Dissertação
Interferência de Poa annua L. em Lolium multiflorum Lam. em função do ambiente de competição e do momento de estabelecimento
Fecha
2021-06-22Autor
Conceição, Danúbia Quadros da
Institución
Resumen
The species Poa annua, of the poaceae family, has been shown to occur in pasture
environments in the state of Rio Grande do Sul. There is a great presence of this species as
a weed during the winter period, occupying an extensive area of pastures, competing with
ryegrass forage, for example. The objective was to evaluate the interference of Poa annua in
different populations and conditions of competition with a single ryegrass plant. Two
experiments were carried out in a completely randomized design with five replications in a
3x5 factorial scheme, testing different competition strata (aerial part, root system, and aerial
part and root system) and ryegrass establishment times (together or after the competing
species), with growing populations of Poa annua (0, 35, 139, 279, 419 plants m-2). The
variables analyzed 50 days after the start of the competition were plant height, length of the
root system, stem diameter, and green mass of the aerial part and ryegrass root system. The
variables were subjected to analysis of variance, normality (Shapiro-Wilk) and homogeneity
(O’Neill-Matthews). The levels of factor A were differentiated by calculating the confidence
interval of the averages and in factor B the complementary analysis was by quadratic
regression. In the first experiment, interaction between factors was observed for the variables
root length, stem diameter and green mass of the aerial part and root system. For the second
experiment, there was an interaction between factors for all variables. It is concluded that the
negative interference of Poa annua on ryegrass is greater when the plants compete entirely
for the resources of the environment, that is, for the aerial part and root system. There is a
detrimental effect on ryegrass growth and less competitive ability when it is established after
Poa annua.