中文摘要：

利用1986─2013年典型黄土高原半干旱区春小麦（Triticum aestivum Linn.）试验资料,结合试验区气象站1958─2013年气候要素观测数据,研究气候变化对春小麦产量形成的影响,为应对气候变化提供科学依据。结果表明：1958─2013年试验区降水量呈下降趋势,气候倾向率为-10.966 mm/10 a;降水量年际波动大,变异系数为20.3%。春小麦主要生长发育时段的3─6月降水量也呈减少趋势,3─6月降水量变异系数为33.2%。试验区气温呈极显著上升趋势,气候倾向率为0.378℃/10 a。春小麦生长季干燥指数也呈上升趋势。20世纪90年代后暖干化特征明显。试验区春小麦产量与5月下旬─6月上旬气温呈极显著负相关（r=-0.492,P〈0.01）,气温偏高,小花分化速度加快,有效小花减少,无效小花增加,结实率降低,导致春小麦产量下降。试验区春小麦产量与其生长季降水呈显著正相关（r=0.306,P〈0.05）,说明黄土高原半干旱区小麦全生育期降水不足是影响春小麦产量的主要气候因素。而春小麦产量形成对5月中旬─5月下旬降水量的变化尤为敏感,此时段是小花开始分化到花粉母细胞四分体形成时的水分临界期,是春小麦需水关键期,降水量减少,部分花粉和胚珠不育,结实率显著下降,产量降低。结论：降水量是影响春小麦产量形成的关键气候因子;而气温增高是春小麦产量形成的主要限制因子。黄土高原半干旱区气候暖干化背景下,春小麦产量呈下降趋势;气候因素对春小麦发育和产量的负效应增大,产量的不确定性增加。

英文摘要：

The impacts of climate change on spring wheat yield is studied by using experimental data of spring wheat of typical semi-arid regions on Loess Plateau in 1986─2013, with the combination of meteorological observing data gained from meteorolog-ical stations in experimental regions in 1958─2013. It provide the scientific basis for coping climate change. Results showed that, there is a declining trend on precipitation in experimental regions in 1958─2013; the climate tendency rate is -10.966 mm/10 a; an-nual fluctuation of precipitation is large and the variation coefficient is 20.3%. Precipitation has a declining trend from March to June, which is the main growth period for spring wheat, the variation coefficient of precipitation during March and June is 33.2%. The temperature in experimental region has a very obvious ascending trend and the climate tendency rate is 0.378℃/10 a. The aridity index of spring wheat is also showing an ascending trend. After the 90s of twentieth century, the warming and drying character was becoming obvious. Spring wheat yield in experimental regions had an extremely obvious negative relation with the temperature in last ten days of May and first ten days of June（r=-0.492,P〈0.01）. Higher temperature leads to a higher velocity of blossom differen-tiation, useful blossom decrease and useless blossom increase, maturing rate decrease and all these caused the decrease in spring wheat yields. The yields of spring wheat in experimental regions have an obvious positive relation with its seasonal precipita-tion（r=0.306,P〈0.05）, which demonstrate that the lack of precipitation during spring wheat’s whole growing period in semi-arid regions of Loess Plateau is the main factor which influence the yields, a decrease in precipitation caused the decrease of yields of spring wheat. Meanwhile, the yields of spring wheat are extremely sensitive to the changes of precipitation during the middle ten days and late ten days in May, this time period is water critical period for the bloss