黄土高原半湿润区气候变化对冬小麦生长发育及产量的影响

利用黄土高原半湿润区西峰农业气象试验站冬小麦生长发育定位观测资料、加密观测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,以及冬小麦穗干重生长与气象条件的关系。结果表明,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。降水量存在3、8a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℃/10a。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0.069/10a,20世纪90年代至2010年明显趋于暖干化。受气候变暖的影响,冬小麦播种期每10 a推后2—3d,返青期每10a提前4—5 d,开花期和成熟期每10a提前5—6 d。冬小麦越冬期每10a缩短5—6 d、全生育期每10a缩短7—8 d。冬小麦返青后第83天开始,穗干重的生长由缓慢转为迅速生长阶段,从返青后第101天开始,其生长从迅速生长又转为缓慢生长,在返青后的第87天,穗的干物质积累速度最大。由于气候变暖,冬小麦生育期大部分时段热量充足。播种—越冬前和拔节—开花期产量对气温变化的响应十分敏感;降水量的影响函数同温度的影响函数呈反相位分布,除成熟期降水量对产量形成为负效应外,其余时段降水量对产量影响均为正效应,而在冬小麦播种期和返青—拔节期产量对降水量变化的响应也十分敏感。

Impacts of climate change on growth and yield of winter wheat in the semi-humid region of the Loess Plateau

Winter wheat growth and meteorological observation data in a semi-humid region of the Loess Plateau are used to analyze the effects of climatic change on winter wheat growth,and the relationship between ear dry weight growth of winter wheat and meteorological conditions.Results show that the interannual trend of precipitation in the study region fluctuated,and was a minimum in the 1990s.An interannual periodic change of 3 a and 8 a was observed.The interannual temperature trend was upward,and a linear fit of this trend produced a rate of 0.325 ℃/10 a.The crop aridity index during the growing season showed a marked upward trend,with a linear fit giving a rate 0.069/10 a.There was a significant drying and warming tendency from the beginning of the 1990s through 2010.Because of climate warming,the sowing time of winter wheat would be postponed by 2—3 d/10 a.Reviving time would advance by 4—5 d/10 a,and flowering and maturing times by 5—6 d/10 a.Overwintering days would be reduced by 5—6 d/10 a,and the entire growth period would shorten by 7—8 d/10 a.Growth speed of ear dry weight was much greater on the 83rd day after reviving,and then reverted to a slow speed on the 101st day after reviving.The highest ear dry material speed was on the 87th day after reviving.Because of climate warming,the amount of heat was abundant in most of the winter wheat growing period.The yield was very sensitive to climate change during the period between sowing and just before winter,as well as between the jointing and flowering stages.Every 1 ℃ increment in average temperature per ten days could decrease the yield of winter wheat by 10—15 g/m2.Sensitive periods are 20—25 d and 30—40 d.The precipitation influence and heat functions showed an opposite phase.except for the maturation stage,precipitation was positively correlated with yield.Yield was also very sensitive to precipitation change during the seeding and reviving-jointing stages.Every 1 mm increment in precipitation per ten days would increase yield by 15—20 g/m2.Sensitive periods are 20—25 d and 50—60 d.Abundant solar illumination during the overwintering stage would improve cold resistance training,and it had a strongly positive effect on yield during the postulation period.Every 1 h increment in sunshine duration per ten days would augment yield by 5—10 g/m2.The sensitive period is 25—35 d.Long sunshine duration would aid the accumulation of dry materials.