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

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Krutz, L. J. Articles by Steinriede, R. W. Search for Related Content PubMed PubMed Citation Articles by Krutz, L. J. Articles by Steinriede, R. W., Jr. Agricola Articles by Krutz, L. J. Articles by Steinriede, R. W. Related Collections Pesticides Organic Compounds Other Environmental Contamination

TECHNICAL REPORTS

Surface Water Quality

Reduced Surface Runoff Losses of Metolachlor in Narrow-Row Compared to Wide-Row Soybean

^a USDA-ARS, Southern Weed Science Research Unit, P.O. Box 350, Stoneville, MS 38776
^b USDA-ARS, Crop Genetics and Production Research Unit, P.O. Box 350, Stoneville, MS 38776
^c USDA-ARS, National Sedimentation Lab., P.O. Box 1157, Oxford, MS 38655

^* Corresponding author (Jason.krutz{at}ars.usda.gov).

Received for publication December 19, 2006. Cultural management practices that reduce the off-site transport of herbicides applied to row crops are needed to protect surface water quality. A soybean [Glycine max (L.) Merr.] field study was conducted near Stoneville, MS on Sharkey clay to evaluate row spacing (50 cm vs. 100 cm) effects on metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(methoxy-1-methylethyl) acetamide] transport. One day after the foliar application of metolachlor to 2.03 m wide by 2.43 m long plots, 60 mm h^–1 of simulated rainfall was applied until 25 min of runoff was generated per plot. The calculated mass of metolachlor intercepted by the soybean foliage was greater in narrow-row than wide-row soybean, 0.39 kg ha^–1 vs. 0.23 kg ha^–1, respectively. Field and laboratory studies indicated that less than 2% of the metolachlor intercepted by the soybean foliage was available for foliar wash-off 1 d after application. Antecedent soil water content at the start of the simulations was lower in narrow-row soybean. In turn, there was a 1.7-fold greater time to runoff on narrow-row plots. The greater time to runoff likely contributed to lower metolachlor concentration in runoff from narrow-row plots. Cumulative metolachlor losses were significantly greater in wide-row than narrow-row soybean, 3.7% vs. 2.2%, respectively. Findings indicate that narrow-row planting systems may reduce metolachlor runoff following a post-emergence application.

Abbreviations: MDL, method detection limit