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Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations

July 31, 2015


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).


The model accurately simulated field-measured metolachlor transport in drainage. A 3-yr simulation indicated that 50% residue removal decreased subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4 to 5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, ~ 2-fold reductions in OXA losses were simulated with residue removal.


RZWQM indicated that if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase due to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease due to the more rapid movement of the parent compound into the soil.

Publication Year 2016
Title Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations
DOI 10.1002/ps.4087
Authors Martin J. Shipitalo, Robert W. Malone, Liwang Ma, Bernard T. Nolan, Rameshwar S. Kanwar, Dale L. Shaner, Carl H. Pederson
Publication Type Article
Publication Subtype Journal Article
Series Title Pest Management Science
Index ID 70150308
Record Source USGS Publications Warehouse
USGS Organization National Water Quality Assessment Program