| 摘要: |
| 近年来，鄱阳湖流域种植系统氮磷的过度输入与低效利用造成了氮磷负荷增加等环境问题，因此，定量追溯鄱阳湖流域种植系统的氮磷时空格局，对保护流域生态系统可持续性具有重要意义。本研究采用物质流分析方法，分析了鄱阳湖流域2000-2022年种植系统氮磷通量的时空变化，并基于种植系统氮磷污染物排放现状设计了基准情景，减少耕地化肥投入情景、秸秆回收率提高情景和综合措施情景，在各种情景下定量描述减排潜力，提出了氮磷污染物减排防治的策略。结果表明，流域内氮磷输入情况总体呈现先上升、后平稳波动的变化，于2015年前后氮磷输入量出现峰值；空间分布上，鄱阳湖环湖区氮磷总输入量最高，分别为28.1万吨和6.4万吨；化肥和有机肥是最大来源，贡献了一半以上的氮磷输入量；从种植系统养分利用效率来看，氮和磷的综合利用率分别为48.5%和31.0%，2010年以来各种作物氮磷利用率呈下降趋势，养分投入氮磷比（N/P）也在持续下降，平均输入N/P为3.9。综合措施情景结果表明，到2050年，氮磷污染排放可减少15.9万吨，与基准情景相比减少了53.4%的污染物，排入环境中的氮磷比可升至6.5。通过定量分析鄱阳湖流域种植氮磷结构，追溯20来流域氮磷输入情况，识别判断氮磷比的变化趋势，可系统评估种植系统的氮磷代谢关键过程，并通过评估未来情景的潜在结果，为鄱阳湖流域建立有效的氮磷综合管理措施提供科学依据。 |
| 关键词: 可持续农业 氮磷流动 鄱阳湖流域 种植系统 |
| DOI： |
| 分类号: |
| 基金项目:国家重点研发计划项目(2023YFE010460)；国家自然科学(52200215；52270182)；江西省社会科学(24ZXST06) |
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| Spatiotemporal dynamics and mitigation potential of nitrogen-phosphorus fluxes in cropping systems of Poyang Lake Basin |
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Liu Huimin,Fu Hang,Li Yuanhang,Sun Yuheng,Yuan Wen,Luo Binhua,Shi Lei
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Nanchang University
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| Abstract: |
| Abstract: In recent years, excessive input and inefficient utilization of nitrogen and phosphorus in the cropping system of the
Poyang Lake Basin have led to significant losses of these elements, resulting in persistent exceedances of nitrogen and phosphorus standards, as well as other environmental issues. Therefore, quantitatively tracing the spatiotemporal patterns of nitrogen and phosphorus metabolism in the cropping system of Poyang Lake Basin is crucial for ensuring the sustainability of the basin"s ecosystem. This study applied the Material Flow Analysis (MFA) method to investigate the spatiotemporal variations of nitrogen and phosphorus fluxes in cropping systems across the Poyang Lake Basin from 2000 to 2022.Four scenarios were designed based on the current status of nitrogen and phosphorus pollutant emissions: a baseline scenario, a scenario with reduced fertilizer inputs to arable land, a scenario with increased straw recycling rates, and a scenario with comprehensive measures. The emission reduction potentials was quantitatively calculated under various scenarios and finally the optimal strategies for nitrogen and phosphorus pollutant emission reduction and prevention were proposed. The results show that the nitrogen and phosphorus inputs in the basin initially increased, then fluctuated stably, peaking around 2015. Spatially, the total nitrogen and phosphorus inputs are highest in the coastal lake district, reaching 281,000 tons of nitrogen and 64,000 tons of phosphorus, respectively, with chemical and organic fertilizers accounting for over half of the total inputs. In terms of the nutrient use efficiency, the combined use rate of nitrogen and phosphorus were 48.5% and 31.0% respectively. The nitrogen and phosphorus utilization rates for all crops has declined since 2010, and the nutrient input nitrogen and phosphorus ratio has also decreased continuously, with an average N/P of 3.9. Scenario analysis suggests that implementing measures to reduce chemical fertilizer use could decrease nitrogen output by 150,000 tonnes by 2050, nitrogen and phosphorus emissions can be reduced by 159,000 tons, reducing pollutants by 53.4%. compared with the baseline scenario, the ratio of N/P discharged into the environment can rise to 6.5. Reducing fertilizer application accounts for 75.7% of the emission reduction, demonstrating its effectiveness as a mitigation strategy. By quantitatively analyzing the nitrogen and phosphorus structure of cropping system and tracing the nitrogen and phosphorus inputs over the past 20 years in Poyang Lake Basin, identifying and judging the change trend of the nitrogen and phosphorus ratio, This analysis allows us to systematically evaluate the key processes of the agricultural system and provides a scientific basis for developing effective integrated nitrogen and phosphorus management measures in the Poyang Lake Basin by evaluating the potential outcomes of future scenarios. |
| Key words: Sustainable agriculture nitrogen and phosphorus metabolism Poyang Lake Basin cropping system |
