Extreme climate increased crop nitrogen surplus in the United States
Extreme climate increased crop nitrogen surplus in the United States
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DOI：
10.1016/j.agrformet.2021.108632
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发表时间：
2021-11
影响因子：
6.2
通讯作者：
Jien Zhang;Chaoqun Lu;H. Feng;D. Hennessy;Yong Guan;M. Wright
中科院分区：
文献类型：
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作者：
Jien Zhang;Chaoqun Lu;H. Feng;D. Hennessy;Yong Guan;M. Wright
日益严重的极端气候条件对美国的作物氮素管理和环境保护构成了重大威胁。以往的研究已经研究了极端气候对作物生产的影响，但往往忽略了其对氮素从农业地区流失到环境的影响。在这里，我们研究了1981-2016年美国县级氮盈余（作物无法回收的氮部分）与玉米极端气候条件之间的关系。采用多源玉米氮收支和生长季（定义为5 - 8月）最高温度和降水量的长期数据集，为每个玉米种植县。与长期氮素盈余趋势相比，极端高温和极端少雨分别使玉米氮素盈余增加了51%和47%。一个温和的N盈余增加（20%）与极高的降水量，而14%的N盈余减少被证明是与极低的温度。在美国，当极端气候条件发生时，中西部和北方大平原被确定为氮盈余热点。作为主要的玉米种植区，中西部占全国极端县年样本的35%，但产生了68%的全国总氮盈余与极端气候条件。我们的研究结果强调了了解极端气候条件对作物养分损失的影响以及确定有效的干预措施以适应未来更频繁的极端气候的紧迫性。
Increasing extreme climate conditions present significant threats to crop nitrogen (N) management and environmental conservation in the United States. Previous studies have examined the impacts of extreme climate on crop production but often overlooked its impacts on N loss from agricultural areas to the environment. Here we examined the relationship between county-level N surplus (the part of N that is not recovered by crops) and extreme climate conditions for corn in the U.S. during 1981–2016. We adopted multi-source long-term datasets of corn N budget and growing season (defined from May to August) maximum temperature and precipitation for each corn-planting county. Compared with the long-term N surplus trend, we found an increase of 51% and 47% in corn N surplus associated with extremely high temperature and extremely low precipitations, respectively. A moderate N surplus increase (20%) was associated with extremely high precipitations, while an N surplus decrease of 14% was shown to be related to extremely low temperatures. Across the U.S., the Midwest and the Northern Great Plains were identified as N surplus hotspots when extreme climate conditions occur. As the major corn-planting region, the Midwest accounted for 35% of the national extreme county-year samples but yielded 68% of the national total N surplus associated with extreme climate conditions. Our results highlighted the urgency of understanding the impacts of extreme climate conditions on crop nutrient losses and identifying the effective intervention practices to adapt to more frequent climate extremes in the future.