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Spatial variation in herbicide leaching from a marine clay soil via subsurface drains
Author(s) -
Ulén Barbro M,
Larsbo Mats,
Kreuger Jenny K,
Svanbäck Annika
Publication year - 2014
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3574
Subject(s) - topsoil , environmental science , leaching (pedology) , lessivage , mcpa , spatial variability , subsoil , hydrology (agriculture) , subsurface flow , soil science , soil water , agronomy , pesticide , groundwater , geology , statistics , mathematics , geotechnical engineering , biology
Background Subsurface transport via tile drains can significantly contribute to pesticide contamination of surface waters. The spatial variation in subsurface leaching of normally applied herbicides was examined together with phosphorus losses in 24 experimental plots with water sampled flow‐proportionally. The study site was a flat, tile‐drained area with 60% marine clay in the topsoil in southeast Sweden. The objectives were to quantify the leaching of frequently used herbicides from a tile drained cracking clay soil and to evaluate the variation in leaching within the experimental area and relate this to topsoil management practices (tillage method and structure liming) . Results In summer 2009, 0.14, 0.22 and 1.62%, respectively, of simultaneously applied amounts of MCPA , fluroxypyr and clopyralid were leached by heavy rain five days after spraying. In summer 2011, on average 0.70% of applied bentazone was leached by short bursts of intensive rain 12 days after application. Peak flow concentrations for 50% of the treated area for MCPA and 33% for bentazone exceeded the Swedish no‐effect guideline values for aquatic ecosystems. Approximately 0.08% of the glyphosate applied was leached in dissolved form in the winters of 2008/2009 and 2010/2011. Based on measurements of glyphosate in particulate form, total glyphosate losses were twice as high (0.16%) in the second winter. The spatial inter‐plot variation was large (72–115%) for all five herbicides studied, despite small variations (25%) in water discharge . Conclusions The study shows the importance of local scale soil transport properties for herbicide leaching in cracking clay soils. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.