Fate of herbicide residues in soil- Australian context: insights towards mechanism, aspects, and recent advancements

Abstract

Herbicides are chemical compounds that are toxic to weed plants. Modern agriculture relies heavily on herbicides for the control of weeds to maximize yield in crops. It is estimated that herbicide usage in the Australian grains industry increased by more than 30% from 2002 to 2018, approximately $1.80 billion. The increased popularity of herbicides in farming systems has not only raised concerns about their negative impacts on the environment, human health, and agricultural sustainability due to the rapid evolution of herbicide resistance, but also raised questions about their fate in soil. Due to excessive use of herbicides, there is great concern about contamination which can lead to soil and water pollution, reduced biodiversity, and depression in soil heterotrophic bacteria (including denitrifying bacteria) and fungi. Moreover, understanding the fate of herbicides in soil is a prerequisite for the precise assessment of its behaviour and potential environmental risk. This review illustrates a brief overview of the present status of herbicide residues in Australian farming systems with a detailed understanding of the transport and degradation processes of herbicides in soil. Furthermore, this review also encompasses microbial degradation, mechanisms, factors, and microorganisms associated with degradation and recent advancement in microbial degradation of herbicides.