Effects of Glyphosate-, Glufosinate- and Flazasulfuron-Based Herbicides on Soil Microorganisms in a Vineyard

Abstract

In a vineyard we examined the effects of broad-spectrum herbicides with three different active ingredients (glyphosate, glufosinate, flazasulfuron) on soil microorganisms. Mechanical weeding served as control treatment. Treatments were applied within grapevine rows and soil samples taken from there in 10–20 cm depth 77 days after application. Fungi were analyzed using classical sequencing technology and bacteria using next-generation sequencing. The number of colony-forming units (CFU) comprising bacteria, yeasts and molds was higher under flazasulfuron compared to all other treatments which had similar CFU levels. Abundance of the fungus Mucor was higher under flazasulfuron than glufosinate and mechanical weeding; Mucor was absent under glyphosate. Several other fungi taxa were exclusively found under a specific treatment. Up to 160 different bacteria species were found – some of them for the first time in vineyard soils. Total bacterial counts under herbicides were on average 260% higher than under mechanical weeding; however due to high variability this was not statistically significant. We suggest that herbicide-induced alterations of soil microorganisms could have knock-on effects on other parts of the grapevine system.

Commercial glyphosate-based herbicides effects on springtails (Collembola) differ from those of their respective active ingredients and vary with soil organic matter content

“…These and our findings suggest that Collembola are briefly stimulated by microbial communities that decompose certain chemical substances of herbicides, until the decomposition of the chemicals occurs, and the population comes back to normal. An initial stimulation after GBH application has also been reported for earthworms (Gaupp-Berghausen et al 2015) or soil microorganisms (Mandl et al 2018). Clearly, more research is needed to further elucidate the underlying mechanisms.…”

“…In contrast, others found significant increases in the decomposition stability of plant litter due to GBH (Roundup Speed, Roundup Alphee) application (Gaupp-Berghausen et al 2015). Certain soil microbiota might also be stimulated by GBH application (Roundup PowerFlex) leading to an increased plant litter decomposition (Mandl et al 2018).…”

Yeast diversity in the vineyard: how it is defined, measured and influenced by fungicides

“…Generally, the poor fermenters Cryptococcus and Rhodotorula exist during the early stages of berry development, but as berries ripen, Hanseniaspora , Candida and Metschnikowia ascomycetes appear on the berry surface (Rosini et al 1982, Combina et al 2005, Raspor et al 2006). But farming practices including fungicide and herbicide sprays, and canopy management can have a large effect on fungal populations, and potentially mask other influences (Martins et al 2012, Bokulich et al 2014, Gilbert et al 2014, Wang et al 2015, Morrison‐Whittle et al 2017, Chou et al 2018, Mandl et al 2018, Carneiro et al 2019, Vincent and Lasnier 2020). As discussed above, rainfall and its timing may alter fungal populations, but rainfall will also impact berry physiology, itself an important determinant of fungal populations, and potentially also wash sprays from grapevines.…”

How did the Addition of Indaziflam Affect on Carbon and Nitrogen Mineralizations in a Vineyard Soil?

“…Prevention of trunk damage by mechanical weeding machines and decrease of working time spent in the vineyard were provided by herbicides [5]. Herbicides have become the most important control method for weed while these chemicals were more considered than other methods due to their easy application and being effective and reliable in weed control [6].…”