Information
Atrazine degradation and transport in runoff on a Black Vertosol – Felton Eastern Darling Downs
Level 1 General description
Purpose:
To better understand availability, dissipation, sorption, and runoff of atrazine, DEA, and DIA on the Darling Downs the fate of atrazine was monitored during the growth of a sorghum crop.
Methods (brief)
Two paddocks cropped with grain sorghum on a Black Vertosol were monitored for atrazine, potassium chloride (KCl) extractable atrazine, desethylatrazine (DEA), and desisopropylatrazine (DIA) at 4 soil depths (0–0.05, 0.05–0.10, 0.10–0.20, and 0.20–0.30 m) and in runoff water and runoff sediment.
Key findings (brief)
- Only 0.5% of applied atrazine moved deeper than 0.20m into the soil, where it dissipated rapidly.
- In runoff (including suspended sediment) atrazine concentrations were greatest during the first runoff event (57 days after application) (85 μg/L) and declined with time.
- Even after 98% of the KCl-extractable atrazine had dissipated (and no longer provided weed control), runoff concentrations still exceeded the human health guideline value of 40 μg/L.
Location
A set of nested catchments south-east of Toowoomba on the Darling Downs, Queensland.
Related studies
Connolly and Rattray