Competitive Interaction between Weeds and Onion Crop

Among the factors that affect crop productivity are weeds that compete for the resources present in the environment. Then, the objective of this study was to evaluate the competitiveness of turnip and ryegrass infesting the onion crop. The experiment was conducted in a greenhouse, in a randomized complete block design, arranged in a 2x8 factorial scheme, with four replications. In factor A, were allocated the weeds (turnip and ryegrass) and in the B, were allocated populations of these species (0, 1, 2, 3, 4, 5, 6 and 7 pot-1 plants) living with an onion plant. 50 days after transplanting, were evaluated the height, stem diameter, leaf area and dry mass of the aerial part of the onion plants. For the weeds, only the dry mass of the aerial part was determined. In face of the results, it can be observed that the onion has a low competitive capacity, being the turnip the weed more aggressive in the competition, for all evaluated variables.