Effect of Tillage Systems and Rainfall Patterns on Atrazine Distribution in Soil
- A. M. Sadeghi * and
- A. R. Isensee
High variability of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5 triazine) residues in soil and shallow groundwater have been reported under various agricultural management systems. This 2-yr study was conducted to evaluate atrazine residue levels in soil as influenced by no-till (NT) vs. conventional-till (CT) under natural rainfall conditions. Atrazine was applied annually (at 1.34 kg/ha), 1 d after corn (Zea mays L.) planting, to two NT and two CT plots. Atrazine residues within the 0- to 10-cm soil depth of CT plots were higher than in the NT plots, regardless of the difference in the rainfall patterns. Higher (ca. 61%) mean atrazine residues in the CT plots over NT plots in 1955 was most likely related to the rainfall that began 12 h after application. In contrast, in 1987, it rained 3 to 4 d after application and the residues in the CT were only 31% higher than in NT. These results indicate that even a subtle difference in rainfall distribution (temporal) can result in marked spatial variability in the distribution of atrazine.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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