Influência do horário de aplicação e volume de calda do herbicida glifosato em dessecação de plantas daninhas

Abstract

Inadequate weed management can compromise the established field crop and jeopardize future crops by maintaining the seed bank in the soil. Some ways used in the field to increase the operational yield of weed control are, reduction of the volume of the syrup and the continuous application in non ideal times. Based on this hypothesis, an experiment was conducted in the experimental field of annual crops of the Universidade Tecnológica Federal do Paraná - UTFPR, Campus Dois Vizinhos, between September and November 2018. The experimental design was a randomized complete block design, with three replicates. The RoundUp Original DI® herbicide, 4 L ha-- was applied in plots of 2x3 m each. The factors were the variations of schedules being, factor A: 5:00 hrs; 9:00 a.m.; 14:00 hrs; 18:00 hrs; 21:00 hrs, and factor B the volume variations of the syrup: 60 L ha-'; 80 L ha-1; 120 L ha-?; 200 L ha?. In this way it can be concluded that the time of application directly influences the control efficiency. Up to 14 days after application of glyphosate, o The volume of the syrup had an influence on the weed control efficiency up to the 14 DAA of the herbicide. The nocturnal application is feasible in all volumes tested after 14 days of application of glyphosate. Except for the application at 14:00 hrs, all schedules present excellent control of weeds. The time of 14:00 hrs should be avoided for the application of glyphosate. The decrease in the volume of the syrup up to 60 L ha-1 showed a lower efficiency up to 14 days after application of glyphosate, being more evident this effect in the time of 14:00 hrs.