Simulation of concentration effects on mobility and persistence of alachlor
Lesikar, Bruce James
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/20643
Description
Title
Simulation of concentration effects on mobility and persistence of alachlor
Author(s)
Lesikar, Bruce James
Issue Date
1992
Doctoral Committee Chair(s)
Hirschi, Michael
Department of Study
Agricultural and Biological Engineering
Discipline
Agricultural Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Agronomy
Engineering, Agricultural
Environmental Sciences
Language
eng
Abstract
The effect of concentration on mobility and persistence of alachlor was investigated. The investigation was divided into two components: soil column study and model study. In the soil column study, PVC pipe was hand packed to a depth of 30 cm with Catlin silt loam soil. The surface of the soil columns was contaminated with alachlor at rates of 3, 30 and 3000 kg a.i./ha. Columns were then subjected to a simulated rainfall of constant or variable intensity three times during a two month period. Leachate from the columns was collected twice during each rainfall event. Six times during the two months, columns were analyzed to determine pesticide persistence and mobility.
The mass of alachlor leached increased with an increasing application rate. However, the mass leached as a percentage of the alachlor present in the columns was either approximately the same for all rates or less for the 3000 kg a.i./ha rate. The mobility of alachlor was not increased by an increasing application rate. The majority of the alachlor remained within 10 cm of the soil surface for all application rates. Persistence of alachlor in the soil columns increased with an increasing application rate.
In the model study, several currently available simulation models were reviewed for the potential to represent the mobility and persistence of high concentrations of pesticides. The simulation model LEACHMP was selected as the model for detailed study.
The simulation model LEACHMP over-estimated the center of pesticide mass for the 3 and 30 kg a.i./ha rates and under-estimated the center of pesticide mass for the 3000 kg a.i./ha rate. Based on the normalized objective function values for pesticide distribution, the estimated concentration for each layer was off by 100-200 percent of the average measured concentration. The simulation model under-estimated the mass of pesticide in the profile for the 3 and 30 kg a.i./ha rate columns and over-estimated the mass of pesticide in the soil profile for the 3000 kg a.i./ha rate. The simulation model under-estimated the quantity of alachlor leached from the soil columns.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
