Heilonggang valley is the winter wheat major production belt of Hebei Province,and is short of water resource. In order to study the effects of nitrogen fertilizer application ratios on yield and water use efficiency of three different type winter wheat cultivars,Han 6172 with high kernel weight,Henong6049 with multiple kernels and Heng 4399 with multiple spikes. 3 ra tios of base and topdressing of3 ∶7,5∶5 and 7∶3 of nitrogen fertilizer under the amount of nitrogen fertilizer 270 kg/hm~2 had been tested. T...