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Modeling pesticide movement in forested watersheds: Use of przm for evaluating pesticide options in loblolly pine stand management
Author(s) -
Dowd J.F.,
Bush P.B.,
Berisford Y.C.,
Neary D.G.,
Taylor J.W.
Publication year - 1993
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620120305
Subject(s) - environmental science , hydrology (agriculture) , pesticide , lindane , soil water , leaching (pedology) , evapotranspiration , groundwater , soil science , ecology , geology , biology , geotechnical engineering
The fate of pesticides in forest ecosystems is strongly influenced by climatic conditions. Drought or excessive rainfall may seriously affect dissipation rates, routes, and the extent of movement through soil profiles. The pesticide root zone model (PRZM) is designed to predict pesticide movement in unsaturated soils within and below the plant root zone in agricultural systems. The applicability of this model to a forested watershed was tested by using on‐site hydrologic data to simulate a field application of lindane. PRZM‐predicted data were compared with measured residue levels and found to estimate accurately lindane movement and leaching at shallow soil depths (0‐10 cm), but underestimated residue levels at deeper soil depths (40‐50 cm). Model simulations were used to evaluate various insecticide and herbicide application scenarios used in pine plantation management. Results from these simulations indicate that insecticides commonly used for gypsy moth ( Lymantria dispar L.) or southern pine beetle ( Dendroctonus frontalis Zimm.) control either are not sufficiently persistent or are adsorbed in the soil to such an extent that they do not pose a potential groundwater contamination problem. In contrast, site preparation herbicides show a potential to leach whenever proper meteorological conditions such as rainfall prevail after application. These herbicides are persistent ( t 1/2 > 50), moderately adsorbed (10 > K d > 0.1, assuming 1.7% organic matter), and applied under conditions of reduced evapotranspiration.