The association of management practices, such as population level and forms of nitrogen fertilizer application, may increase the competitive potential of a crop against concurrent plants. The aim of this study was to establish the relative contributions of oat genotypes and management practices and their combined use in modifying the competitivity of the oat plant against concurrent plants. Thus, a field experiment was conducted at the Universidade Federal de Pelotas, in Capão do Leão-RS, during the winter season of 2006, in a completely randomized block design, with four replicates, in a 2 x 2 x 2 x 2 factorial scheme.The competition conditions were (absence of concurrent plants or presence of association of flax + wheat as concurrent plants), oat cultivars (ALBASUL or UPF 16), oat population (230 or 150 plants m-2), and forms of nitrogen splitting were (10 kg of N ha-1 at seeding time, 15 kg of N ha-1 at the four leaf stage, and 20 kg of N ha-1 at the seven leaf stage, or, alternatively, 20, 15, and 10 kg of N ha-1 at those same times) as the factors studied. Additionally, a comparative check was added comprising only the association flax + wheat. The morphological characteristics of the oat plants, as well as of their competitors were evaluated in the beginning of the development period and other traits at oat maturity. The oat cultivar UPF 16 showed a greater competitive potential, compared to ALBASUL, at the initial period of growth. .Larger oat plant population and increase of nitrogen application at seeding time favor oat grain yield increase as well as its competitive potential increase, stimulating the suppression of the concurrent species.
Avena sativa; weeds; interference; competition; plant population; nitrogen application
