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The objective of this study was to determine the effect of the longitudinal distance between a cutting disc and a fertilizer furrow opener on the operational performance of the furrow opener working at different forward speeds during soil mobilization. The soil in the experimental area was classified as Typic Hapludalf with a loam soil texture. The experiment involved 24 treatment combinations in a 2 × 3 × 4 factorial scheme. These combinations were formed by the interaction of the following factors: furrow opening mechanisms, longitudinal distance from the center of the cutting mechanism to center of the furrow opener, and forward speeds. The effects of the tools on the soil mobilization variables were characterized in three phases: analysis of the natural profile and elevation and mobilization of the soil using a microprofilometer. A statistical analysis of variance was performed on the acquired data and the significance of the factors was verified using an F test. The furrow opener factor significantly substantially influenced all variables, whereas the distance significantly modified only the soil swelling and elevated soil area, with a reduction of approximately 30% in this variable when separating the mechanisms by an additional meter. Likewise, for a hoe furrow opener, the speed significantly influenced only the maximum depth of the furrow. Hence, we recommend the installation of fertilizer furrow openers close to the cutting mechanisms to increase the quality of the furrows produced in seeding operations using the direct planting system.

The objective of this study was to evaluate the weed community in a raw sugarcane renovation area with three soil managements and peanut sowing in succession. The experiment was conducted during the 2007/08 season on a raw sugarcane area harvested without prior burning in the last five cuts. A randomized block design with treatments arranged in a split plot and arranged in four replications was used. The main treatments consisted of three cropping systems: conventional tillage, minimum tillage and direct planting, and subplots consisted in the absence (resting) or presence of crop rotation with peanuts. After 135 days from planting peanuts and 180 days of sugarcane harvest, the number of weeds m-2 was counted and the shoot dry biomass of the weeds collected was determined. The data were interpreted by analysis of variance and the means were compared by Tukey's test at 5% probability so that phytosociological indices a, b, c e d were calculated. The use of soil conservation tillage and peanut in rotation with sugarcane in the renovation areas is effective in controlling weeds and suppression of weed species difficult to control like Cyperus rotundus, Commelina bengalensis, Urochloa plantaginea, and Digitaria nuda. Acredita-se ser possível reduzir o custo com o controle de plantas daninhas em áreas de reforma de cana crua adotando-se sistemas de manejos adequados. Objetivou-se com este trabalho avaliar a comunidade infestante em área de reforma de cana crua submetida a diferentes manejos. Nesta pesquisa, utilizando-se uma área de um canavial colhido sem queima prévia, nos últimos cinco cortes foram avaliados três sistemas de cultivo: convencional, mínimo e plantio direto, associados ao pousio e cultivo do amendoim. Após 135 dias da semeadura do amendoim e 180 dias da colheita da cana-de-açúcar, foi feita a contagem do número de plantas daninhas por meetro quadrado e da matéria seca da parte aérea das plantas daninhas coletadas. Todos os dados obtidos foram analisados estatisticamente. Para interpretação dos resultados, utilizou-se o teste de Tukey a 5% de probabilidade e valores dos índices fitossociológicos a, b, c e d calculados. Conclui-se que a utilização do sistema de plantio direto associado ao cultivo do amendoim em rotação com a cana-de-açúcar em áreas de cana crua favorece o controle e a supressão de espécies de plantas daninhas de difícil controle, como Cyperus rotundus, Commelina benghalensis, Urochloa plantaginea e Digitaria nuda.