Abstract
The fate of glyphosate in soil and water is dependent on the properties of glyphosate and its envoronement. Behaviour of glyphosate in soil, sediment and water is strongly influenced the way by which it can be adsorbed by soils, sediments, and suspended material in water. The role of soil organic matter, clay mineral, and amorphous minerals on the adsorption of glyphosate depends primarily on the nature and properties of the soil itself and the properties of glyphosate. Environmental factors have some influence on sorption and degradation of glyphosate. Glyphosate is rapidly inactivated in soil, is in part due to adsorption. Some soil properties have been identified strongly influence adsorption of glyphosate, such as clay minerals, composition of cations in exchangeable site of clay and organic matter, unoccupied phosphate adsorption site, degree of humification, and soil pH. Adsorption limits the availability of glyposate for microbial degradation. The sorbed glyphosate is not directly available to microorganisms in soil. Evidence also suggests that not only a strongly sorbed compound such as paraquat but also weakly sorbed compounds such as flumetsulam and picloram can persist for long periods when they are sorbed by soil constituents. This suggests that the interaction between sorption and biodegradation should be considered in predicting the fate of pesticides in soils and sediments.
Highlights
In order to be able to effectively control the environmental risk resulting from the application of pesticides, it is important to understand how pesticides behave in soils and water
Glyphosate has been reported to be rapidly inactivated when in contact with mineral and organic soils (Sprankle, et al, 1975b; Suwardji, 1998), and this rapid inactivation of glyphosate in soil has been suggested to be a result of rapid adsorption to soil constituents
As the roots of plant have been reported to be unable to absorb glyphosate (Hance, 1976), low activity of glyphosate in soil in these studies may be due to the combination of moderate adsorption and low acropetal uptake of this compound when applied to the root (Hance, 1976)
Summary
In order to be able to effectively control the environmental risk resulting from the application of pesticides, it is important to understand how pesticides behave in soils and water. Adsorption and degradation are two of the most important processes influencing the residue behaviour of most pesticides in soils and sediments (Cox, et al 1993; Hermosin & Carnejo 1990; Rao and Hornsby 2001). The use of a Non Steady State Compartmental Analysis (NSSCA) (Winkler, 1971) using glyphosate degradation data has been shown to discriminate between the soluble and sorbed glyphosate “in situ” (Eberbach, 1998) This technique shows its applicability for explaining the dependence of herbicide degradation on strength of adsorption, but as yet has not been used extensively in herbicide research (Suwardji, 1998).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
