Leaching of Atrazine in the Root Zone of an Alluvial Soil in Nebraska

Abstract

AbstractLeaching of atrazine [2‐chloro‐4‐(ethylamino)‐6 (isopropylamino‐s‐triazine] was measured from the soil surface to below the root zone in an irrigated field under continuous corn (Zea mays L.). The field was located in the Platte River Valley of central Nebraska in the central Great Plains area of the USA. This nearly level site is typical of the Platte River Valley with a coarse‐ to medium‐textured soil of alluvial origin that contains low levels of organic matter, and with a water table at a 5‐m depth. Vacuum soil water extractors located 1.5 m below the soil surface recovered an average of 0.072% of the atrazine applied to the surface during 1979 and 1980. Analysis of groundwater recovered from wells on opposite ends of the experimental field indicated enrichment with atrazine in the direction of the hydraulic gradient. Results support direct downward leaching as largely responsible for the low‐level atrazine contamination detected in groundwater throughout the irrigated corn production areas of the valley.