Effects of antecedent rain history on particulate phosphorus loss from a small forested watershed of Japanese cypress (Chamaecyparis obtusa)
Effects of antecedent rain history on particulate phosphorus loss from a small forested watershed of Japanese cypress (Chamaecyparis obtusa)
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DOI：
10.1016/j.jhydrol.2008.01.012
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发表时间：
2008-05
影响因子：
6.4
通讯作者：
J. Ide;H. Haga;M. Chiwa;K. Otsuki
中科院分区：
文献类型：
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作者：
J. Ide;H. Haga;M. Chiwa;K. Otsuki
本研究旨在澄清前期降雨历史对颗粒态磷（PP）流失的影响，主要覆盖在一个小的山地流域的种植园林日本柏树（Chamaaparis obtusa）。在24小时内，我们分析了8个不同流量水平的降雨过程中，15- 60分钟间隔的流量和PP浓度。PP浓度与流量（PPC-Q）的关系表现出顺时针滞后回线的八个事件监测。放电可以解释PP浓度的变化下降，但不是上升的边缘的过程。在上升肢，放电的变化率（dQ/dt）和PP负载（dL/dt）之间的正相关关系被发现为每个事件。这表明大量的PP在快速增加的放电时强烈地脉动。这些结果表明，dQ/dt是PP电源背后的驱动力，并且是PPC-Q关系的顺时针磁滞回线的主要控制。前期降水指数和dL/dt与dQ/dt关系的斜率之间存在很强的负相关性。这表明，随着先前的水分条件变得更干燥，即使排放量略有增加，PP负荷也会迅速增加。干旱条件下土壤的斥水性和快速径流响应支持土壤干燥化增加了与坡面流土壤侵蚀相关的PP供应。因此，我们得出结论，前期降雨历史影响PP的流动性，通过土壤干燥。这项研究的结果将填补空白，在我们的理解的时间变化释放细泥沙和相关的PP在以前的研究报告。
This study aimed to clarify the effects of antecedent rain history on particulate phosphorus (PP) loss in a small mountainous watershed covered primarily with a plantation forest of Japanese cypress (Chamaecyparis obtusa). We analyzed stream discharge and PP concentration at 15–60min intervals during 24h in eight rain events with different discharge levels. The PP concentration versus stream discharge (PPC–Q) relationships exhibited clockwise hysteresis loops for each of the eight events monitored. Discharge could explain changes in PP concentration on the falling but not rising limb of the hydrograph. On the rising limb, a positive relationship between the rate of changes in discharge (dQ/dt) and the PP load (dL/dt) was found for each event. This indicates that a large amount of PP is strongly pulsed at times of rapidly increased discharge. These results suggest that dQ/dt is the driving force behind PP supply and the primary control on the clockwise hysteresis loop of PPC–Q relationship. There was a strong negative correlation between the antecedent precipitation index and the slope of the dL/dt versus dQ/dt relationship. This shows that a rapid increase in PP load occurs even with slight increases in discharge as antecedent moisture conditions become drier. The soil water repellency and rapid runoff response following dry conditions support that soil desiccation increases the PP supply associated with soil erosion via overland flow. Therefore, we concluded that the antecedent rain history affects the mobility of PP via soil desiccation. The findings of this study will fill gaps in our understanding of temporal variations in released fine sediment and associated PP as reported in previous studies.