The effects of herbicides on soil microbiota are not well studied by researchers but are a matter of serious concern.  Repeated and uncontrolled application of herbicides can upset the balance between beneficial soil microbes and pathogenic species, affecting related critical soil functions. Many herbicides have been shown to cause a transient reduction in microbial population, including cyanobacteria, Nitrobacter agilis (nitrite oxidizer) and other fungal species. This is interlinked with the soil’s biological equilibrium as any disturbances to the soil microbiota may result in reduced fertility. It may result in disturbed soil heterotrophic respiration, nutrient cycling and Organic matter decomposition (Singh et al, 2020). Many herbicides threaten the reproduction, growth and health of earthworms, which are critical components of the soil system. They are highly necessary for improving soil fertility, enhancing soil infiltration, nutrient cycling, decreasing runoff and also in the biocontrol of some parasites. A detrimental effect on their existence can also bring about negative impacts on soil health (Zarea and Karimi, 2012).

The risks posed by a herbicide can be estimated from its capability to persist in soil. Herbicides with higher persistence remain in the treated soil for a long period in their active stage. This can lead to another interlinked issues such as leaching (moved away from the soil via rainwater etc.), contamination of nearby water resources, upsetting the soil equilibrium and associated life forms and can also increase exposure risks to humans.

Like we discussed before, many plants considered unwanted in modern agriculture are of significant medical and consumable value. They were once considered important sources of nutritious food by indigenous communities and were part of traditional medicine. This knowledge is now being ignored due to the dominance of monocultural systems in agriculture. Many important food sources are destroyed in large scale for reaping economic benefits. In a way this practice contributes to nutritional insecurity in our country.

Presence of herbicide residues in crop produces is another major concern. Detectable amounts of residues have been found in diverse food products including harvested vegetables, cereals and grains. The persistence of herbicide residues in consumables is a serious issue as this can pose serious risks via prolonged ingestion. Various herbicides, especially HHPs like glyphosate, paraquat, oxyfluorfen, pendimethalin etc. have been extracted from vegetables collected from herbicide treated fields in detectable amounts. This is frightening as most of the crop produces available in the markets are collected from herbicide treated fields. We all are at risk of such exposure.