Spatial distribution of sorption and desorption process of 14C-radiolabelled hexazinone and tebuthiuron in tropical soil

Chemosphere. 2021 Feb;264(Pt 1):128494. doi: 10.1016/j.chemosphere.2020.128494. Epub 2020 Oct 1.


The understanding of the interaction between soil physicochemical attributes and herbicide behavior is fundamental for optimizing the efficient use of PRE-emergence herbicides in a more sustainable approach. However, it is still a poorly studied area within precision agriculture. Thus, the objective of this research was to evaluate the correlation of soil physicochemical attributes with the sorption and desorption processes of hexazinone and tebuthiuron to support application maps considering the field level variability. Soil samples from an agricultural area had their physicochemical attributes analyzed and were submitted to sorption and desorption studies of 14C-tebuthiuron and 14C-hexazinone using the batch equilibrium method. The values of sorption and desorption apparent coefficients (Kd), sorption and desorption percentage and bioavailability were correlated with soil attributes by Pearson's correlation. The Kd values of tebuthiuron and hexazinone sorption ranged from 1.2 to 2.9 mL g-1 and 0.4-0.6 mL g-1, respectively. For desorption of tebuthiuron and hexazinone, Kd values ranged from 3.4 to 4.4 mL g-1 and 2.6-3.0 mL g-1, respectively. A positive correlation among clay content, soil organic matter (OM), and tebuthiuron and hexazinone sorption Kd values were found. Both herbicides had variable retention according to geographic position in the area. The recommendation of application of PRE herbicides, such as tebuthiuron and hexazinone, observing the physicochemical attributes of the soil is an alternative to increase efficiency in weed control and decrease the risk of environmental contamination.

Keywords: Pre-emergence herbicide; Precision agriculture; Retention; Variability mapping.

MeSH terms

  • Adsorption
  • Herbicides* / analysis
  • Methylurea Compounds
  • Soil
  • Soil Pollutants* / analysis
  • Triazines


  • Herbicides
  • Methylurea Compounds
  • Soil
  • Soil Pollutants
  • Triazines
  • tebuthiuron
  • hexazinone