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. |