The impact of temperature variability on wheat yields
The impact of temperature variability on wheat yields
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DOI：
10.1111/j.1365-2486.2010.02262.x
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发表时间：
2011-02-01
影响因子：
11.6
通讯作者：
Turner, Neil C.
中科院分区：
文献类型：
--
作者：
Asseng, Senthold;Foster, Ian;Turner, Neil C.
小麦目前的年产量超过6亿吨，是仅次于玉米和大米的世界第三大作物，也是数百万人碳水化合物的重要来源。虽然小麦在各种环境中生长，但在主要小麦生产国，在土壤湿度下降和温度升高的情况下发生灌浆是很常见的。在过去的几十年里，全球平均气温一直在上升，预计还会继续上升，同时极端炎热天气的频率也会增加。世界上主要的小麦种植区已经报道了这样的事件。然而，过去的温度变率以及平均和极端温度的变化对小麦产量的直接影响尚未量化。由于其他因素的混杂影响，不可能将近几十年来观测到的产量变化归因于温度等单一因素。通过使用模拟模型，我们能够将温度的影响与其他因素分开，并表明温度对小麦生产的影响被低估了。令人惊讶的是，在澳大利亚主要小麦种植区，观察到的平均生长季节温度+/- 2摄氏度的变化可能导致谷物产量减少多达50%。这主要是由于温度升高导致叶片衰老。世界上主要小麦产区灌浆期间的温度条件与澳大利亚灌浆期间的温度条件相似。随着全球变暖，预计全球平均气温和高温事件的频率将增加，仅在重要的灌浆阶段，由于温度升高而导致的产量下降就可能严重破坏未来的全球粮食安全。现在需要考虑适应策略，以防止由于未来热胁迫增加而造成的小麦大量产量损失。
With current annual production at over 600 million tonnes, wheat is the third largest crop in the world behind corn and rice, and an essential source of carbohydrates for millions of people. While wheat is grown over a wide range of environments, it is common in the major wheat-producing countries for grain filling to occur when soil moisture is declining and temperature is increasing. Average global temperatures have increased over the last decades and are predicted to continue rising, along with a greater frequency of extremely hot days. Such events have already been reported for major wheat growing regions in the world. However, the direct impact of past temperature variability and changes in averages and extremes on wheat production has not been quantified. Attributing changes in observed yields over recent decades to a single factor such as temperature is not possible due to the confounding effects of other factors. By using simulation modelling, we were able to separate the impact of temperature from other factors and show that the effect of temperature on wheat production has been underestimated. Surprisingly, observed variations in average growing-season temperatures of +/- 2 degrees C in the main wheat growing regions of Australia can cause reductions in grain production of up to 50%. Most of this can be attributed to increased leaf senescence as a result of temperatures > 34 degrees C. Temperature conditions during grain filling in the major wheat growing regions of the world are similar to the Australian conditions during grain filling. With average temperatures and the frequency of heat events projected to increase world-wide with global warming, yield reductions due to higher temperatures during the important grain-filling stage alone could substantially undermine future global food security. Adaptation strategies need to be considered now to prevent substantial yield losses in wheat from increasing future heat stress.