Historically the use of herbicides in complex and diverse biological systems to control invasive plants has led to controversy due to the negative impact on the environment and weeds resistance cases. Herbicides application in agriculture has increased over the last 30 years, triggered by the persistence and emerging new invasive weeds. Glyphosate, the most widely used herbicide in the world, is often used to control invasive weeds. In this study, we analysed the effects of glyphosate on agricultural soil properties when it was applied to control the invasive plant giant reed (Arundo donax).
The study was conducted in four areas in the North-East of Spain. Glyphosate was applied at 10 L/ha. Preliminary sampling was conducted in order to determine the initial soil properties and six months after, soil samples were taken to determine the changes in the structural and chemical properties (mg HCO3/kg, mg CO3/kg, Kjeldahl nitrogen, organic and ammoniacal nitrogen, soil texture, pH, conductivity, dissolved oxygen and total K, Mg, Na, P), including glyphosate soil concentration.
The results showed that there were not significant changes in the physical and chemical soil parameters which would influence the composition of these environments. Glyphosate concentration was not detected in the second sample sets because the residues were below the limit of quantification of the instruments used according to the standard that regulates their analysis. Our findings were consistent with the literature referring to the properties of glyphosate. However, it is necessary to study in deep other areas of the pesticides evaluation, life ecotoxicology and human toxicology, in order to safeguard that its application does not pose an unacceptable risk to human or animal health or the environment, as established in the European regulation for the authorization of plant protection products (Regulation (EC) nº 1107/2009) and the Directive of Sustainable Use of Pesticides (Directive 2009/128/EC) in 2011.