气候变化背景下有限供水冬小麦的适宜播期研究

A study on the suitable sowing date of winter wheat with limited water supply under the background of climate change

  • 摘要: 自工业革命以来气候变化加剧导致华北平原中北部冬小麦-夏玉米生长条件发生改变, 调整冬小麦播期为该地区实施“两早-两晚”技术具有重要意义。本试验基于中国科学院栾城农业生态系统试验站2016—2023年限水灌溉条件下冬小麦7个生育期4个播期2个品种的试验数据, 确定以稳产为前提的冬小麦适宜播期及满足适播的热量条件。四个播期分别为当地正常播期(播期1)、正常播期基础上每个播期推迟5~7天(播期2、3和4)。结果表明, 冬小麦在播期2后产量明显下降, 播期4与其他3个播期下的产量差异显著(P<0.01), 根据本试验条件适播日期为10月12日至10月24日, 以作物发育基点温度为0℃计算的冬前积温和生育期总积温需分别达到350 ℃·d和2010 ℃·d。不同播期通过积温影响冬小麦各阶段生育期, 随着播期的推迟, 不同生长阶段(播种-越冬、越冬-拔节、拔节-扬花和扬花-收获)持续时间变化分别为缩短、延长、延长和缩短, 且不同品种对播期的响应不同。晚播冬小麦冬前不具备充分分蘖的气象条件, 在拔节期形成最大群体, 发育进程滞后影响群体数量以及生殖生长持续时间, 从而导致作物减产。不同播期晚播冬小麦扬花前生物量增长速率与小麦群体动态变化同步, 若冬末春初遇到高温能弥补前期生长进程过慢产生的差距。播期对产量三要素产生的影响为: 穗数降低、穗粒数增加和千粒重变化无统计学差异, 晚播冬小麦收获指数高于早播, 籽粒品质随播期推迟存在下降趋势, 但不同品种间存在差异。通过本研究得到以下结论在温度升高的气候变化背景下, 冬小麦适宜播种日期可推迟2.6 d, 为夏玉米延长灌浆期晚收获创造了条件, 以上为华北平原中北部实施“两早-两晚”技术的决策提供理论支撑, 为农业发展适应气候变化减轻压力。

     

    Abstract: Since the industrial revolution climate change has intensified, leading to changes in the growth conditions of winter wheat and summer maize in the central and northern parts of North China Plain. It is of great significance to adjust the sowing date of winter wheat to implement the “two early−two late” technology in this area. Based on the interannual variation of meteorological factors in the growing season of winter wheat from 1984 to 2023 at Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences, this experiment studied the suitable sowing date of winter wheat under the background of climate change. Using the field measured data of two cultivars of winter wheat for 7 growing seasons from 2016 to 2023 with 4 sowing dates under limited irrigation from 2016 to 2023, the suitable sowing date and necessary heat conditions of winter wheat were determined for achieving stable yield. The four sowing dates were the normal (date 1), and extended 5−7 days each for delayed sowing dates as date 2, date 3 and date 4. The results showed that yield of winter wheat decreased after date 2 and the yield for date 4 was significantly lower as compared with the yield of other three sowing dates (P<0.01). Under the current climate conditions, the suitable sowing date was from 12th Oct. to 24th Oct., the thermal time before winter and the total thermal time during the growth period should reach 350 °C·d and 2010 °C·d, respectively. Different sowing dates affected duration of different stages of winter wheat through thermal time. With the delay of sowing date, the duration of different growth stages (sowing-winter dormancy, winter dormancy-jointing, jointing-anthesis, and anthesis-maturity) was shortened, prolonged, prolonged, and shortened, respectively, and the response to sowing date of different cultivars was different. Late sowing winter wheat was not be capable of sufficient tillering before winter and formed the largest population at the jointing stage. The lag of development process had negative effects on spikes number, shrank the duration of reproductive growth, resulting in crop yield reduction eventually. Before anthesis rate of biomass production of late sowing winter wheat with different sowing dates was synchronized with the dynamic changes of community. If high temperature was encountered in late winter and early spring, the gap caused by the slow growth process in the early stage could be narrowed. The effects of sowing date on the three elements of yield were as follows: spikes number decreased, kernels per spike increased and there was no statistically significant difference in 1000-kernel weight per spike. The harvest index of late sowing winter wheat was higher than that of early sowing. The grain quality decreased with the delay of sowing date, but there were differences among different cultivars. The conclusion of this study that the suitable sowing date is postponed under the background of climate change provides theoretical support for the decision to implement the “two early−two late” technology in the central and northern parts of North China Plain, and reduces the pressure on agricultural development to adapt to climate change.

     

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