返青期断根对秸秆覆盖冬小麦产量及叶片光合特性的影响

Effect of Spring Root Pruning on Yield and Flag Leaf Photosynthetic Characteristics of Winter Wheat under Straw Mulching

为了解返青期断根对黄土高原旱地保护性耕作下小麦产量形成及水分利用的调控作用,在陕西长武县开展旱地秸秆覆盖条件下冬小麦返青期断根试验,分析了返青期断根对冬小麦籽粒产量、地上部生物量、收获指数、产量构成三要素、拔节期群体数量、生育期耗水量、水分利用效率、花后旗叶光合特性及衰老特性的影响。结果表明,返青期断根对冬小麦地上部生物量、穗数、粒重和生育期耗水量没有显著影响。与CK(不断根)相比,返青期断根后冬小麦拔节期总茎数减少了11.9%,开花期叶面积指数、花后旗叶叶绿素含量、光合速率和蒸腾速率提高,分蘖成穗率、穗粒数、籽粒产量、收获指数和水分利用效率分别增加了14.1%、10.5%、8.2%、10.4%、17.5%和20.4%。这说明返青期断根可促进秸秆覆盖条件下冬小麦分蘖成穗,增加花后旗叶光合作用,改善穗部结实特性,提高籽粒产量和水分高效利用。

Improvement of crop management practices to increase wheat yield and water use efficiency are imperative on dryland farming in the Loess Plateau of China.We investigated the effects of spring root pruning on winter wheat grain yield,shoot biomass,harvest index,yield components,and population size at jointing stage,evapotranspiration(ET)and water use efficiency(WUE),and flag leaf photosynthetic characteristics and senescence characteristics under straw mulching in the Loess Plateau.The results showed that root pruning in spring had no significant effect on shoot biomass,spike number,grain weight and ET relative to control.However,spring root pruning obviously decreased total tillers at jointing stage by 11.9%,and improved leaf area index(LAI)at anthesis,flag leaf chlorophyll content(SPAD value)and net photosynthetic rate and transpiration rate after anthesis.Spring root pruning also significantly improved percentage of productive tiller,grain number per spike,grain weight,grain yield,harvest index,and water use efficiency by 14.1%,10.5%,8.2%,10.4%,17.5%and 20.4%,respectively.It is suggested that spring root pruning could promote tillers and spikes,increase photosynthetic rate of flag leaf after anthesis,improve grain setting characteristics,and increase grain yield and water use efficiency.