Water flow patterns and pesticide fluxes in an upland soil in northern Thailand

Rapid percolation of water through soil facilitates both the recharge and the contamination of ground-water reservoirs. We have studied the variation of water flux and pesticide leaching through a soil in northern Thailand. At a depth of 55cm, two pits were equipped with tensiometer-controlled glass...

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Main Authors: H. Ciglasch, W. Amelung, S. Totrakool, M. Kaupenjohann
Format: Journal
Published: 2018
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http://cmuir.cmu.ac.th/jspui/handle/6653943832/61989
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Institution: Chiang Mai University
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spelling th-cmuir.6653943832-619892018-09-11T09:20:40Z Water flow patterns and pesticide fluxes in an upland soil in northern Thailand H. Ciglasch W. Amelung S. Totrakool M. Kaupenjohann Agricultural and Biological Sciences Rapid percolation of water through soil facilitates both the recharge and the contamination of ground-water reservoirs. We have studied the variation of water flux and pesticide leaching through a soil in northern Thailand. At a depth of 55cm, two pits were equipped with tensiometer-controlled glass suction lysimeters that were connected to a novel on-line solid-phase extraction device. Nine insecticides varying in water solubility from 10-2 to 10 +6 mg-1 were applied on the soil surface, and leaching was monitored for 8 weeks. Measured water fluxes were compared with simulated values. Total recovery ranged from traces (malathion, triazophos) to 1.3% (dimethoate) of the applied amount, showing a decreasing retardation with increasing polarity of the substances. All pesticides were detectable in the soil solution during the first rain after application. Due to fingering, 83% of the leachate was transported through 38% of the area at leaching rates of < 2mm per day. A new adaptation of the Simpson Index revealed that the diversity of the flow pattern increased exponentially with decreasing rates of seepage water flux (R2 = 0.80). No such correlation was found when leaching was faster, indicating that the flow pattern switched from a fingering- to a matric-dominated flux. No long-term leaching of insecticides was observed. The two profiles studied behaved similarly in terms of both water and pesticide transport. Therefore we suggest that the flow pattern is a stable property of the soil that can be accurately described by our combination of novel experimental setup and statistical analysis of the flow field. © 2005 British Society of Soil Science. 2018-09-11T09:20:40Z 2018-09-11T09:20:40Z 2005-12-01 Journal 13652389 13510754 2-s2.0-28944436221 10.1111/j.1365-2389.2005.00712.x https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=28944436221&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/61989
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
topic Agricultural and Biological Sciences
spellingShingle Agricultural and Biological Sciences
H. Ciglasch
W. Amelung
S. Totrakool
M. Kaupenjohann
Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
description Rapid percolation of water through soil facilitates both the recharge and the contamination of ground-water reservoirs. We have studied the variation of water flux and pesticide leaching through a soil in northern Thailand. At a depth of 55cm, two pits were equipped with tensiometer-controlled glass suction lysimeters that were connected to a novel on-line solid-phase extraction device. Nine insecticides varying in water solubility from 10-2 to 10 +6 mg-1 were applied on the soil surface, and leaching was monitored for 8 weeks. Measured water fluxes were compared with simulated values. Total recovery ranged from traces (malathion, triazophos) to 1.3% (dimethoate) of the applied amount, showing a decreasing retardation with increasing polarity of the substances. All pesticides were detectable in the soil solution during the first rain after application. Due to fingering, 83% of the leachate was transported through 38% of the area at leaching rates of < 2mm per day. A new adaptation of the Simpson Index revealed that the diversity of the flow pattern increased exponentially with decreasing rates of seepage water flux (R2 = 0.80). No such correlation was found when leaching was faster, indicating that the flow pattern switched from a fingering- to a matric-dominated flux. No long-term leaching of insecticides was observed. The two profiles studied behaved similarly in terms of both water and pesticide transport. Therefore we suggest that the flow pattern is a stable property of the soil that can be accurately described by our combination of novel experimental setup and statistical analysis of the flow field. © 2005 British Society of Soil Science.
format Journal
author H. Ciglasch
W. Amelung
S. Totrakool
M. Kaupenjohann
author_facet H. Ciglasch
W. Amelung
S. Totrakool
M. Kaupenjohann
author_sort H. Ciglasch
title Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
title_short Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
title_full Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
title_fullStr Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
title_full_unstemmed Water flow patterns and pesticide fluxes in an upland soil in northern Thailand
title_sort water flow patterns and pesticide fluxes in an upland soil in northern thailand
publishDate 2018
url https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=28944436221&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/61989
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