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Corn stover harvest increases herbicide movement to subsurface drains – Root Zone Water Quality Model simulations
Author(s) -
Shipitalo Martin J,
Malone Robert W,
Ma Liwang,
Nolan Bernard T,
Kanwar Rameshwar S,
Shaner Dale L,
Pederson Carl H
Publication year - 2016
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.4087
Subject(s) - metolachlor , atrazine , environmental science , hydraulic conductivity , drainage , soil water , corn stover , loam , dns root zone , tillage , surface runoff , subsurface flow , tile drainage , agronomy , soil science , hydrology (agriculture) , chemistry , groundwater , pesticide , geology , ecology , biochemistry , geotechnical engineering , hydrolysis , biology
BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model ( RZWQM ), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel‐tilled plot, was used to investigate effects of 50 and 100% corn ( Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor and metolachlor oxanilic acid ( OXA ). RESULTS The model accurately simulated field‐measured metolachlor transport in drainage. A 3 year simulation indicated that 50% residue removal reduced subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4–5‐fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, approximately twofold reductions in OXA losses were simulated with residue removal. CONCLUSION The RZWQM indicated that, if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase owing to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease as a result of the more rapid movement of the parent compound into the soil. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.