Corn stover harvest increases herbicide movement to subsurface drains – Root Zone Water Quality Model simulations

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 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.

Lignocellulosic‐based bioenergy and water quality parameters: a review

“…Crop residue removal also increases contaminant loss associated with runoff water and leaching (Shipitalo et al ., ). Crop residue affects interception, sorption, dissipation, transformation, wash‐off, and transport of contaminants such as herbicides (Green et al ., ; Locke & Bryson, ).…”

“…Crop residue affects interception, sorption, dissipation, transformation, wash‐off, and transport of contaminants such as herbicides (Green et al ., ; Locke & Bryson, ). Studies indicate that some crop residues (e.g., corn residue) retain chemicals like alachlor and reduce contaminant loss in runoff (Shipitalo et al ., ) and leaching of pesticides (Giori et al ., ).…”

New Lead Discovery of Herbicide Safener for Metolachlor Based on a Scaffold-Hopping Strategy

“…Herbicide application has been a prominent weed-control measure in recent decades under field conditions [4,5]. For example, metolachlor, one of the most widely used chloroacetanilide herbicides, is applied to crops (e.g., rice, corn, and soybean) to control pre-emergent and early post-emergent broadleaf and grass weeds [6][7][8][9][10][11]. However, the use of herbicides as metolachlor for weed controls is phytotoxic to crop plants [12][13][14].…”