Civil Engineering, National University of Ireland, Galway, Co Galway, Ireland.
J Environ Manage. 2012 Dec 30;113:78-84. doi: 10.1016/j.jenvman.2012.08.026. Epub 2012 Sep 17.
Losses of phosphorus (P) when pig slurry applications to land are followed by a rainfall event or losses from soils with high P contents can contribute to eutrophication of receiving waters. The addition of amendments to pig slurry spread on high P Index soils may reduce P and suspended sediment (SS) losses. This hypothesis was tested at laboratory-scale using runoff boxes under simulated rainfall conditions. Intact grassed soil samples, 100 cm-long, 22.5 cm-wide and 5 cm-deep, were placed in runoff boxes and pig slurry or amended pig slurry was applied to the soil surface. The amendments examined were: (1) commercial grade liquid alum (8% Al(2)O(3)) applied at a rate of 0.88:1 [Al:total phosphorus (TP)] (2) commercial-grade liquid ferric chloride (38% FeCl(3)) applied at a rate of 0.89:1 [Fe:TP] and (3) commercial-grade liquid poly-aluminium chloride (PAC) (10% Al(2)O(3)) applied at a rate of 0.72:1 [Al:TP]. The grassed soil was then subjected to three rainfall events (10.3 ± 0.15 mm h(-1)) at time intervals of 48, 72, and 96 h following slurry application. Each sod received rainfall on 3 occasions. Results across three rainfall events showed that for the control treatment, the average flow weighted mean concentration (FWMC) of TP was 0.61 mg L(-1), of which 31% was particulate phosphorus (PP), and the average FWMC of SS was 38.1 mg L(-1). For the slurry treatment, there was an average FWMC of 2.2 mg TP L(-1), 47% of which was PP, and the average FWMC of SS was 71.5 mg L(-1). Ranked in order of effectiveness from best to worst, PAC reduced the average FWMC of TP to 0.64 mg L(-1) (42% PP), FeCl(3) reduced TP to 0.91 mg L(-1) (52% PP) and alum reduced TP to 1.08 mg L(-1) (56% PP). The amendments were in the same order when ranked for effectiveness at reducing SS: PAC (74%), FeCl(3) (66%) and alum (39%). Total phosphorus levels in runoff plots receiving amended slurry remained above those from soil only, indicating that, although incidental losses could be mitigated by chemical amendment, chronic losses from the high P index soil in the current study could not be reduced.
当猪粪施用于土地后发生降雨事件或土壤中磷含量高导致磷损失时，可能会导致接收水体富营养化。在高磷指数土壤上添加改良剂可减少磷和悬浮泥沙（SS）的损失。本研究在模拟降雨条件下使用径流箱在实验室规模上进行了测试。将 100 厘米长、22.5 厘米宽、5 厘米深的完整草皮土壤样本放置在径流箱中，并将猪粪或改良猪粪施用于土壤表面。研究的改良剂包括：（1）商业级液体硫酸铝（8%Al2O3），以 Al:总磷（TP）比 0.88:1 的比例添加；（2）商业级液体氯化铁（38%FeCl3），以 Fe:TP 比 0.89:1 的比例添加；（3）商业级液体聚氯化铝（PAC）（10%Al2O3），以 Al:TP 比 0.72:1 的比例添加。然后，在施浆后 48、72 和 96 小时的时间间隔内，对草皮土壤进行了三次降雨事件（10.3±0.15mmh-1）。每个草皮都接受了三次降雨。三次降雨事件的结果表明，对于对照处理，TP 的平均流量加权平均浓度（FWMC）为 0.61mgL-1，其中 31%为颗粒磷（PP），SS 的平均 FWMC 为 38.1mgL-1。对于粪浆处理，TP 的平均 FWMC 为 2.2mgL-1，其中 47%为 PP，SS 的平均 FWMC 为 71.5mgL-1。从最佳到最差的效果排序，PAC 将 TP 的平均 FWMC 降低到 0.64mgL-1（42%PP），FeCl3 将 TP 降低到 0.91mgL-1（52%PP），硫酸铝将 TP 降低到 1.08mgL-1（56%PP）。当按降低 SS 的效果对改良剂进行排序时，效果相同：PAC（74%）、FeCl3（66%）和硫酸铝（39%）。接收改良粪浆的径流区的总磷水平仍高于仅土壤的水平，表明尽管通过化学改良可以减轻偶然损失，但在当前研究中，高磷指数土壤的慢性损失无法降低。
