Extreme heat effects on wheat senescence in India
Extreme heat effects on wheat senescence in India
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DOI：
10.1038/nclimate1356
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发表时间：
2012-03-01
影响因子：
30.7
通讯作者：
Ivan Ortiz-Monasterio, J.
中科院分区：
文献类型：
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作者：
Lobell, David B.;Sibley, Adam;Ivan Ortiz-Monasterio, J.
预测气候变化对农业影响的一个重要不确定性来源是对作物对极高温度的反应的了解有限（1，2）。这种不确定性在一定程度上反映了对农民在极端高温下的作物行为的观察相对缺乏。我们利用卫星对印度北方小麦生长的九年测量，监测暴露在34摄氏度以上的温度下小麦的衰老速度。我们检测到极端高温对衰老的加速作用在统计学上是显著的，超过了平均温度升高的影响。两个常用的基于过程的作物模型的模拟表明，现有的模型低估了热衰老的影响。由于衰老的开始是对籽粒灌浆的重要限制，因此谷物产量，作物模型可能低估了+2摄氏度的产量损失，对于某些播种日期高达50%。这些结果表明，气候变暖对小麦的挑战比以前的模拟研究所暗示的更大，适应的有效性将取决于它们如何降低作物对炎热天气的敏感性。
An important source of uncertainty in anticipating the effects of climate change on agriculture is limited understanding of crop responses to extremely high temperatures(1,2). This uncertainty partly reflects the relative lack of observations of crop behaviour in farmers' fields under extreme heat. We used nine years of satellite measurements of wheat growth in northern India to monitor rates of wheat senescence following exposure to temperatures greater than 34 degrees C. We detect a statistically significant acceleration of senescence from extreme heat, above and beyond the effects of increased average temperatures. Simulations with two commonly used process-based crop models indicate that existing models underestimate the effects of heat on senescence. As the onset of senescence is an important limit to grain filling, and therefore grain yields, crop models probably underestimate yield losses for +2 degrees C by as much as 50% for some sowing dates. These results imply that warming presents an even greater challenge to wheat than implied by previous modelling studies, and that the effectiveness of adaptations will depend on how well they reduce crop sensitivity to very hot days.