底墒对冬小麦植株生长及产量的影响

设计5种不同底墒处理,结合冬小麦苗期控水、抽穗复水的人工干预,通过钻取0~200cm根系样本和生育期内连续观测最大根深,对应分析地上部生物量及产量因素,以了解底墒通过调控根系在土壤中的垂直分布和土壤水分的利用对冬小麦地上植株生长发育和产量形成的影响。底墒充足时诱导根系相对较多地向土壤纵深下扎,形成了上层相对较少、深层相对较多的根系构型,其0~30cm浅层根系生物量占0~200cm整层比例较底墒较差的处理少10.95个百分点,而100~200cm深层偏多5.70个百分点,延深了根系汲取土壤水分的深度,而且底墒在冬小麦全生育期中持续发挥着水分调节作用。底墒充足时收获指数、水分利用效率(WUE)都最高,其收获指数为0.4920,WUE为1.5479g/(m2·mm),分别比底墒较差的处理偏高0.0823和0.3030g/(m2·mm)。

Impact of Available Soil Water at Planting on Plant Growth and Yield of Winter Wheat

5 water treatments were carried out on winter wheat with different available soil water at planting and rewater treatment after spiking stage. The maximal rooting depth at each growth stage was determined by root drill. And the shoot growth and yield formation were also analysed. The result indicated that sufficient available soil water at planting favored to control the vertical distribution of wheat root dry matter and thereby control the soil water use in different soil profile, consequently regulated the shoot growth and development and the yield formation. That is, when supplied with sufficient available soil water at planting, the wheat tend to develop more root in deep soil, and to distribute relatively less dry matter to the root in the upper soil profile. This kind of root formation contributes to use more soil water in the deep soil profile. Besides, the available soil water at planting plays an important role in regulating the soil water use during the whole growth period of winter wheat. The harvest index and water use efficiency under the treatment with sufficient available soil water at planting are the highest among 5 water treatmentss.