玉米生长指标的土壤水分上下限调控机理

采用桶栽试验,开展了土壤水分不同上下限组合处理对夏玉米生长指标调控效应的研究。结果表明:不同灌水上下限处理夏玉米株高、茎粗、叶面积等生长指标及产量和水分利用效率(WUE)均存在显著差异;苗期55%θF(拔节期以后60%θF,下同)灌水下限的中度水分胁迫和85%θF(90%θF)灌水上限的中水复水有利于提高水分利用效率(2.93)和产量(113.70 g·株-1),相比于苗期65%θF(70%θF)灌水下限的充分灌溉,灌水上限为苗期75%θF(80%θF)的高频次低定额灌溉有利于提高产量(115.44 g·株-1);苗期~拔节期,(根重/干物质重)×全株干重(2.604)较小,拔节~灌浆期,茎粗/根重(5.010)和(茎粗/株高)×干物质量(7.860)较小,灌浆~成熟期,干物质重/株高(0.914)、(茎粗/株高)×干物质重(17.434)或穗重/叶面积(0.044)较大。叶干重/茎干重(0.930)较大的夏玉米为试验条件下节水高产的合理生长株型,对应的水分处理为:苗期~拔节期灌水上下限分别为85%θF和55%θF;拔节~灌浆期,灌水上下限分别为80%θF和70%θF;灌浆~成熟期,灌水上下限分别为100%θF和50%θF。

Growth indicators of summer corn under irrigation soil moisture upper and lower limit

The pot experiment investigated studied the controlling the effect of different combination of soil moisture upper and lower limit on growth of of summer corn,with the objective of obtaining for getting the optimal growth indica-tors .There existed markedly different responses of plant height,stem diameter,leaf area,yield and WUE,to different soil moisture upper and lower limits have significant differences .The treatment of moderate rewatered whose irrigation up-per limit is 85%θF at seedling stage(90%θF at jointing stage,the same as below)after moderate water stress with a whose irrigation lower limit of is 55%θF(60%θF,showing)has a positive effect on improving WUE(2 .93)and yield (113.70 g·plant-1).For full irrigation with a whose irrigation lower limit of is 65%θF(70%θF)and with a upper limit of 75%θF(80%θF),high frequency and low irrigation quota is conducive to had favorable effect on grain yield improving yield (115 .44 g·plant-1).In order to obtain higher grain yield,soil moisture limit should be between 85%θF and 55%θF during the seedling stage to jointing stage,80%θF and 70%θF during the jointing stage to milking stage,100%θF and 50%θF during the filling period to mature period .