Prevention of yield losses caused by glyphosate in soybeans with biostimulant

Abstract

Enhanced selectivity can be achieved for some herbicide treatments through the application of chemicals that reduce or protect plants from injuries. The objective of this work was to evaluate the potential to prevent herbicide yield losses in glyphosate-resistant soybean by the use of the biostimulant Fertiactyl PÓS. Based on results from two field experiments, the association of Fertiactyl PÓS with glyphosate applied post emergence of soybeans reduced foliar injuries and prevented yield losses caused by the herbicide, either when glyphosate was applied in one single application or when it was applied in two sequential applications. However, the application of the Fertiactyl PÓS was not enough to assuage the injuries caused by the mixtures of glyphosate+lactofen and glyphosate+chlorimuron-ethyl.

Performance of RR soybean submitted to postemergence application of glyphosate with a foliar elicitor product

“…This phenomenon can possibly be explained by the fact that the plant had been exposed to a greater period of time in which to metabolize the herbicide, which could ultimately have interfered with crop growth. Other studies have already reported that the sequential application of glyphosate, whether isolated or in conjunction with other herbicides, can cause reductions in crop yield (ALONSO et al, 2010;CONSTANTIN et al, 2016).…”

“…In soybean cultivars with glyphosate tolerance, the occurrence of symptoms of damage is visible after the application of glyphosate (ALONSO et al, 2011;CONSTANTIN et al, 2016). Even with the transgenic insertion of the gene that codifies the EPSPS enzyme (which allows the plant to manifest an enzyme which is not sensitive to the aforementioned active ingredient; (BECKIE; HALL, 2014), the plant is not capable of totally detoxifying glyphosate in certain situations, or there are observable secondary symptoms derived from the herbicide's phytotoxic action, such as the chelating action of glyphosate, leading to symptoms of deficiency in the micronutrients manganese, iron, and zinc (SERRA et al, 2011;ZOBIOLE et al, 2012).…”

“…The advent of soybean cultivars with glyphosate tolerance (RR and later IPRO) brought a series of benefits for the producer, notable among these is the decreased cost of dealing with weeds (when comparing the price of glyphosate in relation to other products used in conventional soybean cultivation), an increased range of control (due to the effectiveness of glyphosate towards mono-and dicotyledon species), and the nonoccurrence of carryover to crops planted subsequent to the soy because of the absence of residual herbicidal activity (CONSTANTIN et al, 2016;GREEN, 2018). Despite the benefits brought about by this technology, the linear increase in the adoption of glyphosate-resistant soybean has brought visible bottlenecks in the system of production that have used these materials.…”

“…The scope of the damage caused by the occurrence of resistant weeds is enormous and causes serious concern, but another situation in which reductions in soybean yield have been observed -and at times neglected -is related to the real selectivity that glyphosate demonstrates for cultivars that contain traits conferring tolerance to the herbicide. In the literature there are a series of studies that report the deleterious effect that glyphosate has on parameters of growth and soybean production (ZOBIOLE et al, 2011;CONSTANTIN et al, 2016). The negative effects that can be seen after the application of glyphosate are related to micronutrient deficiency, lower photosynthetic efficiency, greater water absorption by the plants in order to metabolize the herbicide, and lower soybean nodulation (SERRA et al, 2011;ZOBIOLE et al, 2010a;2010b;KRENCHINSKI et al, 2017).…”

“…In order to mitigate the negative effects caused by glyphosate in resistant soybean cultivars, one of the possibilities that has been amply researched relates to the use of products that provide the plants with improved growth. In this context, the products that have been most widely used are foliar fertilizers, biostimulants, and amino acids (CONSTANTIN et al, 2016;MATYSIAK et al, 2018;MACHADO et al, 2018). Each of these products presents a specific mechanism that aims to attenuate the effects resulting from the application of glyphosate.…”