ARS | Publication request: How constant are pesticide Kd values during a rainfall event?

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2012
Publication Date: N/A

Technical Abstract: Pesticide partitioning between water and sediment (Kd) and surface processes controlling runoff and sediment production determine the magnitude of pesticide losses associated with infiltration, runoff and/or sediment from agricultural fields during a rainfall event. Pesticide Kd values have traditionally been calculated from slurries in lab settings and assumed constant. However, under non-equilibrium, field conditions, soil and rainfall characteristics and management practices (tillage, irrigation) affect erosional processes and effective Kds during rainfall events by altering the soil surface, antecedent water content, and how soil surface water content changes at the onset of a rainfall event. We will present experimental results that show the range in Kd values for multiple pesticides (Kds) during a rainfall event under conventional-till, seedbed conditions. Implications of variable Kd on model predictions will be discussed.