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

This Article Full Text (PDF) An erratum has been published 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 Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (75) Citing Articles via Google Scholar Google Scholar Articles by White, R. E. Articles by Yaron, B. Search for Related Content PubMed Articles by White, R. E. Articles by Yaron, B. Agricola Articles by White, R. E. Articles by Yaron, B.

Leaching of Herbicides Through Undisturbed Cores of a Structured Clay Soil¹

ABSTRACT

The leaching of the herbicides bromacil and napropamide through large undisturbed cores of a structured Evesham clay (Aquic Eutrochrept) was studied under continuous and discontinuous watering regimes and at different initial moisture contents. A greater proportion of both herbicides was leached from initially dry cores ( = 0.24) than from prewet cores ( = 0.35). This was consistent with differences in the amount of herbicide retained in the soil, most of which was retained in the top 0.05 m. Continuous leaching resulted in greater herbicide breakthrough than did the discontinuous treatment, presumably because some herbicide diffused from the conducting channels into the soil aggregates during the quiescent period, where it was less susceptible to subsequent leaching. At a continuous input rate of 12 mm h^–1 to initially dry soil, 85% of the applied napropamide (K_d = 17.7 L kg^–1) and almost 100% of bromacil (K_d = 1.73 L kg^–1) were leached out of the soil by one pore volume of water. Chloride was used as a tracer for water flow through the soil. Chloride breakthrough curves were analyzed using a transfer function equation, which yielded the median travel time of a solute molecule in the soil. It is suggested that preferential flow of water down cracks and channels between soil aggregates led to short travel times and apparently low volumes of soil water participating in solute transport (_st). The _st values were inversely correlated with the percentages of the applied herbicides that were leached.

¹ Contribution from the Soil Science Laboratory, Univ. of Oxford, England, in cooperation with the Institute of Soils and Water, Bet Dagan, Israel.

² University Lecturer and Graduate Student, Univ. of Oxford, Parks Road, Oxford OX1 3PF, England, and Scientists, Institute of Soils and Water, ARO, Volcani Center, 50-250, Bet Dagan, Israel.

Received for publication February 26, 1985.

This article has been cited by other articles:

				J. M. Kohne, S. Kohne, B. P. Mohanty, and J. Simunek Inverse Mobile-Immobile Modeling of Transport During Transient Flow: Effects of Between-Domain Transfer and Initial Water Content Vadose Zone J., November 1, 2004; 3(4): 1309 - 1321. [Abstract] [Full Text] [PDF]

				M. Javaux and M. Vanclooster Robust Estimation of the Generalized Solute Transfer Function Parameters Soil Sci. Soc. Am. J., January 1, 2003; 67(1): 81 - 91. [Abstract] [Full Text] [PDF]

				C. S. Frazier, C. S. Frazier, R. C. Graham, P. J. Shouse, M. V. Yates, and M. A. Anderson A Field Study of Water Flow and Virus Transport in Weathered Granitic Bedrock Vadose Zone J., August 1, 2002; 1(1): 113 - 124. [Abstract] [Full Text] [PDF]