Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River
Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River
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DOI：
10.1073/pnas.0708300105
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发表时间：
2008-03-18
影响因子：
11.1
通讯作者：
Kucharik, Christopher J.
中科院分区：
文献类型：
--
作者：
Donner, Simon D.;Kucharik, Christopher J.
美国的玉米种植预计将增加，以满足对乙醇的需求。氮从施肥的玉米田淋溶到密西西比-阿查法拉亚河系统是每年夏天墨西哥湾北方大陆架底层水缺氧的主要原因。在这项研究中，我们结合联合收割机农业土地利用的情况下，基于物理模型的陆地和水生氮研究的影响，目前和未来扩大玉米为基础的乙醇生产氮出口的密西西比河和阿查法拉亚河墨西哥湾。结果表明，玉米种植的增加，以满足15-36十亿加仑的可再生燃料的目标，到2022年建议由最近的美国参议院能源政策将增加溶解无机氮（DIN）的年平均通量由密西西比河和阿查法拉亚河的出口10- 34%。到2022年，生产150亿加仑的玉米乙醇将增加年度DIN出口超过墨西哥湾缺氧目标的可能性。对极端缓解方案的研究表明，如果粮食生产和农业管理不发生大的变化，扩大玉米乙醇生产将使减少向墨西哥湾的氮出口和缺氧程度这一本已困难的挑战变得几乎不可能。
Corn cultivation in the United States is expected to increase to meet demand for ethanol. Nitrogen leaching from fertilized corn fields to the Mississippi-Atchafalaya River system is a primary cause of the bottom-water hypoxia that develops on the continental shelf of the northern Gulf of Mexico each summer. In this study, we combine agricultural land use scenarios with physically based models of terrestrial and aquatic nitrogen to examine the effect of present and future expansion of corn-based ethanol production on nitrogen export by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico. The results show that the increase in corn cultivation required to meet the goal of 15-36 billion gallons of renewable fuels by the year 2022 suggested by a recent U.S. Senate energy policy would increase the annual average flux of dissolved inorganic nitrogen (DIN) export by the Mississippi and Atchafalaya Rivers by 10-34%. Generating 15 billion gallons of corn-based ethanol by the year 2022 will increase the odds that annual DIN export exceeds the target set for reducing hypoxia in the Gulf of Mexico to >95%. Examination of extreme mitigation options shows that expanding corn-based ethanol production would make the already difficult challenges of reducing nitrogen export to the Gulf of Mexico and the extent of hypoxia practically impossible without large shifts in food production and agricultural management.