Selectivity of pre-and post-emergence herbicides to very-early maturing soybean cultivars

Abstract

The combination of pre- and post-emergence herbicides may affect their selectivity to soybean plants, especially to short-cycle cultivars. The objective of this work was to evaluate the selectivity of pre- and post-emergence herbicides to very-early maturing soybean cultivars. Two field experiments were conducted, one in Mandaguaçu, Paraná (E1) and other in Rio Verde, Goiás (E2), Brazil, using a 4×7 factorial arrangement. The treatments consisted of four pre-emergence herbicide managements (S-metolachlor at 1440 g ha-1, diclosulam at 25.2 g ha-1, sulfentrazone at 300 g ha-1, and no herbicide application); and seven post-emergence herbicide managements (lactofen at 120 g ha-1, chlorimuron-ethyl at 12.5 g ha-1, bentazon at 720 g ha-1, lactofen at 120 g ha-1 + chlorimuron-ethyl at 12.5 g ha-1, glyphosate at 900 g a. e. ha-1, two sequential glyphosate applications at 720 g a. e. ha-1 each, and no herbicide application). The early-maturing soybean cultivars evaluated showed sensitivity to the herbicides used. The combined use of pre- and post-emergence herbicides increased the occurrence of injuries in the plants. Diclosulam and sulfentrazone were the least selective pre-emergence herbicides. All herbicide combinations used affected soybean grain yield in E1; lactofen, chlorimuron, and bentazon presented the least selectivity in E2.

Can pre- and/or post-emergent herbicide application affect soybean seed quality?

“…Application of ACCase inhibitors in association with the broadleaf herbicides 2,4-D, triclopyr, dicamba, carfentrazone, saflufenacil and chlorimuron had no effect on soybean seed quality. Some studies reported negative effects for post-emergent chlorimuron application in soybean, especially visible injuries (FORNAZZA et al, 2018;SILVA et al, 2018b), but without altering seed quality (SILVA et al, 2018b), as observed in the present study. Although synthetic auxins can compromise emergence in the subsequent soybean crop (FRANCISCHINI et al, 2020;PERES-OLIVEIRA et al, 2020), there are generally no negative effects when the label-recommended time between application and planting is followed, as evident in seed quality in the present study.…”

“…As previously mentioned, the effect of diclosulam and other pre-emergent herbicides on seed quality is little investigated. Nevertheless, some studies have reported negative effects on soybean with diclosulam or sulfentrazone application, such as injury, stunted plant growth and even yield loss in certain situations (FORNAZZA et al, 2018;DALAZEN et al, 2020;GAZOLA et al, 2021).…”

“…For pre-emergent herbicides, studies have evaluated their effectiveness in weed control (DE SANCTIS et al, 2021;PATEL et al, 2023) and/or selectivity for soybean, as well as their effect on initial growth, yield and other agronomic performance parameters (FORNAZZA et al, 2018;ARSENIJEVIC et al, 2021). Research on the quality of the seeds produced is scarce; however, Marchi et al (2021) found that flumioxazin applied preemergence had a minimal effect on the electrical conductivity of soybean seeds.…”

Soybean tolerance to sulfentrazone and diclosulam in sandy soil

“…The selectivity observed in the first season are similar with other studies regarding the absence of effect on grain yield in response to diclosulam at 25.2 g ha -1 (Lopez-Ovejero et al, 2013;Osipe et al, 2014). On the other hand, Fornazza et al (2018) observed a reduction of 8 to 11% in soybean grain yield with the application of diclosulam (25.2 g ha -1 ) and sulfentrazone (300 g ha -1 ) in preemergence of early soybean cultivars in soil with clayey texture. Similarly, Constantin et al (2018) observed a reduction in soybean grain yield in this same dose applied in pre-emergence of the crop.…”

Growth and agronomic performance of soybean applied with pre-emergence herbicides

“…Other studies report the selectivity of sulfentrazone (Belfry et al 2016), flumioxazin (Hay et al 2019), s-metolachlor (Fornazza et al 2018), pendimethalin (Yadav et al 2017), trifluralin (Movahedpour et al 2010), imazethapyr (Belfry et al 2015), and oxyfluorfen (Cataneo et al 2005) for soybean. The use of pre-emergence herbicides with different mechanisms of action and mixtures of these herbicides are fundamental for the management and prevention of selection of herbicide-resistant weed biotypes.…”