黄土高原半湿润区气候变化对冬小麦生育及水分利用效率的影响

Impacts of Climatic Change on the Growth and Water Use Efficiency of Winter Wheat in the Semi-humid Region of Loess Plateau

利用黄土高原半湿润区1981～2010冬小麦生长发育定位观测资料和对应平行气象观测资料,分析气候变化对冬小麦生长发育的影响,以及冬小麦水分利用效率与气象条件的关系。结果表明:(1)研究区域降水量年际变化呈波动变化,20世纪90年代降水量最少,并存在3年、8年的年际周期变化;气温年际变化呈上升趋势,气温变化曲线线性拟合倾向率为0.325℃/10年;作物生长季干燥指数呈显著上升趋势,干燥指数变化曲线线性拟合倾向率为0.069/10年,20世纪90年代至2010年明显趋于暖干化;研究区域冬小麦播种至成熟期间≥0℃积温为2 000℃～2 200℃,降水量为300～350mm,日照时数为1 900～2 100h。(2)受气候变暖的影响,研究区域冬小麦播种期每10年推后2～3d,返青期每10年提前4～5d,开花期和成熟期每10年提前5～6d;冬小麦越冬期每10年缩短5～6d、全生育期每10年缩短7～8d。(3)由于研究区冬春季气温显著升高,越冬死亡率下降,冬小麦水分利用率呈上升趋势;冬小麦播种～出苗期和起身～拔节期气温对冬小麦水分利用效率的影响为负效应,其余时段气温对水分利用效率的影响为正效应,其中的乳熟期～成熟期水分利用效率对气温变化十分敏感;播种～出苗期、分蘖～冬前停止生长期和乳熟～成熟期降水量对冬小麦水分利用效率影响为负效应,且乳熟期～成熟期水分利用效率对降水量变化十分敏感;越冬期和返青～拔节期降水量对冬小麦水分利用效率影响为正效应,并在冬小麦越冬后期和返青期前后水分利用效率对降水量变化十分敏感。

Winter wheat growth and meteorological condition observational data for a semi-humid region of the Loess Plateau were used to analyze the effects of climatic change on winter wheat growth and the relationship between the water use efficiency of winter wheat and meteorological conditions from 1981 to 2010.The results showed that precipitation displays a fluctuation changes,and it was minimum in 1990s.In addition,an annual periodic change of 3a and 8a was observed.The temperature displayed an ascending trend and changed at a rate of 0.325℃/10a.The aridity index displayed a marked ascending trend and changed at a velocity of 0.069/10a.The dry-warming tendency was significant from the beginning of the 1990s to 2010.It is showed that winter wheat needs 270~290 d,about 2 000℃~2 200℃ accumulated temperature above 0℃,about 300~350 mm precipitation and about 1 900~2 100 h sunshine duration from sowing to maturing.The sowing time of winter wheat would be postponed by 2~3 d/10a,the reviving time would be advanced by 4~5 d/10a,the flowering time and the maturing time would be advanced by 5~6 d/10a because of climate warming.Over wintering days reduced by 5~6 d/10a,whole growth period shorted by 7~8 d/10a.The water use efficiency displayed an ascending trend because of the winter wheat death rate decrease and the temperature markedly higher temperature during winter and spring,except for the sowing-seeding stage and rising-jointing stage,the temperature was positively correlated with the water use efficiency.The water use efficiency of the milk stage-maturing stage was very sensitive to temperature.The precipitation is negatively correlated with the water use efficiency in the sowing-seeding stage and tillering-before wintering stage and milk stage-maturing stage.The water use efficiency of the milk stage-maturing stage was very sensitive to precipitation.The precipitation is positively correlated with the water use efficiency in the over-wintering stage and regreen-jointing stage.The water use efficiency of the later wintering stage and around regreen stage was very sensitive to precipitation.