Decreased buffering capacity and increased recovery time for legacy phosphorus in a typical watershed in eastern China between 1960 and 2010
Decreased buffering capacity and increased recovery time for legacy phosphorus in a typical watershed in eastern China between 1960 and 2010
复制标题
1960年至2010年间，中国东部典型流域的残留磷缓冲能力下降，恢复时间延长
DOI：
10.1007/s10533-019-00585-2
复制
发表时间：
2019
期刊：
影响因子：
4
通讯作者：
y A.Dahlgren
中科院分区：
文献类型：
--
作者：
Dingjiang Chen;Yufu Zhang;Hong Shen;Mengya Yao;Minpeng Hu;R;y A.Dahlgren
历史上过量磷输入在流域中积累的遗留磷被认为是流域水污染控制和可持续磷管理的重要组成部分。然而，很少有人知道流域磷缓冲能力如何响应传统的磷压力随着时间的推移，以及需要多长时间河流磷浓度恢复到目标水平，特别是在发展中国家。通过分析永安流域长期（1960 - 2010年）累积的磷存量、磷缓冲能力和河流TP通量动态，预测河流磷还原恢复时间。由于传统磷储量的增加，加上土地利用和气候的变化，估计的短期和长期缓冲指标（即，流域对当年和历史累积盈余P的截留能力分别下降了65%和36%，导致1980年至2010年期间河流P通量增加了15倍。开发了一个经验模型，将累积的遗留磷存量和年降水量结合起来（R2 = 0.99），并用于估计22.2吨P km − 2（95% CI 19.4 - 25.3吨P km − 2）的临界遗留磷存量，这将防止河流TP浓度达到0.05 mg P L − 1的目标。利用指数衰减模型，估算了2010年消耗遗留磷存量的恢复时间，（29.3吨P km − 2）至临界水平（22.2吨P km − 2）通过河流通量为456年（95% CI 353 - 560岁），159岁（95% CI 57 - 262岁）和318岁（95%CI 238 - 400年），在年磷输入减少4%，完全停止磷输入的情景下，年平均降水量增加10%时，年磷输入量减少4%。由于河流磷缓冲能力较低，恢复时间较长，因此减少磷输入，利用土壤遗留磷进行作物生产是有效控制河流磷污染和保护全球岩石磷资源的必要策略。一个长期的角度来看，结合当代和历史的信息，需要制定可持续的磷管理战略，以优化在流域尺度的农艺和环境效益。
Legacy phosphorus (P) accumulated in watersheds from excessive historical P inputs is recognized as an important component of water pollution control and sustainable P management in watersheds worldwide. However, little is known about how watershed P buffering capacity responds to legacy P pressures over time and how long it takes for riverine P concentrations to recover to a target level, especially in developing countries. This study examined long-term (1960–2010) accumulated legacy P stock, P buffering capacity and riverine TP flux dynamics to predict riverine P-reduction recovery times in the Yongan watershed of eastern China. Due to a growing legacy P stock coupled with changes in land use and climate, estimated short- and long-term buffering metrics (i.e., watershed ability to retain current year and historically accumulated surplus P, respectively) decreased by 65% and 36%, respectively, resulting in a 15-fold increase of riverine P flux between 1980 and 2010. An empirical model incorporating accumulated legacy P stock and annual precipitation was developed (R2= 0.99) and used to estimate a critical legacy P stock of 22.2 ton P km−2(95% CI 19.4–25.3 ton P km−2) that would prevent exceedance of a target riverine TP concentration of 0.05 mg P L−1. Using an exponential decay model, the recovery time for depleting the estimated legacy P stock in 2010 (29.3 ton P km−2) to the critical level (22.2 ton P km−2) via riverine flux was 456 years (95% CI 353–560 years), 159 years (95% CI 57–262 years) and 318 years (95% CI 238–400 years) under scenarios of a 4% reduction in annual P inputs, total cessation of P inputs, and 4% reduction of annual P inputs with a 10% increase in average annual precipitation, respectively. Given the lower P buffering capacity and lengthening recovery time, strategies to reduce P inputs and utilize soil legacy P for crop production are necessary to effectively control riverine P pollution and conserve global rock P resources. A long-term perspective that incorporates both contemporary and historical information is required for developing sustainable P management strategies to optimize both agronomic and environmental benefits at the watershed scale.