Measuring atrazine degradation and PRZM-2 testing

Abstract

This study investigated spatial and temporal variation of atrazine concentration and its transportation in the Daneshkadeh soil series (fine, mixed, mesic, Calcixerollic Xerochrepts) at the experimental fields of the Agricultural College, Shiraz University, Iran. It also assessed the risk of soil and water contamination due to applying atrazine, and evaluated the PRZM-2 model for the simulation of atrazine concentration. The experiment had 3 plots of size 209 m2 (19 by 11 m). Irrigation water was applied according to corn evapotranspiration by a solid-set sprinkler system. Seven weeks after planting of maize (Zea mays L.) in early summer, atrazine (2-chloro-4-ethylamino-6-isopropylamins-s-triazine) was applied at a rate of 3.5 kg a.i./ha to each plot. During the growing season, soil samples were collected from each plot 7 times to 1 m soil depth at 0.10-m increments. The PRZM-2 model was applied using our field data for atrazine transport simulation. The observed data showed temporal reduction of atrazine concentrations in the soil profile. The maximum depth of atrazine traced was about 0.5 m below the soil surface. Statistical parameters ME, RMSE, EF (model efficiency), and CRM (coefficient of residual mass) were obtained to compare predicted and observed soil residue concentrations, and were 2.78 (mg/kg soil), 12.73, 0.49, and 0.25, respectively. The simulation results were in close agreements with the observed data, especially 1 month after application due to the small effect of ambient and soil temperature on atrazine transformation. pesticides, transport