Premium
Formulation and Adjuvant Effects on Leaching of Atrazine and Metolachlor
Author(s) -
Hall J. K.,
Jones G. A.,
Hickman M. V.,
Amistadi M. K.,
Bogus E. R.,
Mumma R. O.,
Hartwig N. L.,
Hoffman L. D.
Publication year - 1998
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1998.00472425002700060010x
Subject(s) - atrazine , chemistry , loam , simazine , leaching (pedology) , metolachlor , lysimeter , acetamide , sorghum , nuclear chemistry , zoology , agronomy , soil water , pesticide , environmental science , organic chemistry , soil science , biology
Atrazine (6‐chloro‐ N ‐ethyl‐ N′ ‐(methyethyl)‐1,3,5‐triazine‐2,4‐diamine) and metolachlor (2‐chloro‐ N ‐(2‐ethyl‐6‐methylphenyl)‐ N ‐(2‐methoxy‐1‐methylethyl) acetamide) levels in pan lysimeter leachates, collected 1.2 m deep in a Hagerstown silt loam (fine, mixed, mesic Typic Hapludalf), were used to evaluate leaching of these chemicals applied in combination (1.7 + 1.7; 3.4 + 3.4 kg a.i. ha −1 ) as a commercial formulation (CF) or adjuvant (polyacrylate polymer)‐amended (AA)‐CF and as a microencapsulated (ME) or starch‐encapsulated (SE) formulation in conventional tillage (CT) and no‐tillage planted corn ( Zea mays L.). Atrazine leached more under NT than CT conditions. Areal losses of atrazine in 1992 from NT at the low rate were 4, 66, and 277 µg m −2 for the treatment sequence (CF, SE, and AA‐CF); at the high rate, losses were 887, 488, and 334 µg m −2 . These amounts represented losses of <0.01 to 0.16% and 0.26 to 0.10%, respectively, of applied rates. In 1993, areal losses for the treatment succession (lesser rate) were 888, 253, and 497 µg m −2 of atrazine (0.52, 0.15, and 0.29%); these treatments (greater rate) yielded 5440, 1220, and 1600 µg m −2 of applied chemical (1.60, 0.36, and 0.47%). Application of ME (polyurea polymer) and AA‐metolachlor reduced mobility of this chemical at both rates in 1993, but their effect was especially exemplified at the greater rate where a loss of 2.29% (CF) was reduced to 0.83% (ME) and 0.54% (AA). Where herbicide leaching was reduced, greater concentrations, particularly atrazine, were detected in the surface 15 cm of soil in late‐season and in leachates, 6 to 12 mo following application.