Water quality degradation can be caused by excessive agricultural nutrient transfers from fertilised soils exposed to wet weather. Mitigation measures within the EU Nitrates Directive aim to reduce this pressure by including ‘closed’ fertiliser spreading periods during wet months. For organic fertilisers such as slurry and manure, this closed period requires sufficient on-farm winter storage and good weather conditions to relieve storage at the end of the period. Therefore, robust scientific evidence is needed to support the measure. Incidental nutrient transfers of recently applied organic fertilisers in wet weather can also be complicated by synchronous transfers from residual soil stores and tracing is required for risk assessments. The combination of nutrient monitoring and biomarker analyses may aid this and one such biomarker suite is faecal steroids. Accordingly, this study investigated the persistence of steroids and their association with phosphorus during leaching episodes. The focus was on the coupled behaviour of steroids and total phosphorus (TP) concentrations in sub-surface hydrological pathways. Cattle slurry was applied to monolith lysimeters either side of a closed period and concentrations of both steroids and TP were monitored in the leachate. The study showed no significant effect of the treatment (average p = 0.17), though tracer concentrations did significantly change over time (average p = 0.001). While the steroidal concentration ratio was validated for herbivorous faecal pollution in the leachate, there was a weak positive correlation between the steroids and TP. Further investigation at more natural scales (hillslope/catchment) is required to confirm tracer behaviours/correlations and to compliment this sub-surface pathway study.

水质恶化可能是由于受肥土壤暴露在潮湿天气中的过度农业养分转移造成的。欧盟硝酸盐指令中的缓解措施旨在通过在潮湿月份包括“封闭”施肥期来减轻这种压力。对于泥浆和粪肥等有机肥料，这个封闭期需要有足够的农场冬季储存量和良好的天气条件，以在期末缓解储存量。因此，需要强有力的科学证据来支持该措施。最近施用的有机肥料在潮湿天气中的附带养分转移也可能因残留土壤储存的同步转移而变得复杂，风险评估需要追踪。营养监测和生物标志物分析的结合可能有助于这一点，其中一种生物标志物是粪便类固醇。因此，本研究调查了类固醇在浸出过程中的持久性及其与磷的关联。重点是类固醇和总磷（TP）浓度在地下水文路径中的耦合行为。在封闭期的任一侧将牛浆施加到整体蒸渗仪，并监测渗滤液中类固醇和 TP 的浓度。研究显示治疗没有显着效果（平均 重点是类固醇和总磷（TP）浓度在地下水文路径中的耦合行为。在封闭期的任一侧将牛浆施加到整体蒸渗仪，并监测渗滤液中类固醇和 TP 的浓度。研究显示治疗没有显着效果（平均 重点是类固醇和总磷（TP）浓度在地下水文路径中的耦合行为。在封闭期的任一侧将牛浆施加到整体蒸渗仪，并监测渗滤液中类固醇和 TP 的浓度。研究显示治疗没有显着效果（平均p  = 0.17），尽管示踪剂浓度确实随时间发生了显着变化（平均p  = 0.001）。虽然类固醇浓度比验证了渗滤液中的草食性粪便污染，但类固醇与 TP 之间存在弱正相关。需要在更自然的尺度（山坡/集水区）进行进一步调查，以确认示踪剂的行为/相关性并补充这种地下路径研究。