Use of gleams to predict insecticide losses from pine seed orchards

Abstract

Intensive pine forest management practiced in the southern United States relies heavily on seed orchards to produce genetically improved seedlings to achieve high productivity. One of the most critical problems is the control of seed and cone insects requiring heavy and frequent applications of insecticides. Hydrologic modeling of insecticide fate in surface water and ground water is a useful technique for evaluating the environmental fate of the applied insecticides. The GLEAMS (groundwater loading effects of agricultural management systems) model was used to evaluate the differences between fate of insecticides at four pine seed orchard sites in different physiographic regions of the southern United States. A 50‐year simulation period was used. Insecticides selected for simulation were carbofuran, azinphosmethyl, fenvalerate, and permethrin. The simulations of insecticide losses in storm flow and percolate at each of the seed orchards demonstrated the importance of the time of application relative to precipitation occurrence, effective rooting depth, and soil‐water conditions. Although the absolute insecticide losses may not be accurately simulated by GLEAMS, the model can predict the seasonal patterns of loss and relative loss among different insecticides likely to occur under actual seed orchard conditions.

Nonpoint sources

“…A model to simulate transport of conservative and nonconservative chemicals to ground water using transfer functions was presented by Roth and Jury ( 1993). The GLEAMS model was used to demonstrate the importance oftime of application relative to a precipitation event, effective rooting depth, and soil-water conditions in predicting insecticide losses from pine seed orchards (Nutter et al, 1993). The PRZM model was used to show that insecticides used to control pine beetles and gypsy moths do not pose a ground water contamination problem; however, site preparation herbicides do pose a potential problem under certain meteorological conditions (Dowd et al, 1993).…”

The use of a simple sediment budget model to estimate long-term contaminant export from small catchments

“…The first approach involves the application of a model that is capable of simulating the long-term redistribution and export of sediment and sediment-associated contaminants based on climate factors, catchment morphological parameters, soil characteristics, and contaminant concentrations in the topsoil. For example, Nutter et al (1993) simulated the export of insecticides from pine seed orchards in the southern USA using the GLEAMS model (Leonard et al, 1987), which contains a soil erosion module based on a modified version of the Universal Soil Loss Equation (USLE). Van der Perk and Slávik (2003) simulated the losses of Chernobyl-derived radiocaesium from a small Slovakian catchment using a simple geographical information system (GIS)-based sediment redistribution model.…”