Competitiveness of goosegrass with soybean/Competitividade de capim-pe-de-galinha com soja

The competition is a negative interference in which individuals compete for environmental resources. The objective was to evaluate the competitiveness of goosegrass with soybean. The experiment was conducted in green-house conditions, in a completely randomized design with four replications. The treatments were five proportions of crop and weed, respectively, 8:0, 6:2, 4:4, 2:6 and 0:8, which corresponded to 100, 75, 50, 25 and 0% of plants soybean and opposite to the goosegrass, which constant population of eight plants per pot (8L), corresponding to approximately 250plants [m.sup.-2]. The competitiveness analysis was accomplished through diagrams applied to replacement series experiments and competivity index. Soybean showed competitiveness superior to goosegrass for the variables of dry matter, when both were in similar proportions of plants. Key words: Glycine max, Eleusine indica, competition, replacement series. A competicao e uma interferencia negativa, na qual individuos competem por recursos do meio. Objetivou-se avaliar a competitividade do capim-pe-de-galinha com soja. O experimento foi realizado em casa-de-vegetacao, em delineamento inteiramente casualizado e quatro repeticoes. Os tratamentos foram cinco proporcoes da cultura e da especie daninha, respectivamente, 8:0, 6:2, 4:4, 2:6 e 0:8, que correspondeu a 100, 75, 50, 25 e 0% de plantas de soja, e o inverso para o capim-pe-de-galinha, com populacao final constante de oito plantas [vaso.sup.-1] (8 L), correspondendo a aproximadamente 250 plantas [m.sup.-2]. A analise da competitividade foi realizada por meio de diagramas aplicados a experimentos substitutivos e indices de competitividade. A soja apresentou competitividade superior ao capim-pe-de-galinha para as variaveis de materia seca, quando ambos estavam em proporcoes iguais de plantas. Palavras-chave: Glycine max, Eleusine indica, competicao, serie de substituicao.