BIOESTIMULANTE À BASE DE Ascophyllum nodosum NA ATENUAÇÃO DE INJÚRIAS CAUSADAS POR HERBICIDAS EM SORGO E SOJA

Abstract

The interference caused by weeds in large crops added to the increase in resistance due to the massive use of few herbicide molecules, makes it necessary to expand and diversify the active principles. However, some herbicides, even being selective, cause phytotoxicity, such as lactofen in soybean and tembotrione in sorghum. Therefore, strategies are needed to allow greater adoption of these herbicides, such as the use of biostimulants. In this sense, with the objective of observing the effects of the application of a biostimulant based on Ascophyllum nodosum on the reduction of intoxication of the herbicide lactofen in soybean plants and of tembotrione in sorghum, three experiments were carried out. In the experiments carried out in a greenhouse with soybean and sorghum plants, a completely randomized design was used, evaluating five treatments (control; biostimulant; herbicide; herbicide + biostimulant; and herbicide + biostimulant 6 DAA) and four replications. An experiment was also carried out in the field in the soybean crop in the 2017/18 and 2018/19 harvests, using a randomized block design with six replications and fourteen treatments. These were composed of increasing doses of the biostimulant (0.33; 0.66 and 0.99 L p.c. ha-1) applied at four times in relation to the application of the lactofen herbicide (0; 3; 6 and 9 DAA), plus the control without application of biostimulant and an additional treatment without application of lactofen and biostimulant. The application of the biostimulant contributed to the reduction in phytotoxicity, with pigment retention, protection of the photosynthetic apparatus and reduction of oxidative stress. As a result, less tissue damage occurred, maintaining the vegetative and productive capacity of the plants, which translates into recovery in the profitability of the crop. In this sense, the application of the biostimulant based on A. nodosum is an interesting strategy to increase the diversification of active principles of herbicide molecules in the control of weeds, allowing greater adoption of the herbicide lactofen in soybean and tembotrione in soybean. sorghum.