Influência de extratos de plantas de cobertura sobre a germinação e crescimento inicial de Digitaria insularis

Abstract

Being one of the main invasive plants of summer crops, bitter grass (Digitaria Insularis L. Fedde) is a perennial weed of the Poaceae family, over the years it has received more and more attention mainly due to the complications it can cause in the . soybean (Glycine max) cultivation due to the cycle in the same period of the weed. Bitter grass, with an erect habit and easily dispersed seeds, became tolerant to the herbicide glyphosate in 2008, making its control even more difficult. In view of this, the objective of this work will be to verify if the extract of three cover crops (vetch, velvet bean, forage radish) have any allelopathic effect on seed germination and initial growth of bitter grass seedlings. The bioassays will be conducted in Gerbox boxes, with 25 seeds for each treatment, totaling 16 treatments with concentrations (0%, 0.5%, 1.25%, 2.5%, 3.75% and 5%) of aqueous extract of the 3 cover plants. 4 repetitions will be done. The Gerbox boxes will be kept in a B.O.D type incubator, with a photoperiod of 12h/light and at a controlled temperature of 35°C during the day and 20°C at night. The results obtained allow us to conclude that, as the concentrations of the tested extracts increase, there is a negative allelopathic effect of suppression on the germination percentage, germination speed index and also seedling length.