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

Pest Management Science
By: , and 

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Abstract

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-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.

CONCLUSION

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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations
Series title Pest Management Science
DOI 10.1002/ps.4087
Volume 72
Issue 6
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) National Water Quality Assessment Program
Description 9 p.
First page 1124
Last page 1132
Online Only (Y/N) N
Additional Online Files (Y/N) N