Abstract

This study investigated the correlation between atrazine mineralization and weed biomass in a continuous corn field with a 10 yr annual atrazine application history and a 7 m elevation change. Two hundred locations in a 15 by 30 m grid, representing the summit, backslope, and toeslope landscape positions were sampled immediately after herbicide application (May 23, 1997), and 2, 4, 8, 12, and 18 wks after application. Field dissipation rates of atrazine at each sampling point and atrazine mineralization rates at 50 sampling points were determined. Field dissipation rates ranged from 0.008 to 0.18 d⁻¹ and atrazine mineralization ranged from 6 to 63% after 8 wks of incubation. Weed biomass was correlated positively with field dissipation rate (r = 0.14; P = 0.05) and mineralization potential (r = 0.36; P = 0.05). These data may explain at least a part of the variability seen in weed control patterns across landscape positions.

Copyright © 1999. . Copyright © 1999 by the American Society of Agronomy, Inc. Crop Science Society of America, Inc. Soil Science Society of America, Inc. 5585 Guilford Rd., Madison, WI 53711 USA