Atrazine and Alachlor Transport in Claypan Soils as Influenced by Differential Antecedent Soil Water Content.

The article provides information on a study that investigated the effect of claypan soils at initial field capacity versus permanent wilting level on atrazine and alachlor transport. It evaluates the effects of highly contrasting antecedent soil water content on herbicide transport and degradation. It identifies the impact that shrinkage cracks have for different moisture conditions on preferential transport of herbicides in claypan soils. The methodology and results of the study are discussed. Simulation models for claypan soils will improve by understanding the effects of preferential flow paths on herbicide transport.