Spatial and Temporal Patterns of Nitrogen Mobilization in Residential Lawns
Spatial and Temporal Patterns of Nitrogen Mobilization in Residential Lawns
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DOI：
10.1007/s10021-023-00848-y
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发表时间：
2023-05
期刊：
影响因子：
3.7
通讯作者：
A. Suchy;P. Groffman;L. Band;J. Duncan;A. Gold;J. Grove;D. Locke;Laura Templeton;Ruoyu Zhang
中科院分区：
文献类型：
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作者：
A. Suchy;P. Groffman;L. Band;J. Duncan;A. Gold;J. Grove;D. Locke;Laura Templeton;Ruoyu Zhang
确定容易输出氮（N）的位置，也称为输出控制点，在住宅景观，是决定氮缓解策略的关键。在住宅景观中，草坪有可能通过吸收和反硝化作用作为氮的汇，或通过添加如肥料作为氮的来源。草坪排水不透水的表面更有可能是通过直接连接的遏制和下水道流动路径的N负载接收水体的来源。我们利用小规模的降雨实验，以研究是否水文地球化学测量潜在的反硝化和饱和渗透率预测的N动员，以及如何潜在的出口控制点（位置内的上四分位数的N动员值）的空间和时间上的变化在巴尔的摩，马里兰州的住宅草坪。我们发现潜在的反硝化作用，但不渗透，是预测径流和渗滤液中的N动员，只有施肥草坪。潜在的出口管制点更多地出现在夏末和秋季，85%的出口管制点位于施肥的草坪上。降雨事件前不久施用化肥使径流和渗滤液中的氮迁移率增加了一个数量级。郊区前院也有更多的潜在出口控制点相比，后院，这是值得注意的前院被不透水的表面，增加其脆弱性运输N到下游生态系统包围。这些研究结果突出了草坪上氮动员的时空变异性。有针对性的位置，如脆弱的前院，或行为，如施肥的时间，可能是有用的N缓解策略。
Identifying locations prone to exporting nitrogen (N), also called export control points, within residential landscapes, is key to determining N mitigation strategies. Within residential landscapes, lawns have the potential to act as either a sink of N via uptake and denitrification, or a source of N via additions such as fertilizer. Lawns draining to impervious surfaces are more likely to be sources of N loading to receiving water bodies through directly connected curb and sewer flow paths. We utilized small-scale rainfall experiments to examine whether hydrobiogeochemical measurements of potential denitrification and saturated infiltration rates were predictive of N mobilization, and how potential export control points (locations within the upper quartile of N mobilization values) varied spatially and temporally on residential lawns in Baltimore, Maryland. We found potential denitrification, but not infiltration, was predictive of N mobilization in runoff and leachate, only on fertilized lawns. Potential export control points occurred more often in the late summer and fall and 85% were on fertilized lawns. Applying fertilizer shortly before a rainfall event increased the N mobilization in runoff and leachate by an order of magnitude. Suburban front yards also had more potential export control points compared to backyards, which is notable as front yards are surrounded by impervious surfaces increasing their vulnerability to transporting N to downstream ecosystems. These findings highlight the spatial and temporal variability of N mobilization on lawns. Targeting locations such as vulnerable front yards, or behaviors, such as timing of fertilizer application, may be useful N mitigation strategies.