My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in JEQ

  1. Vol. 22 No. 4, p. 811-818
     
    Received: Feb 14, 1992
    Published: Oct, 1993


    * Corresponding author(s):
 View
 Download
 Alerts
 Permissions
 Share

doi:10.2134/jeq1993.00472425002200040025x

Atrazine, Alachlor, and Metolachlor Mobility through Two Sandy Wisconsin Soils

  1. R. C. Wietersen,
  2. T. C. Daniel *,
  3. K. J. Fermanich,
  4. B. D. Girard,
  5. K. McSweeney and
  6. B. Lowery
  1. Dep. of Soil Sci., Univ. of Wisconsin, Madison, WI 57606;
    Dep. of Agronomy, Univ. of Arkansas, Fayetteville, AR 72701.

Abstract

Abstract

Pesticide mobility through Sparta sand from the Lower Wisconsin River Valley (LWRV) and Plainfield sand from the Central Sands (CS) of Wisconsin was examined to interpret results from state-sponsored groundwater monitoring programs and to identify fundamental mechanisms important in pesticide transport through the unsaturated zone. The mobility of 14C-labeled atrazine [2-chloro-(4-ethylamino)-6-(isopropylamino)-s-triazine], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxym ethyl) acetamide], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] was monitored through replicated intact soil column-microlysimeters. Soil columns of Sparta sand (sandy, mixed, mesic Entic Hapludolls) from the LWRV and Plainfield sand (sandy, mixed, mesic Typic Udipsamments) from the CS were instrumented in the greenhouse to simulate field conditions. All pesticides were shown to be much more mobile through the Sparta sand as compared to Plainfield sand. Peak atrazine concentration was 15 times greater in the leachate from the Sparta soil than from the Plainfield sand. Percentage loss of applied pesticide was four times greater in the leachate from the Sparta soil than from the Plainfield sand. Similar results were found for metolachlor and alachlor. The relative order of mobility for each soil was found to be atrazine > metolachlor > alachlor. Factors found to contribute to increased mobility of pesticides through the Sparta sand include higher hydraulic conductivity, smaller water-holding capacity, and less atrazine adsorption due to less organic C and clay content. The hydraulic conductivity (Ksat) of the upper motzone (0–20 cm) of the Sparta soil is five times faster than the Plainfield soil. The waterholding capacity and the atrazine adsorption coefficient (Kd) of the Plainfield sand were measured to be 1.6 and 1.8 times greater, respectively, than those of the Sparta soil.

Research supported by the College of Agricultural and Life Sciences, Univ. of Wisconsin-Madison.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .