Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Department of Agronomy, University of Nebraska, Lincoln, Nebraska 68583, USA.
Nat Plants. 2015 Feb 2;1:14026. doi: 10.1038/nplants.2014.26.
The United States is one of the largest soybean exporters in the world. Production is concentrated in the upper Midwest(1). Much of this region is not irrigated, rendering soybean production systems in the area highly sensitive to in-season variations in weather. Although the influence of in-season weather trends on the yields of crops such as soybean, wheat and maize has been explored in several countries(2-6), the potentially confounding influence of genetic improvements on yields has been overlooked. Here we assess the effect of in-season weather trends on soybean yields in the United States between 1994 and 2013, using field trial data, meteorological data and information on crop management practices, including the adoption of new cultivars. We show that in-season temperature trends had a greater impact on soybean yields than in-season precipitation trends over the measurement period. Averaging across the United States, we show that soybean yields fell by around 2.4% for every 1 °C rise in growing season temperature. However, the response varied significantly among individual states, ranging from -22% to +9%, and also with the month of the year in which the warming occurred. We estimate that year-to-year changes in precipitation and temperature combined suppressed the US average yield gain by around 30% over the measurement period, leading to a loss of US$11 billion. Our data highlight the importance of developing location-specific adaptation strategies for climate change based on early-, mid- and late-growing season climate trends.
美国是世界上最大的大豆出口国之一。大豆生产集中在中西部北部地区。（1）该地区大部分没有灌溉，导致该地区的大豆生产系统对季节性天气变化高度敏感。（2-6）尽管已经在几个国家探讨了季节性天气趋势对大豆、小麦和玉米等作物产量的影响，但遗传改良对产量的潜在影响却被忽视了。（7）在这里，我们使用田间试验数据、气象数据和作物管理实践信息（包括采用新的品种），评估了 1994 年至 2013 年间美国大豆产量受季节性天气趋势的影响。我们表明，在测量期间，季节性温度趋势对大豆产量的影响大于季节性降水趋势。（8）平均而言，我们发现生长季节温度每升高 1℃，大豆产量就会下降约 2.4%。（9）然而，这种反应在各个州之间差异很大，范围从-22%到+9%，并且也与发生变暖的一年中的月份有关。我们估计，在测量期间，降水和温度的年际变化共同抑制了美国大豆平均产量的增长约 30%，导致美国损失 110 亿美元。（10）我们的数据强调了根据早期、中期和后期生长季节的气候趋势，制定针对气候变化的特定地点的适应策略的重要性。
