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Soil Column Mobility of Metribuzin from Alginate-Encapsulated Controlled Release Formulations

The mobility of metribuzin [4-amino-6-(1,1-dimethylethyl)3-methylthio) 1,2,4-triazin-5(4H)-one] from alginate-encapsulated controlled release (CR) formulations was investigated in four contrasting soil profiles. Two CR formulations based on sodium alginate (1%), kaolin (10%), and Tween 20 (0.5%) wer...

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Bibliographic Details
Published in:Journal of agricultural and food chemistry 1995-01, Vol.43 (1), p.241-246
Main Authors: Johnson, Richard M, Pepperman, Armand B
Format: Article
Language:English
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Summary:The mobility of metribuzin [4-amino-6-(1,1-dimethylethyl)3-methylthio) 1,2,4-triazin-5(4H)-one] from alginate-encapsulated controlled release (CR) formulations was investigated in four contrasting soil profiles. Two CR formulations based on sodium alginate (1%), kaolin (10%), and Tween 20 (0.5%) were compared to technical grade (TG) metribuzin and to a commercial liquid (CL) metribuzin formulation (Sencor 4L). In addition to the basic components, the CR-Oil formulation contained 4% linseed oil and the CR-N formulation did not. All herbicide treatments were labeled with [14C]metribuzin and were applied to duplicate soil columns containing a surface and a subsoil horizon. Each horizon was packed to a depth of 12.5 cm, giving a total column length of 25 cm. The columns were leached with 21 (420 mL) to 30 cm (600 mL) of 0.01 M CaCl2 for a period of 7 - 10 days. For the TG treatment, the total amounts of [14C]metribuzin leached were 85, 62, 66, and 58% for the Evesboro, Ochlocknee, Conover, and Commerce soils, respectively. This is compared to 91, 52, 51, and 43% for the CL formulation. The CR-Oil formulation leached 9, 13, 9, and 9% of the applied [14C]metribuzin, compared to 49, 53,41, and 48% for the CR-N formulation. The CR-Oil formulation also increased the amount of [14C]metribuzin retained in the soil surface horizon (13 - 27%), compared to the CR-N (2-5%), TG (2-3%), and CL (1-2%) formulations
ISSN:0021-8561
1520-5118
DOI:10.1021/jf00049a043