Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds
Agricultural watersheds in the North Central United States have been intensively farmed for decades with widespread application of fertilizer and extensive tilling practices. Soil phosphorus built up in sediments over time as a result of these practices may be released under anaerobic conditions, su...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-02-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/16/5/642 |
| _version_ | 1797263790266384384 |
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| author | Nadia Alsadi Christian Lenhart |
| author_facet | Nadia Alsadi Christian Lenhart |
| author_sort | Nadia Alsadi |
| collection | DOAJ |
| description | Agricultural watersheds in the North Central United States have been intensively farmed for decades with widespread application of fertilizer and extensive tilling practices. Soil phosphorus built up in sediments over time as a result of these practices may be released under anaerobic conditions, such as flood events. These floods are increasing in frequency and intensity due to climate change, leading to downstream water-quality concerns. Edge-of-field best management practices, including constructed treatment wetlands, provide a natural buffer for excess phosphorus runoff, but may only be a temporary solution if soil becomes oversaturated with phosphorus over extended periods of time. Preventing wetlands from becoming sources of phosphorus to water bodies may be essential for management in future years when considering impacts from climate change. This research assesses how wetland plant harvesting can reduce soil phosphorus accumulation (measured as Olsen phosphorus) in edge-of-field treatment wetlands, thereby preventing these systems from becoming phosphorus sources and ensuring the longevity of water-quality benefits from these systems. Using several 380 L controlled wetland mesocosm experiments in 2018–2019, we assessed above-ground plant material (<i>S. tabernaemontani</i> and <i>B. fluviatilis</i>) and soil Olsen P through the growing season and after harvest. We observed a reduction in soil phosphorus from wetland plant harvesting between 1–50% over one year, with a mean reduction of 7.9 mg/kg. <i>B. fluviatilis</i> initially contained higher P concentration early in the season (0.82% P content) compared to <i>S. tabernaemontani</i> (0.76% P), but <i>S. tabernaemontani</i> retained higher P later in the season (0.3% P content) compared to <i>B. fluviatilis</i> (0.25%). Time of season may significantly impact plant P removal potential, including accessibility of treatment wetland sites. While controlled mesocosm experiments may not always be applicable to real landscape-level management, this study highlights the potential for reductions in soil phosphorus and corresponding downstream phosphorus fluxes in edge-of-field treatment wetlands through plant harvest during the growing season. Plant harvesting can be used by land managers in edge-of-field treatment wetlands as an adaptation mechanism for shifting environmental conditions, such as increased heavy rainfall occurrences and flood events, that are exacerbated by climate change in this region. |
| first_indexed | 2024-04-25T00:18:36Z |
| format | Article |
| id | doaj.art-2cc1c1d7089b4fce82dc155f004961ad |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-04-25T00:18:36Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-2cc1c1d7089b4fce82dc155f004961ad2024-03-12T16:57:32ZengMDPI AGWater2073-44412024-02-0116564210.3390/w16050642Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural WatershedsNadia Alsadi0Christian Lenhart1The Nature Conservancy, Minneapolis, MN 55415, USAThe Nature Conservancy, Minneapolis, MN 55415, USAAgricultural watersheds in the North Central United States have been intensively farmed for decades with widespread application of fertilizer and extensive tilling practices. Soil phosphorus built up in sediments over time as a result of these practices may be released under anaerobic conditions, such as flood events. These floods are increasing in frequency and intensity due to climate change, leading to downstream water-quality concerns. Edge-of-field best management practices, including constructed treatment wetlands, provide a natural buffer for excess phosphorus runoff, but may only be a temporary solution if soil becomes oversaturated with phosphorus over extended periods of time. Preventing wetlands from becoming sources of phosphorus to water bodies may be essential for management in future years when considering impacts from climate change. This research assesses how wetland plant harvesting can reduce soil phosphorus accumulation (measured as Olsen phosphorus) in edge-of-field treatment wetlands, thereby preventing these systems from becoming phosphorus sources and ensuring the longevity of water-quality benefits from these systems. Using several 380 L controlled wetland mesocosm experiments in 2018–2019, we assessed above-ground plant material (<i>S. tabernaemontani</i> and <i>B. fluviatilis</i>) and soil Olsen P through the growing season and after harvest. We observed a reduction in soil phosphorus from wetland plant harvesting between 1–50% over one year, with a mean reduction of 7.9 mg/kg. <i>B. fluviatilis</i> initially contained higher P concentration early in the season (0.82% P content) compared to <i>S. tabernaemontani</i> (0.76% P), but <i>S. tabernaemontani</i> retained higher P later in the season (0.3% P content) compared to <i>B. fluviatilis</i> (0.25%). Time of season may significantly impact plant P removal potential, including accessibility of treatment wetland sites. While controlled mesocosm experiments may not always be applicable to real landscape-level management, this study highlights the potential for reductions in soil phosphorus and corresponding downstream phosphorus fluxes in edge-of-field treatment wetlands through plant harvest during the growing season. Plant harvesting can be used by land managers in edge-of-field treatment wetlands as an adaptation mechanism for shifting environmental conditions, such as increased heavy rainfall occurrences and flood events, that are exacerbated by climate change in this region.https://www.mdpi.com/2073-4441/16/5/642agricultural watershedsbest management practiceswetland plant harvestingsoil phosphorus |
| spellingShingle | Nadia Alsadi Christian Lenhart Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds Water agricultural watersheds best management practices wetland plant harvesting soil phosphorus |
| title | Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds |
| title_full | Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds |
| title_fullStr | Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds |
| title_full_unstemmed | Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds |
| title_short | Treatment Wetland Plant Harvests as a Tool for Soil Phosphorus Reduction in North Central US Agricultural Watersheds |
| title_sort | treatment wetland plant harvests as a tool for soil phosphorus reduction in north central us agricultural watersheds |
| topic | agricultural watersheds best management practices wetland plant harvesting soil phosphorus |
| url | https://www.mdpi.com/2073-4441/16/5/642 |
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