Sorption behaviour of forchlorfenuron in soil

Area of Science:

• Environmental Chemistry
• Soil Science
• Agrochemicals

Background:

• Forchlorfenuron is a synthetic cytokinin used as a plant growth regulator.
• Understanding its fate in soil is crucial for assessing environmental impact and agricultural practices.
• Soil properties like organic matter and clay content significantly influence pesticide behavior.

Purpose of the Study:

• To investigate the adsorption and desorption kinetics of forchlorfenuron on three distinct Indian soil types.
• To determine the thermodynamic parameters governing forchlorfenuron adsorption.
• To evaluate the leaching potential of forchlorfenuron in these soils.

Main Methods:

• Batch equilibrium adsorption-desorption experiments were conducted at 298 K and 308 K.
• Lindstrom model was used to determine adsorption-desorption rate constants.
• Linear and Freundlich isotherms were applied to analyze adsorption data; Groundwater Ubiquity Score (GUS) was calculated.

Main Results:

• Adsorption equilibrium was reached within 48 hours, with the highest adsorption rate observed in sandy-loam soil, followed by clay and silty-clay soils.
• Desorption rates followed the reverse trend of adsorption.
• Thermodynamic data indicated chemical adsorption, and isotherm analysis showed a good fit (R² > 0.97). Forchlorfenuron exhibited low to medium leaching potential (GUS 1.6–2.2).

Conclusions:

• Soil organic matter and clay content are key factors controlling forchlorfenuron adsorption.
• Forchlorfenuron undergoes chemical adsorption on Indian soils.
• The plant growth regulator poses a low to medium risk for groundwater contamination.