Controls of event-based pesticide leaching in natural soils: A systematic study based on replicated field scale irrigation experiments

Julian Klaus*, Erwin Zehe, Martin Elsner, Juliane Palm, Dorothee Schneider, Boris Schröder, Sibylle Steinbeiss, Loes Van Schaik, Stephanie West

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

19 Citations (Scopus)

Abstract

Tile drains strongly influence the water cycle in agricultural catchment in terms of water quantity and quality. The connectivity of preferential flow to tile drains can create shortcuts for rapid transport of solutes into surface waters. The leaching of pesticides can be linked to a set of main factors including, rainfall characteristics, soil moisture, chemical properties of the pesticides, soil properties, and preferential flow paths. The connectivity of the macropore system to the tile drain is crucial for pesticide leaching. Concurring influences of the main factors, threshold responses and the role of flow paths are still poorly understood. The objective of this study is to investigate these influences by a replica series of three irrigation experiments on a tile drain field site using natural and artificial tracers together with applied pesticides. We found a clear threshold behavior in the initialization of pesticide transport that was different between the replica experiments. Pre-event soil water contributed significantly to the tile drain flow, and creates a flow path for stored pesticides from the soil matrix to the tile drain. This threshold is controlled by antecedent soil moisture and precipitation characteristics, and the interaction between the soil matrix and preferential flow system. Fast transport of pesticides without retardation and the remobilization could be attributed to this threshold and the interaction between the soil matrix and the preferential flow system. Thus, understanding of the detailed preferential flow processes clearly enhances the understanding of pesticide leaching on event and long term scale, and can further improve risk assessment and modeling approaches.

Original languageEnglish
Pages (from-to)528-539
Number of pages12
JournalJournal of Hydrology
Volume512
DOIs
Publication statusPublished - 6 May 2014
Externally publishedYes

Keywords

  • Irrigation experiment
  • Pesticide transport
  • Preferential flow
  • Threshold

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