QUALIDADE FISIOLÓGICA DE SEMENTES DE SOJA PRODUZIDAS SOB MANEJO QUÍMICO DE PLANTAS DANINHAS

Abstract

Soybean [Glycine max (L.) Merrill] is one of the most relevant economically important crops in the world, and in Brazil is one of the most main oleaginous and commodity of the country. The occurrence of weeds is one of the factor that most affects soybean cultivation and control tactics must be taken. Herbicide application is common practice in this crop management, however concerns about chemical effects on humans, environment and non-target crops. Effects of herbicide action possibly reflect on soybean seeds. Therefore, this work aimed to evaluate the physiological quality of soybean seeds cultivated under chemical management of weed with different doses of two herbicides, comparing to manual weeding practices. The treatments were applied on field conditions with different herbicide doses: chemical group benzothiadiazinone (0.625 L ha-1, 0.750 L ha-1 and 0.875 L ha-1) and chemical group aryloxyphenoxypropionic (1.000 L ha-1, 1.100 L ha-1 e 1.200 L ha-1), as well as control treatments with manual weeding and without weeding. We evaluated emergence percentage; the velocity of emergence index and velocity of emergence, shoot and root length, and seedling shoot and root dry matter weight. The herbicide of chemical group aryloxyphenoxypropionic (1.000 L ha-1) promoted less soybean percentage of emergences. Management of weed with herbicide of chemical group aryloxyphenoxypropionic (1.100 L ha-1), unlike manual weeding, influence positively velocity of emergence index, as well as shoot and root length and dry matter weight of G. max. Manual weeding as soybean weeding management is not a favorable practice to physiological parameters comparing with use of herbicide of chemical group aryloxyphenoxypropionic, especially in doses 1.100 L ha-1.