Processes controlling the flux of legacy phosphorus to surface waters at the farm scale
Phosphorus (P) leaching from agriculture is a major driver of water eutrophication in downstream rivers and lakes. In drained lowland areas with intensive agriculture, a reduction in the fertilizer applications may be insufficient to improve the water quality in the short term as the P accumulated i...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/abcdd4 |
| _version_ | 1797747665455284224 |
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| author | Victoria Barcala Joachim Rozemeijer Leonard Osté Bas Van der Grift Laurens Gerner Thilo Behrends |
| author_facet | Victoria Barcala Joachim Rozemeijer Leonard Osté Bas Van der Grift Laurens Gerner Thilo Behrends |
| author_sort | Victoria Barcala |
| collection | DOAJ |
| description | Phosphorus (P) leaching from agriculture is a major driver of water eutrophication in downstream rivers and lakes. In drained lowland areas with intensive agriculture, a reduction in the fertilizer applications may be insufficient to improve the water quality in the short term as the P accumulated in the soil during decades of high fertilization may continue leaching for many years. A complementary approach to reduce P exports from agriculture is to implement edge-of-field mitigation measures at the farm scale. The selection of effective measures requires a detailed insight into the chemical and hydrological transport mechanisms. Here, we determined the main P sources, processes, and transport routes at the farm scale to support the selection of appropriate mitigation measures. We quantified the legacy P, the different P pools stored in the upper soil, and related it to the yearly P export downstream. To do this, we combined high-resolution monitoring data from the soil, groundwater, surface water, and ditch sediments. The legacy P in the topsoil was high, about 2500 kg ha ^−1 . The predominant subsurface flow and the subsoils’ P sorption capacity retained the P mobilized from the topsoil and explained the relative moderate flux of P to surface waters (0.04 kg ha ^−1 during the 2018–2019 drainage season). The dissolved P entering the drainage ditch via groundwater discharge was bound to iron-containing particles formed due to the oxidation of dissolved ferrous iron. Once leached from the soil to the drainage ditch, resuspension of P-rich sediment particles during flow peaks were the most important P transport mechanism (78%). Therefore, we expect that hydraulic constructions that reduce flow velocities and promote sedimentation of P-containing particles could reduce the export of P further downstream. |
| first_indexed | 2024-03-12T15:54:49Z |
| format | Article |
| id | doaj.art-7c45ecc1969e4215b0bef3756717200d |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:54:49Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-7c45ecc1969e4215b0bef3756717200d2023-08-09T14:59:49ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-0116101500310.1088/1748-9326/abcdd4Processes controlling the flux of legacy phosphorus to surface waters at the farm scaleVictoria Barcala0Joachim Rozemeijer1Leonard Osté2Bas Van der Grift3Laurens Gerner4Thilo Behrends5Inland Water Systems, Deltares , Utrecht, The NetherlandsInland Water Systems, Deltares , Utrecht, The NetherlandsInland Water Systems, Deltares , Utrecht, The NetherlandsKWR Water Research Institute , Nieuwegein, The NetherlandsWater Board Rijn and IJssel , Doetinchem, The NetherlandsDepartment of Earth Sciences, Faculty of Geosciences, Utrecht University , Utrecht, The NetherlandsPhosphorus (P) leaching from agriculture is a major driver of water eutrophication in downstream rivers and lakes. In drained lowland areas with intensive agriculture, a reduction in the fertilizer applications may be insufficient to improve the water quality in the short term as the P accumulated in the soil during decades of high fertilization may continue leaching for many years. A complementary approach to reduce P exports from agriculture is to implement edge-of-field mitigation measures at the farm scale. The selection of effective measures requires a detailed insight into the chemical and hydrological transport mechanisms. Here, we determined the main P sources, processes, and transport routes at the farm scale to support the selection of appropriate mitigation measures. We quantified the legacy P, the different P pools stored in the upper soil, and related it to the yearly P export downstream. To do this, we combined high-resolution monitoring data from the soil, groundwater, surface water, and ditch sediments. The legacy P in the topsoil was high, about 2500 kg ha ^−1 . The predominant subsurface flow and the subsoils’ P sorption capacity retained the P mobilized from the topsoil and explained the relative moderate flux of P to surface waters (0.04 kg ha ^−1 during the 2018–2019 drainage season). The dissolved P entering the drainage ditch via groundwater discharge was bound to iron-containing particles formed due to the oxidation of dissolved ferrous iron. Once leached from the soil to the drainage ditch, resuspension of P-rich sediment particles during flow peaks were the most important P transport mechanism (78%). Therefore, we expect that hydraulic constructions that reduce flow velocities and promote sedimentation of P-containing particles could reduce the export of P further downstream.https://doi.org/10.1088/1748-9326/abcdd4legacy phosphorusleachingdiffuse sourcesmitigation measuresgroundwater–surface water interactionsagriculture |
| spellingShingle | Victoria Barcala Joachim Rozemeijer Leonard Osté Bas Van der Grift Laurens Gerner Thilo Behrends Processes controlling the flux of legacy phosphorus to surface waters at the farm scale Environmental Research Letters legacy phosphorus leaching diffuse sources mitigation measures groundwater–surface water interactions agriculture |
| title | Processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| title_full | Processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| title_fullStr | Processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| title_full_unstemmed | Processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| title_short | Processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| title_sort | processes controlling the flux of legacy phosphorus to surface waters at the farm scale |
| topic | legacy phosphorus leaching diffuse sources mitigation measures groundwater–surface water interactions agriculture |
| url | https://doi.org/10.1088/1748-9326/abcdd4 |
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