|Lamb, J - UNIVERSITY OF MINNESOTA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 20, 1998
Publication Date: N/A
Technical Abstract: Farming systems that protect water quality, and allow crop production, are needed. A 4-yr field study evaluated the effectiveness of ridge tillage fo protecting ground water under a corn and soybean rotation. The study site characterized as a sandy soil (Alfic Udipsamment) overlying a surfacial aquifer at 3.3 m. Atrazine was applied pre-emergence in a 0.25 m band centered over the corn row. Application rate was 1.7 kg a.i. ha**-1 in th treated area, a loading rate of 0.47 kg a.i. ha**-1 every 2 yr. Dissipatio movement were documented by analyzing soil cores taken following greater th 12 mm of rain and/or irrigation water for residual atrazine. By 60 days after treatment (DAT), soil atrazine levels were < 110 ug kg**-1 even in th 0 to 0.15 m layer containing the banded product, while interrow concentrations were all less than 7 ug kg**-1. Below 0.30 m, atrazine concentrations did not exceed 15 ug kg**-1, and these levels were restricte eto the area directly beneath the application band. By 729 DAT, less than percent of all interrow soil samples contained detectable (less than 5 ug kg**-1) atrazine.