Climate trends account for stalled wheat yields in Australia since 1990
Climate trends account for stalled wheat yields in Australia since 1990
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DOI：
10.1111/gcb.13604
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发表时间：
2017-05-01
影响因子：
11.6
通讯作者：
Horan, Heidi
中科院分区：
文献类型：
--
作者：
Hochman, Zvi;Gobbett, David L.;Horan, Heidi
全球粮食安全要求粮食产量到2050年继续增加，但许多发达国家的粮食产量已经停滞不前。到目前为止，这一令人不安的趋势只得到了部分解释。在这里，我们显示澳大利亚的小麦产量自1990年以来一直停滞不前，并调查了气候趋势在多大程度上解释了这一观察结果。基于对50个地点的高质量天气数据的模拟，这些地点代表了农业生态区和谷物区的土壤类型，我们表明，从1990年到2015年的26年间，水分限制产量潜力下降了27%。我们将这一下降归因于降雨量的减少和气温的上升，而大气二氧化碳浓度上升的积极影响防止了相对于1990年产量的4%的进一步损失。对三个地点的进一步调查揭示了水限制产量对水可获得性、水分胁迫和最高温度的模拟反应的本质。3个地点的最高气温都加快了播种到开花和成熟的时间，降低了每平方米粒数和平均单粒重。由于气候原因导致的限水产量下降了27%，但实际的国家产量并没有完全体现出来。这是由于前所未有的技术推动的收益速度，缩小了实际产量和限水潜力之间的差距25公斤ha(-1)年(-1)，使相对产量从1990年的39%增加到2015年的55%。技术能否继续维持当前的收益率，更不用说在2050年之前将其提高到所需的水平，还有待观察。
Global food security requires that grain yields continue to increase to 2050, yet yields have stalled in many developed countries. This disturbing trend has so far been only partially explained. Here, we show that wheat yields in Australia have stalled since 1990 and investigate the extent to which climate trends account for this observation. Based on simulation of 50 sites with quality weather data, that are representative of the agro-ecological zones and of soil types in the grain zone, we show that water-limited yield potential declined by 27% over a 26 year period from 1990 to 2015. We attribute this decline to reduced rainfall and to rising temperatures while the positive effect of elevated atmospheric CO2 concentrations prevented a further 4% loss relative to 1990 yields. Closer investigation of three sites revealed the nature of the simulated response of water-limited yield to water availability, water stress and maximum temperatures. At all three sites, maximum temperature hastened time from sowing to flowering and to maturity and reduced grain number per m 2 and average weight per grain. This 27% climate-driven decline in water-limited yield is not fully expressed in actual national yields. This is due to an unprecedented rate of technology-driven gains closing the gap between actual and water-limited potential yields by 25 kg ha(-1) yr(-1) enabling relative yields to increase from 39% in 1990 to 55% in 2015. It remains to be seen whether technology can continue to maintain current yields, let alone increase them to those required by 2050.