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浙江大學環境與資源學院陳丁江教授團隊首次針對中國最大的流域——長江流域長期（1980—2015）淨人為磷輸入和河流磷通量動態進行了研究。相關成果發表於Water Research（IF=7.913）。
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Highlights
NAPI increased 1.4-fold during 1980–2015 mainly from fertilizer and food/feed inputs.
Spatio-temporal NAPI variations were associated with intensity of human activities.
Riverine TP and PP fluxes decreased, while DP flux increased 7-fold.
Riverine P dynamics affected by river regulation, vegetation cover and input sources.
Developed models were consistent with measured riverine DP, PP and TP fluxes.
Abstract
Quantitative information on long-term net anthropogenic phosphorus inputs (NAPI) and its relationship with riverine phosphorus (P) export are critical for developing sustainable and efficient watershed P management strategies. This is the first study to address long-term (1980–2015) NAPI and riverine P flux dynamics for the Yangtze River basin (YRB), the largest watershed in China. Over the 36-year study period, estimated NAPI to the YRB progressively increased by 1.4 times, with NAPIA (chemical fertilizer input + atmospheric deposition + seed input) and NAPIB (net food/feed imports + non-food input) contributing 65% and 35%, respectively. Higher population, livestock density and agricultural land area were the main drivers of increasing NAPI. Riverine total phosphorus (TP), particulate phosphorus (PP) and suspended sediment (SS) export at Datong hydrological station (downstream station) decreased by 52%, 75% and 75% during 1980–2015, respectively. In contrast, dissolved phosphorus (DP) showed an increase in both concentration (7-fold) and its contribution to TP flux (16-fold). Different trends in riverine P forms were mainly due to increasing dam/reservoir construction and changes in vegetation/land use and NAPI components. Multiple regression models incorporating NAPIA, NAPIB, dam/reservoir storage capacity and water discharge explained 84% and 92% of the temporal variability in riverine DP and PP fluxes, respectively. Riverine TP flux estimated as the sum of DP and PP fluxes showed high agreement with measured values (R2 = 0.87, NSE = 0.84), indicating strong efficacy for the developed models. The model forecasted an increase of 50% and 7% and a decrease of 15% and 22% in riverine DP flux from 2015 to 2045 under developing, dam building, NAPIA and NAPIB reduction scenarios, respectively. This study highlights the importance of including enhanced P transformation from particulate to bioavailable forms due to river regulation and changes in land-use, input sources and legacy P pools in development of P pollution control strategies.
長期淨人為磷輸入（NAPI）的定量信息及其與河流磷輸出的關係對於制定可持續和有效的流域磷管理戰略至關重要。本研究首次針對中國最大的流域——長江流域（YRB）長期（1980—2015）NAPI和河流磷通量動態進行了研究。在36年的研究期間，估計長江流域的NAPI增加了約1.4倍，其中NAPIA（化肥輸入+大氣沉降+種子輸入）和NAPIB（淨食品/飼料輸入+非食品輸入）分別貢獻了65%和35%。人口、牲畜密度和農用地面積的增加是NAPI增加的主要原因。大同水文站（下遊站）的河流總磷（TP）、顆粒磷（PP）和懸浮沉積物（SS）在1980-2015年間分別下降了52%、75%和75%。相比之下，溶解磷（DP）的濃度（約7倍）及其對TP通量的貢獻（約16倍）都有所增加。河流磷形態的不同趨勢主要是大壩/水庫建設的增加、植被/土地利用以及NAPI組分的變化導致的。採用NAPIA、NAPIB、大壩/水庫蓄水量和排水量的多元回歸模型可以解釋河流DP和PP通量84%和92%的時間變異性。使用DP和PP通量之和估計的河流TP通量與實測值吻合較好（R2=0.87, NSE=0.84），表明所建立的模型具有較強的有效性。該模型預測了2015年至2045年，在開發、大壩建設、NAPIA和NAPIB降低的情況下，河流DP通量分別增加50%、增加7%、減少15%、減少22%。本研究強調，在制定磷汙染控制戰略時，必須考慮河流調節和土地利用、輸入源和遺留磷池的變化，從而加強磷從顆粒形態向生物可利用形態的轉化。