Le chiendent commun (Elymus repens), étant une graminée adventice, vivace, envahissante et difficile à réprimer, il importe de trouver une méthode pour le maîtriser à long terme. Cette méthode doit prioriser la destruction des organes souterrains du chiendent, rhizomes et bourgeons des rhizomes, organes qui assurent sa dispersion. L'utilisation d'une bâche de plastique opaque est une méthode qui n'a pas été étudiée chez le chiendent, mais qui connaît du succès auprès d'autres adventices vivaces envahissantes (Lepidium latifolium et Pueraria montana). C'est une méthode qui peut être utilisée pour différentes durées et à différents moments dans la saison. Cette étude a permis de montrer que l'application d'une bâche de plastique opaque sur un terrain infesté de chiendent procure une maîtrise efficace de l'adventice. De plus, les résultats indiquent que la bâche peut être installée dès le printemps ou plus tard dans la saison pour obtenir un effet semblable sur les rhizomes du chiendent. Aussi, elle peut être installée pendant 6, 12 ou 18 semaines et avoir le même effet à long terme sur les rhizomes du chiendent. Les bâches ont diminué de 70 % la biomasse sèche des rhizomes ainsi que le nombre de bourgeons sur les rhizomes dans la même année. Cet effet s'est poursuivi dans le temps, un an après le retrait des bâches, où les rhizomes du chiendent étaient encore réduits en moyenne à 70 %.

Il est bien connu que le chiendent est à la fois très agressif et persistant. Il est considéré comme l'une des graminées vivaces les plus nuisibles, car il se propage rapidement par ses rhizomes. En agriculture biologique, de nombreuses tentatives ont été faites pour contrôler cette mauvaise herbe, mais sans succès. Dans le contexte d'une agriculture durable respectueuse de l’environnement, la lutte mécanique contre le chiendent représente une alternative intéressante aux moyens chimiques. Dans cette recherche, l'efficacité de la herse rotative, du cultivateur à dents en forme de "C" et du cultivateur à dents en forme de "S" seul ou en combinaison pour contrôler le chiendent dans une prairie a été étudiée. Dans ce contexte, des essais ont été effectués en 2009 sur une prairie en utilisant un plan expérimental en carré latin. Trois traitements ont été considérés: (1) quatre passages avec un cultivateur à dents en forme de "C", (2) un passage avec une herse rotative suivie par trois passages du cultivateur à dents en forme "C", et (3) un passage avec une herse rotative suivie par trois passages du cultivateur à dents en forme de "S". Chaque traitement a été répété trois fois. Le nombre de repousses de chiendent par unité de surface a été déterminé à plusieurs reprises après le passage des traitements sur une période d’une année, en utilisant un quadrat d'un mètre carré placé dix fois au hasard dans la parcelle. Aussi, le temps requis pour chaque passage ainsi que la consommation de carburant ont été déterminés pour chaque traitement. L'analyse des données a révélé que les trois traitements sont comparables en termes de contrôle du chiendent. Toutefois, le traitement no 3 est recommandé puisqu’il requiert moins de temps et de carburant. / It is well known that quackgrass is both very aggressive and persistent. It is considered as one of the most troublesome perennial grassy weeds as it rapidly spreads by creeping rhizomes. In organic farming, many attempts have been made to control this weed without success. Within the context of a sustainable agriculture, mechanical control of quackgrass represents an interesting alternative to chemical means. In this research study, the effectiveness of using a rotary cross-harrow, a C shaped mounted tine cultivator, and an S shaped tine cultivator alone or in combination to control quackgrass in grassland was investigated. Trials were carried out in 2009 on grassland using a Latin square experimental design. Three treatments were considered: (1) four passages using a C shaped mounted tine cultivator, (2) one passage using a rotary cross-harrow followed by three passages of a C shaped mounted tine cultivator, (3) use of the rotary cross-harrow followed by three passages of an S shaped trailed tine cultivator. Each treatment was replicated three times. The number of quackgrass shoots present in each experimental plot was determined before and after the treatments using a one square meter quadrat randomly located in the plot and replicated ten times. Also, the time required for each passage as well as the fuel consumption were computed for every treatment. Analysis of the data revealed that the three treatments were comparable in terms of quackgrass control. However, treatment no. 3 required less time and fuel.

Made available in DSpace on 2016-04-26T20:48:32Z (GMT). No. of bitstreams: 1 Patrick Rodrigues Andrade.pdf: 1437637 bytes, checksum: 0adc2dee140d02db386fb1bdf2f53b1a (MD5) Previous issue date: 2011-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work is structured in two essays on rampant and crisis of capital, and, in the end, some notes as an outline for a critic of underconsumption. The first essay has its central issue the critics elaborated by Rosa Luxemburg to the schemes of social reproduction of Karl Marx, and the interpretation of the author to the meaning of the crisis of capital at the beginning of the 20th century. The first section argues about the theoretical status of the schemes of social reproduction of Marx, the debate surrounding them in the early twentieth century and the analysis undertaken by Rosa Luxemburg in her work The Capital Accumulation (1913). In the second section of this first essay, the analysis focuses on Luxemburg s perspective regarding the crisis of capitalism and her critic of Marx, particularly in terms of a "mismatch" between the schemes of reproduction extended in the second book of Capital and the conception of the capitalist global process of social of the third book. The third section examines some theoretical problems of Luxemburg, presented in earlier sections, under the terms of dialectical logic refined of the notion of "negation of negation", a perspective derived from the Western Marxism, which reaffirms the negative as such. What is questioned is the own conceptual processuality of capital and crisis developed by Karl Marx, a mediation involving the proper relationship between the concept and the non-conceptual. The second essay first discusses the "real abstraction" at the base of the capitalist form of wealth production, which puts dissimilar products in equality and then moves on the sense of the inequality of the same as the distribution rules of surplus-value no longer maintain a direct relationship with the production rules of surplus-value to such an extent that through the transformation of values in prices the value law itself is inverted and the ownership of capital becomes predominant , for how the development of fetishism opens a gap within the capital s profit itself. This essay discusses the commodity fetishism, the fetish of money and finally the capitalist relationship fully reificated in interest-bearing capital, emphasizing, to use a lacanian term, how reality itself has the structure of a fiction. Behind this discussion is the negativity inherent to the capitalist dynamic as a movement of constant resilience and recovery of its contradictions in "higher" levels. The notes, on the end, are limited to comments regarding a current Marxist debate between Michel Husson/Alain Bihr and Francois Chesnais/Louis Gill, however, without great damage, it is possible to extend such considerations, in "old" meaning of "critique of political economy," to the question of the underconsumption within the Marxist tradition, which refers to Rosa Luxemburg (in The Accumulation of Capital), Otto Bauer (in his political testament entitled Between the wars?), Henryk Grossman (in his series of lectures reunited on the volume The law of accumulation and the collapse of the capitalist system), and especially Paul Sweezy (The theory of capitalist development), that marks the end of an intellectual age the "classic tradition" of Marxism / O presente trabalho está estruturado em dois ensaios sobre desmedida e crise do capital, e, ao final, algumas notas como esboço de uma crítica do subconsumismo. O primeiro ensaio tem como assunto central as críticas elaboradas por Rosa Luxemburg aos esquemas de reprodução social de Karl Marx, e a interpretação da autora quanto ao significado das crises do capital no início do séc. XX. A primeira seção discorre a respeito do estatuto teórico dos esquemas de reprodução social de Marx, o debate envolvendo-os no início do século XX e a análise empreendida por Rosa Luxemburg em sua obra A acumulação de Capital (1913). Na segunda seção desse primeiro ensaio, a análise se concentra na perspectiva de Luxemburg a respeito das crises do capitalismo e sua crítica dirigida a Marx, principalmente no que concerne a uma incompatibilidade entre os esquemas de reprodução ampliada do livro segundo de O Capital e a concepção do processo de produção global capitalista do livro terceiro. A terceira seção examina certos problemas teóricos de Luxemburg, apresentados nas seções anteriores, sob o ponto de vista da lógica dialética acrisolada da noção de negação da negação , uma perspectiva oriunda do marxismo ocidental, que reafirma o negativo enquanto tal. O que é posto em questão é a própria processualidade dos conceitos de capital e crise desenvolvidos por Karl Marx, em uma mediação que envolve a própria relação entre o conceito e o não-conceitual. Quanto ao segundo ensaio, discute-se inicialmente a abstração real existente na base da forma capitalista de produção de riqueza, que põe os produtos desiguais em relação de igualdade e, posteriormente, se move no sentido da desigualdade dos iguais de como as regras de distribuição da mais-valia já não guardam relação direta com as regras de produção da mais-valia, a tal ponto que através da transformação dos valores em preços a própria lei do valor se inverte e a propriedade do capital se torna preponderante , para como o desenvolvimento do fetichismo abre uma lacuna no interior do próprio lucro do capital. O ensaio discute o fetichismo da mercadoria, o fetiche do dinheiro e finalmente a relação capitalista plenamente reificada no capital portador de juros, destacando, para usar um termo de Lacan, como a própria realidade tem a estrutura de uma ficção. Por trás dessa discussão está a negatividade inerente à dinâmica do capitalismo enquanto movimento de constante superação e reposição de suas contradições em níveis superiores . As notas se restringem a comentários quanto ao debate marxista atual entre Michel Husson/Alain Bihr e François Chesnais/Louis Gill, todavia, sem grandes prejuízos, é possível estender tais considerações, no velho sentido da crítica da economia política , à questão do subconsumismo no interior da tradição marxista, que remete a Rosa Luxemburg (em sua obra A acumulação de Capital), Otto Bauer (em seu testamento político intitulado Entre duas guerras?), Henryk Grossman (em sua série de palestras reunidas no volume A lei da acumulação e o colapso do sistema capitalista) e especialmente Paul Sweezy (A teoria do desenvolvimento capitalista), sendo que a concepção desse último marca o fim de uma era intelectual a tradição clássica do marxismo