Condições hidricas do solo na ação de herbicidas para o controle e crescimento de Lolium multiflorum Lam

Abstract

The species Lolium multiflorum Lam. is often reported as a weed that is difficult to control, which can be caused by environmental variability. This work aimed to identify the growth response and chemical control of Lolium multiflorum Lam., under different soil water conditions and duration periods. Two studies were carried out in a greenhouse. The first included two soil moisture conditions: 30% of the water holding capacity (WRC), water depth of 5 cm above the ground, inserted in six different periods and additional treatment with ideal development conditions (80% WRC). Height were evaluated every five days during the entire development cycle, shoot and root dry mass and seed production at the end of the experiment. The second subjected the ryegrass plants to two water conditions (30% WRC and a water depth of 5 cm above the ground) for six different periods (0, 5, 10, 15, 20 and 25 days) prior to the application of four increasing doses. of herbicides: glyphosate, cletodim. A shoot dry mass was evaluated, corrected for percentage in relation to the zero day treatment. It was concluded that plant height is more affected when cultivated under water depth conditions, however the periods of stress were equally harmful, causing a reduction in root and shoot dry mass, with greater SOD and POD enzymatic activity in this period. Both soil moisture conditions favored the chemical control provided by Glyphosate and Cletodim, evidencing the variability of possible exposures to the stress environment.