HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Mbuya, O.S. Articles by Boote, K.J. Search for Related Content PubMed PubMed Citation Articles by Mbuya, O.S. Articles by Boote, K.J. GeoRef GeoRef Citation Agricola Articles by Mbuya, O.S. Articles by Boote, K.J. Related Collections Ground Water Quality Sorghum Agricultural Pesticides Water Pollution

TECHNICAL REPORT
GROUND WATER QUALITY

Fate of Atrazine in Sandy Soil Cropped with Sorghum

^a Center for Water Quality, Florida A&M Univ., Tallahassee, FL 32307-4100
^b Dep. of Soil and Water Science, Univ. of Florida, Gainesville, FL 32611-0290
^c Dep. of Agronomy, Univ. of Florida, Gainesville, FL 32611-0500

Corresponding author (Odemari.Mbuya{at}famu.edu)

Received for publication October 6, 1998. A field study was conducted to determine the fate of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) within the root zone (0 to 90 cm) of a sandy soil cropped with sorghum [Sorghum bicolor (L.) Moench] in Gainesville, Florida. Atrazine was uniformly applied at a rate of 1.12 kg a.i. ha^-1 to a sorghum crop under moderate irrigation, optimum irrigation, and no irrigation (rainfed), 2 d after crop emergence. Bromide as a tracer for water movement was applied to the soil as NaBr at a rate of 45 kg Br^- ha^-1, 3 d before atrazine application. Soil water content, atrazine, and Br^- concentrations were determined as a function of time using soil samples taken from the root zone. Atrazine sorption coefficients and degradation rates were determined by depth for the entire root zone in the laboratory. Atrazine was strongly adsorbed within the upper 30 cm of soil and most of the atrazine recovered from the soil during the growing season was in that depth. The estimated half-life for atrazine was 32 d in topsoil to 83 d in subsoil. Atrazine concentration within the root zone decreased from 0.44 kg a.i. ha^-1 2 days after application (DAA) to 0.1 kg a.i. ha^-1 26 DAA. Negligible amounts of atrazine (5 µg kg^-1) were detected below the 60-cm soil depth by 64 DAA. Most of the decrease in atrazine concentration in the root zone over time was attributed to degradation. In contrast, all applied bromide had leached past the 60-cm soil depth during the same time interval.

Abbreviations: DAA, days after application • ET, evapotranspiration • OC, organic carbon