensis, clomazone isolado ou em associação com metribuzin ou linuron proporcionaram melhor controle. Parcelas tratadas com clomazone apresentaram sintomas de fitotoxicidade aos 10 DAE, porém as plantas se recuperaram aos 30 DAE. Os maiores níveis de produtividade foram observados nos tratamentos com clomazone e metribuzin aplicados isolados. No entanto, metribuzin reduziu o teor de sólidos solúveis, o que afeta o rendimeno industrial. Dessa forma, para esta cultivar os herbicidas considerados mais seletivos foram clomazone e linuron, aplicados isolados ou em associação.
Mestre em Agronomia
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21

Lemos, João Paulo. "Eficiência de roçadas no controle de Bidens pilosa e Commelina benghalensis em competição com a cultura do milho." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/4542.

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Among the factors that difficult the expansion of the area cultivated with organic corn is the control of weeds. On this crop system only the cultural and mechanical control methods are allowed, which most of the times are little efficient and not adequate to the direct planting system. On this work the efficiency of weed clearing was evaluated (Bidens pilosa and Commelina benghalensis) about the physiological and growth characteristics of corn plants. Three experiments were conducted: the first one evaluated the influence of weed clearing over the growth of corn plants; the second one evaluated the effects of clearings on the development of B. pilosa and C. benghalensis species; and the third evaluated the effect of clearings over the physiological characteristics of corn crops. When in competition without using clearings, C. benghalensis did not interfere on the radicular dry mass rate and on the relationship aerial part/radicular system of corn plants. On the opposite, B. pilosa species, when in competition with corn crops, affected all evaluated characteristics, except the crop stalk diameter. Two clearings of weeds provided the biggest benefits to the culture. It was not observed the influence of corn plants over the development of B. pilosa plants, for the evaluated characteristics. However, corn plants affected the accumulation of root dry matter mass and seeds from C. benghalensis plants. Two clearings reduced the interference of B. pilosa and C. benghalensis weeds over the morphological characteristics of corn (total dry matter mass, aerial part/radicular system rate, radicular mass rate and foliar mass rate). Still, these clearings did not influence the physiological aspects (photosyntetical rate, stomatal conductance, internal carbon/external carbon rate, carbon consumed, transpiration and efficiency of water use) evaluated on corn plants in competition with weeds. The C. benghalensis species reduced the photosyntethic rate and the transpiration of corn plants when in competition with this culture.
Dentre os fatores que dificultam a expansão da área cultivada com milho orgânico destaca-se o controle das plantas daninhas. Neste sistema de cultivo são permitidos apenas os métodos de controle culturais e mecânicos, que na maioria das vezes são pouco eficientes e não adequados ao sistema de plantio direto. Neste trabalho avaliou-se a eficiência da roçada das plantas daninhas (Bidens pilosa e Commelina benghalensis) sobre as características fisiológicas e de crescimento de plantas de milho. Foram conduzidos três experimentos: no primeiro avaliou-se a influência da roçada das plantas daninhas sobre o crescimento das plantas de milho; no segundo, os efeitos da roçada no desenvolvimento das espécies B. pilosa e C. benghalensis; e no terceiro, o efeito da roçada sobre as características fisiológicas da cultura do milho. Quando em competição sem uso de roçadas, a C. benghalensis não interferiu na razão de massa seca radicular e na relação parte aérea/sistema radicular das plantas de milho. Ao contrário, a espécie B. pilosa, quando em competição com plantas de milho, afetou todas as características avaliadas, exceto o diâmetro do colmo da cultura. Duas roçadas das plantas daninhas proporcionaram os maiores benefícios à cultura. Não se observou influência das plantas de milho sobre o desenvolvimento das plantas de B. pilosa, para as características avaliadas. Entretanto, as plantas de milho afetaram o acúmulo de massa da matéria seca da raiz e das sementes de plantas de C. benghalensis. Duas roçadas reduziram a interferência das plantas daninhas B. pilosa e C. benghalensis nas características morfológicas do milho (massa da matéria seca total, razão parte aérea/sistema radicular, razão de massa radicular e razão de massa foliar). Todavia, essas roçadas não influenciaram os aspectos fisiológicos (taxa fotossintética, condutância estomática, razão carbono interno/carbono externo, carbono consumido, transpiração e eficiência do uso da água) avaliados nas plantas de milho em competição com as plantas daninhas. A espécie C. benghalensis reduziu a taxa fotossintética e a transpiração de plantas de milho quando em competição com esta cultura.
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22

Silva, Kaliane de Souza. "Eficiência de herbicidas para a cultura do feijão-caupi (Vigna unguiculata (L.) Walp.)." Universidade Federal Rural do Semi-Árido, 2012. http://bdtd.ufersa.edu.br:80/tede/handle/tede/59.

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In order to evaluate the efficiency of weedkillers in the culture of caupi beans (Vignaunguiculata (L.)Walp.), an experiment was conducted in split plots distributed in randomized complete block design with four replications and the plots were evaluated nine weedkillers/mixtures (S-metolachlor,bentazon + imazamox, S-metolachlor + bentazon + imazamox, imazamox + fluazifop-p-butyl, imazethapyr + fluazifop-p-butyl, bentazon + fluazifop-p-butyl, bentazon+ imazamox + fluazifop-p- butyl,lactofen + fluazifop-p-butyl, fluazifop-p-butyl) and a control without weedkiller, while the sub-plots, two treatments were evaluated: with weeding and no hoeing, to determine the selectivity and effectiveness of weedkiller, respectively. At 21, 28 and 45 days after planting (DAP) were evaluated visually in the culture of intoxication and weed control. At 45 DAP, was carried out assessment of dry mass of weeds. At harvest, when plants of caupi had 80% of dry pods were evaluated the number of pods per plant, hundred grain weight and yield of caupi as a function of the strategies for weed management. Plants treated with the mixture of weedkillerslactofen + fluazifop-p-butyl suffered severe intoxication, later recovering with delayed flowering and harvest in eight days. The main species of infesting plants were Cleome affinisDC., Trianthemaportulacastrum L., Amaranthusspinosus L., Commelinabenghalensis L. and Digitariabicornis Lam., all of them were efficiently controlled by the weedkillers S metolachlor + bentazon + imazamox and lactofen + fluazifop-p-butyl,while S-metolachlor, bentazon + fluazifop-p-butyl and the imazamox + fluazifop-p-butyl did not exert efficient control over Cleome affinis, Amaranthusspinosus and Trianthemaportulacastrum, respectively. The interference of species Amaranthusspinosus caused reduction in the productivity of treated plots bentazon + fluazifop-p-butyl, similarly to the control without hoeing. Despite the severe intoxication, weedkillerslactofen + fluazifop-p-butyl provided higher yield when compared to other treatments, because it reduces the intense vegetative growth provided by high rainfall during the experimental period. It was concluded that the weedkillers S-metolachlor, bentazon + imazamox, S-metolachlor + bentazon + imazamox, imazamox + fluazifop-p-butyl, imazethapyr + fluazifop-p-butyl, bentazon + fluazifop-p-butyl, bentazon + imazamox + fluazifop-p-butyl,fluazifop-p-butyl were selective for the culture and that the effectiveness of these depends on infesting species in the area
Com o objetivo de avaliar a eficiência de herbicidas para a cultura do feijão-caupi (Vigna unguiculata (L.) Walp.), conduziu-se um experimento no esquema de parcelas subdivididas distribuídas no delineamento experimental de blocos casualizados, com quatro repetições, sendo que nas parcelas foram avaliados nove herbicidas/misturas (S-metolachlor,bentazon+imazamox,S-metolachlor + bentazon + imazamox,imazamox + fluazifop-p-butyl,imazethapyr + fluazifop-p-butyl,bentazon + fluazifop-p-butyl,bentazon + imazamox + fluazifop-p-butyl,lactofen + fluazifop-p-butyl,fluazifop-p-butyl) e uma testemunha sem herbicidas, enquanto nas subparcelas foram avaliados dois tratamentos: com capinas e sem capinas, para determinar a seletividade e a eficácia dos herbicidas, respectivamente.Aos 21, 28 e 45 dias após o plantio (DAP) foram realizadas avaliações visuais de intoxicação na cultura e de controle de plantas daninhas. Aos 45 DAP, foi realizada avaliação de massa seca de plantas daninhas. Por ocasião da colheita, quando as plantas do feijão-caupi estavam com 80% das vagens secas, foramavaliados o número de vagens por planta, peso de cem grãos e a produtividade do feijão-caupi em função das estratégias de manejo de plantas daninhas.As plantas tratadas com a mistura dos herbicidas lactofen + fluazifop-p-butyl sofreram severa intoxicação, se recuperando posteriormente, com retardo do florescimento e colheita em oito dias.As principais espécies de plantas infestantes foramCleome affinis DC., Trianthema portulacastrum L., Amaranthus spinosus L., Commelinabenghalensis L. eDigitaria bicornisLam,sendo todas controladas com eficiência pelos herbicidasS-metolachlor + bentazon+imazamox e lactofen + fluazifop-p-butyl,enquanto que o S-metolachlor, o bentazon + fluazifop-p-butyl e o imazamox + fluazifop-p-butyl não exerceram controle eficiente sobre Cleome affinis, Amaranthus spinosus eTrianthema portulacastrum, respectivamente. A interferência da espécie Amaranthusspinosus ocasionouredução na produtividade da parcela tratada combentazon + fluazifop-p-butyl, de modo semelhante à testemunha sem capinas. Apesar da severa intoxicação causada, os herbicidas lactofen + fluazifop-p-butyl proporcionaram maior produtividade em relação aos demais tratamentos, por reduzir o intenso crescimento vegetativo proporcionado pelo elevado índice pluviométrico no período experimental. Concluiu-se queos herbicidas S-metolachlor, bentazon + imazamox, S-metolachlor + bentazon + imazamox, imazamox + fluazifop-p-butyl, imazethapyr + fluazifop-p-butyl, bentazon + fluazifop-p-butyl, bentazon + imazamox + fluazifop-p-butyl e fluazifop-p-butyl foram seletivos para a cultura e que a eficácia dos herbicidas depende da comunidadede plantas infestantes da área
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23

Cieslik, Lucas Fernando. "Interferência de fatores morfoambientais e horários de aplicação de fluazifop-p-butyl e fomesafen no controle de infestantes, seletividade e lucratividade da cultura do feijoeiro (Phaseolus vulgaris L.)." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/263.

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Fundação Araucária, CNPQ
Plantas daninhas competem com as cultivadas e dentre as influências negativas desse convívio está a redução da produtividade das culturas. O controle químico é a principal forma de gestão das infestantes na cultura do feijão (Phaseolus vulgaris L.). Sua eficácia depende de uma série de fatores, entre eles: condições ambientais (em função dos horários de aplicação) no momento da aspersão do herbicida e doses utilizadas. Um programa de pesquisa foi desenvolvido no curso de Agronomia da UTFPR, Pato Branco, PR, durante a safra 2010/11 com os objetivos gerais de analisar o impacto de horários de aplicação (e por consequência das variáveis ambientais) e de doses de fluazifop-p-butyl e de fomesafen sobre: o desempenho desses herbicidas no controle de plantas daninhas mono e dicotiledôneas, respectivamente; a seletividade do feijoeiro ao fomesafen e; a lucratividade da lavoura de feijão. As variáveis ambientais, de acordo com o horário do dia ou a época do ano em que os produtos foram aplicados, influenciaram no controle das infestantes. Fluazifop-p-butyl teve atividade favorecida quando aspergido às 06:00h, com umidade relativa do ar e ângulo foliar das gramíneas influenciando de maneira mais significativa no resultado. Para esse mesmo herbicida, aplicação noturna foi eficaz em mitigar os efeitos negativos da aplicação vespertina. O desempenho de fomesafen no controle das plantas daninhas dicotiledôneas foi máximo quando o produto foi aspergido às 11:00h e às 16:00h. Nesse caso, a irradiância e a temperatura do ar foram os principais determinantes da eficácia do herbicida. As doses de fluazifop-p-butyl + fomesafen que propiciaram maior controle da infestação resultaram em aumento da produtividade do feijoeiro e da rentabilidade da produção. Em alguns casos, a maximização da renda líquida foi obtida com dose menor do que a recomendada no rótulo do produto e aquela necessária para a obtenção da máxima eficácia do produto. Fomesafen provocou toxicidade nas plantas de feijão, as quais recuperaram-se das injúrias com o decorrer do tempo. O grau de fitointoxicação foi mais acentuado com doses elevadas do produto e quando esse foi aspergido às 11:00h e às 16:00h. Nesses horários, a temperatura do ar e a irradiância estavam mais acentuadas. Pode-se sintetizar que a eficácia no controle das plantas infestantes e a toxicidade dos herbicidas ao feijoeiro foram dependentes dos herbicidas utilizados, das condições ambientais em função do horário do dia em que os herbicidas foram aplicados e das doses utilizadas. A escolha correta do horário e da dose de aplicação favorece a eficiência do controle das plantas daninhas, minimiza os prejuízos à cultura em função da competição e eleva a lucratividade da lavoura.
The weeds compete with the cultivated crops and among the negative effects of this interaction is the reduction of the crop yields. The chemical method is the main weed control technic in the common bean crop (Phaseolus vulgaris L.). The efficacy of the herbicides depends on a number of factors, including: environmental conditions (in function of the time of application) at the moment of spraying of the herbicide and doses used. A research program was developed on the Agronomy course of UTFPR, Pato Branco, PR, during the 2010-11 with the main objectives to evaluate the impact of the application time (and therefore environmental variables) and doses of fluazifop-p-butyl and fomesafen on the: performance of these herbicides in the control of mono and dicotyledonous weeds, respectively; selectivity of bean crop to fomesafen; and the lucrativity of the common bean crop. The environmental variables, according to the time of day or season of year in which herbicides were applied, influence the control of weeds. Fluazifop-p-butyl activity has been favored when sprayed at 06:00h. The relative humidity and grass leaf angle were the factors most important affecting this herbicide performance. For this same compound, night application has been effective to mitigate the negative effects of the afternoon application. The performance of fomesafen to control broadleaf weeds has been maximum when the product was sprayed at 11:00h and 16:00h. In this case, the irradiance and the air temperature have been the main factors to affect the herbicide efficacy. The doses of fluazifop-p-butyl + fomesafen which allowed best weed control have increased grain yield and profitability of the common bean crop production. In some cases, the maximum net return has been obtained with a dose lower than that needed for maximum herbicide efficacy. Fomesafen has injured the common bean plants, but they have recovered with time. The degree of phytointoxication has increased at high fomesafen doses and when it has been sprayed at 11:00h and 16:00h. During these times, the air temperature and irradiance were the highest. It can be summarized that the efficacy on weed control and on the common bean injury was dependent on the herbicide used, on the environmental conditions during the time of the herbicide spray, and on the rates applied. The selection of the correct time of the day and rate of application can optimize the weed control, can reduce the crop yield losses due to competition, and can optimize the crop profitability.
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24

Ottman, Michael. "Small Grain Growth and Development." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/147020.

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25

Cheriere, Timothée. "Approche fonctionnelle du choix de l’espèce associée au soja et arrangement spatial dans les associations de cultures : impact sur les services obtenus pendant et après la culture. Species choice and spatial arrangement in soybean-based intercropping: Levers that drive yield and weed control." Thesis, Angers, 2020. http://www.theses.fr/2020ANGE0018.

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La diversification des systèmes de culture est un enjeu important pour améliorer leur durabilité. Cependant, l’introduction de cultures de diversification est confrontée à de nombreux freins. Le soja, une légumineuse produisant des graines riches en protéines, est une culture de diversification potentielle qui bénéficie d’un contexte favorable à son développement en France. Mais la maitrise de la croissance des adventices et la stabilisation des rendements sont des défis importants pour les producteurs. Afin de pallier ces problèmes, nous proposons d’utiliser l’association de cultures comme outils d’aide à la diversification des systèmes de culture. Pour tester la pertinence de cette stratégie, quatre services, la production de soja, celle de la culture associée, le contrôle des adventices et l’effet précédent lié à l’azote sont évalués sous l’influence de deux leviers de gestion de l’association : le choix de l’espèce associée et l’arrangement spatial des cultures. Une approche fonctionnelle est mobilisée pour identifier des traits associés à la croissance et aux fonctions des cultures. L’espèce associée a un impact sur l’ensemble des services considérés dans ce travail. Les services de production de soja et de contrôle des adventices se sont révélés être antagonistes mais cet antagonisme peut être modulé dans certaines associations grâce à l’arrangement spatial. L’approche fonctionnelle a permis d’identifier des traits liés à la dynamique de croissance des cultures et à la persistance des résidus après récolte. De plus nous montrons que la réponse des traits des espèces à la gestion des associations est faible. Enfin, l’association du soja modifie certains postes du bilan azoté ainsi que les quantités et qualités des résidus de culture. Cependant, aucune différence d’effet sur le blé suivant n’a été mesurée entre les associations et le soja pur
Diversification is necessary to improve cropping systems sustainability. However, diversification crop introduction into cropping systems is confronted to many barriers. Soybean, a leguminous crop producing protein rich grain, is a potential diversification crop which beneficiate from a favourable context for its development in France. Weed growth reduction et yield stabilisation are important issues for producers. In order to facilitate cropping system diversification, we suggest the use of intercropping to solve these problems. To test this strategy, four services: soybean grain production, associated crop grain production, weed control and nitrogen pre-crop effect are assessed under the influence of two management levers: associated crop species choice and spatial arrangement of crops. Functional approach was used to identify traits associated to crop growth and functions. Associated crop had an impact on all services considered in this work. A trade-off was identified between soybean production service and weed control service. Nonetheless this trade-off could be modulated in some intercrops through spatial arrangement. Functional approach helped identify effect traits related to the growth dynamics of the crops and to the persistence of crop residues. In addition we show that crop traits response to management was low. Finally, intercropping soybean mofifies some parts of nitrogen balance as well as the quantity and quality of crop residues. Nonetheless, no differences were measured on the following wheat between intercrops and sole cropped soybean
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Meiss, Helmut. "Diversifying crop rotations with temporary grasslands : potentials for weed mangement and farmland biodiversity." Phd thesis, Université de Bourgogne, 2010. http://tel.archives-ouvertes.fr/tel-00575607.

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Crop rotation may be used to prevent the continuous selection of particular weed species adapted to one crop type. This might be useful for weed management, economy in herbicide applications and promoting biodiversity. Common simple crop sequences might be diversified by introducing perennial forage crops. Impacts of such perennial crops on weeds were studied with four approaches : 1) Large-scale weed surveys in 632 fields in western France showed that weed species composition differed most strongly between perennial alfalfa crops and annual crops. Comparisons of fields before, during and after perennial alfalfa suggested that community composition varies in a cyclic way during such crop rotations. Several weed species problematic in annual crops were suppressed during and after perennial crops, but the appearance of other species led to equal or even higher plant diversities. 2) A 3-year field experiment with contrasting crop management options allowed an investigation of the underlying mechanisms for this: The absence of soil tillage reduced weed emergence but increased the survival of established plants. The permanent vegetation cover and frequent hay cuttings reduced weed growth, plant survival and seed production. 3) Greenhouse experiments testing the regrowth ability of individual plants after cutting showed strong differences between species and functional groups. An two-factorial experiment suggested that the negative impacts of cutting and competition on weed growth were mainly additive. 4) Special measurements of weed seed predation in the field experiment showed positive correlations with vegetation cover, indicating that this ecosystem service may be particularly fostered by perennial crops. Consistent preferences of seed predators for certain weed species indicates that seed predation may be another cause of the observed weed community shifts.
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Achard, Raphaël. "Etude du fonctionnement d'associations entre le bananier et une couverture vivante ; évaluation des potentialités et stratégies d'utilisation de plantes de service pour contrôler les adventices." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLA036/document.

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L’objectif de cette thèse est de proposer une démarche pour identifier des plantes de service (Pds) utilisables en couverture vivante pour contrôler les adventices en bananeraie. Nous avons d’abord quantifié les effets de compétition réciproque entre le bananier et une couverture contrôlée par fauchage pour Brachiaria decumbens et Cynodon dactylon. Ces couverts ont eu des effets dépressifs sur la nutrition azotée du bananier et la productivité en premier cycle, le second cycle n’étant pas affecté. Dans un deuxième temps nous avons caractérisé au champ, en plantes isolées, la croissance en biomasse de huit légumineuses candidates sous différentes intensités lumineuses. En conditions lumineuses non limitantes, chaque espèce répondait à une dynamique exponentielle, définie par la biomasse 14 jours après semis et le taux de croissance relative (RGR). En conditions d’ombrage limitant, le RGR est réduit et le rapport surface foliaire sur biomasse aérienne croît. Ces réponses permettent de définir quatre stratégies d’adaptation à l’ombrage et d’identifier les Pds adaptées sous bananeraie. Pour trois de ces espèces, sur la base de la réponse de l’efficience photosynthétique, nous proposons un modèle de croissance en fonction de la ressource lumineuse. En peuplement, en présence d’adventices, aucune espèce évaluée n’a pu contrôler les grandes graminées, Stylosanthes guianensis et Centrosema pascuorum ont cependant réduit la biomasse des autres adventices de 60%. En bananeraie, les deux espèces évaluées ont exercé un contrôle sur les adventices mais ont réduit la productivité du premier cycle. Pour autant, ces résultats sont encourageants pour l’utilisation de Pds en bananeraie à des fins de contrôle des adventices
The objective of this PhD thesis was to provide an approach to identify suitable cover crops (Pds) for weed control use in banana plantations. Firstly, we quantified the reciprocal effects between the banana crop and a grass cover controlled by mowing, for Brachiaria decumbens or Cynodon dactylon. These cover crops have had similar depressive effects on the nitrogen nutrition and on the productivity of the first cycle, but not afterward during the second cycle. Second step, we carried out a field characterization of eight legume cover crops, on isolated plants, under a range of light intensity. In non-limited light growth conditions, the biomass growth corresponded to an exponential dynamic, mathematically defined for each species by the biomass 14 days after sowing, and the relative growth rate (RGR). When affected by the shade, the RGR was reduced and the ratio between Leaf area and aerial plant biomass increased. We defined four adaptive strategies of the cover crops to the shade, what constitute criteria guidelines for cover crop use in banana cropping systems. For three of these species, on the basis of the response of the radiation use efficiency, we are proposing a plant growth model without any limiting factor other than light resource. In stands with the presence of weeds, neither of this cover crops was able to control the tall gramineous, but Stylosanthes guianensis and Centrosema pascuorum reduced the biomass of other weeds by 60%. Finally, in banana plantations, the two evaluated species provided a control of the weeds but reduced the productivity of the first cycle. Our results are comforting for the use of cover crops in banana plantation as a mean for weed control
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Dayoub, Elana. "Compétitivité des légumineuses vis-à-vis des adventices : traits impliqués dans la capture précoce de l’azote minéral du sol et complémentarité des traits entre espèces dans des associations légumineuse-non légumineuse." Thesis, Angers, 2017. http://www.theses.fr/2017ANGE0031/document.

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Accroître la compétitivité des cultures vis-à-vis des adventices est un levier essentiel pour concevoir des systèmes de culture moins dépendants des herbicides. Les légumineuses sont des espèces majeures pour diversifier les systèmes mais elles sont réputées peu compétitives vis-à-vis des adventices. Cependant la variabilité entre espèces en particulier pendant la phase précoce a été peu explorée. Ce travail vise à i) étudier, via deux expérimentations en rhizotrons en serre, les traits impliqués dans la croissance et l’acquisition d’azote (N) en début de cycle chez une gamme d’espèces de légumineuse et les conséquences sur la compétition légumineuse-adventice et à ii) quantifier au champ l’intérêt d’associations légumineuse-non légumineuse (colzalégumineuses, maïs-légumineuses pérennes, la légumineuse étant plante de service) sur la croissance et la composition de la flore adventice. Nous montrons qu’il existe une variabilité entre espèces de capture d’N en début de cycle en lien avec les réserves azotées de la semence et l’exploration racinaire. La croissance et l’acquisition d’N de l’adventice sont impactées différemment selon l’espèce de légumineuse pendant la phase précoce. Les essais au champ montrent l’intérêt de combiner des espèces aux traits complémentaires pour l’utilisation des ressources conduisant à un meilleur contrôle des adventices tout en maintenant la productivité de la culture. Cette étude montre aussi que la composition de la flore est modifiée en fonction de la légumineuse insérée dans le système en lien à la fois avec les traits des légumineuses et les traits de réponse des adventices
Enhancing crop competitiveness against weeds is a relevant way in order to design cropping system less dependent on herbicides. Legumes are key species in diversified cropping systems but they are known to be low competitive against weeds. However, inter-specific variability especially in the early growth had been little studied. Our work aims to i) study, via two greenhouse experiments in rhizotrons, the traits involved in the growth and nitrogen (N) acquisition for a range of legume species and the impacts on weed-legume competition at the beginning of crop cycle and to ii) quantify under field experiments the interest of legume-non legume intercropping (oilseed rapelegumes, maize-perennial legumes, where legume species were grown as service plant) on weed growth and weed species composition. Our results highlighted the inter-specific variability for soil N uptake in the early growth in relation with seed reserves and rooting exploration. Weed growth and N acquisition are influenced differently as a function of legume species in the early growth. Field experiments show the advantage of species combinations with complementary traits for using resources, leading to better weed control while maintaining crop productivity. This study shows also that weed species composition was modified as a function of legume species in relation with both legume traits and weed traits response
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Neyret, Margot. "Adventices et érosion du sol dans un agroécosystème montagneux du Nord de la Thaïlande : une étude multidisciplinaire." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS285.

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L’intensification et l’expansion rapide des plantations d’Hevea brasiliensis dans les régions montagneuses d’Asie du sud-est ont conduit à d’importantes dégradations de la biodiversité et des sols. Les adventices remplissent de nombreux services écosystémiques, par exemple en favorisant la protection du sol. Toutefois, les facteurs déterminants les communautés adventices et les interactions entre ces communautés et les processus d’érosion du sol sont mal connus. Deux fois par an entre 2016 et 2018, nous avons réalisé des inventaires botaniques et des caractérisations de sol à Huai Lang, au nord de la Thaïlande, dans 20 champs appartenant à plusieurs types d’usage du sol correspondant à la transition entre les cultures annuelles et les plantations d’hévéa. Nous avons également mesuré l’effet du type d’usage du sol et des pratiques de désherbage sur le ruissellement et le détachement de sol dans des plots d’érosion de 1m2. Les résultats montrent que la composition des communautés végétales est principalement déterminée par le type d’usage du sol et les caractéristiques paysagères, tandis que la variabilité temporelle des cultures dans un champ favorise la diversité végétale. Les plantations d’hévéa matures supportent des communautés végétales très spécifiques et favorisent des ruissellements et détachements de sol très élevés, qui peuvent être atténués par la présence d’un couvert végétal. Cette étude suggère que la conservation du sol et de la biodiversité en Asie du sud-est devrait être fondée à la fois sur une évolution des pratiques à l’échelle du champ (par ex. désherbage moins intense) et sur un maintien de la diversité spatiale des agroécosystèmes
In Mountainous South-East Asia, rapid agricultural intensification and the expansion of rubber tree plantations in the past decades led to drastic biodiversity losses and intense soil degradation. Weeds provide diverse ecosystem services, including soil protection and support for biodiversity at higher levels. However, the determinants of weed communities in mountainous areas of Southeast Asia, and the interactions of these communities with soil characteristics and erosion processes, are still largely unknown. We conducted soil characterisation and botanical inventories in Huai Lang, Northern Thailand, in 20 fields from different land uses along the transition from annual crops to mature rubber tree plantations twice a year from 2016 to 2018. Using 1m2 erosion microplots, we also measured runoff and soil erosion in different land uses, and in rubber tree plantations under different weeding practices. We show that weed communities composition was mostly determined by land use and landscape characteristics, while crop temporal variability was an important determinant of plant diversity. Rubber tree plantations had specific weed communities and had exceptionally high soil detachment rates compared to maize or young plantations, but weed cover was effective in decreasing these erosion rates. Altogether, our results suggest that soil and plant biodiversity conservation in mountainous Southeast Asia should involve both on-field adaptations (e.g. less intense weeding practices, especially under rubber tree plantations) and landscape-scale management programs, with a focus on maintaining landscape diversity
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Bernhard-Bitaud, Corinne. "Modifications de la matière organique et conséquences sur l'adsorption de l'atrazine dans un sol brun de prairie mis en culture." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL128N.

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En conditions de plein champ après retournement d'une prairie permanente, on compare pendant cinq ans l'évolution des propriétés d'un sol brun entre deux parcelles, l'une exempte de tout traitement chimique, l'autre désherbée à l'atrazine. On observe au cours du temps une diminution de la stabilité structurale (-30%) et de la teneur en matière organique (- 20%), ainsi qu'une augmentation du rapport isotopique ¹³C/¹²C, du taux d'humification et de l'extractibilité des acides humiques. Toutefois, l'étude des caractéristiques chimiques de la matière organique ne révèle pas de différence majeure entre les deux parcelles tout au long des cinq années. Un fractionnement des agrégats à 50 [micro]m permet de mettre en évidence une plus grande richesse en carbone de la fraction grossière (50-2000 [micro]m) du sol non désherbé par rapport au sol traité, qui peut être attribuée aux importants retours de matière organique fraiche par les adventices. Ces derniers n'affectent cependant pas les caractéristiques qualitatives des matières organiques totales ; ainsi le rapport C/N reste constant et identique dans les deux parcelles. L'analyse en spectroscopie d'absorption infra-rouge des acides humiques et fulviques extraits montre que les groupements fonctionnels des composés humifiés ne sont affectés de façon majeure ni par l'évolution générale du sol ni par le traitement à l'atrazine. Cependant, l'étude de la cinétique d'adsorption de l'atrazine met en évidence une diminution de la vitesse de mise à l'équilibre entre les échantillons les plus anciens et les plus récents. Par ailleurs, la comparaison de l'adsorption entre la fraction fine (0-50 [micro]m) et la fraction grossière (50-200 [micro]m) d'un même échantillon de sol montre que l'adsorption est moins rapide mais également moins réversible sur la fraction grossière. Ces différences de comportement rendent compte de variations très fines de la réactivité des matières organiques, et sont commentées en relation avec la structure hypothétique du complexe argilo-humique
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Ugarte, Nano Claudia Carolina. "Etude de la variabilité des propriétés physiques et hydrodynamiques d'un sol argileux sous l'effet de conduites en protection intégrée contre les adventices." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS003/document.

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Les systèmes de culture en Protection Intégrée de Cultures contre les adventices (systèmes PIC-adventices) sont d’un grand intérêt pour réduire significativement l’utilisation des herbicides en les substituant par une combinaison complexe de différentes techniques culturales. L’objectif principal de notre travail a été de contribuer au volet environnemental de l’évaluation multicritère des systèmes PIC-adventices mis en place depuis 2000 sur le domaine expérimental de l’INRA à Bretenière (21). La variabilité des propriétés physiques et hydrodynamiques qui interviennent dans le transfert de l’eau dans le sol a été étudiée dans les 5 systèmes de culture présents sur le site (1 système de référence et 4 systèmes PIC-adventices). Le premier volet du travail a consisté à étudier la rétention de l’eau dans la couche du sol travaillée dans les 5 systèmes de culture. La rétention de l’eau a été comparée dans des échantillons de sol dont la structure a été soit « conservée », soit « remaniée » afin d’identifier la part de la variabilité liée aux caractéristiques physiques intrinsèques du sol de celle induite par les pratiques culturales. Les résultats ont montré que le sol du système de culture avec suppression totale des herbicides, associant une teneur élevée en argile, une teneur moyenne en C organique et un travail superficiel intensif, présentait les valeurs les plus élevées de rétention de l’eau dans la couche de sol travaillée. Le second volet a porté sur l’étude de la variabilité de la conductivité hydraulique proche de la saturation, K(h), aux échelles de l’année culturale et du profil du sol. Pour cette étude, 3 systèmes PIC-adventices (système de culture en semis direct et systèmes de culture avec travail du sol modéré à intensif) ont été caractérisés pendant 2 ou 3 années culturales consécutives, en considérant 3 profondeurs de sol incluant la couche du sol travaillée et l’horizon sous-jacent. Les résultats n’ont montré aucune variabilité de K(h) à l’échelle verticale. Par contre, ils ont mis en évidence les effets à long terme des systèmes PIC-adventices sur les valeurs de K(h). Enfin, le dernier volet a étudié la dynamique de l’eau dans le sol de 2 systèmes PIC-adventices contrastés (système avec conduite du sol en semis direct et système sans herbicide avec travail du sol intensif) en suivant une approche d’hydraulique agricole et par le biais de la caractérisation in situ du potentiel matriciel de l’eau dans le sol et de la mesure des quantités d’eau collectée au moyen de lysimètres à mèche. L’approche utilisée a permis la description de la dynamique de l’eau du sol pendant la période de drainage, la validation du fonctionnement des lysimètres à mèche et le calcul de la surface de sol équivalente qui contribuait au transfert de l’eau dans ces dispositifs. Ces premiers résultats prometteurs nécessiteront néanmoins d’être validés au cours de prochaines campagnes de mesure. L’ensemble des résultats recueillis constituent une première évaluation du fonctionnement physique et hydrodynamique du sol des systèmes PIC-adventices présents sur le dispositif expérimental. La base de données constituée permettra ultérieurement la poursuite du travail engagé en modélisant le transfert de l’eau, de solutés, de pesticides ou d’autres polluants dans le sol de ces systèmes PIC-adventices
Integrated weed management (IWM)-based cropping systems are of great interest due to their significant reduction of herbicide inputs by using a complex combination of agricultural techniques. The main objective of our work was to contribute to the environmental dimension of the multi-criteria evaluation of IWM-based cropping systems which were set up since 2000 on the experimental domain of the National Institute for Agronomical Research (INRA) to Bretenière (France). The variability of physical and hydrodynamic soil properties involved in the transfer of water through the vadose zone was studied for the 5 cropping systems present on the experimental site (1 reference cropping system and 4 IWM-based cropping systems). The first section of our study consisted in studying the water retention of the tilled soil layers for the 5 cropping systems. Water retention values were compared between undisturbed and repacked soil samples in order to distinguish the part of the variability due to the intrinsic soil properties from the one induced by the agricultural practices. Our results show that the soil from cropping system without any herbicides, associating high clay content, average organic C content and intensive superficial tillage, may increase soil water retention in the tilled soil layer. The second section carried on the study of the annual and vertical variability of the near-saturated hydraulic conductivity, K(h). For this study, 3 IWM-based cropping systems (no-tilled cropping system and moderate to intensive tilled cropping systems) were characterized during 2 or 3 consecutive years and considering 3 depths including the soil tilled layer and the underlying no-tilled layer. The results showed no vertical variability of K(h). However, they highlighted the long-term effect of IWM-based cropping systems on K(h). Finally, the third section studied the soil water dynamics of 2 contrasted IWM-based cropping systems (no-tilled and zero herbicide cropping systems with intensive tillage) by using ,a hydraulic agricultural approach and by the means of the in situ characterization of soil matric potential and the measure of the amounts of water collected with wick lysimeters. This approach allowed the description of the water dynamics during the drainage season, the validation of the wick lysimeters functioning and the calculation of the surface contributing to water flows collected by the wick lysimeters. These promising results will need to be validated during forthcoming campaigns of measurement. All data collected provided constitute a first evaluation of the soil physical and hydraulic functioning of IWM-based cropping systems present on the experimental site. The established database will allow later the pursuit of work by modeling the water transfer and the transport of solutes, pesticides or other pollutants through the vadose zone of these IWM-based cropping systems
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Tasli, Samira. "Devenir de l'atrazine en culture de mais : études en plein champ -site de la Cote Saint André, Isère, France- et au laboratoire : recherche de solutions alternatives de traitement." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10209.

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Le travail presente dans ce memoire concerne une etude du devenir d'un herbicide du mais, l'atrazine en condition de plein-champ: bilan et modes de dissipation. Des experimentations de laboratoire mettant en jeu des methodes diverses (suivi de l'atrazine #1#4c, couches minces et colonnes de terre, lysimetre non remanie) permettent d'etayer les resultats obtenus sur la parcelle experimentale du site observatoire des pollutions diffuses du lycee agricole de la cote saint andre (isere, france) ou a ete suivie pendant 3 ans la composition en herbicide et metabolites du sol sur 1 metre de profondeur et celle de l'eau interstitielle prelevee par bougies filtrantes. La matiere active (1 kg/ha) apportee annuellement fin avril se dissipe selon cinq voies d'importances tres inegales: volatilisation (15%), absorption par la culture (10%), adsorption sur le complexe argilo-humique et metabolisation (40-50%), entrainement vers les eaux profondes (30-40%). Dans la situation etudiee, les deux voies principales sont la metabolisation par la microflore du sol et l'entrainement lors des episodes pluvieux precoces. Apres un an de culture, la teneur en atrazine et derives au sein du premier metre de sol est voisine de 400 g/ha ce qui indique que l'evacuation de la matiere active n'est pas complete. Notre etude de terrain completee par une experimentation de laboratoire, conduit a mettre en evidence la possibilite de pertes precoces importantes de matiere active durant les deux premiers mois de culture. Trois concepts importants relatifs a l'efficacite d'un herbicide de prelevee emergent de notre etude: la concentration critique dans l'eau du sol, la duree critique durant laquelle cette concentration doit etre maintenue pour assurer l'effet herbicide, la profondeur critique qui represente la couche de sol dans laquelle doit jouer l'effet herbicide. Pour l'atrazine en culture de mais, dans nos conditions, ces criteres ont ete mesures: concentration critique: entre 50 et 200 micromoles ; duree critique: deux mois ; profondeur critique: 10 cm. Avec 1 kg/ha d'atrazine sous forme de suspension concentree, les trois criteres d'efficacite sont remplis malgre d'importantes pertes par drainage lors des episodes pluvieux precoces. Des modifications de formulation ayant pour consequence un relargage progressif devrait permettre l'economie d'une part importante de matiere active. La derniere partie de ce travail concerne une approche de mise en place de solutions alternatives de traitements herbicides en culture de mais
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Green, Jessica M. (Jessica Marie). "Structuring habitat to conserve ground beetles (Coleoptera: Carabidae) and reduce summer annual weeds in agroecosystems." Thesis, 2010. http://hdl.handle.net/1957/19544.

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Weed management in sustainable farming systems often requires the integration of several different pest management techniques. Cultural, biological, and chemical pest control efforts can be utilized to contribute to the common goal of reducing weeds in vegetable row crop systems. This research addresses how common disturbances such as tillage and insecticide use affect: carabid beetle assemblages; predation of weed seeds by invertebrates; and weed seed recruitment. Field experiments were conducted over three years at two different locations on the OSU Vegetable Research Farm, Linn Co., OR. We found that activity-density of carabid beetles varied seasonally and peaked in late August-September each year. Insecticide applied in year 1 affected seed loss in year 2, suggesting possible long-term effects of land management on weed seed removal. Weed recruitment was highly variable between treatment, site, and year. Conserving biological weed control agents in combination with cultural techniques such as reducing tillage and the use of cover crops, helps growers shift from expensive, density-independent control efforts to more ecological, long-term solutions for weed management in agroecosystems.
Graduation date: 2011
Access restricted to the OSU community, at author's request, from Dec. 15, 2010 - Dec. 15, 2011.
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