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Atrazine Loss in Runoff from No‐Tillage and Chisel‐Tillage Systems on a Houston Black Clay Soil
Author(s) -
Pantone D. J.,
Potter K. N.,
Torbert H. A.,
Morrison J. E.
Publication year - 1996
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/jeq1996.00472425002500030024x
Subject(s) - surface runoff , atrazine , tillage , environmental science , udic moisture regime , chisel , agronomy , hydrology (agriculture) , conventional tillage , vertisol , soil water , soil science , loam , geology , pesticide , ecology , biology , geography , geotechnical engineering , archaeology
Herbicide concentration and mass load of runoff depends, to a large extent, on soil management. This study was conducted to determine how tillage impacts herbicide losses in runoff from a vertisol soil on the Blackland Prairie of Texas. Atrazine [6‐chloro‐N‐ethyl‐ N ′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] was applied at a rate of 2 kg a.i. ha −1 to a Houston Black clay soil (fine, montmorillonitic, thermic Udic Pellustert) in 1993 at the Blackland Research Center in Temple, TX. For 4 yr, the test area was under continuous management using a wide‐bed system with a wheat ( Triticum aestivum L.), corn ( Zea mays L.), and grain sorghum [ Sorghum bicolor (L.) Moench] rotation. Tillage treatments consisted of no‐tillage or chisel‐tillage. All experiments were repeated four times. A rainfall simulator with an intensity of 12.5 cm h −1 was used to apply rainfall 24 h after the atrazine application. Sediment and runoff samples were collected during five time periods (from runoff initiation to 5, 5 to 10, 10 to 20, 20 to 30, and 30 to 40 min). No differences in atrazine concentrations were found among treatments in either the runoff water or sediment from any of the five time periods; however, crop residues prevented surface seal development and erosion resulting in reduced runoff and sediment losses. No‐tillage treatments significantly reduced runoff and sediment yield, rather than the atrazine concentration of the runoff, resulting in a 42% decrease of the atrazine load in the runoff and a 77% decrease in atrazine associated with the sediment. As a percentage of the total amount applied, runoff accounted for <2% of the atrazine. Sediment‐transported atrazine was much less important and represented <0.03% of the total amount applied.