Finnish Environment Institute, Syke, Latokartanonkaari 11, 00790 Helsinki, Finland.
Department of Economics and Management, University of Helsinki, Finland.
J Environ Manage. 2024 Apr;357:120706. doi: 10.1016/j.jenvman.2024.120706. Epub 2024 Mar 29.
Amending agricultural fields with gypsum has been proposed as a cost-effective measure to reduce P load on coastal waters. We treated 1490 ha of clayey fields with phosphogypsum (4 t ha) in Southwest Finland and monitored the recipient river with online sensors and water sampling for the preceding spring and 5 years after the amendment. Gypsum immediately decreased the riverine fluxes, the effect lasting at least 5 years for particulate P (PP), total suspended solids (TSS), and dissolved organic C (DOC) and 1-2 years for dissolved reactive P (DRP). Compared with an upstream control area, the fluxes of PP, TSS, and DOC decreased by 15%, 25%, and 8.9%, respectively, as a 5-year average. Assuming the change in the fluxes occurred only due to gypsum, the amended fields showed 35%, 59%, and 64% lower losses for PP, TSS, and DOC than the unamended ones. More than half of the gypsum remained in the soil even after 5 years; thus, although the efficiency of gypsum lessened over time, its residual effect may be present. However, the difference in the erodibility between the control and treatment areas impacted the validity of the results, especially as the pre-gypsum period was short. In addition, the performance of gypsum showed spatial variation.
用石膏改良农业用地被提议为一种降低沿海地区磷负荷的具有成本效益的措施。我们在芬兰西南部用磷石膏（4 吨/公顷）处理了 1490 公顷粘土地，并在改良前的春天和之后的 5 年内使用在线传感器和水样监测受纳河流。石膏立即降低了河流通量，对颗粒磷（PP）、总悬浮固体（TSS）和溶解有机碳（DOC）的影响至少持续 5 年，对溶解反应性磷（DRP）的影响持续 1-2 年。与上游对照区相比，PP、TSS 和 DOC 的通量分别减少了 15%、25%和 8.9%，作为 5 年的平均值。假设通量的变化仅归因于石膏，那么与未改良的田地相比，改良田地的 PP、TSS 和 DOC 的损失分别降低了 35%、59%和 64%。即使经过 5 年，仍有超过一半的石膏留在土壤中；因此，尽管石膏的效率随着时间的推移而降低，但它的残留效应可能仍然存在。然而，对照区和处理区之间的可侵蚀性差异影响了结果的有效性，尤其是因为石膏处理前的时期较短。此外，石膏的性能表现出空间变异性。
