International Centre for Agricultural Research in the Dry Areas (ICARDA), P.O. Box 950764, Amman 11195, Jordan.
International Centre for Agricultural Research in the Dry Areas (ICARDA), P.O. Box 950764, Amman 11195, Jordan.
Sci Total Environ. 2018 Jan 1;610-611:219-233. doi: 10.1016/j.scitotenv.2017.07.270. Epub 2017 Aug 11.
Different aspects of climate change, such as increased temperature, changed rainfall and higher atmospheric CO concentration, all have different effects on crop yields. Process-based crop models are the most widely used tools for estimating future crop yield responses to climate change. We applied APSIM crop simulation model in a dry Mediterranean climate with Jordan as sentinel site to assess impact of climate change on wheat production at decadal level considering two climate change scenarios of representative concentration pathways (RCP) viz., RCP4.5 and RCP8.5. Impact of climatic variables alone was negative on grain yield but this adverse effect was negated when elevated atmospheric CO concentrations were also considered in the simulations. Crop cycle of wheat was reduced by a fortnight for RCP4.5 scenario and by a month for RCP8.5 scenario at the approach of end of the century. On an average, a grain yield increase of 5 to 11% in near future i.e., 2010s-2030s decades, 12 to 16% in mid future i.e., 2040s-2060s decades and 9 to 16% in end of century period can be expected for moderate climate change scenario (RCP4.5) and 6 to 15% in near future, 13 to 19% in mid future and 7 to 20% increase in end of century period for a drastic climate change scenario (RCP8.5) based on different soils. Positive impact of elevated CO is more pronounced in soils with lower water holding capacity with moderate increase in temperatures. Elevated CO had greater positive effect on transpiration use efficiency (TUE) than negative effect of elevated mean temperatures. The change in TUE was in near perfect direct relationship with elevated CO levels (R>0.99) and every 100-ppm atmospheric CO increase resulted in TUE increase by 2kghamm. Thereby, in this environment yield gains are expected in future and farmers can benefit from growing wheat.
气候变化的不同方面，如温度升高、降雨变化和大气 CO2 浓度升高，都会对作物产量产生不同的影响。基于过程的作物模型是估计未来气候变化对作物产量影响的最广泛使用的工具。我们应用 APSIM 作物模拟模型，以约旦为监测点，在干旱的地中海气候下，评估考虑两种代表性浓度路径（RCP）情景下的气候变化对小麦产量的影响，这两种情景分别为 RCP4.5 和 RCP8.5。仅气候变量对谷物产量有负面影响，但在模拟中考虑到升高的大气 CO2 浓度后，这种不利影响就会被抵消。在本世纪末，RCP4.5 情景下，小麦的作物周期缩短了两周，而 RCP8.5 情景下则缩短了一个月。平均而言，在未来几十年，即 2010 年代至 2030 年代，近期可预期中等气候变化情景（RCP4.5）下的谷物产量增加 5%至 11%，中期气候变化情景（RCP4.5）下的谷物产量增加 12%至 16%，本世纪末可预期的气候变化情景（RCP4.5）下的谷物产量增加 9%至 16%；在未来几十年，即 2010 年代至 2030 年代，近期可预期剧烈气候变化情景（RCP8.5）下的谷物产量增加 6%至 15%，中期气候变化情景（RCP8.5）下的谷物产量增加 13%至 19%，本世纪末可预期的气候变化情景（RCP8.5）下的谷物产量增加 7%至 20%，这是基于不同土壤的情况。在持水能力较低的土壤中，升高 CO2 的积极影响更为显著，同时温度适度升高。升高的 CO2 对蒸腾作用利用效率（TUE）的积极影响大于对平均温度升高的负面影响。TUE 的变化与升高的 CO 水平呈近乎完美的直接关系（R>0.99），大气中每增加 100ppm CO2，TUE 就会增加 2kghamm。因此，在这种环境下，未来的产量预计会有所增加，农民可以从种植小麦中受益。
