Predicting the Fate of Preferentially Moving Herbicides
Simulation of preferential flow remains a challenge despite being a recognized phenomenon. With short-interval data, we adapted and tested the preferential flow model (PFM) to simulate the vertical transport of herbicides to lower soil layers. The PFM divides the soil profile into a top distribution...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2019-05-01
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| Series: | Vadose Zone Journal |
| Online Access: | https://dl.sciencesocieties.org/publications/vzj/articles/18/1/180193 |
| _version_ | 1819009333277491200 |
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| author | Bahareh Hassanpour Brian K. Richards Larry D. Goehring Jean-Yves Parlange Tammo S. Steenhuis |
| author_facet | Bahareh Hassanpour Brian K. Richards Larry D. Goehring Jean-Yves Parlange Tammo S. Steenhuis |
| author_sort | Bahareh Hassanpour |
| collection | DOAJ |
| description | Simulation of preferential flow remains a challenge despite being a recognized phenomenon. With short-interval data, we adapted and tested the preferential flow model (PFM) to simulate the vertical transport of herbicides to lower soil layers. The PFM divides the soil profile into a top distribution zone and a conveyance zone below. The distribution zone acts as a reservoir, with an exponential loss of solutes to the conveyance zone. In the conveyance zone, water and solutes move as convective–dispersive flow through multiple flow paths—preferential and matrix—to shallow groundwater. Our field experiment was performed on a structured Hudson silty clay loam soil (a fine, illitic, mesic Glossaquic Hapludalf) that exhibits preferential flow. The site was instrumented with a variety of soil water samplers placed at depths of 60 cm to monitor the volume and quality of the leachate. Agronomic application of atrazine [6-chloro--ethyl-′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and 2,4-D [2-(2,4-dichlorophenoxy)acetic acid] was used, followed by 75 cm of controlled and natural rainfall over 100 d. In addition, Cl was applied as a conservative tracer. All samplers monitored during this period showed a fast breakthrough of solutes consistent with the occurrence of preferential flow, with two groups of breakthrough curves observed. By fitting the Cl breakthrough curve for each group, PFM input parameters were estimated including water velocity in preferential flow paths and the fraction of water moving through each flow path. With two additional parameters for herbicide adsorption and degradation rates, the model successfully simulated the extent of preferential flow of herbicides. |
| first_indexed | 2024-12-21T00:54:42Z |
| format | Article |
| id | doaj.art-683ed6bb65514b278f5debd5c6dd1bc7 |
| institution | Directory Open Access Journal |
| issn | 1539-1663 |
| language | English |
| last_indexed | 2024-12-21T00:54:42Z |
| publishDate | 2019-05-01 |
| publisher | Wiley |
| record_format | Article |
| series | Vadose Zone Journal |
| spelling | doaj.art-683ed6bb65514b278f5debd5c6dd1bc72022-12-21T19:21:19ZengWileyVadose Zone Journal1539-16632019-05-0118110.2136/vzj2018.10.0193Predicting the Fate of Preferentially Moving HerbicidesBahareh HassanpourBrian K. RichardsLarry D. GoehringJean-Yves ParlangeTammo S. SteenhuisSimulation of preferential flow remains a challenge despite being a recognized phenomenon. With short-interval data, we adapted and tested the preferential flow model (PFM) to simulate the vertical transport of herbicides to lower soil layers. The PFM divides the soil profile into a top distribution zone and a conveyance zone below. The distribution zone acts as a reservoir, with an exponential loss of solutes to the conveyance zone. In the conveyance zone, water and solutes move as convective–dispersive flow through multiple flow paths—preferential and matrix—to shallow groundwater. Our field experiment was performed on a structured Hudson silty clay loam soil (a fine, illitic, mesic Glossaquic Hapludalf) that exhibits preferential flow. The site was instrumented with a variety of soil water samplers placed at depths of 60 cm to monitor the volume and quality of the leachate. Agronomic application of atrazine [6-chloro--ethyl-′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and 2,4-D [2-(2,4-dichlorophenoxy)acetic acid] was used, followed by 75 cm of controlled and natural rainfall over 100 d. In addition, Cl was applied as a conservative tracer. All samplers monitored during this period showed a fast breakthrough of solutes consistent with the occurrence of preferential flow, with two groups of breakthrough curves observed. By fitting the Cl breakthrough curve for each group, PFM input parameters were estimated including water velocity in preferential flow paths and the fraction of water moving through each flow path. With two additional parameters for herbicide adsorption and degradation rates, the model successfully simulated the extent of preferential flow of herbicides.https://dl.sciencesocieties.org/publications/vzj/articles/18/1/180193 |
| spellingShingle | Bahareh Hassanpour Brian K. Richards Larry D. Goehring Jean-Yves Parlange Tammo S. Steenhuis Predicting the Fate of Preferentially Moving Herbicides Vadose Zone Journal |
| title | Predicting the Fate of Preferentially Moving Herbicides |
| title_full | Predicting the Fate of Preferentially Moving Herbicides |
| title_fullStr | Predicting the Fate of Preferentially Moving Herbicides |
| title_full_unstemmed | Predicting the Fate of Preferentially Moving Herbicides |
| title_short | Predicting the Fate of Preferentially Moving Herbicides |
| title_sort | predicting the fate of preferentially moving herbicides |
| url | https://dl.sciencesocieties.org/publications/vzj/articles/18/1/180193 |
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